The spark of Life

This article The spark of Life, the biggest mystery was originally an integral part of the parent article "Why are we here?", but given the fact the parent article was growing extremely huge, I decided for the sake of simplicity to have the section "The spark of Life" on a separate thread for simplicity and easy reading. See below the summary of the main article "Why are we here?" and the location of The spark of Life, in section 2 article 3. I recommend and encourage you to read all these articles in order (after all, they follow the chronological order of our creation) so that you get the whole picture of really why are we here

Section 1, our star the Sun, without it nothing will be possible

  1. The Primeval Atom
  2. The grapefruit fluctuations at quantum level
  3. The inflation period
  4. Floating in the magic of hydrogen
  5. The Helios nebula

Section 2, the perfect position of planet Earth in the Universe, and the chain of random accidents that caused your existence

  1. The kiss of planet Theia
  2. Diving into the origins of Water
  3. The spark of Life
  4. Jupiter, the Great Benefactor
  5. In the wrong side of the Congo

Section 3, the abstract of your thoughts and the illusion of control

  1. Ancient Civilizations, our roots
  2. Language and Mathematics, the building blocks of humankind
  3. Religion and believes, the intangible reality
  4. Our brains, the biggest mystery
  5. Conclusion

 

 

3. The spark of Life - 500 million years ago to 2 million years ago

In this chapter we'll try to understand how Life came about to materialise on our planet. We have now seen all the really bizarre (Theia's collision with all its variables?) and strange circumstances (a stable Sun, Jupiter to protect us, our planet position in the Habitable Zone?) that make our planet hospitable for Life.... let me just rephrase that: that make our planet "suitable" for Life, far away from hospitable as we'll see now: Life is indeed a chemical reaction with all the potential to annihilate itself

This chapter covers the span of our Earth from 500 million to 2 million years ago, but as we know Life emerged in our planet as far back as 3.5 billion years ago, fossilised bacteria found in Western Australia indicate that, though there is not yet a consensus by scientists in the specific times as to when Life really started, they all agree that it emerged pretty quickly after the formation of our planet. I want to explore in this chapter the jump needed for a chemical reaction to be alive, and then all the number of extinctions and ups and downs that Life has endured on this planet, in order to understand how come that we are here. So, yes, let's have another long cup of tea with this chapter!

We have already gone through the lots of variables, conditions and events that needed to have occurred in the past so that Life could even have a chance to exist. All of these variables do challenge the Laws of Probabilities. Are we a cosmic accident? What are the changes of all of these circumstances (Theia, the magnetic field, the Moon, the Late Heavy Bombardment, etc) happening on another planet? Would Life had evolved if one of these variables was altered? Of course not, all of these events are absolutely critical for the growth and flourish of Life on our planet. Let's say, if you remove the Magnetic Field (not enough nickel on the core could do it) then that's it: bye bye Life. Planet Earth will be flooded in deadly radiation from the Sun and break any DNA on the surface, no chance for complex bacteria to evolve into a forest for example. If you remove the LHB, then there won't be enough water and definitely not enough materials like Carbon or Zinc to kick start Life on the surface of planet Earth. Life indeed did emerge from non-living ingredients

We stick to the facts: the oldest fossils on Earth was found to be 3.5 billion years ago. Life must have started not long after Theia and the Late Heavy Bombardment, when the oceans must have just been formed and chemistry reactions had a chance to develop undisrupted. Life is nothing more than a chemical reaction involving Hydrogen, Oxygen, Carbon and Nitrogen, together with Sulphur and Phosphorus in what is called the 6 Building Blocks of Life or CNOHPS. Of all these elements (two of which we know compose water) Carbon is indeed the signature of Life and an absolutely essential ingredient of it. The presence of water does not necessary means Life, but for Life "as we know it" Carbon has to be there. That's right, when you hear the sentence "Life as we know it" that means Life carbon-based, which is the only type of Life that we know

Credit: Start of Life - abiogenesis hypothesis

 

As this wonderful video explains below, the key of Carbon life-based relies on its atomic structure. The fact is that, just like with the origins of water, nobody knows the root cause of the origins of Life: no one has a clue what caused Life to start, and how non-living materials became animated. Some people argue that absolutely everything is alive, and that the animated state is simple a transformation of the compounds, just like when water transforms from liquid to gas, in both stages it is water but only on one it can form clouds. Every living thing, after some time, become a non-living thing and so on, in a continuous regeneration of materials found on our beautiful planet Earth. Life is powered by normal chemical reactions, but how did all start?

 

 

Carbon shares some similarities with Oxygen, both materials are created by stars and yet both are also the ultimate Gods of Life, with Carbon regulating the temperature of the planet as C2O and Oxygen allowing the development of complex life forms. Carbon is a material very versatile, happy to form bounds and create structures like amino-acid, proteins and eventually DNA, and all these structures are supported by water, that carries nutrients and energy along the compounds. Now we need to put this into action: where did Life got started? Carbon and Water must have been there, but also some sort of energy to kick-start the chemical reaction. Nobody has a clue of how Life got started, of the jump between inorganic compound to organic molecules, but there are some theories that aim to pinpoint the location of where this could have happened:

  • It came from outer space; this theory claims that Life formed elsewhere and was delivered to Earth by asteroids. Okay.... where did that Life form then? On Mars? on Venus? All of them were subjected to the Late Heavy Bombardment, just like Earth, with the same probabilities of Life to at least get started. This theory argues that amino-acids landed in Earth, in meteorites big enough for them not be burned out completely when entering the thick atmosphere of CO2 and sulphuric acid that back then our Earth must have had. Comets diving into our oceans delivering organic compounds, and they surviving the extreme pressure of the impact, even in the oceans? Researches show that organic molecules not only survive, but they even use the energy of the impact to grow larger and form peptide, the building block of proteins. The LHB was a solar system party event, therefore Venus and Mars must have had them too. Still, this theory doesn't explain how Life started in the first place, did it really start in the vacuum of the space, bathed with radiation and with an average temperature close to absolute zero? Everybody knows that this is not possible, so if this theory only implies that Life was magically delivered to our planet, where did Life started, and why it did not originally started on our planet, which we know is the only place in the Universe so far able to support Life? To summarise, I think this theory doesn't hold itself at all
  • It came from inside Earth; methane gases, extreme pressure and certain amount of water are present in the Earth interior, and that could have been the right location where Life got started, away from the surface where the Late Heavy Bombardment would have made all but impossible for microorganism to transform to Life. Bacteria has been found deep inside Earth (South Africa mines) where they reproduce once every 1,000 years! I personally doubt Life started in Earth's crust given the fact that this environment has not change in billions of years, it could have been used as a refuge, not questions about that, but as the origin of Life? nah? Life likes easy things, like getting energy from the Sun, and only evolve if the surrounded are challenged. Methane is deep in every mine, why? it has been trapped from the atmosphere, they say, or does it originates from within the crust?
  • It came from the surface of the planet; meaning from hydrothermal pools exposed to the atmosphere. I find this very unlikely because there is no evidence of the magnetic field being formed until around the same time that Life formed, meaning that the surface was covered by Sun radiation which breaks down any carbon molecule trying to assemble. Furthermore, the Moon was still pretty close and the tidal forces on the earlier oceans must have been formidable, with water entering inland hundred of miles, distributing minerals, destroying mountains and flooding valleys. These massive waves would have destroyed any hydrothermal pond dared to exist close to the ocean, and instead these massive waves must have taken all minerals from land and bust them into the oceans. With the Moon still so close, gigantic earthquakes must have been a common event. There was to oxygen in the atmosphere yet, therefore no ozone layer existed capable of absorbing the ultraviolet light energy beams
  • It came from the bottom of the ocean; this could be it. Volcanic vents in ocean floors are the prime candidates for Life to have evolved. The bottom of the ocean is where the minerals that the tidal waves of the Moon were removing from the surface of the planet ended up, and this is also where from hundred on millions of years conditions could remain relatively the same, away from the surface where 500-miles hurricanes where still happening due to the proximity of the Moon. If this is where Life started....then many planets must have Life too. Minerals have chemical properties and we still need them to be alive, they are part of the equation that results in the origin of Life

Hydrothermal vents, did Life started here? Credit: Evidence of Hadean Eon Life

For a period of 3 billion years only single-cellular and colonies of these organisms populated the Earth. We are going to assume that Life formed first at the bottom of the ocean, I personally believe this is the most plausible option. Life does not change unless forced to, and here comes the change when after million of years the oceans where Life was were receding due to tectonic planets. Sunlight began to hit these organisms and they develop the real engine of Life: photosynthesis, they started to harvest the energy from the Sun rather than from volcanic vents, producing oxygen as a waste product in the way. But what about the radiation? If oxygen wasn't present in the atmosphere yet, there was no ozone layer (the ozone gas is created from oxygen when it interacts with ultraviolet light) and therefore the first organism developing photosynthesis would have been fried by the radiation of the Sun. How did that happened then? Photosynthesis developed under the sea, and the water itself must have been acting as a filter for radiation. Nothing was living in land until about 500 million years ago

To conclude, all creatures that have ever existed on Earth have the same LUCA (Last Universal Common Ancestor), a single bacteria, archaea or Eukaryota from where all other organism in the planet evolved, but nobody had the least remote idea of how did it happen, how all of the sudden there was a chemical reaction called Life where before there only was raw inorganic materials. Let's understand now how the planet behaves when it has Life, and let's investigate too how the planet "breathes" and regulates its temperature, because there is an equilibrium of which we really need to have a clear understanding. I've called this "breath" process of the planet the Greenhouse Effect Index (GFI) and I'm surprise the Science has not come out with this measurement before, considering that ALL the planets where we hope Life could evolve need to have a certain level of Greenhouse Effect Index to support Life; the initial GFI  that I've thought about goes something like this:

  1. Action GFI; the planet experience a volcanic eruption or is hit by a comet/asteroid, and that creates lots of CO2 in the atmosphere. The amount of gases expelled goes from Green (lots of CO2) to Amber (a lot more of CO2) to Red, with Red containing the most amount of greenhouse gases into the atmosphere, including methane
  2. Heat GFI; Earth is warm by the Sun, and the surface emits energy in the form of radiation that is absorbed by the greenhouse gases and water vapour (they vibrate), preventing this energy from escaping into the space and keeping the planet warm. When an Action-Red GFI occurs, the Earth reacts by creating a Heat-Red GEI that causes the planet to be extremely hot, with many gases -including methane- keeping the atmosphere warm. With a Heat-Red GFI condition in place, the planet reaches a positive loop, with more water vapour being evaporated and contributing more and more to a high level of Heat-Red GFI of the planet
  3. Cold GFI; if there are no greenhouses then all the heat that reaches the planet during the day will vanish into the space at night, with no gases able to maintain the planet warm. Snowball events are a prime example of this, with all the CO2 of the atmosphere removed by cyanobacteria, leaving them with basically nothing to breath but the waste and poisoned product that they produced called Oxygen
  4. The levels of O2 don't affect the temperature of the planet, otherwise during the Carboniferous, when the the oxygen levels were 50%, why didn't it trigger another Snowball event? The CO2 must be the one related to the temperature

 

It seems to me that the trigger to a high development of species occurred right after the Cryogenian Glaciation (Stuart-Varangian), also called Snowball Earth 2, 650 million years ago. Under the extreme pressure to survive that the cyanobacteria at the time would had found, when all the sudden the source of energy (the Sun) was seriously depleted, they began to ate one another, to develop multicellular organism to survive the predation rate and... invented sex as a means to reproduce rather than cloning themselves as they have been doing it till that glaciation. Early Earth was brutal for Life, and for about 3 billion years it was put on check by the environment... but we all know that Life if tough.. and it really is! There are micros discovered on ice crystal left by receding oceans hundred of million of years ago, that when heated up again came to life! They were just hibernating waiting for conditions to be good again to reproduce, how amazing is that? Life can survive millions of years frozen in salt. Life did work its way through, persisting and slowly changing the atmosphere and a complete geo-biotransformation the planet head to toe, pumping oxygen into the atmosphere and creating the first ever... ice! First ice ever since Theia's kiss. What happens thereafter is a roller-coaster and Life vs Extinction, random extinctions based in either external factors or by the composition of our atmosphere until finally (or at least for now) a fine-tuned equilibrium has been reached, but oh boy! It has been hard, and at any time disaster can strike again and push all Life against the cliff of extinction. No wonder that we have evolved to be so aggressive to one another, it is encoded on our genes after so many stressed times lived. We've been getting lucky so so so so so many times. We are here simply because we are lucky. We are at the end of a change of random events that could have played either way!

 

List of Extinction Events

I have finally removed this section and formed a separated article from it, it was growing at an inside rate so I thought it was best to treat this subject of Life versus Extinction on a totally separated link, to easy my logistic and research, and ultimately to facilitate the reading of this article:

 

Click here to read the section of "List of Extinction Events", such a great battle that is!

 

To be honest, it is important that you read this section, or at least have a look at it, in order to comprehend the scale of time that we are talking about and the incredibly huge number of creatures that have populated this planet, our Earth, home too to every single one of them. In our quest to find the answer of "Why are we here?" inevitable we also need to ask ourselves why were all these creatures here, and now all gone for good. Were they a temporarily bridge of evolution towards us? If so, it seems to me a very erratic and bumpy road to take! If for the contrary there were no other purpose in for example the existence of the dinosaurs, other than serve the cycle of the CO2 just like rocks also do, are we destined to have the same incongruence and futile fate?

 

 

Acid rain takes away carbon dioxide form the atmosphere and lock it in the ocean in the form of limestones, this process is called weathering. Open sea absorb sunlight, keeping the ocean warm, but when snowball happens ice start taking over the sea, and it was actually reflects sunlight thus cooling Earth even more. Single-cell bacteria were the only things that survived snowball Earth... how? Thermal-vents must have come to a rescue; extremophiles where also living inside glacial caves. Cyanobacteria are able to change their DNA structure under extreme conditions, you can for example dry them for hundred of years and then put water on them, after a few hours they're alive!

The Sun has been getting hotter as time passed by, given more energy for every sun-beam as the million of years were passing by. Photosynthesis is the gateway to Life as we know it, by far the most successful way of utilising energy, and it spread out all over the planet. Stromatolites are communities of bacteria that deposit limestone to form structures; stromatolites contains cyanobacteria, which have learnt to use the sunlight as their source of food and energy, splitting water molecules and freeing the O of H2O, creating oxygen as a by-product. That waste gas produce by cyanobacteria, oxygen, began to rust the oceans. Iron may have erupted from undersea volcanos, and all the iron was turn into iron ore and the whole of the oceans in the planet began to oxygenate due to photosynthesis. The Moon was receding, weather patters began to easy, days began to be longer, oxygen accumulated in the ocean jumped to the atmosphere, turning the reddish colour of the sky into a blue one, and that started a dance of Life vs Temperature vs level of O2+Co2 that still last today, with many extension occurring on our planet. We are all survivor on these extensions and they are key to understand the force that drove Life to evolve and for all entities to be so violent to certain degree and eat each other without compassion: we needed to live

Reverse of the magnetic field, what causes it? Is Life at risk in the middle of a reverse flux? Once every 200,000 years the flip occurs, and lots of radiation.  goes into the surface at that time. The Inner Core, hotter than the outer, is solid. Does the centre of the Earth function as a massive nuclear reactor? Do we have Uranium and Plutonium inside? Could Jupiter have them too? That gigantic planet generates twice as much radiation as it receives from the Sun. The Ort Cloud contains around 1 million comets, all on a very nestable orbit

 

References:

Precambrian https://www.britannica.com/science/Precambrian

Introduction to the Cyanobacteria https://ucmp.berkeley.edu/bacteria/cyanointro.html

The History of Life on Earth https://www.astro.indiana.edu/gsimonel/build/History_of_Life.pdf

Carbon Bonding https://www.britannica.com/science/chemical-compound/Carbon-bonding

What is Iron Ore https://geology.com/rocks/iron-ore.shtml 

Structure and Function of RNA https://courses.lumenlearning.com/microbiology/chapter/structure-and-function-of-rna/

Namibia: the stromatolites' last hurrah https://all-geo.org/highlyallochthonous/2007/06/namibia-the-stromatolites-last-hurrah/

The big five mass extinctions https://cosmosmagazine.com/palaeontology/big-five-extinctions

Welsh Cakes and Snotities https://www.sterling-adventures.co.uk/2009/01/14/welsh-cakes-and-snottites/

LUCA: Last Universal Common Ancestor https://earthhow.com/luca-last-universal-common-ancestor/

Ordovician-Silurian Mass Extinction: Causes, Evidence & Species https://study.com/academy/lesson/ordovician-silurian-mass-extinction-causes-evidence-species.html

New Theory for what caused Earth's Second-Largest mass extinction https://www.nationalgeographic.com/news/2015/09/15911-metals-extinction-ocean-oxygen-ordovician-silurian/ 

The Devonian extinction saw the oceans choke to death http://www.bbc.co.uk/earth/story/20150624-the-day-the-oceans-died 

Gorgonospia https://alchetron.com/Gorgonopsia 

Arsenic-Eating Bacteria Opens New Possibilities for Alien Life https://www.space.com/158-arsenic-eating-bacteria-opens-possibilities-alien-life.html

Protein Structure https://www.nature.com/scitable/topicpage/protein-structure-14122136/ 

A Climate Catastrophe paved the way for the Dinosaurs' Reign https://www.theatlantic.com/science/archive/2018/10/dinosaurs-dolomites/573286/ 

If CO2 if only 0.04% of the atmosphere, how does it drives global warming? https://blogs.ei.columbia.edu/2019/07/30/co2-drives-global-warming/ 

The secret of how Life on Earth began  http://www.bbc.com/earth/story/20161026-the-secret-of-how-life-on-earth-began

Origins of the building block for life https://www.sciencedirect.com/science/article/pii/S1674987117301305

Precise radiometric age establishes Yarrabubba, Western Australia, as Earth’s oldest recognised meteorite impact structure https://www.nature.com/articles/s41467-019-13985-7

Los diamantes que guardan el secreto del origen del planeta https://www.elmundo.es/ciencia-y-salud/ciencia/2019/08/15/5d5535d521efa0984e8b469a.html

 

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