Tree of Life: What Creature Was at the Fork?

[rush1169]

Exactly the same, except I usually have time passing to the right, so when I made it I meant that we are C, B is the last to produce gametes compatible with us and C is last to produce gametes compatible with B.

My mistake.

I'm talking about this:

C=Human Gamete
B=First to produce C compatible
A=B's older sibling, not compatible with C

*Note: B's older sibling A is not compatible with C. A is not a 500K year distant relative. That is why I asked:

B was born with a mutation in it's DNA such that it's gamete has become C-compatible. It is a DNA arrangement that when mated with C will produce a fertile, viable offspring. The B's DNA arrangement is also A-compatible. It is a DNA arrangement that when mated with A will produce a fertile, viable offspring. Yet, even though B can make a baby with either A or C, C and A cannot produce a baby. But doesn't there need to be a 'perfect matching' between gametes to produce a fertile, viable offspring?

In other words, how could B mate with a sibling or a human, but B's sibling could not mate with a human?

 

[CabVet]

In other words, how could B mate with a sibling or a human, but B's sibling could not mate with a human?

Where did these siblings come from? If B was able to mate with humans, it is likely that it's entire generation (including all of it's siblings) could.

 

[rush1169]

Where did these siblings come from? If B was able to mate with humans, it is likely that it's entire generation (including all of it's siblings) could.

Siblings and/or peers would be present when the birth of the first creature that was sexually compatible with humans appeared. If the entire population could mate with humans, then you've not gone back far enough.

 

[mzungu]

Siblings and/or peers would be present when the birth of the first creature that was sexually compatible with humans appeared. If the entire population could mate with humans, then you've not gone back far enough.

When you find your Adam and Eve let us know

 

[CabVet]

Siblings and/or peers would be present when the birth of the first creature that was sexually compatible with humans appeared. If the entire population could mate with humans, then you've not gone back far enough.

Ok, I will play, there was one pair who had one offspring that was genetically compatible with the entire human race 500,000 years ago (let's call this man "Adam"). That particular mutation did not make him incompatible with their siblings/peers, but made him compatible with present-day humans and only those carrying this mutation were able to mate with present day humans.

However, because X chromosomes evolve separately from Y chromosomes, it is extremely unlikely that the one female ancestor of the entire human race lived at the same time as this man.

 

[Loudmouth]

@CabVet - This is what I don't understand. If you take a human gamete from today, let's call it's compatibility 'A', back in time to the first creature born that can successfully mate with 'A', then that distant ancestor must produce an 'A' gamete also. It's parents and peers do not produce an 'A' compatible gamete, so we'll call their gamete 'B' compatible.

And there is the false dichotomy. This is where you keep tripping yourself up.

You have A, B, and C. A is modern humans, B is you "first producer", and C is a generation prior to B. A is not B. B is compatible with both A and C, but that does not make B into A or C.

 

[rush1169]

Ok, I will play, there was one pair who had one offspring that was genetically compatible with the entire human race 500,000 years ago (let's call this man "Adam"). That particular mutation did not make him incompatible with their siblings/peers, but made him compatible with present-day humans and only those carrying this mutation were able to mate with present day humans.

However, because X chromosomes evolve separately from Y chromosomes, it is extremely unlikely that the one female ancestor of the entire human race lived at the same time as this man.

Yeah, that's what it seems to me too. There had to be a first human-compatible gamete producer. I'm not sure why so many disagree with that idea. We are heavily outnumbered

PS - When you said "OK, I will play. . ." does that mean you don't think there was a first human?

 

[CabVet]

Yeah, that's what it seems to me too. There had to be a first human-compatible gamete producer. I'm not sure why so many disagree with that idea. We are heavily outnumbered

I don't think that we are outnumbered. I think we all agree here, as long as you don't want to call that first person "Adam" or "Eve".

 

[rush1169]

I don't think that we are outnumbered. I think we all agree here, as long as you don't want to call that first person "Adam" or "Eve".

Oh, that was that other poster (mzunga) - He'd pop in and bring up Adam and then leave. But yeah, just go back and read the thread. You are the first person to agree (if you actually do agree, in a previous post you said "OK, I'll play. . ." which kinda makes me think you don't really).

 

[Loudmouth]

Yeah, that's what it seems to me too. There had to be a first human-compatible gamete producer. I'm not sure why so many disagree with that idea. We are heavily outnumbered

I highly doubt there would have been a "first one" since that would have been impossible to really test. There could have even been a situation where one person was compatible, none of their children were compatible, but one of their grandchildren were compatible. Compatiblity could have jumped generations.

You are also trying to prove a negative. How many attempted fertilizations do you have to do in order to prove compatibility? How many people do you test, both modern and ancestral? I would think that your n number needs to approach infinity in order to make the conclusions you want to make.

 

[CabVet]

Oh, that was that other poster (mzunga) - He'd pop in and bring up Adam and then leave. But yeah, just go back and read the thread. You are the first person to agree (if you actually do agree, in a previous post you said "OK, I'll play. . ." which kinda makes me think you don't really).

Yes, I do agree that at some point in the past there was one (and only one) person that was fully genetically compatible with all humans alive today. I also know that this person did not live at the same time as the opposite sex earliest fully compatible person.

I don't think this observation in any way shape or form supports any religious narrative.

 

[rush1169]

Yes, I do agree that at some point in the past there was one (and only one) person that was fully genetically compatible with all humans alive today. I also know that this person did not live at the same time as the opposite sex earliest fully compatible person.

Yeah, for the first opposite sex compatible person to be born with the same mutation as the original, while the original was still alive, would be quite a coincidence. I would like to talk more about this first human gamete producer, maybe early next week?

I don't think this observation in any way shape or form supports any religious narrative.

I think it's only mzunga who wants to bring religion into the discussion.

 

[CabVet]

Yeah, for the first opposite sex compatible person to be born with the same mutation as the original, while the original was still alive, would be quite a coincidence.

 

[mzungu]

Oh, that was that other poster (mzunga) - He'd pop in and bring up Adam and then leave. But yeah, just go back and read the thread. You are the first person to agree (if you actually do agree, in a previous post you said "OK, I'll play. . ." which kinda makes me think you don't really).

I have asked you to explain what your intentions are regarding your questions. Your insistence on a first human can only lead me to believe that you are after Adam and Eve. All you have to do is explain why you ask and insist on your first human concept. You have not answered to this my question and have basically ignored me. Besides since this is a creationism vs evolution section of CF then suffice it to say my suspicions are well founded.

 

[Kylie]

Okay, let me try this again...

Let's say that we have an animal which lives for a year. They are all born at the same time, they all breed at the same time, and they all lay eggs at the same time. As soon as they lay the eggs, they all die. Shortly afterwards, the eggs hatch and form the next generation.

Let's look at one particular generation. We'll call it Generation X. Generation X is the product of a long period of evolution, going back countless generations. And this population will continue to evolve in the future.

So Generation X will produce Gen X+1 next year. And the year after that, it will be Gen X+2. Then Gen X+3. And so on.

Likewise, before now we had Gen X-1 and Gen X-2.

So if you could look at the whole chain of generations, it would look like this:

... Gen X-100, Gen X-99, Gen X-98 ... Gen X-2, Gen X-1, Gen X, Gen X+1, Gen X+2 ... Gen X+98, Gen X+99, Gen X+100 ...

Now, let's say that you have sex cells (gametes, such as sperm or eggs) from each of these generations. You can bring them together and see what happens.

You find that if you take a sperm and an egg from the same generation, then they have a 100% chance of becoming fertilised. So, if you take a Gen X-57 sperm and a Gen X-57 egg, then they are guaranteed to become fertilised. Likewise if you took them from Gen X+22, or Gen X-71.

But, each generation you move away reduces the chances of fertilisation by 1%. So while you have a 100% chance that a sperm from Gen X+48 will fertalise an egg from Gen X+48, that same sperm will only have a 99% chance of fertilising an egg from Gen X+49. So, if you take 100 sperms from Gen X+48 and inject them into 100 eggs from Gen X+49, 99 of those eggs will become fertilised, but one of them will not fertilise.

And the further you get away, the lower the chances of fertilisation. So if you took a sperm from Gen X, then it will have only a 50% chance of fertilising an egg from Gen X-50. It will also only have a 50% of fertilising an egg from Gen X+50.

So we know that Gen X can interbreed with both Gen X-50 and Gen X+50.

But what are the chances that a sperm from Gen X-50 could fertilise an egg from Gen X+50? With this many generations separating them, the chance has reduced to 0%. The changes that evolve in each generation have, over these 101 generations, caused so much change that the two generations cannot interbreed. They have become different species.

Do you understand this?

 

[rush1169]

Yes, I do agree that at some point in the past there was one (and only one) person that was fully genetically compatible with all humans alive today. I also know that this person did not live at the same time as the opposite sex earliest fully compatible person.

I don't think this observation in any way shape or form supports any religious narrative.

One's worldview should not come into play with the logical deduction that there had to be a first fully genetically compatible with humans creature born at some point in the past. Why do you think the majority of posters in this thread, as well as prominent atheists, arrive at a different conclusion?

 

[CabVet]

One's worldview should not come into play with the logical deduction that there had to be a first fully genetically compatible with humans creature born at some point in the past. Why do you think the majority of posters in this thread, as well as prominent atheists, arrive at a different conclusion?

They don't.

 

[rush1169]

One's worldview should not come into play with the logical deduction that there had to be a first fully genetically compatible with humans creature born at some point in the past. Why do you think the majority of posters in this thread, as well as prominent atheists, arrive at a different conclusion?

They don't.

Well crud. Two hundred posts of what appeared to be disagreement was actually agreement. Go figure. OK, so I misunderstood.

When that first individual was born that was sexually compatible with humans, given the infinite gradations between species, would it be appropriate in layman terms to call that individual the first human? Would it be scientifically appropriate?

 

[Loudmouth]

One's worldview should not come into play with the logical deduction that there had to be a first fully genetically compatible with humans creature born at some point in the past. Why do you think the majority of posters in this thread, as well as prominent atheists, arrive at a different conclusion?

The conclusion we are disagreeing with is that this first compatible individual could not have come from incompatible parents.

 

[rush1169]

The conclusion we are disagreeing with is that this first compatible individual could not have come from incompatible parents.

I think I know what you are saying, but for clarity see if I rewrite what you said correctly:

The conclusion we are disagreeing with is that the first human compatible individual could not have come from human incompatible parents.