Tree of Life: What Creature Was at the Fork?

[CabVet]

No it would not! You have not defined at what percentage success rate that copulation will result in a fertile offspring!

You are still making the same mistake. By your logic then a human will be traced all the way back to the single celled ancestor because every generation is compatible with the next and previous generation.

What is your point? I know you are avoiding me but I ask in earnest!

I am also missing his point, but his question to me was clear, how far back can present humans mate? I think it would be about half a million years.

 

[mzungu]

I am also missing his point, but his question to me was clear, how far back can present humans mate? I think it would be about half a million years.

And my question is; at what success rate? He is trying to find a single individual (Adam) and there was no single individual. Evolution does not work that way.

He is totally missing the point where every generation is compatible with the next and previous generation. So even if you went far enough where compatibility even at 1% you will still find the next non compatible generation being compatible with the last compatible (next) and the previous one.

Can't you see he is trying to fit Adam and Eve into the formula?

 

[CabVet]

Can't you see he is trying to fit Adam and Eve into the formula?

Oh, so he is trying to shoehorn Genesis into what we actually observe, interesting...

 

[mzungu]

Oh, so he is trying to shoehorn Genesis into what we actually observe, interesting...

Yes; this I suspect very much! He is still on the asking stage. The next stage, if he gets the answer he wants; mainly that there was a first couple who are mankind's ancestors, is to openly claim that science supports genesis.

I have seen this all too often.

 

[Loudmouth]

I am also missing his point, but his question to me was clear, how far back can present humans mate? I think it would be about half a million years.

The question and answer are clear. The problem is that the answer includes a continuum of fertility, and rush1169 is trying to change this continuum into a dichotomous set of humans and non-humans.

 

[CabVet]

The question and answer are clear. The problem is that the answer includes a continuum of fertility, and rush1169 is trying to change this continuum into a dichotomous set of humans and non-humans.

Drawing an arbitrary line in speciation never works, neither in time nor in space.

 

[Loudmouth]

Drawing an arbitrary line in speciation never works, neither in time nor in space.

Exactly. It appeared to me that Rush's main push was to show that if there were a person who was compatible then they could not have come from a generation that was incompatible since they would have no one to mate with. Therefore, evolution is false.

 

[CabVet]

Exactly. It appeared to me that Rush's main push was to show that if there were a person who was compatible then they could not have come from a generation that was incompatible since they would have no one to mate with. Therefore, evolution is false.

Well, this hypothetical "Adam" 500,000 years ago would be compatible with everyone going back another 500,000 years at least.

 

[rush1169]

@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.

'A' is human compatible.
'B' is not human compatible.

That first exhibitor of 'A' must also be compatible with 'B'. That first exhibitor of 'A' could procreate with a human gamete 'A' and a non-human compatible 'B' producer. How does that work? It seems to me that if that first was human compatible (A) and peer compatible (B), then it's peers would also be human compatible. Since that's not true, then the first producer of human compatible (A) would need to produce a mixture of both A and B gametes, but that doesn't sound correct, but maybe? What is your 'take'?

 

[CabVet]

@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.

'A' is human compatible.
'B' is not human compatible.

That first exhibitor of 'A' must also be compatible with 'B'. That first exhibitor of 'A' could procreate with a human gamete 'A' and a non-human compatible 'B' producer. How does that work? It seems to me that if that first was human compatible (A) and peer compatible (B), then it's peers would also be human compatible. Since that's not true, then the first producer of human compatible (A) would need to produce a mixture of both A and B gametes, but that doesn't sound correct, but maybe? What is your 'take'?

There are mutations in every generation. Your gametes today are not 100% identical to your father's gametes. They are compatible because they are close "enough". So, let's draw an arbitrary yardstick (and please bear with me here, those numbers are completely fictitious and simplified for easy math):

Imagine that in every generation we are 1% different from our parents. Now imagine that the yardstick is 80%, so after 20 generations you will not be compatible with your parents. But if you look at it from your parent's perspective, they will be compatible with the 20 future and 20 previous generations.

So, following your reasoning, think of it in terms of A (ancestor), B (Adam), C (humans). In this case A would be compatible with B, B would be compatible with C, but C would not be compatible with A.

 

[mzungu]

@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.

'A' is human compatible.
'B' is not human compatible.

That first exhibitor of 'A' must also be compatible with 'B'. That first exhibitor of 'A' could procreate with a human gamete 'A' and a non-human compatible 'B' producer. How does that work? It seems to me that if that first was human compatible (A) and peer compatible (B), then it's peers would also be human compatible. Since that's not true, then the first producer of human compatible (A) would need to produce a mixture of both A and B gametes, but that doesn't sound correct, but maybe? What is your 'take'?

Still beating the dead horse Rush?

 

[rush1169]

There are mutations in every generation. Your gametes today are not 100% identical to your father's gametes. They are compatible because they are close "enough". So, let's draw an arbitrary yardstick (and please bear with me here, those numbers are completely fictitious and simplified for easy math):

Imagine that in every generation we are 1% different from our parents. Now imagine that the yardstick is 80%, so after 20 generations you will not be compatible with your parents. But if you look at it from your parent's perspective, they will be compatible with the 20 future and 20 previous generations.

So, following your reasoning, think of it in terms of A (ancestor), B (Adam), C (humans). In this case A would be compatible with B, B would be compatible with C, but C would not be compatible with A.

Because zygote formation and subsequent fertile, viable offspring seems highly dependent on a specific 'matching up' of two gametes. How is it that A+B are specific enough, B+C are specific enough, but A+C result in failure?

 

[CabVet]

Because zygote formation and subsequent fertile, viable offspring seems highly dependent on a specific 'matching up' of two gametes. How is it that A+B are specific enough, B+C are specific enough, but A+C result in failure?

You didn't read my post, did you? It is all about percent difference. I will try to make this simpler, imagine that humans can only mate with other humans that are 1 foot taller and 1 foot shorter than themselves. A person that is 5 foot tall can mate with people that are 4 foot tall and people that are 6 foot tall, but a person that is 6 foot tall cannot mate with a person that is 4 foot tall. Do you get it now?

If I can mate with someone that is 2% different than me, I will be able to mate going back to those 2% (or 500,000 years). If someone 500,000 years ago can mate with people that are 2% different, they will be able to mate with people 500,000 years ahead and 500,000 years before them. 500,000 in the future, I will be able to mate with my descendants, but my ancestors from 500,000 years ago will not because they will be 4% different.

I don't know how I can make this anymore clear.

 

[[serious]]

So if one were to take a human gamete back in time and test it for it's ability to produce an offspring, one would never find it not compatible or always find it compatible clear back to the very single celled life?

All would be compatible to their immediate predecessors. Take a look at ring species. Each population can breed with neighboring islands with no issues. That's true end to end. But if you skip those and just compare the two most separated islands, you don't get compatibility.

 

[rush1169]

You didn't read my post, did you? It is all about percent difference. I will try to make this simpler, imagine that humans can only mate with other humans that are 1 foot taller and 1 foot shorter than themselves. A person that is 5 foot tall can mate with people that are 4 foot tall and people that are 6 foot tall, but a person that is 6 foot tall cannot mate with a person that is 4 foot tall. Do you get it now?

I read your post, I'm trying to understand it in terms of gamete compatibility. Retaining your A, B, and C labels:

B was born with a mutation in it's DNA such that it's gamete has become A-compatible. It is a DNA arrangement that when mated with A will produce a fertile, viable offspring. The B's DNA arrangement is also C-compatible. It is a DNA arrangement that when mated with C 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?

 

[CabVet]

I read your post, I'm trying to understand it in terms of gamete compatibility. Retaining your A, B, and C labels:

B was born with a mutation in it's DNA such that it's gamete has become A-compatible. It is a DNA arrangement that when mated with A will produce a fertile, viable offspring. The B's DNA arrangement is also C-compatible. It is a DNA arrangement that when mated with C 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?

Genetic distance accumulates with time, therefore:

---------------------------TIME-------------------------------
-------------------Genetic distance--------------------------

A------2% difference------B--------2% difference--------C

A is 2% different from B therefore they can mate
B is 2% different from C therefore they can mate
A is 4% different from C therefore they cannot mate

 

[rush1169]

Genetic distance accumulates with time, therefore:

---------------------------TIME-------------------------------
-------------------Genetic distance--------------------------

A------2% difference------B--------2% difference--------C

A is 2% different from B therefore they can mate
B is 2% different from C therefore they can mate
A is 4% different from C therefore they cannot mate

But there is zero time between B and C.

 

[CabVet]

But there is zero time between B and C.

No, there is 500,000 years between B and C, and 500,000 years between A and B.

We are C, B is the last ancestor that could mate with us, A is the last ancestor that could mate with B.

 

[rush1169]

No, there is 500,000 years between B and C, and 500,000 years between A and B.

Oh, I guess we are talking about two different things.

I'm talking about this:

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

 

[CabVet]

Oh, I guess we are talking about two different things.

I'm talking about this:

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

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.