Question about the evolution process..how exactly would a man evolve from a primate..what is the process?

Question

Just say I am a student of evolution and you were an evolution teacher...how would you explain this. Yes I know it took millions of years, but if you could look at the process and I guess put it into supper sonic fast forward how would the process take place. I mean losing the long tail, the hairy body, developing the higher brain intelect and all the other changes that had to occur for humans to evolve. Is anybody familure with this evolving process and how to accurately describe it?

Answer 1

Well, evolution just means "slow change over generations."

There are two things you need to understand.
(1) Why does that slow change occur?
(2) How does one species branch into two species?

The answer to (1) is what Darwin called "natural selection". In any population of many individuals there is "variation" ... they vary from individual to individual, and this is fed by new mutations that appear in new individuals from time to time. If some variations or mutations provide some advantage *no matter how small*, those individuals who have those characteristics that help them compete better against others of their species (e.g. survive predators better, find food better, attract the ladies better, whatever) will produce more babies *on average* than the other members of their species. Most bad mutations don't survive long. The small number of good mutations spreads throughout the population. In this way, the population (the species) as a whole slowly *changes over generations*.

The answer to (2) is that if a population of primates gets isolated from the other members of its species (e.g. the territory between them becomes uninhabitable) that same "change over generations" described above eventually (after enough generations) causes the two populations to lose the ability to interbreed with each other ... their genetics are no longer compatible and they cannot make babies ... even if the isolation were to stop and they were to come in contact again.

Once that has occurred, the subpopulation is by definition a *new species*. The temporary isolation is now permanent. They will never again be able to interbreed. Ever.

Now you have two species that are very similar in appearance, but genetically different species. But both species will continue to "change over generations" getting more and more different. Since they cannot interbreed, mutations and changes in one species do not affect the other species at all.

So each species continues to change over generations. Change, change, change.

Both species may split again into more species. Branching, branching, branching.

One branch may keep its tail as it is good for climbing and swinging (what we now call the monkeys), while another branch may lose its tail as it gets in the way of sitting on the ground (what we now call the apes). One branch may develop better ability with its hands, which leads to brain development from manipulating objects.

Again, remember that changes in the species cannot be passed to species already split ... but those changes will get passed to descendant species.

Eventually, one of those branches finds itself in an environment changing slowly from jungle to savannah (almost desert) where the trees are more sparse and separated, and to survive, the animal learns to travel long distances on foot. It becomes more upright. This frees its hands up for more manipulation of objects, more brain development, and development of vocal cords, which again accelerates brain development of the language centers of the brain, and social interractions. The animal becomes so smart it is able to have very complex groups, make tools for digging and making weapons for hunting, to capture fire for warmth, and use the pelts of animals for clothing ... to the point where its own fur is not only unnecessary, but a hindrance in the hot sun.

Again, more "change over generations" causes all these things to change slowly until it is a completely upright animal, much smarter, with very complex language and social structure, almost completely hairless (except on the head where the sun still beats down when walking upright), etc. etc.

Meanwhile all the other branches are changing too. Changing and branching. So humans become more human, chimps become more like modern chimps, gibbons become more like modern gibbons, etc. etc.

There ... that's millions of years of evolution ... from primates to humans ... in a nutshell.

Please remember that this leaves out a *lot* of detail. This is just a summary. If you have questions, ask away (and feel free to email me).

Answer 2

To give you an idea of how a single change can have a huge effect, you can look at the ASPM gene.

There is a similar gene in humans and other primates with part of the gene called the IQ domain which repeats multiple times. In humans, there are more repeats of the IQ domain than in other primates and the result is that the number of neurons increases more rapidly in develpment and the brain grows 3 fold in size. Some people have a mutation in this gene and they are born with a condition called microcephaly, or a small brain, and severely deminished mental capacity.

So, it looks like a small mutation in a single gene could have been responsible for a large increase in brain size and function between chimpanzees and humans. This mutation did not require the miraculous creation of some totally new information - just a copying of information which was already present.

That is just one small but important step in the evolution between apes and man.

Answer 3

Evolution is just change over time. It has been demonstrated that organisms change over time so it is not really an issue that is in doubt.

By far the most reasonable and logical explanation for why animals change is described by the phrase "survival of the fittest". There are several ways to define that but in its simplest form it just means that the most fit animals will be the ones that will survive to have offspring and their traits will be expressed in later generations in higher numbers because more of the fitter organisms will survive.

When something like a tail is no longer needed it will tend to disappear. The animal that doesn't grow it will be at an advantage because it takes less energy to grow up. He didn't waste it on a tail. A reason he might no longer need a tail could be that he started swing from his arms because he became too large to swing from his tail. That is probably basically how the first apes began, as a large monkey that didn't use their tails anymore.

Why we lost our hair is a very controversial subject and there have been many theories. Most used to think we lost hair to cool off but that is not the reason I think we lost hair. I think it was more sexual selection and wearing animal skins that contributed more to it. When you loose your hair, you will not have as many lice and that is also a great benefit. You loose physical protection from sunlight and branches so I am of the opinion that it is a more recent adaptation of the last couple of million years.

The brain getting larger was thought to have occurred because we started scrounging for bones and got a large supply of lipids needed for a large brain. If that were totally true than vegetarians would have smaller brains. We probably started growing larger brains about 3 million years ago and it was because of social pressures and hunting that drove the selection of smarter hominids.

Evolution is driven by selection. There needs to be an advantage and that advantage is not always bigger or more complex. It is just something that helps a particular organism survive.

Answer 4

The Plesiadapiformes lived about 55 million years ago. These were rat-sized creatures that had crude grasping digits and side facing eyes.

The first phase is an increase in mass accompanied by increased visual capabilities. The eyes became forward facing for binocular vision and two-spectrum color vision arose by the time Old World and New World primates split.

Three-spectrum color vision developed before most the Old World primate lines split from the main group.

The monkeys and apes divided with apes developing a looser shoulder girdle. Further mass increases in both monkey and ape lines favored progressively shorter tails as prehensile tails could no longer be weight bearing.

The apes continued to differentiate. The orangutans/gorilla line could be characterized from the human/chimp line by a variety of mutations including the CYP21A locus involved in steroid hormone production.

The pre-human line moved from forests to plains. Several favorable feedback loops shaped the current human form. Walking erect enabled more control of height for scouting/hiding while freeing the upper limb for delicate tasks such as throwing and tool making. The hand flattened, become more versatile but less effective for tree climbing. Tool making enabled hunting, which created a higher protein diet, which enabled more brain development, which made for better tool making.

Skinning enabled survival without hair and a mutation in the KRTAP23-1 hair collagen gene appears not to be deleterious.

This is a simplification, but summing up 55 million years and millions of generations should not be easy.

Answer 5

Through a long series of mutations. Since there are about 15 million mutations that now separate mankind and chimpanzees, and mutations occur at a fairly constant rate, about 7.5 million mutations have taken place since our common primate ancestor. Many of these have been documented in the technical literature [examples, refs. 1 - 3]. An overview of the process is available in Dawkins [ref. 4].

Answer 6

No one *knows* the answer to this question. In fact, highpowered big named biologists have been having a high-profile argument about it for decades. There are several contested theories about how it occurred - what environment was required, what order changes happened in, how rapidly they happened, etc. We can't know the answer without more empirical evidence than we have.

In a scientific world view, that is not a rationale for denying that it did happen. It is the assumption supported by the best evidence we have, and any other scientific theory to explain how we evolved involves invoking extremely improbable circumstances.

Answer 7

It was simply through adaptation. what i mean is that say if a group of primates migrated to an area with warmer temperatures primates with less fur would better survuive. so if someone was slightly mutated and they survuived better they could go on to reproduce making more offspring like them and the process keeps repeating. i hope thats a good enough answer i know a lot more but to lazy to type.

Answer 8

I heard one compelling theory that evolving to walk upright preceded the expansion of brain-size.

To all you creationists: More and more humanoid-like species seem to be discovered every year. Well I guess God must of ****ed up when he "created" all those obsolete humanoid creatures that didn't fit into his grand plan. (Oh yeah! I get it! They were all wiped out in the big flood!).

Answer 9

the only time it will happen is when they adapt on their climate and place. But the thing is..man is so versatile that they don't have any evidence that man evolved. thus Evolution is just more likely a fiction now... and that's the reason why it contradicts the Genesis. Because man cannot accept supernatural and out-of-the-void explanation.

Answer 10

It was too long ago to know the exact details, but if that TV show Cavemen comes out this fall, maybe we can ask them.