Evolution: common ancestor?

[dysert]

If I'm not mistaken the ToE says that all life ultimately came from one common ancestor. Going back in time, what do you think was that common ancestor? Thanks.

 

[Dusty Bin]

Who knows?
If we never find out it will just mean that we never find out, but if you're desperate for an answer you can make one up,
oh yes I forgot, you already have.

 

[Dusty Bin]

If I'm not mistaken the ToE says that all life ultimately came from one common ancestor. Going back in time, what do you think was that common ancestor? Thanks.

For clarity, evolution started once life began, it had nothing to do with how live began.

 

[Armoured]

If I'm not mistaken the ToE says that all life ultimately came from one common ancestor. Going back in time, what do you think was that common ancestor? Thanks.

Google "last common ancestor" there's been an awful lot of work already done on this question.

 

[Armoured]

For clarity, evolution started once life began, it had nothing to do with how live began.

The last common ancestor wasn't necessarily the first life form.

 

[DogmaHunter]

If I'm not mistaken the ToE says that all life ultimately came from one common ancestor. Going back in time, what do you think was that common ancestor? Thanks.

As Armoured stated, the last common ancestor isn't necessarily the first "living" thing. For example, it could be that after the first billion years, something happened that killed everything except some sub-branch of the evolutionary tree of life. The ancestor of that branch would be the "last common ancestor", while this ancestor would actually have been the product of a billion years of evolution itself. (Speaking hypothetically, I don't know if there's any knowledge about this in the field and too lazy to look it up)

Having said that, first "life" was most likely some type of simple self-replicating molecule thingy. I also consider it quite unlikely that there was just one such molecule that kickstarted life.

If we assume that this molecule is the product of some chemical reaction, then I'ld expect this event to have produced more then just one of those things. They'ld all have been the same though (or at least extremely similar).

Once you have that, evolution kicks in.

 

[Sectio Aurea]

The last common ancestor wasn't necessarily the first life form.

All life (on earth) has decended genetically from the very first life form, which was probably a prokaryote, such as Cyanobacteria and bacteria.

 

[dysert]

Who knows?
If we never find out it will just mean that we never find out, but if you're desperate for an answer you can make one up,
oh yes I forgot, you already have.

I'm not desperate; I'm just curious what evolutionists believe was *the* common ancestor that kicked things off.

For clarity, evolution started once life began, it had nothing to do with how live began.

I realize that, but thanks for the clarification.

 

[dysert]

Google "last common ancestor" there's been an awful lot of work already done on this question.

I'm sure there's been a ton of speculation. For now, I'm just interested in the thoughts of the evolutionists in this forum so we can have a conversation.

The last common ancestor wasn't necessarily the first life form.

Now this is quite interesting. Would you please elaborate?

 

[DogmaHunter]

Now this is quite interesting. Would you please elaborate?

I did in my post

 

[SkyWriting]

If I'm not mistaken the ToE says that all life ultimately came from one common ancestor. Going back in time, what do you think was that common ancestor? Thanks.

An interesting fiction is that the planet was one very complex organism. This would explain increasing entropy leading up to man.

 

[lesliedellow]

The question presupposes that, at some point, there was a clear and unambiguous transition from non life to life. Probably there wasn't, and the exact moment of transition would be a bit fuzzy, even if we had the entire process available on video tape.

Before anybody else points it out, that video tape would be perhaps 500 million years long.

 

[Armoured]

All life (on earth) has decended genetically from the very first life form

Yes, but we're talking about the most recent common ancestor. Not the earliest.

 

[Armoured]

I'm sure there's been a ton of speculation. For now, I'm just interested in the thoughts of the evolutionists in this forum so we can have a conversation.

It was almost certainly a very simple prokaryote. What else would you like to discuss?

Now this is quite interesting. Would you please elaborate?

It's really not that complicated. The first life form had progeny which did not all survive. At some point, there was a "most recent common ancestor" organism of everything alive today, and yes that was a long time ago, and yes it was very simple. But there's no reason to assume that it was the first living organism.

 

[Resha Caner]

Having said that, first "life" was most likely some type of simple self-replicating molecule thingy. I also consider it quite unlikely that there was just one such molecule that kickstarted life.

If we assume that this molecule is the product of some chemical reaction, then I'ld expect this event to have produced more then just one of those things. They'ld all have been the same though (or at least extremely similar).

These are all very interesting statements. I'm curious if this is just intuition or if some research has been done on these points. While the common ancestor concepts are straight-forward enough, whenever I delve into the details I always leave wondering exactly what biologists can say on the matter.

 

[bhsmte]

.

 

[Dizredux]

I'm sure there's been a ton of speculation. For now, I'm just interested in the thoughts of the evolutionists in this forum so we can have a conversation.

Now this is quite interesting. Would you please elaborate?

It was probably not a single individual but more likely a surviving population as Armoured and DogmaHunter mentioned. With horizontal gene transfer it could have been a mix of more than one population. We just don't know yet.

Dizredux

 

[Shemjaza]

Well, since there are an abundance of single celled organisms alive today, and we'd assume that their ancestors weren't multi-celled, I guess that means the most recent common ancestor was also a single celled critter.

 

[Resha Caner]

It was probably not a single individual but more likely a surviving population as Armoured and DogmaHunter mentioned. With horizontal gene transfer it could have been a mix of more than one population. We just don't know yet.

And I believe some biologists have said they'll never know*, which is what makes this so confusing. If it was a population and not an individual, how much can really be said to be "common" and how is it a "universal" ancestor?

* I don't have the paper I was thinking of at my fingertips, but this reference mentions the issue in the "Outstanding questions" box.

http://www-bac.esi.umontreal.ca/~db...erts-horizontaux/HGT_genome_Olga_TIG_2004.pdf

 

[Resha Caner]

Well, since there are an abundance of single celled organisms alive today, and we'd assume that their ancestors weren't multi-celled, I guess that means the most recent common ancestor was also a single celled critter.

That would be a bad assumption. There are posited cases of multi-celled organisms producing single-celled organisms. See:

Alga takes first evolutionary leap to multicellularity - life - 06 November 2013 - New Scientist