Evolution question

[painted wolf]

here is another good site on human evolutionary evidence The Smithsonian Human Acestors Family Tree.
Human Ancestors Hall: Tree

Here is a modern (published June 2008) cladogram of the hominid line using the best preserved skulls avalable.
PALAEOBLOG: Cladistic Analysis of Humans

Orrorin has been shown to have been bipedal. Studies done on the leg bones that were found show that the bone density is exactly what would be found in a bipedal animal.
(now if it was a bipedal limb walker or a bipedal ground walker is still uncertian.)

wa:do

 

[logician]

Same with horses and donkeys as well. That gets into part of the definition for species I gave before: two animals are the same species if they can mate to produce reproductively viable offspring, i.e. offspring who can reproduce themselves.

It also points out the problems of delineating fossil species - many times done with little more than teeth or parts of a jaw. In real life(when they were alive), there could have been more or less obvious differences based upon reproduction, but impossible to tell from fossils alone.

 

[painted wolf]

Not always impossible. Genetic evidence has backed up the species split between Homo sapiens and Homo neanderthalensis.

The species model has several flaws that advances in genetics are addressing.

wa:do

 

[logician]

Not always impossible. Genetic evidence has backed up the species split between Homo sapiens and Homo neanderthalensis.

The species model has several flaws that advances in genetics are addressing.

wa:do

Quite possible for species for which you HAVE the DNA mapping, not possible with most older fossils for which there are no genetics to draw from.

 

[painted wolf]

No but then no one is going to think that a mammoth and a stegosaurus are the same species.

There are some pretty good deductions that can be made from fossils.

wa:do

 

[crystalonyx]

No but then no one is going to think that a mammoth and a stegosaurus are the same species.

There are some pretty good deductions that can be made from fossils.

wa:do

I think the comparison is for those fossils that are quite similiar, not obviously completely different species.

 

[painted wolf]

That's why I intend to eventually get a PhD in comparative anatomy.
So I can tell those differences. (mind you that is a few years down the road for me.)

Teeth are highly diagnostic for example... that is, if you are good enough you can tell a species from its teeth with 90% or better accuracy.

wa:do

 

[rojse]

I realize that there have been many species that have gone extinct, but the fact that ALL of the progressive human-like sub-species (except us) have completely gone extinct is difficult to reconcile.

Three reasons for why this is true:
1. If there are two competing species that eat the same foods, live in the same areas and so forth, one will eventually displace the other because they are better in some regard.
2. We are extremely intolerant
3. If members of one species gains an advantage that helps them reach adulthood, attract mates, or have more children, those without the advantage will eventually be displaced by those with the advantage over multiple generations