Thread: The connection between species in evolution

Many people i talk to about evolution say we didn't just one day turn from monkeys to humans. I explain to them natural selection and how having a genetic mutation that benefits you will increase the chances of you surviving and therefore reproducing and passing on those genes.

They understand that but they say there are mediums found. As in the species inbetween the first homo sapiens and chimps. That if genes only change at a couple at a time there has to be a lot of medium species between homo sapiens and chimps.

Why have we not found these mediums between species of any bacteria, alge, animal, etc.?

First of all, Raymond, the search for "mediums" or missing links or transitional species is an unending one. Say you have species A whose ancestor is species E. Then you find species C, and you say look, we found it! Then people ask, well, what about species B in between A and C, and species D between C and E, have you found them yet? And you can go on and on in this fashion until people won't be satisfied until we have an example from every generation between every species, and that simply isn't going to happen.

In relation to humans and chimps specifically, we did not evolve from them but share a last common ancestor with them. And we have many fossils of many species that evolved from that last common ancestor and eventually into us.

Apes - Humans

Originally Posted by Raymond K

Many people i talk to about evolution say we didn't just one day turn from monkeys to humans. I explain to them natural selection and how having a genetic mutation that benefits you will increase the chances of you surviving and therefore reproducing and passing on those genes.

They understand that but they say there are mediums found. As in the species inbetween the first homo sapiens and chimps. That if genes only change at a couple at a time there has to be a lot of medium species between homo sapiens and chimps.

Humans did not evolve from chimps. Chimps and humans evolved from a common ancestor species which is now extinct. So if you're looking for a transitional species between humans and chimps, finding it would falsify our current understanding of human evolution.

What we have found is a great many fossils of extinct hominini species to which humans, chimps and bonobos are variously related.

Originally Posted by Raymond K

Why have we not found these mediums between species of any bacteria, alge, animal, etc.?

We have found them, millions of them. All known species are "medium species". Some of them are living species, some are extinct and only found in the fossil record. Others we know must have existed by extrapolation from the genetic record. The species known in the fossil record and those still living represent only a small fraction of the species that have existed overall because most species that go extinct do not leave fossil evidence. But we've certainly found enough fossils to build a fairly comprehensive tree of life that agrees entirely with the genetic evidence.

Originally Posted by TheBiologista

Originally Posted by Raymond K

Many people i talk to about evolution say we didn't just one day turn from monkeys to humans. I explain to them natural selection and how having a genetic mutation that benefits you will increase the chances of you surviving and therefore reproducing and passing on those genes.

They understand that but they say there are mediums found. As in the species inbetween the first homo sapiens and chimps. That if genes only change at a couple at a time there has to be a lot of medium species between homo sapiens and chimps.

Humans did not evolve from chimps. Chimps and humans evolved from a common ancestor species which is now extinct. So if you're looking for a transitional species between humans and chimps, finding it would falsify our current understanding of human evolution.

What we have found is a great many fossils of extinct hominini species to which humans, chimps and bonobos are variously related.

Originally Posted by Raymond K

Why have we not found these mediums between species of any bacteria, alge, animal, etc.?

We have found them, millions of them. All known species are "medium species". Some of them are living species, some are extinct and only found in the fossil record. Others we know must have existed by extrapolation from the genetic record. The species known in the fossil record and those still living represent only a small fraction of the species that have existed overall because most species that go extinct do not leave fossil evidence. But we've certainly found enough fossils to build a fairly comprehensive tree of life that agrees entirely with the genetic evidence.

So there must be millions of links that we do not have fossils of, seeing the difference between us and bacteria thats like extremely large amount of mutations, not even counting the ones that had no benifit to the organism.

Is there a website or something that has the genetic links and the mutations along the evolutionairy road from a basic primate to us?

Is there a website or something that has the genetic links and the mutations along the evolutionairy road from a basic primate to us?[/quote]

I'm not sure if this would be of interest to you but I have read that whilst chimps are similar to us the difference is much greater than what the percentages of some similarities suggest. Another thing of interest to me and that is a "suggestion put forward" has been that there are more genetic differences amongst a group of chimpanzees than what would be comparable to what is there is within what's considered modern man. One suggestion put forward for a possoble cause for this is that human numbers dwindled to such low numbers previously and that it most likely contributed to this genetic limit amongst modern man today. But this is just my limited understandings of such things. Quite happy to be corrected .

I have the exact documentation of the mediums between me and my grand-grand-grand-grand-grand-grand-grand-grand-grandfather.

In other words, in some situations the 'intermediates' are extremely well documented.

You could have figured that out yourself.

You didn't.

What does that mean?

And species isn't a natural classification. It's one made by humans for the sake of practicing science.

It doesn't mean anything, besides a collection of individuals we have put together based on variable criteria.

Originally Posted by question mark

Is there a website or something that has the genetic links and the mutations along the evolutionairy road from a basic primate to us?

This is a phylogenetic tree illustrating the evolutionary relationships between living primates; as for a detailed description of everything that happened between the origin of the primate order until humans - it's a work in progress, to say the least. You're not going to find something like that because we still don't know all the details of that specific path. But remember, absence of evidence is not the same thing as evidence of absence. The fact that we don't yet know every tiny detail in the evolution of all life forms is not evidence against evolution.

I'm not sure if this would be of interest to you but I have read that whilst chimps are similar to us the difference is much greater than what the percentages of some similarities suggest.

We have 98-99% genetic identity with chimpanzees and bonobos. This percentage is extremely high and demonstrates the extreme closeness of our evolutionary relationship. However, small changes in genes can lead to large changes in phenotype; the lesson here is that just because two species can look quite different doesn't mean they aren't closely related.

Another thing of interest to me and that is a "suggestion put forward" has been that there are more genetic differences amongst a group of chimpanzees than what would be comparable to what is there is within what's considered modern man. One suggestion put forward for a possoble cause for this is that human numbers dwindled to such low numbers previously and that it most likely contributed to this genetic limit amongst modern man today. But this is just my limited understandings of such things. Quite happy to be corrected .

That is true; chimpanzees have a great degree of genetic variability, and can be legitimately divided into four different subspecies - troglodytes, schweinfurthii, vellerosus, and verus. Humans are all much more similar to each other and there are no subspecies within humans. ("Racial" differences are not nearly high enough to justify designation into subspecies.) And yes, it has been estimated that for a long time the total human species was not greater than 10,000 individuals, and in the blink of an eye (evolutionarily speaking) we suddenly boomed to over 6 billion.

How many chimps are there in the wild?

There's only about 150,000 left today, but this the result of a recent, precipitous population decline thanks to habitat loss. It's estimated that there were as many as a million chimps living in the wild around a century ago.

Edit - for the human number, I should have said 10,000 is the estimated effective population size of humans prior to the advent of agriculture. So that number doesn't include very old and very young individuals who are not reproducing.

[

However, small changes in genes can lead to large changes in phenotype; the lesson here is that just because two species can look quite different doesn't mean they aren't closely related.

[quote]

I can't dispute the closeness of chimps on percentages to us as you so expressed in your previous post.

Your points expressed about the phenotype cover what I was trying to say on that point.

Originally Posted by paralith

There's only about 150,000 left today, but this the result of a recent, precipitous population decline thanks to habitat loss. It's estimated that there were as many as a million chimps living in the wild around a century ago.

Edit - for the human number, I should have said 10,000 is the estimated effective population size of humans prior to the advent of agriculture. So that number doesn't include very old and very young individuals who are not reproducing.

Oh...that's interesting. If a space alien would come to have visited earth some time ago, he might have thought that chimps were the master race?

He had to get his timing perfect of course.

How old is the extant chimp species btw?

Originally Posted by spuriousmonkey

How old is the extant chimp species btw?

How old is Jane Goodall?

Originally Posted by John Galt

Originally Posted by spuriousmonkey

How old is the extant chimp species btw?

How old is Jane Goodall?

Haha, that made me chuckle.

Well, that's hard to say, since we have NO fossils on the chimp side of things after the LCA of chimps and humans. Some of the early hominid finds are probably chimp ancestors but of course the fossil-finders would prefer to find hominids rather than ancient chimps. Anyhow, they split from bonobos about ~1.3 million years ago, so probably sometime after that is a reasonable estimate for when extant chimps really came on the scene.