How did life start?

[Kendodd]

This might actually be better placed in a science topic.

I understand about evolution but how did it all start? If you go back as far as you can go, back to the most basic of life forms, how did they spring to life?

As bacteria and single celled organisms I think. If you take water + sunshine = life

They've found bacterial remains on Mars I think.

Even before anything like a simple cell, there are likely to have been self-replicating chemicals. Are you aware of how DNA replicates itself? Unzipping the two halves, each half pulling in the matching pieces from its surroundings, then you end up with two coies of the original. If you picture even simpler versions of that, you have a "thing" that can replicate itself. Not quite life, but a starting point.

By its nature, it would become more common. Some copies of it might change slightly and develop new chemical properties. Different versions might combine together, eg to for a cell membrane and a central portion.

Then you get to very simple cells and work upwards in complexity from there!

I think there's a theory that it probably happened first in thermal vents - areas of the ocean with volcanic energy coming in, and complex sets of chemicals being formed.

Nobody is entirely sure although there are some very strong clues. It also depends on what you call "life". It seems likely that the first steps were the production of moderately complicated chemical compounds that could self-replicate. This isn't that big a stretch of the imagination as crystals self-replicate, clays can exhibit some quite complex self-organising structures and so on. And/or that simple proteins were formed from amino acids (amino acids are relatively easily formed from the basic chemical building blocks around at the time) and these clumped together.

That would then set up competition for resources at a very basic level, in the same way that one ice crystal growing sets up "competition" for water molecules against other ice crystals.

Whether any of this could be described as "life" is debatable. What seems likely, though, is that the factor of random mutation came in (again, at a very basic, chemical level) and that some of these random mutations made the molecules better at competing for resources and so they took over. Multiply that by a billion years and more complex chemistries built up that eventually resulted in cellular life.

There's a pretty good introduction to the subject on Wikipedia.

God spoke!

we don't know where the first life form came from, some say from another planet (via meteorite), but it's all theories based on guesswork from things ppl see as evidence of evolution, it even could be that there is a god and he just created everything.

personally i think someone dumped us on earth, but then where they dumped us from and how we originated? idk!
what do you think?

what MiNDTHEGAPPP said

So, I assume they have never been able to replicate or observe life spontaneously starting in a lab?

Do we have a 'science' topic?

MTG and mufti- is your god not alive? If they are, then life began before they spoke, did it not?

Kendodd no, not yet. They have observed the spontaneous formation of some of the building blocks such as amino acids and lipids in experiments that tried to replicate conditions on Earth umpty-billion years ago. The Miller-Urey Experiments are the most famous but there have been lots of others. I think there have also been some astronomical data that suggests that quite complex organic chemicals are present in interstellar dust and that could have rained down on the surface of the Earth.

But science has only really been looking at abiogenesis in a number of individual labs, for the last forty or fifty years. By contrast, real abiogenesis happened in a "laboratory" the size of a planet over hundreds of millions of years. That we haven't yet managed to replicate the entire process is hardly surprising.

It depends what you mean by life, but there have certainly been experiments which show organic compounds being created from inorganic ones - Miller-Urey experiment - and people have tried to recreate conditions to allow protein, RNA or DNA to be created, but since nobody is entirely sure what the conditions were, it's not too surprising they haven't hit the right combination yet - Origin of life

Life certainly doesn't keep spontaneously starting, under ordinary conditions on Earth nowadays, because the conditions are nothing like what existed when life began. All life that we know of on Earth works in the same basic ways - I don't think there's any reason to think it was "common" for life to start, even back when it did. We all have the same basic processes, all coming probably from one common ancestor.

"Life certainly doesn't keep spontaneously starting"

That is quite probably correct.

On the other hand, imagine that the occasional, spontaneous generation of a living organism does still happen. Any brand-new life being formed today will immediately find itself in competition with every other form of existing life. And every other form of existing life has had millions and millions of years of evolution to hone them into highly specialised and phenomenally effective competitors. Any new life that's starting from scratch is going to find it pretty much impossible to get anywhere.

That we all have the same basic chemical processes isn't necessarily confirmation that the original lifeform we evolved from was the only one either. We may have all simply evolved from the most capable one that wiped out everything else.

What a good thread for a Sunday night