How did living things come from non living things


so in the begining there were gases and stuff like hydrogn. overtime cuz of gravity they came together and made new stuff like oxygen. but all these were non living gases so how did things like FUBA or Ameba come from

In: 29

This is one of the big unanswered questions. Scientists are still researching it but getting an answer is going to be extremely difficult.

The tricky part of this question is defining what counts as life. Ultimately life is a process, it’s a collection of chemical reactions so life would occur when those reactions could happen. Which reactions happen under which circumstances is complicated.

But let’s say a living thing has two aims, to maintain itself and to copy itself. Then we can look at the points at which self replicating molecules were first stored in containers that protected them.

Thanks to chemistry we can see some molecules spontaneously arrange into spheres. For example if a molecule has an end that’s attracted to water and an end that’s repelled by water those molecules can group together with their hydrophobic ends at the centre of a sphere and their hydrophilic ends on the outside. Now you have a ball that can keep its insides in and its outsides out.

This ball is the perfect place for a self replicating molecule to self replicate without worrying about conditions changing too much.

So for starters let’s go back in time, around 3.8 billion years ago. Keep in mind what I am about to say hasn’t been experimentally proven but we will get to that soon enough.

At the 3.8 bya mark, things were weird. Earth wasn’t the beautiful paradise we live in. It had:

1. tiny bits of oxygen, O2
[the stuff we breathe]

2. Whole lot of Carbon dioxide, CO2
[the stuff plants use to photosythesise]

3. Whole lot of Nitrogen, N2
[The stuff that’s most of our present-day air content]

4. Little bits of–
Hydrogen (H2)

Hydrogen sulphide (H2S)
[that rotten egg smell]

Carbon Monoxide(CO)

[Incomplete burning of stuff like coal can release these, extremely deadly]

Now these are the basic gases that were there.

Now there was of course a hell lot of sunlight and lightning. (Energy sources)

So we have the gases and a source of energy!!

These combined and created organic molecules!! This is a huge deal as till here it’s been proven experimentally by Stanley Miller.

The next part comes in making these molecules grow and grow a hell lot. So here’s the tricky part. We need these molecules to combine and be macromolecules which is fine and dandy.

But they have to replicate themselves!

There is nucleic acid (stuff like your DNA) which does replicate on its own with a template strand (it’s like one strand of your DNA just makes a photocopy of itself)

But at that time DNA wasn’t the first nucleic acid. It was in reality RNA!

So now we have an unstable mutating nucleic acid that just desperately wants to divide and replicate.

So what is hypothesised is that it probably got wrapped in a phospholipid membrane and created a CELL.

(Imagine a filling wrap, where the filling is an RNA and it gets wrapped by Phospholipid)

What’s a phospholipid? It’s what makes up our cell membrane! It looks like a mutated sperm with a head (phosphate) and 2 tails (2 fatty acids)

RNA is like the ancestor of DNA in a sense. This RNA could replicate a ton and mutate a lot too cause it was way too reactive.

The reason why we have DNA for modern species is because it is a hell lot more stable and not unstable like RNA.

Cells divide because of the RNA. Metabolism arises.

What is metabolism? It’s like your food breaking down to give you strength!

Now remember that RNA is hella mutative and mutates rapidly.

Some work out for the cell to survive, and some don’t.

This trial and error keeps happening.

Slowly…like really really slowly they shift into prokaryotes.

What are prokaryotes? Simply put they are the older versions of our cells, with every organ in them just floating around without any membrane or anything in the cell.

Now some prokaryotes like photosynthesis! Like our nowadays plants they can make food too!!

The nucleic acid keeps mutating more and more.

Then we reach something like amoeba and stuff that you mentioned in the question.

Evolution happens, and organisms keep getting created! Complexity and body design become way more difficult to adapt to the harsh and ever-changing environment.

And hence life as we know today is formed.

To be noted that to date no cell has been created by recreating the early earth atmosphere.

I know it’s oversimplified and I skipped a lot of nuances but anyone please be free to add on and say where I might have gone wrong.

Firstly *we don’t know for sure* but there are some plausible steps for which we have varied levels of research.

It might also be worth bearing in mind that nonlife/life is a somewhat vague and arbitrary human designation and that living things are created from non-living all the time now though in ways that couldn’t happen back then.

But basically the organic compound building blocks of life are common in the universe , useful chemical reactions commonplace where there is energy and if you put these together you get more complex ingredients for something like RNA. At the same time we have fats that can naturally form ‘bubbles’ that can encase these things and begin to form the first proto cells and allow certain types of transmission across the barriers.

Purely as just a matter of interest I remember Prof Brian Cox saying that it seems like very basic cells happened relatively quickly once the conditions on Earth had calmed down a bit … it was the event of one ‘eating’ another and both surviving that then created the sort of complex cells we have now that took a long time.