Tree of Life: What Creature Was at the Fork?

rush1169 · Dec 30, 2013

KTS said:
Think of it as a hole in one. If I hit the golf ball, what are the odds of it going straight into the cup? Probably pretty small. But that's starting from the tee (golf aficionados, please forgive my no doubt incorrect use of the terminology!).

But let's say I move closer to the hole. Now, I have an improved chance of getting a hole in one, don't I? It may still be a small chance, but it has nonetheless improved. Let's say I keep moving closer and closer to the hole. As I get closer, my chances of making a hole in one keep getting better. And when the ball is sitting on the edge of the hole, my chances of getting a hole in one are just about certain.

And yet, the hole in one is ALWAYS going to be a yes/no option. Either I get a hole in one or I don't. But the chances of getting it keep increasing. My potential for achieving the hole in one increases as I get closer. There's no magical distance where I have a 0% potential of a hole in one and then an extra step gives me a 100% potential for a hole in one.

If I am at a point where I have a 50% potential for a hole in one, I'll find that I generally get holes in one half the time, but the other half of the time I miss and the ball doesn't go in.

Likewise, the genetic compatibility is different over two individuals separated by many generations. The fewer generations between the two individuals, the greater the chance of genetic compatibility, even though the production of a fertile offspring is a yes or no thing.

Do you understand the golf analogy?

Of course I understand the golf analogy.

My question is: When the first individual was born that produces gametes that can produce a fertile, viable offspring with human gametes how can a fertile, viable offspring birth be expressed as a percentage other than 0% (no fertile, viable offspring) or 100% (a fertile, viable offspring)?

Your answer: Just like the percent chance of making a hole-in-one in golf.

The percent chance of making a hole-in-one is analogous to the percent chance of two gametes finding each other, producing a zygote, and resulting in a fertile, viable offspring. We've already covered this ground and you're right, when two individuals that produce compatible gametes have sex there are many things that reduce chance of producing a fertile, viable offspring.

What I'm talking about is much more specific. We've established that a first individual that produces human compatible gametes was birthed. How can gamete compatibility be expressed as a percentage of compatibility when the only two possible outcomes of a gamete union is a fertile, viable offspring or anything but? The answer can only be 100% or 0%. The two gametes either produce a fertile, viable offspring or they do not. It's nonsensical to say two gametes can produce a 32% fertile, viable offspring.

When that first individual was birthed it produced 100% human compatible gametes AND 100% compatible gametes with it's contemporaries. It's contemporaries produced 0% compatible gametes with humans. It follows that there was an individual born that produced two different gametes.

mzungu · Dec 31, 2013

rush1169 said:
Of course I understand the golf analogy.

My question is: When the first individual was born that produces gametes that can produce a fertile, viable offspring with human gametes how can a fertile, viable offspring birth be expressed as a percentage other than 0% (no fertile, viable offspring) or 100% (a fertile, viable offspring)?

Your answer: Just like the percent chance of making a hole-in-one in golf.

The percent chance of making a hole-in-one is analogous to the percent chance of two gametes finding each other, producing a zygote, and resulting in a fertile, viable offspring. We've already covered this ground and you're right, when two individuals that produce compatible gametes have sex there are many things that reduce chance of producing a fertile, viable offspring.

What I'm talking about is much more specific. We've established that a first individual that produces human compatible gametes was birthed. How can gamete compatibility be expressed as a percentage of compatibility when the only two possible outcomes of a gamete union is a fertile, viable offspring or anything but? The answer can only be 100% or 0%. The two gametes either produce a fertile, viable offspring or they do not. It's nonsensical to say two gametes can produce a 32% fertile, viable offspring.

When that first individual was birthed it produced 100% human compatible gametes AND 100% compatible gametes with it's contemporaries. It's contemporaries produced 0% compatible gametes with humans. It follows that there was an individual born that produced two different gametes.

OK! For argument's sake; let us assume that we have your "first" human! Is there a point you are trying to make? Personally I believe you are trying to include genesis into ToE. I am sincerely curious!

Kylie · Dec 31, 2013

rush1169 said:
Of course I understand the golf analogy.

My question is: When the first individual was born that produces gametes that can produce a fertile, viable offspring with human gametes how can a fertile, viable offspring birth be expressed as a percentage other than 0% (no fertile, viable offspring) or 100% (a fertile, viable offspring)?

Your answer: Just like the percent chance of making a hole-in-one in golf.

The percent chance of making a hole-in-one is analogous to the percent chance of two gametes finding each other, producing a zygote, and resulting in a fertile, viable offspring. We've already covered this ground and you're right, when two individuals that produce compatible gametes have sex there are many things that reduce chance of producing a fertile, viable offspring.

What I'm talking about is much more specific. We've established that a first individual that produces human compatible gametes was birthed. How can gamete compatibility be expressed as a percentage of compatibility when the only two possible outcomes of a gamete union is a fertile, viable offspring or anything but? The answer can only be 100% or 0%. The two gametes either produce a fertile, viable offspring or they do not. It's nonsensical to say two gametes can produce a 32% fertile, viable offspring.

When that first individual was birthed it produced 100% human compatible gametes AND 100% compatible gametes with it's contemporaries. It's contemporaries produced 0% compatible gametes with humans. It follows that there was an individual born that produced two different gametes.

You are looking at individual acts of sex. Of course a single act of sex will either produce a viable offspring or not. It is either 0% or 100%.

But we're talking about a generation here. Let's say that there is a breeding season in our population of hypothetical animals. They all give birth in January. Each year is a new generation. They are born in January, and by the time they get to November, they are able to reproduce. The pregnancy lasts through December and the new generation is born in January again.

Now, in the breeding season, MANY acts of sex take place. Not all of these acts produce offspring. Maybe some males have poor sperm. Maybe illness prevents the females carrying the embryos to term. There could be any number of reasons. So generally speaking, there will not be a 100% chance of fertility. But then again, there won't be a 0% chance of fertility either, because some of these animals will reproduce. Maybe, of all the acts of sex that take place, 80% of them will result in a birth.

So, the compatibility is 80%. Do you get this? Remember, it's POPULATIONS that evolve, not individuals!

rush1169 · Dec 31, 2013

KTS said:
You are looking at individual acts of sex. Of course a single act of sex will either produce a viable offspring or not. It is either 0% or 100%.

But we're talking about a generation here. . . .Remember, it's POPULATIONS that evolve, not individuals!

Hi Kylie,

I'm afraid our conversation just took a jump back several pages and if I were to continue with a response to 'But we're talking about generations' it would result in essentially starting over from post #31. We would have to work out all the points that I thought we had already agreed on. I thank you for our dialog, but I'm afraid we are not internet-conversationally-compatible

I would like to engage others in this discussion in hopes of moving forward. For anyone new to the discussion, this is where my thoughts have taken me and briefly where this thread is as of this post:

Creature A is the future ancestor to not-yet-existent Creature B. For Creature B to exist, there had to be a first born Creature B. That first born Creature B had to have been the product of a pair of Creature As. Creature B had to produce gametes that could reproduce with Creature A and gametes that could reproduce with Creature B. The details of why it must be this way, start at post #100 and continue through to this post.

For me, this is a critical thinking exercise. I've never thought this specifically about this topic. Was there a first human? Some people will answer yes while others will answer no. I'm not interested in those who answer "Yes, there was a first human, his name was Adam." I am interested in the reasoning behind those who answer "No, there was never a first human because <reason>". I want to find a coherent explanation as to why there was not a first human.

It is not sufficient to me to just accept that there was not a first human. It does not make sense that there were once zero humans (fact), humans are birthed one-at-a-time (fact), now there is more than one human (fact) and based on those three facts there was never a first human. My logical circuits explode at this point

What I've found to be most helpful in my thinking exercise has been the many posts in this thread that provide explanations why there was never a first human. Those explanations have caused me to critically focus on those explanations to find something that logically fits with what is known (ie start with zero humans, birth one at a time, now there are humans). In reading the posts and replies, I’ve not found that last puzzle piece needed to tie the concept of ‘no first human’ into what we do know in regards to going from zero to an abundant human population.

My critical focus on the explanations offered is not to find fault but to find applicability to the topic. Most all the explanations were logically sound but they weren’t applicable to the zero-to-many human problem. It’s not sufficient to say something like, “If you take a picture of yourself every day, there will not be a definitive photo where you can say that this photo is the day I became an adult” and tie that to not being able to definitively say that a particular creature became human. The reason the analogy is not sufficient is because a gamete is definitive. The analogy compares indefinite to definite and asks to ignore the definitive nature of a human gamete. A gamete of any creature cannot be 70% one creature and 30% another creature other than in similarity. Functionally it must be either compatible or not compatible with another gamete.

If there is no coherent explanation as to why there was never a first human, are we obliged to just accept it?

mzungu · Jan 1, 2014

rush1169 said:
I would like to engage others in this discussion in hopes of moving forward. For anyone new to the discussion, this is where my thoughts have taken me and briefly where this thread is as of this post:

Creature A is the future ancestor to not-yet-existent Creature B. For Creature B to exist, there had to be a first born Creature B. That first born Creature B had to have been the product of a pair of Creature As. Creature B had to produce gametes that could reproduce with Creature A and gametes that could reproduce with Creature B. The details of why it must be this way, start at post #100 and continue through to this post.

For me, this is a critical thinking exercise. I've never thought this specifically about this topic. Was there a first human? Some people will answer yes while others will answer no. I'm not interested in those who answer "Yes, there was a first human, his name was Adam." I am interested in the reasoning behind those who answer "No, there was never a first human because <reason>". I want to find a coherent explanation as to why there was not a first human.

It is not sufficient to me to just accept that there was not a first human. It does not make sense that there were once zero humans (fact), humans are birthed one-at-a-time (fact), now there is more than one human (fact) and based on those three facts there was never a first human. My logical circuits explode at this point

What I've found to be most helpful in my thinking exercise has been the many posts in this thread that provide explanations why there was never a first human. Those explanations have caused me to critically focus on those explanations to find something that logically fits with what is known (ie start with zero humans, birth one at a time, now there are humans). In reading the posts and replies, Ive not found that last puzzle piece needed to tie the concept of no first human into what we do know in regards to going from zero to an abundant human population.

My critical focus on the explanations offered is not to find fault but to find applicability to the topic. Most all the explanations were logically sound but they werent applicable to the zero-to-many human problem. Its not sufficient to say something like, If you take a picture of yourself every day, there will not be a definitive photo where you can say that this photo is the day I became an adult and tie that to not being able to definitively say that a particular creature became human. The reason the analogy is not sufficient is because a gamete is definitive. The analogy compares indefinite to definite and asks to ignore the definitive nature of a human gamete. A gamete of any creature cannot be 70% one creature and 30% another creature other than in similarity. Functionally it must be either compatible or not compatible with another gamete.

If there is no coherent explanation as to why there was never a first human, are we obliged to just accept it?

I am afraid there is no other way to explain it to you. We have given you examples that clearly show why and how a first human could not be. Yet you insist on asking the same question. Perhaps if you were to study ToE at a higher level and take a course in genetics; then you may have your answer.

You also should ask such questions in pertinent sites where biology and genetics are discussed by scientists of those fields.

Good luck!

rush1169 · Jan 2, 2014

mzungu said:
I am afraid there is no other way to explain it to you. We have given you examples that clearly show why and how a first human could not be. Yet you insist on asking the same question.

If you take a human gamete back in time you must arrive at the birth of the first producer of a human gamete. I've not read examples that explain how either the first human gamete was simultaneously plentifully produced or how the first human gamete has never existed. I realize there have been many different attempts at explanations. If you'd like to look closely at the one you consider the best explanation, please repost it so we can talk about it. Or, what may be more fruitful, post an explanation without using analogies that reflects your understanding of why there was no first human gamete as clearly and concisely as you can and we can talk about that.

The reason it may be better to omit analogies is because if the elements of the analogy don't exactly line up with the topic, then we have to go through a few iterations of why the analogy doesn't line up with the topic. Maybe try this: The reason why, if you take a human gamete back in time that you will never find the first producer of a gamete that is compatible is because. . .<put your answer here, but avoid analogies if possible>.

Just a general answer in a sentence or two is sufficient to restart our conversation. We're just a couple people sitting in a diner having a cup of coffee and talking.

mzungu · Jan 2, 2014

rush1169 said:
If you take a human gamete back in time you must arrive at the birth of the first producer of a human gamete. I've not read examples that explain how either the first human gamete was simultaneously plentifully produced or how the first human gamete has never existed. I realize there have been many different attempts at explanations. If you'd like to look closely at the one you consider the best explanation, please repost it so we can talk about it. Or, what may be more fruitful, post an explanation without using analogies that reflects your understanding of why there was no first human gamete as clearly and concisely as you can and we can talk about that.

The reason it may be better to omit analogies is because if the elements of the analogy don't exactly line up with the topic, then we have to go through a few iterations of why the analogy doesn't line up with the topic. Maybe try this: The reason why, if you take a human gamete back in time that you will never find the first producer of a gamete that is compatible is because. . .<put your answer here, but avoid analogies if possible>.

Just a general answer in a sentence or two is sufficient to restart our conversation. We're just a couple people sitting in a diner having a cup of coffee and talking.

Listen; it makes no difference whether you are talking about a human gamete or a human in full. The answer is the same. What changes is the probability of fertilisation. Even today we do not have 100% probability of fertilization or if you like a fertile offspring. You keep thinking of one individual who you want to consider the first human. This can only be explained by analogy since you simply fail to grasp the concept.

I know you are desperately trying to include genesis into ToE and no matter how hard you try it cannot be done simply because ToE cannot include the unfalsifiable.

I told you before; if you want a complete and detailed scientific answer then you are in the wrong place. Try posting in this forum: Forum - Biology-Online
http://www.biology-online.org/

[serious] · Jan 2, 2014

rush1169 said:
I see many "Tree of Life" depictions. Some look like trees, others are circles, and some look like my March Madness bracket. What I can't seem to find is an illustration that shows/labels what the creature was before the split.

For example, you may find a tree that shows a chimp on the tip of one branch and a human on the tip of another. If you follow both branches to their intersection, there is nothing there. The illustrations imply that at some point before humans and chimps split, they shared a common ancestor. What was that ancestor? Does it have a name? Is there a fossil? Artists rendering?

There must be millions of intersections where two creatures evolved from a common ancestor, but I've never seen intersections labeled with what it was before the split into two creatures. Why is that?

We draw them as hard and fast splits, but they are a gradual process.
Example, Both of these sentences started off black. Where did they split?

rush1169 · Jan 2, 2014

mzungu said:
Listen; it makes no difference whether you are talking about a human gamete or a human in full. The answer is the same. What changes is the probability of fertilisation. Even today we do not have 100% probability of fertilization or if you like a fertile offspring. You keep thinking of one individual who you want to consider the first human. This can only be explained by analogy since you simply fail to grasp the concept.

If one takes a human gamete and matches it up with goat gamete, what is the probability of a fertile, viable offspring? Zero percent, of course. If one takes a human gamete and matches it up with a human gamete, what is the probability of a fertile, viable offspring? Somewhere in the 0% to 100% range, largely dependent on the quality of the two gametes.

For there to be any probability of a fertile, viable offspring, the two gametes must start as reproductively compatible. A human and goat pairing of gametes are not reproductively compatible. I do grasp the concept. I also hold to the notion that there cannot exist a varying degree of reproductive compatibility. Two human gametes are reproductively compatible even though success of a viable offspring is not guaranteed. A human and goat gamete pair are not reproductively compatible and failure to achieve a viable offspring with the pairing is guaranteed.

I hope you see that given two gametes that they either are reproductively compatible or not reproductively compatible. Yes, there is no guarantee that two reproductively compatible gametes will result in a fertile, viable offspring but we are guaranteed that a pair that are not reproductively compatible will never result in an offspring or even a zygote. It's important to separate the chances of success from the possibility of success and refine our focus to the all-or-nothing possibility topic. A human and goat is impossible while a human and human is possible.

Many responses have erroneously focused on the chances of two otherwise sexually compatible gametes. The real focus in drilled down deeper to find the first gamete produced that is sexually compatible with a current human gamete. The focus is not on the odds of producing an offspring with a given of two sexually compatible gametes. The most recent 'hole-in-one' analogy focused on the chances of an offspring with an assumption of gamete compatibility already established.

The chances of an offspring is not relevant to the topic. If we take a human gamete and compare it to every birthed life-form starting now and go backwards and, however it can be done, compare the two for sexual compatibility, we will reach a birth that is not sexually compatible. We will, when comparing to other human gametes, find sexual compatibility for billions of births going backwards. If we arrive at the first generation of sexually compatible gamete producers, we need only go back a little further to the one birth that gave rise to the compatible generation. From that first producer, its parents are necessarily not producers of a sexually compatible gamete.

I realize the difficulty at this point. You have an offspring that produces gametes that are necessarily sexually compatible with it's contemporaries and sexually compatible with up and coming humans. It seems this individual would have to produce two different gametes. This dual-compatibility problem has made me stop and say, "That ain't possible." The problem makes me re-examine my human-gamete-walk-back-in-time thought process to figure out what I've misunderstood. The easy way out is just for me to say, "Eh, I must be missing something" and continue my journey of discovery. I'm not comfortable with such a dismissal so I'm laying it out for input from you and others to help me over this hump.

I'm not here to argue, preach, profess, convert, convince, or otherwise impose my beliefs. I'm trying to understand the specific error that I make in my thought process of taking the human gamete on a journey to the past. Because there has been nothing new presented and very little participation from others, it seems that the reason there was never a first human gamete cannot be explained.

I told you before; if you want a complete and detailed scientific answer then you are in the wrong place. Try posting in this forum: Forum - Biology-Online
Life Science Reference - Biology Online

I've presented my question at that forum. Thank you for the link.

mzungu · Jan 3, 2014

rush1169 said:
I've presented my question at that forum. Thank you for the link.

Let us know if you are given a satisfactory answer.

Kylie · Jan 3, 2014

rush1169 said:
If there is no coherent explanation as to why there was never a first human, are we obliged to just accept it?

I've already explained it to you. Anyone else you ask will tell you essentially the same thing. You insist on using a Human/non-Human way of thinking that just does not work in the real world. You will never get an answer to your question until you learn this.

Oafman · Jan 3, 2014

This seems appropriate:

rush1169 · Jan 6, 2014

mzungu said:
Let us know if you are given a satisfactory answer.

I posted a pretty simple question in the biology forum you provided:
If one could take a human gamete from today and 'test' it for compatibility against every birth of every creature starting at the most recent birth and going backward in time, would one reach a first-to-produce a compatible gamete individual? By 'compatible' I mean able to form a zygote that results in a fertile, viable offspring.

Answer: Depends on if you're talking about a test-tube or womb fertilization. All you need are the same number of chromosomes. So, humans are compatible with muntjacs and antelopes.

At least someone else jumped in and pointed out the error.

So far, no joy.

Loudmouth · Jan 7, 2014

rush1169 said:
I posted a pretty simple question in the biology forum you provided:
If one could take a human gamete from today and 'test' it for compatibility against every birth of every creature starting at the most recent birth and going backward in time, would one reach a first-to-produce a compatible gamete individual? By 'compatible' I mean able to form a zygote that results in a fertile, viable offspring.

Let's say you did go back and found the first generation that was incompatible with modern humans. What would you find if you tested the compatibility of that generation with the generation immediately after and before them? They would be 100% compatible, would they not?

How do you explain this?

Loudmouth · Jan 7, 2014

rush1169 said:
If one takes a human gamete and matches it up with goat gamete, what is the probability of a fertile, viable offspring? Zero percent, of course. If one takes a human gamete and matches it up with a human gamete, what is the probability of a fertile, viable offspring? Somewhere in the 0% to 100% range, largely dependent on the quality of the two gametes.

For there to be any probability of a fertile, viable offspring, the two gametes must start as reproductively compatible. A human and goat pairing of gametes are not reproductively compatible. I do grasp the concept. I also hold to the notion that there cannot exist a varying degree of reproductive compatibility. Two human gametes are reproductively compatible even though success of a viable offspring is not guaranteed. A human and goat gamete pair are not reproductively compatible and failure to achieve a viable offspring with the pairing is guaranteed.

I hope you see that given two gametes that they either are reproductively compatible or not reproductively compatible. Yes, there is no guarantee that two reproductively compatible gametes will result in a fertile, viable offspring but we are guaranteed that a pair that are not reproductively compatible will never result in an offspring or even a zygote. It's important to separate the chances of success from the possibility of success and refine our focus to the all-or-nothing possibility topic. A human and goat is impossible while a human and human is possible.

Many responses have erroneously focused on the chances of two otherwise sexually compatible gametes. The real focus in drilled down deeper to find the first gamete produced that is sexually compatible with a current human gamete. The focus is not on the odds of producing an offspring with a given of two sexually compatible gametes. The most recent 'hole-in-one' analogy focused on the chances of an offspring with an assumption of gamete compatibility already established.

The chances of an offspring is not relevant to the topic. If we take a human gamete and compare it to every birthed life-form starting now and go backwards and, however it can be done, compare the two for sexual compatibility, we will reach a birth that is not sexually compatible. We will, when comparing to other human gametes, find sexual compatibility for billions of births going backwards. If we arrive at the first generation of sexually compatible gamete producers, we need only go back a little further to the one birth that gave rise to the compatible generation. From that first producer, its parents are necessarily not producers of a sexually compatible gamete.

I realize the difficulty at this point. You have an offspring that produces gametes that are necessarily sexually compatible with it's contemporaries and sexually compatible with up and coming humans. It seems this individual would have to produce two different gametes. This dual-compatibility problem has made me stop and say, "That ain't possible." The problem makes me re-examine my human-gamete-walk-back-in-time thought process to figure out what I've misunderstood. The easy way out is just for me to say, "Eh, I must be missing something" and continue my journey of discovery. I'm not comfortable with such a dismissal so I'm laying it out for input from you and others to help me over this hump.

I'm not here to argue, preach, profess, convert, convince, or otherwise impose my beliefs. I'm trying to understand the specific error that I make in my thought process of taking the human gamete on a journey to the past. Because there has been nothing new presented and very little participation from others, it seems that the reason there was never a first human gamete cannot be explained.

I've presented my question at that forum. Thank you for the link.

Your mistake is in thinking that there is a hard line where there are non-humans on one side and humans on the other. Any line you draw in our human lineage will have completely compatible individuals on either side of the divide. Using your example of goats and humans, we can show complete compatibility from one generation to the next for every single one of the goat and human generations until we reach the common ancestor of humans and goats.

Loudmouth · Jan 7, 2014

rush1169 said:
I think we have identified a 'sticking point' between us that needs further fleshing out before we can continue. That sticking point concerns gamete compatibility. I explained my understanding of gamete compatibility and why it appears to be an all-or-nothing issue.

The problem is that you are looking at gamete compatibility between individuals that will never, and never did meet or live at the same time. More importantly, these individuals never had to meet or produce offspring together in order for us to have evolved from a common ancestor with other species that we are currently incompatible with.

What you are essentially doing is getting frustrated because evolution does not operate the way you think it does.

We've reached agreement that there was a time when a human-compatible gamete began to exist.

We are saying that there was never a gamete compatibility issue from one generation to the next anywhere in our lineage, reaching back to common ancestors that we share with other amniotes such as reptiles, birds, and fish. At no time was there birthed a generation that was incompatible with the generation before it.

We agree, given sufficient attempts, that gamete could form a zygote with a human gamete.

We are saying that there is no division between non-human and human. It is an entirely arbitrary distinction, like that between cold and hot.

mzungu · Jan 8, 2014

rush1169 said:
I posted a pretty simple question in the biology forum you provided:
If one could take a human gamete from today and 'test' it for compatibility against every birth of every creature starting at the most recent birth and going backward in time, would one reach a first-to-produce a compatible gamete individual? By 'compatible' I mean able to form a zygote that results in a fertile, viable offspring.

Answer: Depends on if you're talking about a test-tube or womb fertilization. All you need are the same number of chromosomes. So, humans are compatible with muntjacs and antelopes.

At least someone else jumped in and pointed out the error.

So far, no joy.

I know you are desperately trying to reconcile genesis with ToE or are trying to prove through ToE the existence of Adam. I am sorry but this error in thinking has been pointed out to you many a times and will lead you not to an answer but to at best frustration.

You are thinking in black and white and this is not how ToE works.

rush1169 · Jan 9, 2014