What other lines of evidence can be used to support the models of human evolution aside from fossil records?

Question

please discuss it. please..please...

Answer 1

Other lines of evidence besides fossils:

1. Anthropology/archaeology - I.e., human artifacts and mummified remains (tools, cave paintings, campsites, etc.) This could barely be called 'evolution' as this only covers the last 50,000 years or so when humans were pretty close to how they are today. But it does document such things as migration patterns around the world (e.g. when humans arrived in different parts of the world).

2. Genetic evidence - These are the genes that we have in common with other primates. E.g. the fact that we have a huge number of genes (as much as 96%) in common with other great apes. Genetic evidence shows that we are more closely related to chimps than to the other great apes, and more closely related to great apes than to other primates (monkeys).

3. Molecular evidence - These are commonalities in DNA ... which is separate from genetic commonalities ... much of our DNA does not code for genes at all. But random mutations (basically 'typos') enter into DNA at a known rate over the centuries. This is called the 'molecular clock' and again gives excellent evidence of when humans diverged from other apes (about 6 million years ago, according to this molecular clock).

4. Proteins - These are the proteins in common with other primates. This includes things like blood proteins (the things that give us our A, B, O blood typing and the Rh factor (the plus/minus thing) which incidentally stands for 'rhesus monkey'); the exact structure of the insulin molecule; and my favorite, the photophigments: The photopigments are the three proteins responsible for color vision. The specific proteins found in human color vision are exactly the same as those found in Old World primates (the great apes and the monkeys found in Africa and Asia). These proteins are absent in New World primates (the Central and South American monkeys), and from all other mammals. In fact among the New World primates, only the howler monkey has color vision ... but these use slightly *different* proteins, coded on different locations and chromosomes, than humans and the OW primates. This is yet more evidence of a closer link between humans and the OW primates.

5. Vestigial structures - These are structures that are useless, almost useless, or just badly 'designed' (a word I use figuratively), that can only be explained in terms of descent from animals in which they were more useful. Things like wisdom teeth and the appendix are classic examples ... but my favorite is the plantaris muscle: The plantaris muscle is a long thin muscle in your calf that serves no useful purpose in humans. It is so useless that surgeons commonly harvest it for use in reconstructive surgery (such as heart surgery). In fact, it is so useless that 9% of people have no plantaris muscle at all. So why is it there? Because it serves a very important purpose in other primates ... specifically, grasping with the feet.

6. Homology - These are structures and proteins that have commonalities between species, but have a different function. The simplest examples are the fact that all terrestrial vertebrates have four limbs, and most have five fingers (e.g. bats, dolphins, whales, birds, reptiles, etc.). There are also homologous proteins. But my favorite are the five bones in the inner ear of humans and other mammals, which correspond in structure to the five bones of the hinged jaw of reptiles. These are evidences that evolution will often take structures left over from a now useless function, and repurpose them for a new useful function.

7. Embryology - This includes things like tails and gill folds in human embryos and those of all other mammals. But this also includes things that are evidence of other creatures are related to our branch ... such as legs and five webbed fingers, and distinct leg-buds in the embryos of dolphins.

Now all of these just concern human evolution. The lines of evidence for evolution in general are much bigger (e.g. I didn't include things like virology, or bacteriology, or evidences from medicine).

And, as you requested, I excluded evidence from fossils.

However, a bigger point is this: while all of these independently are evidence of the model of human evolution, when considered *together*, and with the fossil evidence, they get even stronger. For example, the molecular clock places the split from other apes at about 6 million years ago, which is consistent with when these early humans first appear in the fossil record. And the split between New World and Old World primates suggested by the structure and genetic locations of photopigment proteins, is further confirmed by the molecular and fossil evidence.

Hope that answers your questions.

Answer 2

Molecular evidence : Humans and chimps share an abundance (>=96%) of DNA supporting a shared common ancestor. The existance of DNA as the universal genetic code points to the commonality of all life to have decended with modification from a common organism.

There is also shared physiology (muscles are well conserved, cell respiration is well concerved), shared morphology (we share placenta's with many mammals), and shared behavior.

None of these require a fossil record but all point to a commonality among life forms

Answer 3

Well, how about the use and invention of tools, and communication techniques? From using our hands to using a stick to eat with, then a spoon or knife. What about art as a model...cave drawings were historical recordings, now you get thrown in jail for tagging! Go figure. Those are two to get your conversation going. Good question! Nana

Answer 4

Is this strictly Biology, because socio-evolution supports human evolution from a social standpoint.

Skin color is an excellent indicator of evolution. It is believed that the human being developed different skin colors (brown, dark brown, peach) in order to adapt to the environment. For example, the sun was very powerful in the land of Africa compared to somewhere like Eurpoe, so they people who lived there had to develop a way to resist sundamage to their skin. Africans developed dark pigment in order to protect their skin from skin cancer and other harmful things from the sun.

Disease resistance is also a huge result of evolution.

Answer 5

I would assume, that, from the development of 'simple' tools, and the dating of those artifacts, would show the progression of logic, and theory with humans. Art, culture, would show up, at some point, as well, in the manufacture, of these items. As man 'grew', he went from basic survival to thought and logic, and imagination.

Answer 6

Comparative skeletal morphology shows, though incomplete, a evolutionary progression from earlier hominids.