List of extinction events

This List of extinction events is a section of the "Why are we here?", an exercise of exploration that I'm also carrying out on my blog. The study of the ancestral fight between Life versus Extinction was originally a part of the chapter "The spark of Life - 500 million years ago to 2 million years ago" in the above article, but after a while I realised that this "List of extinction events" exploration was causing the Spark of Life chapter to be extremely huge, so I decided for the sake of simplicity to have it on a separated thread. This also facilitates the reading, analysis and focus on this crucial matter of the dance between Life and its antagonistic nemesis Extinction over the surface of our planet. Note that Death if not the opposite of Life...Death is actually part of Life but Extinction....that is the end of the game indeed for the species affected

Of all the species that have ever inhabited planet Earth, 95% of them are gone. It is like going to a party that you know is happening at your local club between 7pm and 9pm, and find that only 4 people are there out of the nearly 100 that you were expecting, pretty lame ah? Science summarised in only 5 mayor mass extinctions, each one of them associated to a notorious disaster, but I've added a few more which I think are relevant. Anything that changes the environment quickly, inevitable lead to a extinction because species are unable to adapt or evolve. However, extinctions do not necessary happens because of events (meteor impacts, climate change, massive volcanic eruptions, etc) but also because of 'normal' circumstances in the bumpy road of Evolution of our planet, like some species simply dying out as if t their time to fade away has arrived. Each species has an average life span of roughly 5 million years, so when that time come, DNA degradation may occur and the species will simply vanished back into the carbon cycle into what is call by Biologist mutational meltdown. We are all interconnected, and when a species disappear they don't go alone, other species always follow them, thus creating a mass extinction event, or minor depending on the number of species that are wiped out

This is the list of extinctions events that I have enumerated, for each one of them I've included a few pictures of some of the creatures that are no longer with us (a maximum of 21 pictures and one video if relevant, otherwise I go crazy). The dates for some of the events are always in dispute, so apologies to all palaeontologists and geo-palaeontologists if I've made any mistakes, more than happy to receive comments to improve this "List of Extinction events" article or emails! My email is on the Profile >> About me page

 

Extinction 1 - (3.8 Gya) Archean Eon and the Carbon Genesis

"Life as we know it" means carbon-base Life, our genesis is formally known as Abiogenesis, but there might have been other genesis in our planet. In fact, nowadays Life exist in places where our current biochemistry cannot survive, places full of methane (CH4) and carbon dioxide (CO2), gases that were in our atmosphere in the Archean Eon, long before the arrival of oxygen (O2). When cyanobacteria developed 3.8 billion years ago and started harvesting sunlight, they slowly began polluting the atmosphere with oxygen, and many species of bacteria that could not take oxygen in were force to evolve or die. There is a potential extinction event here, that we should recognised, when the Genesis-Photosynthesis bacteria from which we all descend killed all other entities that might have existed in our planet when it atmosphere was full of carbon dioxide. Who is not to say that the whole surface of the planet and its rivers, rich in iron and methane, were not covered in snottite and other similar bacteria?  Had they had the chance to evolve into something else... what that something else would have been? Okay, that 'something else' might not have been as powerful as we are, organisms who use the rich-energy fuel of oxygen, but still, who knows what creatures could have developed if that bacteria had had time to evolve?

There are still a few survivors of this primitive extinction, hidden in toxic caves, that might belong to other Genesis and don't need oxygen at all to make a living. This kind of bacteria, the survivors, are called extremophile and their existence challenge the idea that there was a unique Genesis or formation of Life. Life indeed needs water as a lubricant and as the main transportation of nutrients around the living body, and of course an external source of energy, together with carbon: all living organisms known to men are carbon-based, and every single molecule that we know of uses carbon as its backbone for its biological processes, but that's about it: there is no need of oxygen for Life to exist

 

 

References

A Geologic Time Scale https://www.geosociety.org/GSA/Education_Careers/Geologic_Time_Scale/GSA/timescale/home.aspx

Geological history of Earth https://www.wikiwand.com/en/Geological_history_of_Earth

List of extinction events https://tok.fandom.com/wiki/List_of_extinction_events

How Thermophilic Bacteria Survive https://bitesizebio.com/2462/how-thermophile-dna-survives/

 

Extinction 2 - (2.4 Gya) Huronian Glaciation, Snowball Earth 1 - Great Oxygenation Event (GOE) - First major Ice Age

The creation of photosynthesis has been pointed out has the root cause of the first global planet glaciation, the first Snowball event. During the Photosynthesis process, bacteria absorb green house gases from the atmosphere, CO2, thus cooling their environment. The bacteria, using primitive photosynthesis, were effectively removing green house gases like methane from the atmosphere and replacing it with oxygen, cooling the planet at first NOT because there was a huge amount of oxygen on it, but because they removed all of the greenhouse gases, reaching a minimum Cold-GFI index. To make things worse, the  super-continent Kenorland began to break up altering the weather pattern, separating land masses which, being surrounded by oceans, retained less heat in their interior, causing all these circumstances the Huronian Glaciation that was to last for 300 million years...think about it.... that's longer than the period of dinosaurs ever roamed the Earth. In theory, after the super-continent Kernorland broke apart in plates, another super-continent began to form: the super-continent Nuna, also called Columbia or Hudsoland, which proves that if you wait long enough everything changes, not even the bedrock remains intact

So, how many types of bacteria died during that glaciation? Sea levels dropped, all water became ice and therefore no rain. This event is know as the Great Oxygenation Event (GOE) and it took million of years to develop, rusting planet Earth and creating in the process rich-iron rock that, an unimaginable amount of time after, will be used by an advanced civilization to power its Industrial Revolution. The Great Oxygenation Event was a a suicide for bacteria, who could not cope with the waste product (Oxygen) that they were pumping into the atmosphere. Out of CO2, the planet began a glaciation which then eventually stopped (but not to a halt) because there was not enough bacteria left to continue the oxygenation process of the planet. Bacteria must have died by the trillions, because no more CO2 was removed from the oceans or from the atmosphere. Incidentally, around this time bacteria had evolved and adapted themselves to deal with the toxic Oxygen they themselves were generating. Eventually, a few volcanic eruptions might have been what was needed to slowly warm up the planet again, pumping CO2 and green houses into the atmosphere and ended this gigantic glaciation; even a small amount of eruptions and CO2 would have done it, as there was literally no process in place to remove any CO2 pumped into the atmosphere, so the planet slowly got warmer and Snowball Earth part 1 ended... though not for long

More research is needed regarding this epoch of our planet, called the "Boring Billion" by pantheologies, with Life making very little progress from the biology point of view, as it turns out that bacteria need a lot of time to geo-transform a planet. This heavy glaciation early in the history of our planet could also be due to the Faint Young Sun Paradox, and issue proposed by Carl Sagan and George Mullen by which, they argue, the Earth must have been frozen over early in its history because the Sun was 30% less brighter and therefore less heat arrived to Earth

Impacts crates also have to be taken into account. Meteors, Asteroids and Comets impacts can be indeed catastrophic and deliver a huge amount of energy to the surface of the planet, releasing heat and vaporised rock to the atmosphere, causing gigantic earthquakes and possible lava moves and eventual volcanic eruptions that can all contribute to a significant pumping of CO2, methane and greenhouse gases into the atmosphere, creating this, after the few initial weeks/months of hell on earth, a drop in temperatures as direct sunlight gets blocked and it cannot warm up the surface (nuclear winter), but thereafter, when the thick clouds disappear, the greenhouse gases will trap any heat coming from the sun (nuclear summer) and thus heating up the planet gradually. The following are ancient impacts craters that could have contributed to the end of the glaciation:

1) Yarrabubba crater; dated 2.229 billion years ago (70 km diameter), it is the oldest crater found in our planet, the Yarrabubba crater is located in south-west Australia, could have been a contributor to the end of this glaciation, smashing through the ice crust of Snowball earth 1, hitting a key point in the continental plates and perhaps creating a shock wave powerful enough to wake up a few volcanos that eventually pumped enough CO2 into our atmosphere for the meltdown to start

2) Vredefort crater; dated 2.023 billion years ago (300 km diameter), the same could be said regarding the second oldest known crater, the gigantic Vredefort crater, in South Africa, the largest single-asteroid verified impact on our planet and that is dated around 2 billions years

3) Sudbury basin crater; dated 1.849 billions years ago (250 km diameter), unlike other impacts, the now totally eroded crater of Sudbury Basin, in Canada, must have been created not by a direct impact but by the gigantic shock-wave of a comet that exploded in the atmosphere, hence its elliptical shape and the nature of the geological composition of the rocks found in the crater. Absolutely fascinating that is

 

 How Bad Was The Great Oxidation Event?

References

These two ancient supermountains may be responsible for evolution of life on Earth https://www.techradar.com/uk/news/these-two-ancient-supermountains-may-be-responsible-for-evolution-of-life-on-earth

Earth Impact Database World Map https://upload.wikimedia.org/wikipedia/commons/c/cc/Earth_Impact_Database_world_map.svg

Impacts and Geology: deep space? http://all-geo.org/erratics/2011/03/impacts-and-geology-deep-peace/

The Paleoproterozoic snowball Earth https://www.pnas.org/doi/10.1073/pnas.0504878102

NASA Determines Australian Meteor Crater is the Oldest Known https://www.nasa.gov/feature/nasa-determines-australian-meteor-crater-is-the-oldest-known

 

Extinction 3 - (650 Mya) Stuartian Glaciation, Snowball Earth 2 - Second Ice Age

So the planet stay frozen for a few million years during Snowball 1, then warm up again and the bacteria began to spread again, depleting the atmosphere of greenhouse gases... again... and causing, you guess it: Glaciation Snowball Earth 2, also called Stuart-Varangian Glaciation. This time there is plenty evidence for this event. There is a BIG, BIG jump of time between snowball events of almost 2 billions years... the time it took bacteria to remove CO2 from the atmosphere and the volcanism of the planet to restore it back again. Glacial Erratics, the rocks left after a glacier is melt, are a clear indication of Snowball events. These sort of erratic rocks are found in Flinders Ranges (Australia) or Death Valley (USA), given evidence for Snowball Earth 2, where the magnetic signature of the rocks shows they were in the tropics... so how can a glacier exist in the Equator? Well.... there you have the Kilimanjaro glacial. The "weathering process" takes away CO2 from the atmosphere and lock it away, furthermore, cyanobacteria generates oxygen so they make things even worse, locking CO2 into stromatolites. That creates more ice (specially sea ice, that reflects 85% of the sunlight it hits it) , which in turn reflects even more sunlight away, thus starting a run away process that cools the Earth to a no return of freeze point that lasted for million of years

The newly formed super-continent Rodinia was located mostly at the Equator, which produces a higher albedo than oceans (continents, when covered with ice, reflect more sunlight than oceans, which initially are hard to freeze unless close to landmasses) causing the planet to absorb less heat in its atmosphere and cooling Earth. It is argue that snowball Earth started when the Rodinia began to break apart, changing the weather pattern with the formation of rivers that increased the nutrients in the oceans, causing this more bacteria to suck CO2 from the atmosphere and replace it with Oxygen, thus cooling the planet further.....looks like it took a long time to fine that cute balance that we have now in our atmosphere of CO2 versus Oxygen, and I just can't help thinking: no matter how much CO2 bacteria were able to remove from the atmosphere, surely a few volcanic eruptions of our much violent ancient Earth would have been enough to replace the missing gasses, so why the planet froze to the point of no return? Young Sun Paradox? Could it happen again? During this period the Marinoan Glaciation also occurred around 635 Mya, and though shorter than the Sturtian Glaciation (only...ehem..30 millions years, kind of 'short' for geological terms, but just imagine how long is that length of time), it could have also caused a Snowball effect, that would have been list of extinction events Snowball Earth 3

But, could this frozen event had been caused by an inclination of Earth orbit or something similar? Apparently, the Earth orbit goes in cycles of 100,000 years or so, where it goes to an extreme elliptic orbit that causes a deep freeze, though this is happening now, back 650 Mya the Moon was much closer to Earth and the orbit parameters of our planet may have been much different than today. We know that big eruptions trigger cooler period on Earth, because the ashes create a blanket that prevent heat from coming into the planet (nuclear winter). So how can that massive eruptions like the Siberian trap,s which happened later, did not cause a snowball event? The key could be the amount of sulphur dioxide (SO2) emitted by the eruption, the more this gas the worse: it interacts with water high in the atmosphere and reflects sunlight, plus it triggers acid rain, what a joy for a lovely gas! No wonder it is related to the perfume of hell

The snowball event triggered the development of complex life (metazoan), perhaps by boosting the levels of phosphate (PO43-) and nutrients in the oceans once the glacials melted: only 3 Mya after the Gaskiers glaciation ended 582 Mya, our planet earth had a massive explosion of life from bacteria into the first multicellular organism, known as the Avalon Explosion, a key point to this evolution was the amount of oxygen present in deeper and deeper waters, not just shallow oceans

4) Beaverhead crater; dated 600 Mya (100 km), located in Idaho, US, and pretty close to Yellowstone park, this impact is very eroded by tectonic plates movements, buy hey, with a diameter of at least 100 kms, it must have caused havoc back on the day when it landed

5) Acraman crater; dated 580 Mya (90 km diameter), is located in South Australia; this impact happened during this epoch, so... did it contribute to speed up the warming process of the planet?

 

 

References

Was the Earth ever frozen solid? https://phys.org/news/2018-05-earth-frozen-solid.html

Kenorland, Rodinia and Pangaea https://someinterestingfacts.net/kenorland-rodinia-and-pangaea/

What caused the snowball earths? https://www.snowballearth.org/cause.html

The Franklin Large Igneous Province and Initiation of the Sturtian Snowball Earth Glaciation http://www.largeigneousprovinces.org/15feb

Beaverhead impact structure https://craterexplorer.ca/beaverhead-impact-structure/

 

Extinction 4 - (542 Mya) End-Ediacaran Extinction

In our list of extinction events, this is the first known biological extinction event, where fossils show an abundance of macroscopic (visible to the naked eye) life on our oceans 575 millions years ago, creatures (they were not animals or plants yet) that drastically declined 24 million years after, thus indicating an extinction event that is called the End-Ediacaran Extinction. It is still a mystery what caused this extinction, the unconfirmed Massive Pre-Cambrian Impact Structure (MAPCIS), a maximum of 2,000 km outer-ring impact crater in central Australia, has been tentatively dated to this time period. An impact of such astronomical proportions would have been utterly devastating for Life, and triggered an stagnated process in the oceans, depleting them of oxygen and hence contributing massively to this extinction event. At that time, the super-continent Pannotia existed, with Australia, where MAPCIS hit, positioned around the equator of planet Earth

A significant creature that got extinct during this period was the Dickinsonia, one of the first complex creatures to have ever existed. The creatures of the late Ediacaran period were called rangeomorphs, not-plants or not-animals, and grew in fractal-like format, with each branch of the creature being a smaller version of the creature itself....interesting, as if they had an intimate knowledge of algebra. The Fibonacci sequence of reproduction was nowhere to be found yet, only fractal, meaning that the DNA of these creatures was very simple indeed and not aware of complex maths multiplications

It is interesting to note that photosyntheses had already been invented, yet rangeomorphs fed themselves with nutrients floating in the sea. Thanks God sex has already been invented :), but  there was no concept of prey and predator, and it is argue as well that the arrival of predators cause the Ediacaran biota to get extinct, when suddenly a new creature had a mutation that allow it to eat another creature, and all Ediacaran biota had no defensive mechanism whatsoever, they were easy target to eat

6) MAPCIS crater; dated 545 Mya (600 km diameter) is a proposed asteroid impact, meaning it is still under study and unconfirmed. If this impact really happened it must have set the clock of Life back, it is a gigantic one! Four times bigger than the crater's meteor that cause the dinosaurs to become extinct

 

 

References

Massive Australian Precambrian/Cambrian Impact Structure https://en.everybodywiki.com/Massive_Australian_Precambrian/Cambrian_Impact_Structure

What caused the mass extinction of Earth's first animals? https://www.sciencedaily.com/releases/2018/06/180627160543.htm

Charnia http://www.prehistoric-wildlife.com/species/c/charnia.html

 

Extinction 5 - (513-517 Mya) End-Botomian Extinction

This is also called the Middle Cambrian Extinction and is estimated to have wiped out around 40% of the marine life. By this time, the Cambrian Explosion of Life had already happened, and the oceans were dynamic and full of Life, where biomineralisation had begun and organisms started to build shells

Fossils indicated an extinction event between 513 to 509 Mya, with an estimate decline in global diversity of 40% of marine species. The reason for this extinction are unknown, but again all points out to anoxic oceans due to volcanic eruptions most likely in The Kalkarindji Large Igneous Province, Australia. These eruptions could have poisoned the oceans and lead to a collapse of the phytoplankton, the base of the food chain. Some trilobites species were already living around this time, meaning that the concept of prey and predator was well established and animals ate one another (trilobites had a hard carcase to protect their softly parts from predators)

 

 

References

Science: The biggest mass extinction of them all? https://www.newscientist.com/article/mg13518322-900-science-the-biggest-mass-extinction-of-them-all/

Hyoliths: Mysterious Cambrian Animals Classified as Lophophorates http://www.sci-news.com/paleontology/hyoliths-cambrian-lophophorates-04531.html

The Kalkarindji Large Igneous Province, Australia https://academic.oup.com/petrology/article/59/4/635/4975734

 

Extinction 6 - (502-497 Mya) Dresbachian Extinction

This is also called the Upper Cambrian Extinction, and is estimated to have decimated 40% of marine life. During the Cambrian period Life existed only in the oceans

The Dresbachian extinction is one of the most poorly documented entries in our list of extinction events, due to the lack of fossils so far back in the history of Life on our planet

 

Extinction 7 - (488 Mya) Cambrian-Ordovician Extinction

This extinction marks the end of the Cambrian period and the beginning of the Ordovician

The reason/s for this extinction are not well understood by Science, but definitely it had something to do with the levels of oxygen in the oceans, they dropped and a lack of oxygen combined with Hydrogen sulphide (H2S), the so-called "rotten egg" gas (it has been detected in many rocks dated around this time), may have surely killed many species. All these animals during the Cambrian period were either predators or prey, or both. To survive, you either have to be an apex predator like Anomalocaris, run fast and don't get caught, or develop a shell or armour so you don't get eaten easily. The most plausible causes for this extinction are:

Glacial cooling hypothesis; a change in climate, driven perhaps by the formation of the super-continent Gondwana, cause ice to form in land masses, with the consequence sea levels to drop, cooling the oceans and reducing the amount of shallow seas, thus killing most of the Cambrian fauna that were adapted to live in warm waters

Oxygen depletion hypothesis; something massive happened in the food chain that caused either algae or bacteria to stagnate the oceans, it could also have been underwater volcanos but to cause such extinction must have been huge. All these resulted in rotten oceans and a positive feedback loop of more animals dying and decomposing in the oceans, removing even more oxygen from it and replacing it with hydrogen sulphide

These are some of the species that were extinct during this event:

 

 

References

Speculated causes for the Cambrian Extinction https://park.org/Canada/Museum/extinction/camcause.html

Hallucigenia: Paleontologists Reconstruct Cambrian Worm-Like Creature http://www.sci-news.com/paleontology/science-hallucigenia-cambrian-worm-like-creature-02949.html

Coronacollina Acula, Oldest Organism with Skeleton Discovered https://scitechdaily.com/coronacollina-acula-oldest-organism-with-skeleton-discovered/

 

Extinction 8  -  (450 Mya) 86% of species lost: (1) Ordovician-Silurian Extinction

This is also called the Late Ordovician Mass Extinction (LOME). Up to this point Life was mostly restricted to the oceans, and though since the Archean period bacteria had been living in  dump areas of rivers, lakes, etc, it was in the form of tiny lichen and green algae, that slowly were colonising coastal areas where their "cryptogamic cover" was breaking down the minerals from rocks and further enriching the oceans with nutrients like phosphorous. All of these early plants were still much dependable of the water nearby, unable to extend further inland into dry areas.....yet. It is argue that the proliferation of plants in dry areas created an "algae bloom" that depleted the oceans from oxygen, thus leading to this extinction

The creation of the Appalachian Mountain range, that were to be our current Himalayas for many million of years to come, could have been a contributor also to this extinction event, as they will likely have changed weather patterns, causing a glaciation of the continent Gondwana and dropping sea levels worldwide, leading to a "first pulse of extinction". Thereafter, a warming of the climate caused a "second pulse of extinction" that lead to many species being lost

Fossils from that epoch shows deformities, as if affected by high level of heavy metals, in particular toxic metals like mercury, perhaps caused by underwater massive volcanic eruptions. Rapid global cooling and sea level drop, with a sudden warm of the climate afterwards, were the main factors for this mass extinction, but what caused all of this? Science has yet to find the root cause. It is theorised, thou, that a gigantic volcanic eruption that took place approximately 452 Mya ago, the Millbrig eruptions in what it is now the Atlantic Ocean, could have been a contributor

7) Clearwater East Lake crater; dated 460 Mya (26 km); with a diameter of just over 25 km, this impact qualifies to my personal list of meteor residents on our planet. Given the fact it may have occurred 10 million years before this extinction, it may not have had an impact in the Ordovician-Silurian list of extinction events, but it is a very interesting impact when we consider that, roughly 175 million years after, another asteroid (mentioned in Extinction 13 entry) will impact our planet....in the same location!! What are the odds of that happening?

 

 

 

References

The Ordovician Extinction: our planet's first brush with death https://www.discovermagazine.com/planet-earth/the-ordovician-extinction-our-planets-first-brush-with-death

Hypothetical effects on Earth in the past https://en.wikipedia.org/wiki/Gamma-ray_burst#Hypothetical_effects_on_Earth_in_the_past

Aegirocassis http://www.prehistoric-wildlife.com/species/a/aegirocassis.html

Tiny algae may have prompted a mass extinction https://eos.org/articles/tiny-algae-may-have-prompted-a-mass-extinction

The greatest volcanic ash falls in the Phanerozoic https://www.sepm.org/files/24article.5bgzn442hichl4um.pdf

Ordovician explosive volcanism http://historyoftheearthcalendar.blogspot.com/2014/03/march-24-ordovician-explosive-volcanism.html

Clearwater East impact crater https://craterexplorer.ca/clearwater-east-impact-crater/

 

Extinction 9 - (428 Mya) Ireviken event

This was an event that occurred in the middle of the Silurian era, and though by our current standards we usually understand as "event" a situation that happens from beginning to end within a limited amount of time, a few minutes or so, due to the large scale of time that we are talking about here, this "event" of the Ireviken extinction lasted for around 200,000 thousands years

The event has been best preserved at a location called Ireviken, in the island of Gotland (Sweden), where fossils show that over 50% of trilobite species became extinct, with 80% of the global conodont species also becoming extinct during this interval. Again, deep-ocean anoxia seems to have caused all of this. Could there be a relation between this event and a glaciation triggered by the Milankovitch cycles? Possibly not, around this time the Moon was much closer to Earth than it is today, meaning the parameters that cause the Milankovitch cycles may have been different due to a stronger gravity presence of the Moon

 

 

References

Brachiopod faunal dynamics during the Silurian Ireviken event https://lup.lub.lu.se/luur/download?func=downloadFile&recordOId=2338196&fileOId=2338197

 

Extinction 10 - (424 Mya) Mulde event

This is the second of the three "minor" extinction events that happened during the Silurian period. It coincided with a drop in sea level worldwide, which probably caused anoxia in the waters and hence the dying of creatures. During this period the oceans did not have the oceanic currents (Ocean Conveyor Belt or Thermohaline circulation) that we enjoy nowadays and that helps oxygenate the waters

 

 

References

Every mass extinction event explained https://www.grunge.com/728628/every-mass-extinction-event-explained/

Paleomap Project by Christopher R. Scotese http://www.scotese.com/earth.htm

Contemporaneous assembly of western Gondwana and final Rodinia break-up https://e-docs.geo-leo.de/bitstream/handle/11858/7064/1-s2.0-S1674987117300294-main.pdf

 

Extinction 11  - (420 Mya) Lau event

The Lau event was the last of the three relatively "minor" extinctions during the Silurian period. This entry in the list of extinction events is estimated to have killed a great number of marine life, up to 85% of it. Again, it seems to have been caused by anoxia in the oceans, in other words lack of oxygen in the waters, but why did that happen? Nobody knows

400 millions years ago, a day was just 21 hours long

References

Abrupt global-ocean anoxia during Late Ordovician-early Silurian https://www.pnas.org/doi/10.1073/pnas.1802438115

 

Extinction 12  - (375 Mya) 86% of species lost : (2) Late Devonian Extinction episode

In the list of extinction events, the Late Devonian is the second great extinction that happened in the oceans, putting an end to the "Age of Fishes". Fossil records indicate that proto-plants and proto-insects (arthropods) were already colonising the land, meaning that creatures that were almost amphibians began to move inland too, surely to feast on those juice proto-insects that had no predator. Another reason to move away from the waters was that the oceans were by now crowded with gigantic apex predators like the Dunkleosteus, whose bite was strong enough to break the armour plate many fishes wore at this time

This extinction episode happened over a long period of time, something between 25 to 30 millions years, in what it is considered to be a prolonge interval of biodiversity decline, which comprises between 3 to 7 different pulses of extinction events, some of these events were:

a) Kellwasser event, 372 Mya, caused by the eruption of the then Frasnian-Famennian LIP (Large Igneous Province), but due to the huge amount of time involved, it is hard to be certain about this and is all open to speculation and of course further investigation

b) Hangenberg crisis, 359 Mya, caused by a rapid sea level drop perhaps due to glaciation, hence leading to an anoxic in the oceans (lack of oxygen, which obviously kill wild life but preserve their bodies); a sediment of black shale marks this event

The coral reefs receded and they never recovered and flourished like they did on the Devonian. The continents Euramerica-Laurussia-Laurentia and Gondwana were merging in what it would be the super-continent Pangea that is characterise by the Central Pangean mountains in the middle. Other causes that could have contributed to this extinction episode are these:

c) SuperNova explosion nearby; if a dying-star were to go supernova within 25 light years of us (the so-called killing distance), the explosion will wipe out the ozone layer, allowing gamma rays to hit the surface and damaging all DNA of living creatures. Plant spore fossils of this epoch suggest they were burn by ultraviolet light, as if this sort of event happened in the backyard on our galaxy

d) Eutrophication events; also called "algae blooms", eutrophication is the process of when waters become enriched with minerals and nutrients that cause anoxic; this could have happened during the Late Devonian in particular as the first forests appeared and the weathering process increased (weathering is the process by which plants break down rocks and extracts from them minerals like phosphorous, silicates and nitrogen)

e) Carberean Cauldron; is a supervolcano caldera which erupted 374 Mya; it is now Lake Eildon National Park in south Australia, close to Melbourne

f) The Vilyuy Traps eruption; located in Eastern Siberia, have thought to have erupted 373 Mya

And indeed, we also need to consider the following extraterrestrial impacts as causes for extinction pulse events:

8) Siljan Ring; dated 376 Mya (52 km diameter), located in the middle of Sweden

9) Woodleigh crater; dated 364 Mya (60 km diameter), located in western Australia

 

  

 

 

References

Miguasha fossils around the world https://www.miguasha.ca/mig-en/miguasha_fossils_around_the_world.php

Soil Fungi: The world beneath our feet https://mikeallsop.wixsite.com/soilfungi/fungi

Large igneous provinces and mass extinctions: an update https://hydra.hull.ac.uk/assets/hull:10877/content

Precisely dating the Frasnian–Famennian boundary https://www.nature.com/articles/s41598-018-27847-7

 

Extinction 13 - (305 Mya) Carboniferous Rainforest Collapse

During the Carboniferous, Life was thoroughly established and in full motion in our planet. The slow collision of the continents Laurasia and Gondwana that were to form the Central Pangean Mountains (Appalachian and Variscan mountains) facilitated an unique ecosystem. Vast areas were covered in tropical forests and swamps, whose remain are the coal that we "enjoy" nowadays (dead trees were making sediments at an estimated rate of around a millimetre per year), being these jungles full of arthropods, insects and amphibians that were co-evolving at the same time that plants were evolving too. Nova Scotia is without doubt the best place to study the Carboniferous

Oxygen levels raised to their highest during the Carboniferous period, at 35% (compared to 21% that we have today) causing the size of insects to increase to gigantic proportions as they breathe through their 'skin'. Some of these insects may have been wiped out during the Carboniferous Rainforest Collapse (CRC), the minor extinction event that occurred around 305 Mya and that affected mostly to plants with the creation of fragmented forest that pushed the amphibious to live far away from water. These amphibious developed what is called Amniotes eggs, eggs with a hard shell that helps the embryo retain water and nutrients, a significant step in evolution

During this extinction, we have to consider too the following extraterrestrial impacts:

10) West and East Warburton Basins; dated sometime between 300 to 360 Mya (400 km diameter), located again in our beloved Australia, this is the largest impact area found in our planet, when a gigantic asteroid split and entered our atmosphere in 2 parts of more of 10km each. Just for comparison, the one that wipe the dynos had 12 km...just imagine the devastation that 2 asteroids of 10km each would have caused at the same time. Shocked quartz has been found in this area of Australia, indicating huge pressures that can only be obtained during an asteroid impact. Due to the precise dating for the yet-to-be-confirmed impact, some scientist are not convinced that this double-punch collision would had had any effect on this entry in our list of extinction events, yet something has to explain these basins formations in Australia as well as the root caused for the Carboniferous Rainforest Collapse

11) Clearwater West Lake crater; dated 290 Mya (diameter of 36 km); this is the second crater of a previous impact that slammed on our planet 460 Mya (mentioned in Extinction 8 entry). These two craters located in north-west Canada are absolutely extraordinary....is it a coincidence that two asteroids impacted our Earth at the same location? I think that is amazing, the fact that this thing has happened when we consider that everything rotates in the Cosmos

 

 

References

Carboniferous Period ~ 358.9–298.9 million years ago http://paleobotanical-photography.blogspot.com/p/carboniferouscarbonifer.html

Giant Asteroid impact basin found in Australia http://www.sci-news.com/geology/science-warburton-giant-asteroid-impact-basin-australia-02627.html

'Meganeura' Was A Prehistoric Dragonfly With A Two-Foot Wingspan https://www.ranker.com/list/meganeura-giant-prehistoric-dragonfly/genevieve-carlton

Paleo Profiles: Arthropleura https://lewisrhystwiby.wordpress.com/2021/09/12/paleo-profiles-arthropleura/

Prehistoric Rainforest Collapse Dramatically Changed the Course of Evolution https://www.seeker.com/earth-conservation/prehistoric-rainforest-collapse-dramatically-changed-the-course-of-evolution

Episode 95 – The Carboniferous Rainforest Collapse https://commondescentpodcast.wordpress.com/2020/09/05/episode-95-the-carboniferous-rainforest-collapsea/

P.E.I. fossil sheds new light on evolution of reptiles: U of T paleontologist https://www.utoronto.ca/news/pei-fossil-sheds-new-light-evolution-reptiles-u-t-paleontologist-0

Surprise! Canadian Double Crater Formed by 2 Separate Impact Events https://www.space.com/28822-double-crater-two-asteroid-impacts.html

 

Extinction 14  -  (272 Mya) Olson's Extinction

This extinction event is also called Olson's gap, and it comes to existence as an indication in the fossil record during the early Permian period, that points out to a drastic reduction of the fauna including plants, tetrapods and marine invertebrates. Climate change seems to have been the culprit for this extinction, but we don't know yet what caused, though it seems the continental drifting of the continents Euramerican and Gondwana would have had a significant impact in the climate

The famous Dimetrodon, of the Synapsids family, and from which humans are descendent, most likely went extinct during this event

 

 

References

A "Botanic Pompeii" beneath our feet https://commonreader.wustl.edu/c/a-botanical-pompeii-beneath-our-feet/

Olson's Extinction: the Permian's dirty little secret die-off https://www.discovermagazine.com/planet-earth/olsons-extinction-the-permians-dirty-little-secret-die-off

Dimetrodon footprints found on P.E.I. bring Island to 'world stage' of paleontology https://www.cbc.ca/news/canada/prince-edward-island/pei-fossil-footprints-discovered-cavendish-park-1.5027811

 

Extinction 15 - (260 Mya) End-Capitanian extinction event

The fossil records (again) indicate a period of decreased species and lack of richness in diversity of fauna, which points out to another extinction event that occurred during the Guadalupian epoch (named after the Guadalupe Mountains in New Mexico), in the middle of the Permian. The cause of this extinction event could have been the volcanic eruption of the Emeishan traps, a large igneous province (LIP) in south-west China

 

 

References

The Late Capitanian Mass Extinction of Terrestrial Vertebrates in the Karoo Basin of South Africa https://www.frontiersin.org/articles/10.3389/feart.2021.631198/full

New mass extinction event identified by geologists https://www.bbc.co.uk/news/science-environment-32397220

The Emeishan large igneous province: a synthesis https://www.sciencedirect.com/science/article/pii/S1674987113001072

Earth has had more major mass extinctions than we realised https://www.nationalgeographic.co.uk/environment-and-conservation/2019/12/earth-has-had-more-major-mass-extinctions-than-we-realised

Guadalupian https://www.wikiwand.com/en/Guadalupian

 

Extinction 16  - (250 Mya) 96% of species lost: (3) The Great Permian Extinction

This was without any doubt the most devastating entry in the list of all extinctions events: the Great Permian Extinction, also called the end of Permian extinction or Great Dying, the closest Life has been to stop existing in our planet, approximately 250 Mya. The super-continent Pangaea was well formed by then, and Scientists believe that a massive basaltic flood eruptions in an area of modern Russia called the Siberian Traps, the size of Europe, was one of the main driving events that caused this gigantic mass extinction. The eruption lasted for about..... 2 million years..... and during that time huge amount of Sulphur Dioxide (SO2) and Carbon Dioxide (CO2) were pumped into the atmosphere, creating initially nuclear winters were temperatures dropped to absolute freezing conditions followed by nuclear summers where the Earth was scorched... and all that cycle, on and off, for 2 million years...it is amazing that Life actually survived. It is estimated that 50,000 years into the eruption, anoxia reached the oceans where marine Life was severely affected; any ocean currents around the super-continent Pangaea would have been shutdown, the oceans would have had a pink colour as seen from space, and the stagnated waters, full of Hydrogen Sulphide (H2S, the so-called "rotten egg" gas) would have been depleted of oxygen. As the planet heated, frozen Methane Hydrate (MH), stored frozen solid at the bottom of the oceans, would have been released, contributing to a positive feedback loop and making the planet even hotter

At the beginning of the Permian the Synapsids group of animals dominated the land, while during this extinction the group that was in charge were the Therapsids (advanced Synapsids) like the Cynodont and Gorgonopsia, the apex predator at that time. The "dead zone" is a layer of rocks during the Permian epoch were fossils are found, corpses of species that do not exist on upper layers of rock. On this dead-zone layer two groups of animals fossils are found: the dominant species Synapsids and Therapsids, whose skull had a single temporal opening (thought to have developed later into mammals) and the Sauropsids, which had two skull openings (thought to have evolved into reptiles, dinosaurs and birds). Insects were still gigantic just before this extinction, and they had developed means of piercing plants and eating them. Plants were also affected for this extinction, and forests did not exist for 10 million years after this event, the time it took for them to recover (this is actually shown as a 'coal gap' in the fossil record)

To comprenehn the extend of this extinion, imagine you are playing the russian rulet with a gun that has 10 chambers, load it with 9 bullets on it, then spit it and shoot yourself: you ohnly got 10% of survival.....4% was the survival rate during this event. And who were the 4% survivors of the Permian Extinction? The Cynodonts, small mammal-alike, survived living underground and eating roots and tubers, as some fossils from South Africa Karoo Basin seems to demonstrate

Like the old saying goes, disaster don't come along, and it looks like this meteor impact could have exacerbated the incredibly harsh conditions created by the Siberian Traps:

12) Wilkes Land crater; dated 250 Mya (240 km diameter), buried nowadays under one mile of ice and therefore very hard to be confirmed, this crater is more than twice the size of the crater impact (Chicxulub) that wiped the dinosaurs. Such a collosal impact would have been absolutely devastated for Life on our planet

 

 

References

Flood Basalt https://www.wikiwand.com/en/Flood_basalt

Largest ever killer crater found under ice in Antarctica https://phys.org/news/2006-06-largest-killer-crater-ice-antarctica.html

Trilobite Extinctions https://trilobites.life/trilobite-extinctions.htm

The cause of the greatest mass-extinctions of all? https://skepticalscience.com/pollution-part-2.html

 

Extinction 17  -  (232 Mya) The Carnian Pluvial Episode (CPE)

Scientists agree that there was a time in the middle of the Triassic where it rain for....2 millions years! Heavy Rain almost everywhere.....almost every day.... every year....for 2 million years. The ground was totally soaked, meaning small-size animals would have had a high risk of being drowned. It is believed this episode facilitated the evolution of the dinosaurs as the dominant species

Large-scale eruptions in the Wrangellia large igneous province, in western Canada, could have facilitated the occurrence of this event. These eruptions lasted for 5 million years and drastically affected the vegetation on our planet with long lasting events that reached us until now! Without the CPE, jungles on our planet would have not been formed, and plants and trees would have had a hard time in conquering the interior of the continents to such a extend as to create tropical forests. The Wrangellia eruptions could have heated the planet up to 15 degrees of normal temperatures, a Climate Change going ballistic, that would have caused huge hurricanes and storms due to the increased energy in the atmosphere and the super-hot oceans, causing the rain to reach deep into Pangaea.... for 2 million years non-stop

Though this asteroid impact is dated around 10 millions after the CPE ended, when dinosaurs where in full motion of evolution, I'd like to mention it:

13) Manicouagan Reservoir crater; dated 214 Mya (70 km diameter); known as the "eye of Quebec", this impact of such high proportions would have been absolutely devastated for the Northern part of Pangaea that it hit, causing perhaps a nuclear winter in the whole planet but did not have long lasting effect that were harmful for the overall Life of our planet. Did not lead to a mass extinction, but indeed it was a warning for the dinosaurs of what it was to come. The asteroid is thought to have been 5 km in diameter

 

 

 

References

Did a million years of rain jump-start dinosaur evolution? https://www.nature.com/articles/d41586-019-03699-7

Volcanically driven lacustrine ecosystem changes during the Carnian Pluvial Episode (Late Triassic) https://www.pnas.org/doi/10.1073/pnas.2109895118

Palaeontologists identify new mass extinction event http://www.sci-news.com/paleontology/carnian-mass-extinction-08857.html

How the West was born https://www.volcanocafe.org/wrangellia-how-the-west-was-won/

 

Extinction 18  - (200 Mya) 80% of species lost: (4) End of Triassic Extinction

This is the most mystery extinction of them all. The boundary between the Triassic and Jurassic period is marked by this extinction event, after which the complete reign of the dinosaurs began, becoming the dominant species during the Jurassic

The breaking down of the super-continent Pangaea could have caused a dramatic Climate Change that triggered this extinction. The eruption of the Central Atlantic Magnetic Province (CAMP), the largest continental large igneous province of the planet, that occurred about 201 Mya and lasted for over 600,000 years, has also being pointed out as a caused, having the effect on our planet being pretty similar to that caused by the Siberian Traps 50 million years earlier

 

 

References

Lystrosaurus: the most unlikely undertherepsid https://www.darwinsdoor.co.uk/feed/lystrosaurus-the-most-unlikely-undertherapsid.html

Lystrosaurus: The Most Humble Badass of the Triassic https://www.nationalgeographic.com/science/article/lystrosaurus-the-most-humble-badass-of-the-triassic

Giant Triassic Predator, Named for Baby-Eating Monster, Discovered in New Mexico http://westerndigs.org/giant-triassic-predator-named-for-baby-eating-monster-discovered-in-new-mexico/

Did phytosaurs have lips? https://ichthyoconodon.wordpress.com/2017/01/14/did-phytosaurs-have-lips/

 

Extinction 19  - (183 Mya) Toarcian turnover

The Toarcian turnover, also known as the Toarcian extinction, Toarcian Oceanic Anoxic Event (TOAE), Pliensbachian–Toarcian or Jenkyns event, is a global extinction event that marked the end of the Pliensbachian age and the start of the Toarcian age of the Early Jurassic period, around 183 million years ago. Scientists believe that a major drop of oxygen in the oceans caused this extinction, but the root cause of that anoxic event are still unknown, though probably it was caused by the Karro-Ferrar large igneous province eruptions

The Sichuan Basin, in central China, was a gigantic lake around this time, and it contains many fossils from the Jurassic, Age of the Reptiles

Tepui Mountains, in Venezuela, are unique ancient continental islands, left overs of the continent Gondwana, and were formed during this time

 

 

References

A major sea-level drop briefly precedes the Toarcian oceanic anoxic event https://www.nature.com/articles/s41598-019-48956-x

Toarcian https://www.sciencedirect.com/topics/earth-and-planetary-sciences/toarcian

Early Jur­as­sic (Pli­ens­ba­chian-Toar­cian) ex­tinc­tion event https://www.marum.de/en/about-us/Isotope-Geochemistry/Page4764.html

Globally enhanced mercury deposition during the end-Pliensbachian extinction and Toarcian OAE https://www.sciencedirect.com/science/article/pii/S0012821X15004276

 

Extinction 20  - (145 Mya) End-Jurassic (Tithonian) extinction

This is not a well understood minor extinction event that occurred in the middle of the Jurassic, where a nuclear winter perhaps caused by a mix of volcanic eruptions and asteroids impacts, like for example these two that occurred around that time:

14) Morokweng crater; dated 146 Mya (70 km diameter) and located in Northern South Africa, it is estimated the asteroid that created such crater would have caused havoc in the planet

15) Tookoonooka crater; dated 133 Mya (60 km diameter), located in South West Queensland Australia

 

 

References

Why I think the Jurassic/Cretaceous boundary is super important http://fossilsandshit.com/why-i-think-the-jurassiccretaceous-boundary-is-super-important/

The Tookoonooka marine impact horizon, Australia: Sedimentary and petrologic evidence https://onlinelibrary.wiley.com/doi/full/10.1111/j.1945-5100.2012.01330.x

 

Extinction 21  - (117 Mya) Aptian Extinction

This event happen in the middle of the Cretaceous and is also called the mid-Aptian extinction event, where many species of dinosaurs where wiped out. The Rajmahal Volcanic Province, part of the Kerguelen Large Igneous Province in eastern Indian, were most likely the cause of this extinction as they erupted around 115 to 118 Mya. The massive Ontong Java Plateau, 1% of Earth surface, that formed around 120 Mya, could have had a say on this extinction too

By this time, mother Nature had already made the most wonderful invention of them all, pleasant to the eyes and according to my personal taste, of course: flowers! The oldest flower discovered on our planet is 130 million years old

 

 

References

Dinosaurs in decline tens of millions of years before their final extinction https://www.pnas.org/doi/10.1073/pnas.1521478113

Subaqueous early eruptive phase of the late Aptian Rajmahal volcanism https://www.sciencedirect.com/science/article/pii/S1674987116300639

The Ontong Java Plateau - Large Igneous Province https://volcanohotspot.wordpress.com/2018/03/16/the-ontong-java-plateau-large-igneous-province/

What the first flower on Earth might have looked like https://www.newscientist.com/article/2142372-what-the-first-flower-on-earth-might-have-looked-like/

 

Extinction 22  - (94 Mya) Cenomanian-Turonian boundary event

The Cenomanian-Turonian extinction event, also called the Bonarelli event or Oceanic Anoxic Event 2 (OAE2), affected the oceans and it was likely caused by a eruption flood basalt of the the Caribbean large igneous province (CLIP)

13) Kara crater; dated 70.3 Mya (120 km in diameter), located in northern Russia, this impact is almost as big as the Chicxulub impact, yet it didn't seem to have cause a dramatic extinction like the former one did, why? My guess is that for the dinosaurs, punch of the Chicxulub impact, together with the double punch of the Deccan Traps eruptions, was the perfect cocktail for extinction

 

References

Prevailing oxic environments in the Pacific Ocean during the mid-Cretaceous Oceanic Anoxic Event 2 https://www.nature.com/articles/ncomms1233

New study confirms the power of Deinosuchus and its 'teeth the size of bananas' https://www.sciencedaily.com/releases/2020/08/200810141002.htm

 

Extinction 23 - (66 Mya) 76% of species lost: (5) End of Cretaceous and the Dinosaurs

From the list of extinction events, this is the most famous of them all: the extinction of the dinosaurs, after an almighty reign in our planet that lasted about 165 millions years. In comparison we primates have been around for only 50 million years, of which our particular species, homo sapiens, has enjoyed roughly 2 million years of our planet. This extinction was caused by the impact of an asteroid that created the Chicxulub crater, in the Yucatan peninsula, Mexico, but also by the poison of the Earth atmosphere that a continuous eruption of the Deccan Traps, in western India, were causing. Most likely, the eruption of Deccan was making the planet a harsh place to live for large animals, and the arrival of the Chicxulub asteroid was a quick dead sentence for any animal that weighted more than 25 kilos: they all were extinguished in a period of a few months after the killer impact

This extinction created a very define and distinctive layer (geological signature) in the sediments called the K-T boundary, Cretaceous and Tertiary boundary, two periods that separate two eras in Earth's biological history: the Mesozoic or middle life and the Cenozoic or recent life. There has been similar and ever bigger asteroid impact in our planet, but this one of the Chicxulub crater in particular is iconic, not just to the fact that it pushed the dinosaurs into extinction, allowing the mammals (and in extension we us, humans) to conquer the planet later on, but because the acknowledgment of this impact extinction by Science shocked the roots of the concepts that for some many centuries scientists had about the nature of Evolution in our planet. "Uniformitarianism" had been the main theory of geologists, stating that the forces that build up and wear down our planet were the same forces that did it in the past, and this theory was sort of extended to Biology too, with the idea that extinction was a phase in the process of evolution, and that species they simply evolve into something else...but all that was to be wrong with the systematic study of decades and the final conclusion that it was an asteroid the culprit of the extinction of the dinosaurs: the "Catastrophism" theory was proved, which state that sometime pure chance and catastrophes clearly define and redirect the evolution of life in our planet

The impact of the Chicxulub meteor over an area of the planet rich in sulphur was pure chance, but that had a devastating effect for the dinosaurs. The impact created as a consequence of limestone weakening the famous cenotes in the Yucatan peninsula, that define the rim of the crater. At the moment of the collision, nothing within a 1,000 miles of the impact ground zero stood a chance, all was incinerated instantly by a superheated 2,000 miles an hour firewall. Then a 90 meter tall mega-tsunami obliterated the coastal areas. Debris from the meteor rain back into the atmosphere, overheating the planet in just a few minutes after the impact, until a point were forest spontaneously combusted and animals were roasted alive in the heat. For about 6 months, the ash completely blocked the sun, and you could not have seen your hand in the middle of the night. Sulphuric acid began to rain killing all plants, and temperatures dropped dramatically. The huge amount of sulphur dioxide that was released during the impact extended these conditions for about 2 years, way longer as decades if the Deccan Traps were intensifying their eruptions around that time which is quite possible. Photosyntheses stopped, and the food change totally collapsed. The survivors were omnivores living underground where they were further protected from the hostile environment. This is not the first time, neither the last, and not even the biggest of the meteor impacts that our planet has endured, but it is the most recent, and as such the one that had been most devastating for Life as we know it now

14) Chicxulub crater, dated 66 million years ago (180 km in diameter), to create the crater structure that this impact has, the asteroid must have entered the Earth from a north-east direction, passing through Nova Scotia and Florida and striking our planet with roughly a 60 degree angle. If the asteroid came from the edge of the solar system (Oort Cloud) it would have taken 38,000 years of travelling before hitting Earth. If the asteroid got detached from the asteroid belt, it will only have taken about 6 months before slamming into our planet

 

 

 

References

The asteroid theory https://www.britannica.com/animal/dinosaur/The-asteroid-theory

Pattern in Palaeontology: the real Jurassic Park https://www.palaeontologyonline.com/articles/2019/patterns-in-palaeontology-jurassic-park/

Dinosaur asteroid's trajectory was 'perfect storm' https://www.bbc.co.uk/news/science-environment-52795929 

Impact or eruptions: are both to blame in the great end-Cretaceous whodunit? https://www.earthmagazine.org/article/impact-or-eruptions-are-both-blame-great-end-cretaceous-whodunit

 

Extinction 24  (56 Mya) Paleocene-Eocene Thermal Maximum (PETM)

(Hot climate). There was a time in our planet where there was no ice at polar cups at all, and in fact they were covered by forests. This period that lasted for around 200,000 years is called the Paleocene-Eocene Thermal Maximum (PETM) or Eocene Thermal Maximum 1 (ETM-1) and is associated with large deep-sea mass extinctions of around 35-50% of foraminifera (deep sea water plankton), with the average oceans temperatures being 20 degrees Celsius....nearly 40 degrees at the equator. This rapid global warming is a close analogy of modern climate change or anthropogenic CO2 emissions, and roughly 1.8 million years after this event, it happened again during another period called Eocene Thermal Maximum 2 (ETM-2) at around 53.7 Mya

The break-up and consequent flood-basalt eruption of the North Atlantic Igneous Province could have caused this slowly but relentless global warming of PETM, though it is speculated that both of this events (ETM-1 and EMT-2) could have been cause by changes in the orbital eccentricity of our planet

The Tethys sea was closed around this time, when continental fragments of Gondwana collided with the rest of Laurasia

With the whole world covered in trees, primates evolved during this time

15) Hiawatha crater; dated 58 million years ago (31 km in diameter); when discovered in 2015, this crater was consider the cause of the Younger Dryas event, but it is now thought to be 58 Mya old, yet the crater looks like very new and hardly eroded, and it has not always been protected under ice like it is now. This asteroid may have created a few years of nuclear winter,but its size is not long enough to prevent the PETM that followed 2 million years after the impact

 

 

References

Ancient climate events: Paleocene Eocene Thermal Maximum https://www.e-education.psu.edu/earth103/node/639

The Paleocene Eocene Thermal Maximum https://sites.google.com/site/thepaleoceneeocenethermalmaxim/home

The First Primates https://www2.palomar.edu/anthro/earlyprimates/early_2.htm

Massive asteroid hit Greenland when it was a lush rainforest, under ice-crater shows https://www.livescience.com/greenland-hiawatha-crater-age

 

Extinction 25 - (33.9 Mya) Eocene–Oligocene Transition event (EOT)

(Cold climate). The Eocene–Oligocene Transition event, also called EOT, makes one of the largest entry in the list of extinctions events that directly affect marine invertebrates in the world oceans, and happened roughly 34 Mya, when the planet transition from the "hothouse" of PEMT to a dramatic "icehouse" of freezing temperatures and polar ice caps much like we have today, with sea levels dropping, cooler temperatures and forests changing into grasslands. The last of the ancient cetaceans, like the Archaeoceti, were extinct during this time

15) Popigai crater; dated 37 Mya (100 km diameter), in northern Siberia, could have drastically caused a nuclear winter that dropped the temperatures

16) Chesapeake Bay crater; dated 36 Mya (85 Km) and located in north east Canada, could have joined the effects of Popigai and cool the planet tremendously. Tom Canyon impact crater (in New Jersey) and Mistastin Lake crater (in Labrador, Canada) were two 'smaller' impacts dated around the same time and could have potentially exacerbated the long-lasting effects of the other two previously mention major impacts, thus creating the flip to a permanent condition of "icehouse" in the planet

 

 

 

References

Synchronous turnover of flora, fauna and climate at the Eocene–Oligocene Boundary in Asia https://www.nature.com/articles/srep07463

The climate-driven mass extinction no one had seen https://today.duke.edu/2021/10/climate-driven-mass-extinction-no-one-had-seen

Russia's Popigai meteor crash linked to mass extinction https://www.livescience.com/46312-popigai-crater-linked-eocene-mass-extinction.html

 

Extinction 26 - (16.9 Mya) Mid Miocene Climate Optimum (MMCO)

(Hot climate) During the Mid Miocene Climate Optimum our planet went into an abrupt period of warmer temperatures that most likely was caused by the largest volcanic eruption in 'recent' times, the massive Columbia River basalt flood that occurred in western America

The continent of Zealandia, of which New Zeeland is part of, was probably completely submerge around this time never to be resurfaced

 

 

References

Why the Miocene matters (and doesn't) today https://skepticalscience.com/print.php?n=2845

Zealandia: Eath's hidden continent https://www.geosociety.org/gsatoday/archive/27/3/article/GSATG321A.1.htm

Meet The Entelodont, The Horse-Sized “Hell Pig” Whose Teeth Were As Thick As A Human Wrist https://allthatsinteresting.com/entelodont-hell-pigs

 

Extinction 27 - (14.5 Mya) Middle Miocene disruption

(Cold climate) The Middle Miocene disruption were a wave of extinction events that occurred roughly 14 million years ago by a steady period of cooling that resulted in the re-establishment of the ice of the East Antarctic Ice Sheet (EAIS) as well as a growth of ice sheet volumes across the globe. This time of cold temperatures could have been caused by an increased in volcanic activity in the Rift Valley as well as by the meteor impact of Nordlinger Ries, in South Germany (diameter of only 24 km), both of which factors could have accelerated the conditions for nuclear winter scenarios, thus helping the formation of ice in Antarctica

With cooler climate there is a reduction of sea levels, and conditions inside the continent become drier, causing a gradual transition from lush forests to grasslands which have an impact in herbivorous and obviously in carnivorous too

 

 

References

Mid-Miocene cooling and the extinction of tundra in continental Antarctica https://www.pnas.org/doi/10.1073/pnas.0802501105

The formation of the Ries crater https://www.geopark-ries.de/en/entstehung-rieskrater/

Continental: The Himalayas https://www.geolsoc.org.uk/Plate-Tectonics/Chap3-Plate-Margins/Convergent/Continental-Collision

Carnivorous mammal larger than polar bear once roamed Kenya http://www.sci-news.com/paleontology/simbakubwa-kutokaafrika-07108.html

 

Extinction 28 - (5.96 Mya) Kapitean-Optian Glacial Event

The Kapitean-Optian Glacial Event was a time where sea level worldwide were relatively shallow due to an increased of ice formation, with macrofauna and microfauna being affected by this. The causes for this glaciation event are unknown, but most likely it was caused due to the tectonic plates creating a fall in "eustatic sea level", a Geology term that measures the distance from the center of the Earth to the sea level. This glaciation created what it is called as the Messinian Salinity Crisis (MSC) or Messinian event, the closure of the straight of Gibraltar and the subsequence evaporation of the Mediterranean sea (part of the ancient Tethys sea)

Yellowstone caldera went off more or less about this time, could that massive eruption be linked to this glacial event?

The number of species that die out due to the acidification and shrinking of the Mediterranean sea in unknown

 

 

 

References

Recognition and correlation of the Kapitean stage https://www.tandfonline.com/doi/abs/10.1080/00288306.1967.10423208

The Gibraltar Corridor: Watergate of the Messinian Salinity Crisis https://www.sciencedirect.com/science/article/abs/pii/S002532271830104X

Extinct Megapiranha could outbite history's largest shark https://www.livescience.com/25741-mega-piranha-packed-deadly-bite.html

 

Extinction 29 - (5.3 Mya) The Zanclean flood

After being dried out for about 500,000 thousands years, the Mediterranean sea got filled by what is called the Zanclean Flood, when the straight of Gibraltar opened again and a dramatic flood occurred with waters raising an estimation of 10 meters a day. Between just a few months and 3 years, the Mediterranean sea that had vanished half a million years ago was restored. How did that affected the climate around Europe, and the planet? How many meters the sea level in the Atlantic and possibly all the oceans decreased? Was there any native species adapted to live in the basin that were wiped out during that massive and constant flood?

Please note that the Zanclean flood has got NOTHING to do with Noah's flood, around this time our ancestors were still monkeys in Africa

Also note that the Chalicotherium went into extinction around this time, NOT with the Megafauna (some 12,000 years ago) as you often see it depicted with, perhaps because he was weird and looks like a Sloth

 

 

 

References

Sea Water https://www.weather.gov/jetstream/seawater

The Myotragus Balearicus in Mallorca https://www.masmallorca.es/en/culture/the-myotragus-balearicus-in-mallorca.html

Island weirdness https://nixillustration.com/tag/myotragus/

About Chalicotherium https://www.newdinosaurs.com/chalicotherium/

Clalicotherium https://dinopedia.fandom.com/wiki/Chalicotherium

 

Extinction 30 - (3 Mya) The Great American Biotic Interchange (GABI)

In our list of extinctions events, the Great American Biotic Interchange (GABI) has a unique entry. Unlike any other extinction events, this one is created by the merging of North American with South America, when the Panama strait closed, allowing animals from the North to migrate to the South and vice-verse. The close of the isthmus may have happened as far back as 19 Mya, allowing for different waves of migrations North-South-North to occur

This event had a significant implication for us, humans, still to be fully developed in the future: the separation of the Pacific and Atlantic oceans triggered the Gulf Stream, warming up considerably the Northern hemisphere that eventually became the habitat for species of homos

 

 

References

The Great American Biotic Interchange a South American perspective https://core.ac.uk/download/pdf/141500148.pdf

New study reaffirms timeline on formation of Isthmus of Panama https://www.tamug.edu/newsroom/2016articles/formationisthmuspanama.html

Disproportionate extinction of South American mammals drove the asymmetry of the Great American Biotic Interchange https://www.pnas.org/doi/10.1073/pnas.2009397117

 

Extinction 31 - (2.6 Mya) Pliocene–Pleistocene boundary extinction

This is the 2nd mass extinction that is potentially related to a supernova explosion, the 1st one being Extinction 12, the Late Devonian extinction. Scientist have evidence in the form of radioactive iron-60 isotopes found in ancient seabed deposits that, around this time, a supernova must have exploded close enough (100 to 130 light-years away approximately) to damaged the Earth's ozone layer, causing this mass extinction that wiped 35% of the species in the ocean. The rare iron-60 isotope can only be created in massive stellar blasts like supernovas

During a bath of ultra-violate radiation coming from a supernova, our planet ozone layer at high latitudes diminished, and ultraviolet rays can come in and break DNA, thus killing live. The equator area of our planet also be greatly affected, as much of the radiation hits the equator band of our planet

The iconic lake Bosumtwi crater; date 1.07 Mya (10.05 km diameter), was created by a visitor (now permanent resident) from outer space after his extinction, and is not related to this event at all, but the impact that could be related and have an influence in this entry in our list of extinction events is this other visitor (also a permanent resident under water now):

15) Eltanin impact, dated 2.5 million years ago (130 km approximately), this impact is unconfirmed but iridium anomaly around the area shows that something hit from outer space in there around two and a half million years ago...and is buried in the ocean after 5km of sea water. Given the fact this asteroid hit a large body of water, it is understandable that it did not leave a significant crater behind, but it is estimated that it created a super-ultra-mega-top-notch-tsunami and evaporated so much water upon impact that cooled the planet significantly

 

 

 

References

Recent Nearby Supernovae May Have Left Their Marks on Earth https://physicstoday.scitation.org/doi/10.1063/1.1485567

Nearly One-Third of Ocean Animals Perished 2.6 Million Years Ago https://www.livescience.com/59624-ancient-mass-extinction-of-ocean-animals.html

Ancient asteroid delivered deadly double-punch https://astronomy.activeboard.com/t5426654/eltanin-impact-structure/

Rare 'Alien' Isotopes in Earth's Crust Point to Recent Brush With a Cataclysmic Event https://www.sciencealert.com/rare-alien-isotopes-in-earth-s-crust-point-to-recent-brush-with-a-cataclysmic-event

Reconstruction of a large Megalodon https://www.fossilguy.com/news/megalodon-body-dimensions-9-8-20/index.htm

Giant Camel https://www.fossilhunters.xyz/disappeared-species/giant-camel.html

 

Extinction 32 - (400,000 years ago) The Homo species extinctions and fire

In this entry in out list of extinction events I would like to mention the extinction of the different Homo species that have been around in our planet, and from which we are all descendants...some more than others. I have chosen the time of 400,000 years ago to make an entry for list of extinction events number 31. Nothing particularly special or disastrous happened 400,000 years ago, with the exception that it is around this time when we have the first irrefutable proof (burnt animals bones together with Paleolithic tools, found on a cave in Israel) that humans controlled fire. Most likely they tamed fire as far back as 1 million years ago, given the fact that fire has fundamentally changed our organisms, allowing us to pre-digest the food, thus reducing the need for strong jaws or molars, which as evolution progresses through the hominids family they become smaller, allowing for an increase capacity of the skull and ultimately in brain size. The average size of a human brain (Homo sapiens) nowadays is 1400 cubic centimetres (cc)

For Palaeoanthropology, the whole family of Homo is subject to change every time a new discovery is made, and the overall pictures of whom our ancestors were grows in complexity. The acquisition of fire in our life, the ultimate tool for destruction, is nothing but the desire that our ancestors had for controlling energy, just like we do nowadays, energy to keep us warm, to cook food and eat, to scare our predators, to destroy our enemies, to check our social media and ultimately the control of energy that could be the gateway for our own extinction

I have enumerated some of the species of Homo according to how related they were to us in terms of morphology and similarity, focusing of course on why they got extinct. Note that "Cro-Magnon" is the name scientist call our early Homo sapiens ancestors that use to live with other species of Homos

1) Homo neanderthalensis; they were extinct about 35,000 years ago, probably as their population was absorbed by the increasing number of Homo sapiens that invaded Europe and Eurasia, where the Neanderthals used to live. Sometimes it just happen that extinction goes as a natural process, and looks like time was up for the Neanderthals, who currently live within our genes, the percentage of Neanderthal DNA in modern humans is zero (or close to zero) in people from Africa origins, and 1 to 2% in people of European or Asian background

2) Homo denisova; they were extinct about 20,000 years ago, and used to live in Siberia, the Tibet plateau and east Asia. It is unclear why they got extinct, and it seems they were absorbed by early Homo sapiens populations, similar to what happened to Neanderthals, Denisovan's dna currently present in South Asia and Pacific islander populations

3) Homo heidelbergensis; got extinct about 28,000 years ago, believe to be due to climate change though that is still very debatable

4) Homo rhodesiensis; also went into extinction about 28,000 years ago. They lived in central Africa

5) Homo floresiensis; went into extinction around 18.000 years ago. They inhabited the island of Flores, Indonesia, and are called "the hobbit" due to their small size

6) Homo luzonensis; went into extinction 50,000 years ago, they lived in the Philippines

7) Red Deer Cave people; they were extinct about 12,000 years ago, thought to be the last survival of Archaic humans. Their fossils were found in south-west China

8) Homo erectus; also called Homo ergaster, by far the species of Homo that has lasted the longer in our planet, they were around for well over a million years, and all other species of Homo are descendent from them. They run into extinction around 110,000 years ago for reason not yet well understood, apparently climate change but.....really? They were doing just fine for over a million years whatever the weather

Other species of homo called "Archaic humans", like Homo habilis, Homo antecessor, Homo naledi, Homo longi have all being extinct for reasons most likely related to climate change, sickness, absorptions by other species, clean wiped out in fight for resources or natural evolution process of adaptation and radiation

 

 

 

References

Human ancesteros tamed fired earlier than thought https://www.history.com/news/human-ancestors-tamed-fire-earlier-than-thought

5 theories on why Neanderthals went extinct https://www.inverse.com/science/what-killed-the-neanderthals/amp

First portrait of mysterious Denisovans drawn from DNA https://www.nature.com/articles/d41586-019-02820-0

Homo heidelbergensis https://www2.palomar.edu/anthro/homo2/mod_homo_1.htm

Last of the Homo Erectus Killed in 'Mass Death' Event as Climate Change Drove Species to Extinction https://www.newsweek.com/homo-erectus-extinction-climate-change-1477930

Climate change may have driven early humans species into extinction https://www.newscientist.com/article/2257479-climate-change-may-have-driven-early-human-species-to-extinction/

The final days of Homo Erectus https://www.insidescience.org/news/final-days-homo-erectus

 

Extinction 33 - (130,000 years ago) The Eemian interglacial

The Eemian interglacial, also known as the last interglacial, is the last warm period that our planet had had before the current one. During the Eemian temperatures were 2 or 4 degrees warmer than today, though the proportion of CO2 in the atmosphere was only half of what we have nowadays. The caused for these glacial and interglacial periods are linked to what is known as the Milankovitch cycles, changes in the Earth orbital parameters of obliquity, eccentricity and perihelion that drives our planet in and out of Ice Ages, meaning that that sometimes the northern hemisphere of our planet does not get enough energy from the sun (due to these astronomical parameters), causing a development of ice in that area

During this warm period, hippopotamus were leaving as far north as the rivers Thames and Rhine, with sea levels up to 10 meters higher than today. The Abbassia Pluvial period, the wet of the Sahara desert, started around this time, which may have contributed to other species of hominids like Homo neanderthalensis to conquest north Africa and Europe before Homo sapiens did. Around this time, Apes were already fully developed, and our species of Homo were still in the Rift Valley but were beginning to spread out, though other species of Homo had  already moved to different areas of the planet

 

 

 

References

Milankovitch (Orbital) Cycles and Their Role in Earth's Climate https://climate.nasa.gov/news/2948/milankovitch-orbital-cycles-and-their-role-in-earths-climate/

The Eemian interglacial https://tambonthongchai.com/2018/12/21/eemian/

The Largest Ape That Ever Lived Was Doomed By Its Size https://www.nationalgeographic.com/science/article/160106-science-evolution-apes-giant

 

Extinction 34 - (74,000 years go) The Toba eruption

The last significant eruption in our planet during the last 2 million years has been the Toba eruption, in Indonesia, which in theory created a dramatic nuclear winter of several years that decimated the Homo sapiens population, creating what is a called as a "genetic bottleneck", but that is still very debatable and there is no conclusive evidence for or against it yet, with some arguments claiming those who survived were different species of homos that eventually got extinct when Home sapiens arrived, and other scientist arguing that the genetic bottleneck originates from the "Founder effect", where only a limited number of individual left the Rift Valley, in Africa, and humans in all over the world (but Africa) are mostly descendent of those few individuals who left the Tarzan's continent

The Toba eruption may have caused a temporarily drop in sea levels (I guess due to the ice formation following a nuclear winter?) that could have sealed and drained the Red sea, allowing early humans to leave Africa through the land bridge towards the lash and green Arabian Peninsula of that time

Orangutans, the prime apes in Asia, who diverted from hominids 12 to 15 million years ago, survived the consequences of this eruption in spite of being so close to it, therefore the nuclear winter that Toba must have generated wasn't "too bad" for them, after all they survived we may say, but what other species of animals, apes and/or homos were not that lucky? That probably we'll never know

 

 

 

References

Understanding the overestimated impact of the Toba volcanic super-eruption on global environments and ancient hominids https://www.sciencedirect.com/science/article/abs/pii/S1040618220303335

New study refutes claims of early humans in India prior to Mount Toba eruption https://phys.org/news/2013-06-refutes-early-humans-india-prior.html

Stone tools show humans in India survived the cataclysmic Toba eruption 74,000 years ago https://theconversation.com/stone-tools-show-humans-in-india-survived-the-cataclysmic-toba-eruption-74-000-years-ago-132101

The Great Human Migration https://www.smithsonianmag.com/history/the-great-human-migration-13561/

Modern humans walked out of Africa and across the Red Sea https://arstechnica.com/science/2011/01/modern-humans-walked-out-of-africa-and-across-the-red-sea/

Modern humans did not settle in Asia before Toba Eruption 74,000 years ago http://www.sci-news.com/othersciences/anthropology/article01150-human-toba-eruption.html

 

Extinction 35 - (46,000 years ago) Quaternary extinction, Australian Megafauna disappearance

After detaching from the super-continent Gondwana, 140 Mya, Australia began developing its own ecosystem in the form of marsupials, a unique kind of mammal. Marsupials reached gigantic proportions in the late Pleistocene and went extinct 46,000 years just as the Homo sapiens, a brand new predator, entered in Australia. Scientist believe that there were periodic changes of climate in Australia, following perhaps the Milankovitch cycles, with increasing periods of deep draughts that were slowly transforming Australia into the harsh environment that it is now. This gradually change of climate into arid conditions was causing the number of megafauna individuals to be diminished, as these large animals needed a lot of food to feed themselves, and the rich forests were slowly changing into savannahs

The arrival of humans and their interaction with the habitat, systematic wild fires to protect themselves of these mega-beasts, and hunting on the youngest of megafauna, the most vulnerable and easy to kill, may have just been the killing punch, pushing the Australian Megafauna to the threshold of extinction from which they could no longer recover

 

 

 

References

Climate change not to blame for late Quaternary megafauna extinctions in Australia https://www.nature.com/articles/ncomms10511

Climate change the likely killer of Australian marsupial lion https://newsroom.unsw.edu.au/news/science-tech/climate-change-likely-killer-australian-marsupial-lion

Procoptodon Goliath https://australian.museum/learn/australia-over-time/extinct-animals/procoptodon-goliah/

Megalania https://dinopedia.fandom.com/wiki/Megalania

Anatomy of Thylacoleo https://www.pbs.org/wgbh/nova/bonediggers/thyl-nf.html

 

Extinction 36 - (14,000 years ago) Quaternary extinction, North America Megafauna disappearance

The last Ice Age maximum lasted from 31,000 to 14,000 years ago....now, the ice is beginning to melt

Just like with the extinction of the Australian megafauna, there is also controversy about what really caused the extinction of the Megafauna in the Late Quaternary - Early Pleistocene in other areas of our planet, like North America, South America and Eurasia. The population of the megafauna appears to have grown and shrink in accordance to global climate changes, with the population thriving during cold snaps that lasted thousands of years and diminished (but never disappearing all together) during warmer periods that also lasted a handful of thousand of years

For thousands of years humans and Megafauna were living together, but around this time something happened to the environment (Younger Dryas?), and the contribution of the formidable predator, Homo sapiens, may have pushed these animals into extinction. Humans in North America, known later on as Clovis people, arrived by crossing the straight of Bering during a glaciation event, 20,000 years ago, when the sea levels were lower. A few millennia after, the increased population of these Homo sapiens, combined with a bit of climate change, probably was a one-way ticket into oblivion for the Megafauna. This theory of blaming the extinction of the megafauna into humans is called "Pleistocene overkill"...and yet again, the Clovis people could at the most be accounted for just a few thousands at the peak of their population, thousand of years after they entered into North America, while the Megafauna were million of individuals, so how can so few kill so many? In particular when we consider that even wolfs (Dire Wolf), a very adaptable mammal, went into extinction as well. Something must have put the Megafauna into real stress for such extinction to happen

One of the most surprising and ironic extinctions from this list of extinction events is that the Horse, which roots originated from North America, became extinct completely (by definition the world 'extinct' includes in itself the word 'completely') around this time. It was not only until the visit of Europeans to North and South America that the Horse was re-introduce again in its original environment, no wonder it fits so perfectly in the North America plains. Had ancient horses not crossed the strait of Bering around 45 Mya and populate Euro-Asia and Africa, where it survived and became zebras, donkeys and eventually got domesticated too, we'd not have horses nowadays. It makes me wonder…how and why did the original North American horse crossed the strait of Bering? The land bridge is only open during glaciations, when it is incredibly cold and harsh to walk and survive over there. Most likely they were avoiding pressure from predators

The same thing could be said about the Camels: they originated in North America 45 Mya ago, then crossed Beringia to populated other areas of the planet, and eventually the descendants of the original Camels, Camelops, went extinct in its own home land, North America, 10,000 years ago

 

 

 

 

References

Climate change, not human population growth, correlates with Late Quaternary megafauna declines in North America https://www.nature.com/articles/s41467-021-21201-8

Global late Quaternary megafura extinctions linked to humans, not climate change https://royalsocietypublishing.org/doi/10.1098/rspb.2013.3254

Humans arrivals wiped out the Caribbean's giant ground sloths https://www.newscientist.com/article/human-arrivals-wiped-caribbeans-giant-ground-sloths/

Arctodus (Short faced bear) http://www.prehistoric-wildlife.com/species/a/arctodus.html

How horses transformed life for plains Indians https://www.history.com/news/horses-plains-indians-native-americans

Scientists discover why the prehistoric Giant Beaver Castoroides went extinct https://allthatsinteresting.com/castoroides-giant-beaver

 

Extinction 37 - (13,000 years ago) Lake Missoula drainage

Lake Missoula and Lake Columbia were ancient Glacial Lakes that existed in North America in what it is now the states of Idaho, Washington and Oregon. The lakes got drained quite a few times (40 times minimum!) during the Pleistocene, due to the ice dams breaking down, causing these huge areas of North America to experience gigantic floods...right into the migration path of animals that were crossing the strait of Bering. How many megafauna, and humans, did those floods kill?

During such massive and rapid floods, all sediments were removed from the land, rendering the fields virtually sterile and depleted of nutrients, meaning that big areas of North America were constantly and repetitively not able to feed the animals that were around, putting pressure on the environment and on other areas that were more fertile, where all those herbivorous where probably cramping one of top of another. All of this, together with other conditions like an increase of arrival of Homo sapiens, may have contributed to the extinction of the megafauna in North America

 

 

 

References

A geologic catastrophe https://www.glaciallakemissoula.org/the-big-picture.html

Lake Missoula Floods https://digitalgeology.aws.cose.isu.edu/Digital_Geology_Idaho/Module13/mod13.htm

 

Extinction 38 - (12,000 years ago) The Younger Dryas

The late glacial interstadial (period of 'warm' weather) lasted from 12,670 to 10,890 BC....and yet, the Younger Dryas smashed right into it

The Younger Dryas was a period of abrupt and intense cold, when temperatures dropped suddenly as much as 10 degrees, just as the planet was about to exit the last Ice Age, that lasted approximately from 12,900 to 11,600, right in the middle of the Quaternary extinction and that's why I have fitted it into these two entries in my peculiar list of extinction events. Its name came from a flower called "Dryas", that grow on very cold conditions, and that in the sediments appear all over the Northern Hemisphere, indicating a period of cold conditions over there that lasted well over 1,000 years. What caused the Younger Dryas? The draining of Lake Agassiz perhaps? For temperatures to fluctuate so dramatically a significant event must have occurred

There is still an active scientific debate to determine the root cause of the Younger Dryas and its impact in the extinction of the Megafauna. Among some of the hypothesis are:

  1. Shutdown of the North Atlantic Conveyor; also known as Gulf Stream, caused by a mega-influx of fresh water from the glacial that were melting in North America. Yet, there is no clear evidence o cannons in the landscape as trillions of fresh water rushed into the oceans to cause this sudden event, perhaps it was a steady but constant flooding instead?
  2. Comet impact in Greenland; that will explain the so-called Younger Dryas Boundary (YDB) or black mat of sediments found in the fossil record. Yet, there is no clear evidence for an impact, the Hiawatha crater discovered in 2018 in northern Greenland is dated 58 Mya
  3. Comet impact over the ice sheet; another plausible theory is that the comet hit the massive ice sheet in North America, hence it left no crater behind it but instead melted a huge amount of water, that went into the Atlantic causing the shutdown of the conveyor belt
  4. Volcanic Eruption; the Laacher See super-volcano in Germany erupted 13,000 years ago, around the time the Younger Dryas started, and history tell us (just read this article from the beginning....) that we should never underestimated the volcanic power of our planet.

Personally, I believe it was option 3 and 4, a combination of the two, being the meteor possibly a fragmented comet that hit several parts of the globe, all on ice thus leaving no crater, which is normally what happens when extinction events occur: there is always more than one factor into place. The shutdown of the North Atlantic Conveyor Belt by a meteor impact on the ice will explain the black mat and the sudden amount of fresh water in the Atlantic. After all, the huge amount of water that was covering North America one mile high mush have gone somewhere. This sudden drop of temperatures was exacerbated by the nuclear winter that the Laacher See eruption created, thus initiating a positive feedback and leading to a dramatic cooling period that lasted over a thousand years. Once the Younger Dryas went to a close, the climate become warmer and drier, with temperatures raising as much as 10 degrees (in just a few decades!), raising sea levels and drastically changing habitats that, together with the Homo sapiens never-ending-killing-attitude, may have well pushed the remaining survivors of the Younger Dryas event into extinction

 

 

 

 

References

The Younger Dryas https://www.ncei.noaa.gov/sites/default/files/2021-11/3%20The%20Younger%20Dryas%20-FINAL%20NOV%20%281%29.pdf

Younger Dryas, the rest of the Story https://wattsupwiththat.com/2012/06/16/younger-dryas-the-rest-of-the-story/

The Younger Dryas impact https://cometresearchgroup.org/comets-diamonds-mammoths/

Eruption of the Laacher See volcano redated https://www.eurekalert.org/news-releases/839673

Evaluating the link between the sulfur-rich Laacher See volcanic eruption and the Younger Dryas climate anomaly https://cp.copernicus.org/articles/14/969/2018/

Massive crater under Greenland's ice points to climate-altering impact in the time of humans https://www.science.org/content/article/massive-crater-under-greenland-s-ice-points-climate-altering-impact-time-humans

Ancient flood brought Gulf Stream to a halt https://www.newscientist.com/article/dn13013-ancient-flood-brought-gulf-stream-to-a-halt/

Evaporation, not outflow, drained ancient Lake Agassiz during the Younger Dryas https://wattsupwiththat.com/2011/10/05/evaporation-not-outflow-drained-ancient-lake-agassiz-during-the-younger-dryas/

 

Extinction 39 - (11,000 years ago) Quaternary extinction, South America Megafauna disappearance

Megafauna is south America also got extinct, just as Homo sapiens entered that part of the continent, coincidence?

Having said all that, the Younger Dryas doesn't explain why Megafauna also vanished in South America, in other words, the and there are indications that humans did contribute to their extinction down there

Consider the Younger Dryas ending....temperatures rose as much as 10 degrees!!! How come all the water that melted did not create another shutdown of the conveyor?

 

 

References

What killed South America's Megamammals https://blogs.scientificamerican.com/laelaps/what-killed-south-america-s-megamammals/

 

Extinction 40 - (10,000 years ago) Quaternary extinction, Eurasia Megafauna disappearance

Though the Megafauna of North/South America and Euro-Asia or Eurasia were interconnected, I've decided it is best to have them in separate extinction events and different entries in my list of extinctions events. That really will help us analyse with more detail what really happened to the Megafauna in the Northern hemisphere. For example, you might argue that the activities of Homo sapiens pushed the Megafauna to extinction in North America, where the Clovis people where all over the place and its population were increasing, acquiring at the same time sophisticated killing techniques....but what about Siberia? Human population has never reached high quantities in Siberia to such an extend that it can put pressure on the environment, furthermore, humans arrived to Siberia around 30,000 years ago, earlier than in America, meaning that for about 20,000 they were living just fine with the Megafauna around there in Siberia, so why did Megafauna go extinct? Climate change?

Consider as well that Homo sapiens is an opportunistic animal: had it had the chance to live closer and longer with North American Horses it would have domesticated them, like it did with Eurasian Horses, rather than pushing them into extinction. Mammoths, with a gestation period of two years, and being big and slow, were much an easier target to hunt and wiped out that Horses, that have babies every 11 to 12 months, meaning their population can be replenish twice as fast as the Mammoths, so why did Horses went into extinction in North America but not in Eurasia?

 

 

 

References

The last woolly mammoths on Earth had disastrous DNA https://www.livescience.com/woolly-mammoth-genetic-problems.html

The human dimension https://www.theextinctions.com/articles-1/europe-part-2-the-human-dimension

Late Pleistocene World Map Exercise http://maxworldhistory.weebly.com/map-exercise.html

Late Pleistocene South American megafaunal extinctions associated with rise of Fishtail points and human population https://www.nature.com/articles/s41467-021-22506-4

 

Extinction 41 - (8,200 years ago) The sinking of Doggerland

It is around this time when the Holocene began, the expansion of the Homo sapiens around the planet, the only species left of homo, and immediately they were struck by disasters, in the form of flooding mostly. Homo sapiens love to settle is coastal areas, so it can take advantage and exploit marine resources as well as nearby inland resources, but of course that renders the settlement of Homo sapiens very expose to raising sea levels, a geological event very, very common on our planet as we have seen several times in our list of extinctions events

Doggerland was an area of dry land that existed during the ice age, at least 30,000 years ago until around this time, and that is now covered by the North sea. It was around this time that the Doggerland area began to get flooded and sunk, flooded by the increasing melting of the glacial as they planet was exiting the Ice Age, and sunken by a process called "isostatic rebound", in which the land that was covered by glacial experiment a re-bounce back when the are free of the huge weight of these glacial, causing the land that is nearby to actually sink, and Doggerland was close to the areas that previously were under stress by the ice sheet. This process can still be observed today in south of the British isles, where the land is sinking as opposite to the North, where the land is actually rising

Doggerland was a rich ecosystem area with multitude of rivers that would have make very attractive for animal and subsequentially human population. You may argue that the sinking of this fertile area does not constitute an extinction event, but we'll never know how many species, if any, of unique flora and animals were gone forever under the waters. The Storegga Slide, a gigantic landslide that happened in Norway around this time, may have caused a mega-tsunami that sunk the remaining parts of Doggerland (Dogger Hills) into the waters, perhaps echoing the sinking of Atlantis

 

 

 

References

Doggerland, the Europe that was https://www.nationalgeographic.org/maps/doggerland/

Archaeologists piece together ‘lost Atlantis’ from 200 extraordinary found objects https://thehill.com/changing-america/sustainability/environment/566123-archeologists-piece-together-lost-atlantis-from/

On Sunken Lands of the North Sea – lived the World’s greatest Civilisation http://prehistoric-britain.co.uk/on-sunken-lands-of-the-north-sea-lived-the-worlds-greatest-civilisation

 

Extinction 42 - (8,000 years ago) The flooding of the Persian Gulf basin

This is probably the flooding (paleoflood, or past floods) that has been mystified by ancient antiquity. This area of the Persian Gulf and the Arabian peninsula had been occupied by humans as early as 70,000 years ago

There was a time during the ice age that the Persian Gulf was actually dry land, and a very fertile one considering that both rivers Tigris and Euphrates irrigated this land from the North, plus two more other rivers (Karun and Wadi al-Batin rivers) came from the East and West, creating a lake a fresh water pretty close to the sea. This situation, and as the evidence of fossils suggest, may have attracted early humans populations to settle on this area. At the end of the ice age, sea levels were on average 120 meters below the current levels, but gradually as all the ice melted, the sea began to raise, and the Persian Gulf flooded

You may argue, okay, so what? This natural flooding as the sea level rise may have caused havoc to the early humans populations, quite possibly destroying the first cities built by Homo sapiens, but this shouldn't be on our list of extinction events, right? Well... I invoke the principle of framing effect in the umbrellas of cognitive biases of our brain, and claim that perhaps there was a unique species of orchids native to the Persian Gulf, and that disappeared forever beneath the waves of this flooding

 

 

 

References

Lost civilization may have existed beneath the Persian Gulf https://www.livescience.com/10340-lost-civilization-existed-beneath-persian-gulf.html

In search of green Arabia https://www.science.org/doi/10.1126/science.345.6200.994

 

Extinction 43 - (7,600 years ago) The Black Sea deluge

Another one of the many floods that have affected early humans population, as well and indigenous species and therefore qualifying as a mention in the list of extinction events, is the deluge of the Black Sea. Before that, probably it was known as Black Lake, a reservoir a fresh water created by the melting of glacial and fed by rivers like the Danube, the largest tributary, as well as the Dnieper, Southern Bug, Dniester and Don. As the sea levels rose, more water was pouring into the Mediterranean by the strait of Gibraltar, which in turn broke the strait of Dardanelles into the mini-Sea of Marmara, and from there created the strait of the Bosphorus and into flooding the Black Lake with a gigantic deluge that took at title as 30 years or so to inundate the Black Lake, raising the shoreline by well over 100 meters

Hydrogen sulphide ("rotten-egg" gas) pours from the Earth crust into the Black sea, depleting it from oxygen, and it is understood that the ancient Black Lake may have got oxygenated as it was in contact with the atmosphere, and probably was rich in marine life, but all that was gone when the deluge happened. The high salinity of the Mediterranean waters did not mix with the fresh water that slowly became saturated with hydrogen sulphide, meaning that from a depth to 100 meters to the very bottom of the Black Sea, roughly 2,000 meters, there is no oxygen and the waters are stagnated and anoxic, with very little bacteria surviving on that harsh environment

Organic matter, like the wood beans of ancient shipwrecks, can be preserved at the bottom of the Black Sea, meaning that this area could be a rich archaeological background frozen in time

I've read a lot about how this deluge may have impacted early human civilization, but obviously nobody care about the amount of flora and fauna that the transformation of the Black Lake into the Black Sea must have created, yep, in our list of extinction events, this is by far one of most neglected by biologists

 

 

 

References

Understanding the dynamics of the Oxic-Anoxic interface in the Black Sea https://agupubs.onlinelibrary.wiley.com/doi/pdfdirect/10.1002/2017GL076206

Could the formation of the Black Sea be responsible for near-Eastern flood myths: what does Geology say? https://www.theposthole.org/read/article/484

 

List of cosmic impacts, asteroids, comets and meteors, potentially linked to extinction events

In my personal list of extinction events, I'm entering this appendix just before I study the Holocene extinction section.  In this list of cosmic impacts, I'm only considering impacts that have a diameter bigger than 50 km, capable to creating long-lasting climate change effects that could lead to a global or localised extinction. And you may wonder, what is the difference between a meteor, a comet and an asteroid?

1) A meteor is a chunk of rock orbiting inside the inner solar system, a left over from the planetary formation, sizes range from a few centimetres to a few meters

2) A comet comes from the outer inner solar system, and are formed mostly of rock and water

3) An asteroid, the most dangerous of the three, comes normally form the Asteroid belt, and are composed of rock and heavy metals, remnants of the rich-iron core that the failed planet Asteroid-Belt would had been, had it not been for the presence of Jupiter and its massive gravitational pull

An impact are the echoes resounding in your dry throat when you see the electricity bill that has just arrived on the post

 

Impact & diameter Age Potentially related to
 1) Yarrabubba crater (70 km) 2.229 billion years ago  Extinction 2 Huronian Glaciation
 2) Vredefort crater (300 km) 2.023 billion years ago
 3) Sudbury basin crater (250 km) 1.849 billion years ago
 4) Beaverhead crater (100 km) 600 Mya  Extinction 3 Stuartian Glaciation
 5) Acraman crater (90 km)  580 Mya
 6) MAPICS crater (600 km) * 545 Mya  Extinction 4 End-Ediacaran
 7) Clearwater East Lake crater (26 km) 450 Mya  Extinction 8 Ordovician-Silurian
 8) Siljan Ring (52 km) 376 Mya  Extinction 12 Late Devonian
 9) Woodleigh crater (60 km) 364 Mya
 10) West & East Warburton basins (400 km)*  300 Mya*  Extinction 13 Carboniferous RC 
 11) Clearwater West Lake crater (36 km) 290 Mya
 12) Wilkes Land Crater (240 km)* 250 Mya*  Extinction 16 Great Permian
 13) Manicouagan Reservoir crater (70 km)  214 Mya  - no mayor effect -
 14) Morokweng crater (70 km)  145 Mya  Extinction 20 End-Jurassic
 15) Tookoonooka crater (60 Km)
 16) Kara crater (120 Km) 94 Mya  Extinction 22 Cenomanian-Turonian
 17) Chicxulub crater (180 Km) 66 Mya  Extinction 23 End Cretaceous
     
     
     

 

* = estimations or unconfirmed impacts

 

List of volcanic eruptions, flood basalt eruptions and Large Igneous Provinces (LIP), potentially linked to extinction events

This is also an appendix in our list of extinction events. 

 

 

Extinction 44 - (ongoing) predicted 80% of species lost: (6) Holocene Extinction

Yes, without any doubt, this is a proper entry in our list of extinction events: the Holocene extinction started a few centuries ago and still happening. Contrary to the disappearance of the Megafauna, on this occasion there is no doubt that human beings are the root cause for this extinction. Unlike any other animal, Homo sapiens has the unique tendency of modifying the environment to suit its needs, which inevitably leads to deforestation and change of habitats for many animals that are then pushed towards the black hole of extinction. If you doubt what I am saying....think about where you live...not long ago that area probably was a forest where many animals lived, all of them now retreated and outlawed as the Homo sapiens extent his lethal mantle of asphalt and concrete, suffocating the lands across the planet. Make no mistake: we are in the middle of a mass extinction event....happening right now

To comprehend the nature of Homo sapiens, let's make a quick list of some disasters that have strike the human race in recorded history:

1) Santorini caldera; the Minoan eruption of 1,600 BC (Before Christ) devastated the island of Thera (also called Santorini, in Greece) and may have set the clock back oh humankind development by wiping out the Minoan civilization

 1783.. the flood basalts eruption in Lucky, southern Iceland, could this have triggered (the gasses) the Little Ice Age?

Etna, 536 ad = https://www.youtube.com/watch?v=cKUz5Vjq9-s

 Krakatoa 1883

These events show that the Homo sapiens is not immune at all to natural disaster, neither to the changes that he himself is performing on our planet, and sooner or later he will be subject to the consequences of his actions

 

 

 

 

References

Caribbean Monk Seals declared extinct https://www.marinebio.org/caribbean-monk-seals-declared-extinct/

New Zealand's extinct giant bird killed like eagle, ate like condor http://www.sci-news.com/paleontology/haasts-eagle-10324.html

This Butterfly is the first US insect to be wiped out by humans https://www.smithsonianmag.com/smart-news/first-us-insect-be-wiped-out-humans-180978260/

 

Extinction Imminent

This entry in the list of extinction events, Extinction Imminent, looks at the animals that are in low numbers....and declining..... meaning that inevitable they will go extinct. I am a superb optimistic person, but also realistic, and looking at the past I have to admit that there is no chance these animals that are now in the brink of extinction will be able to survive into the future. No matter what great organisation like Greenpeace or nutters-reunited like Extinction Rebellion do, we all love our little commodities like for example running water, which implies the creating of metallic pipes, mining, digging and habitat destruction, and I haven't even mention for example the CO2 footprint and pollution that the clothes that you wear have generated. Al these have an implication in resources, and as long as the human population keeps growing, more and more animals will get extinct. It is just pure maths

Of course, it does matter what people of good-will are doing to preserve these animals, but unless they reach a "minimum viable population size", the DNA of these animals will degrade in the decades, centuries and millennia to come, leading to mutational meltdown, founder effect interbreeding diseases and inevitably...to extinction, and that is without considering climate change, alterations to habitats due to invasion of other species, change of diet, etc. Without the full restoration of their natural habitat, something impossible given the fact we Homo sapiens took over or is taking over the resources, the days of these animals on our planet are counted

All of these animals below are very likely to become extinct in the next few months or years, and I have not listed the most popular ones like Asian Elephants (40,000 left), Rhinos (27,000 left), Polar bears (26,000 left), Blue Whales (25,000 left), Panda bears (2,000 left), Mountain Gorillas (800 left), Amur Leopard (100 left), Homo sapiens (7,700,000,000,000 of us left)....oh sorry, my mistake, homos are fine, we are cool! Our population is actually increasing at a rate of 1% per year...

 

 

 

 

References

It's a Mistake to Focus Just on Animal Extinctions https://www.theatlantic.com/science/archive/2017/07/maybe-were-at-the-start-of-a-sixth-mass-extinction-after-all/533124/ 

Are snow leopards endangered? Poaching had led to the species' decline https://www.greenmatters.com/p/why-are-snow-leopards-endangered

Sea Otter https://defenders.org/wildlife/sea-otter

World's smallest porpoise,  the Vaquita, may be extinct by 2022 https://www.newscientist.com/article/2088521-worlds-smallest-porpoise-the-vaquita-may-be-extinct-by-2022/

Time's up: the five steps to prevent animal extinction https://ecobnb.com/blog/2021/02/steps-prevent-animal-extinction/

Endangered Asian 'unicorn' captured, first sighting in decade http://edition.cnn.com/2010/WORLD/asiapcf/09/17/laos.asian.unicorn.saola/index.html

A powerful documentary bring us the story of two men on a mission to learn more about the endangered Pangolin https://theincidentaltourist.com/documentary-african-pongolin/

 

Extinction Futura

Extinction Futura, in my personal list of extinction events, deals exclusively with the human race and the end of it. Our rate of grown, consumption of resources and implication in the climate are unsustainable. Eventually there would be catastrophes, either natural or hand-made induced, that will destroy our civilization, just like it happened in the past with whoever built the pyramids in the Giza plateau

Let's make here a distinction between what I understand of Homo sapiens and what Homo instagramar are

Without drastic measure to control human population density, consumption of resources and limits to prevent damage of environment

We should not accept extinction as inevitable....but we do: it is inevitable

 Bionic humans, they will be taller, gene control, DNA

 https://en.wikipedia.org/wiki/(29075)_1950_DA

https://www.jpost.com/science/apophis-what-you-should-know-about-the-asteroid-skimming-by-earth-in-2029-681657

https://www.vox.com/2014/9/5/6108169/yellowstone-supervolcano-eruption

https://space.nss.org/wp-content/uploads/2000-Report-Of-The-Task-Force-On-Potentially-Hazardous-Near-Earth-Objects-UK.pdf

 All extinction have been caused by Climate Change caused by Volcanism, Meteor impacts or Geo-ingeniering (oxygenation event)

 

 

Extinction Finale

In the list of extinction events, my last entry, Extinction Finale, is about the end of Life in our planet

All Life will eventually go extinct, it is just a matter of time

Our private nuclear reactor, the Sun, is burning steadily and it has a life expectancy of about 5 more billions years before it began to die out, unleashing outer layers of super-heated plasma which eventually will vaporise the rocky inner planets, Mercury, Venus, our planet Earth and also Mars. But the sun gets 10% hotter every billion years

 

 

 

 

 

Hall of Fame - Survivors

cockroaches were twice as big during the Carboniferous

https://fossil.fandom.com/wiki/Dicynodontia they survived the Permian

Wow, this was exhausting! Having listed so many dead species, I guess is only fair to grant a place too to the great survivors of all extinctions, so here we go a gallery from crocodiles to insects to stromatolities, the oldesst specieis living in our planet.....will they survive us too?

 https://www.youtube.com/watch?v=__Woo6L1bl0

 https://www.pinterest.com/pin/780107966691433719/

 

o produce a viable population of a previously extinct animal, genetic samples from many individuals would be needed to create genetic diversity in the cloned population.[14] This is a major obstacle to re-establishing an extinct species population through cloning. One solution could be to cross Celia's clones with males of another subspecies, although the offspring would not be pure Pyrenean ibex. A more ambitious plan would be to remove one X chromosome and add a Y chromosome from another still-existing subspecies, creating a male Pyrenean ibex, but such technology does not yet exist, and it is not known whether this will be feasible at all without irreparable damage to the cell

 

 If you are like me and like Astronomy, Palaeogeography, Palaeobotany,

 The end

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