when divergent evolution occurs?

Question

ok.

say for example, you had a human population that evolved by divergent evolution to form 2 species.

are BOTH of these new species (that share a common ancestor of the human) DIFFERENT from the human?

or does one "branch off" to form a distinctly different species from the human, and the other group just kind of continues being human...

im a bit confused

thanks :)

Answer 1

First, we're considering a hypothetical that is *extremely* unlikely to occur. It would take hundreds of thousands of years of *complete* genetic isolation between the two populations for them to lose the ability to interbreed with each other and thus be considered two species. This is *exceedingly* unlikely especially now that we have developed transportation that basically eliminates all geographical boundaries.

But in your hypothetical, both branches would continue to evolve in different directions.

It would be hard to say that one would still hold the label "human" and the other would not ... they are just two new species, regardless of what we call them. It is possible that one of them would change far less than the other (e.g. if one was a small subpopulation, then, as it has a smaller gene pool, it would tend to evolve (change) faster ... so it would seem that one population was the main species line, and the other was a branch. But if some catastrophe happened and the larger branch was suddenly smaller than the other, then it might then start evolving faster.

So really, we would just say that both are now separate species, and leave it at that.

Answer 2

You've gotten some pretty good answers so far, but let's look at your question from a different angle. You're neglecting an important piece of information in your question. The fact is that both sides of what you postulate may happen.

Let's assume that you DO have some separation of the present human species. For point of the arguments, let's say one branch or present humans stays on earth and one branch goes off in a generational spaceship to the stars. They bring with them only a certain portion of the genetic makeup available to the whole species. 500,000 years down the road, the descendants of both populations come back into contact. It's very possible that both could now be different species -- HOWEVER, both would likely still consider themselves the HUMAN ones and the other a non-human. After all, WE make up the terminology. I'm also considering in this example that the group that has gone to the stars IS the species which has evolved from the parent species, while the population that's remained on earth is still very similar to what we today would consider to be human. There are still examples today on this planet of "primitive" (just meaning earlier) forms existing while "modern" species which have evolved from them (or very similar types) also exist.

There's another possibility as well. Let's also say that at some point here on earth that there is some serious disruption of the biome and organisms, including present day humans, must evolve or die. Maybe the amount of available oxygen in the atmosphere drops fairly drastically over time (it's happened before). Now it's that same 500,000 years in the future and the descendants of those who went to the stars meet the descendants of those who stayed here -- now we have two new species, with the ancestral species (present day humans) no longer in existance. Again, both will likely call themselves "human" but they might well be something that neither you nor I would consider to be "human" and they might well consider "us" to be simply an earlier ancestor that some wouldn't even want to acknowledge as being in their family tree --- same way as some today refuse to acknowledge Australopithecus, etc.

Answer 3

OK, consider that humans, chimps, and gorillas at one point had a common ancestor about 2-6 million years ago.

At that time they were the same species. As the species got separated, a divergence occured, and the species evolved (changed) into two separate species.

Today, humans and apes are different species. Moral and ethical questions aside, there isn't that much of a difference genetically from humans and apes. They could still interbreed because of common ancestry.

Now, if you consider that all animals on the surface of the earth evolved from common ancestry over 500 million years ago, you can see how time creates a great amount of variation.

If you look at comparative morphology, you'll see the roots of common ancestry in all surface animals. Weird, but true. (Notice that all surface animals have bones that could be hands, legs, arms, and spines. There's a similarity there that is not coincidental.)

So, let's say a population of humans travels to another planet. We are separated from them for 100,000 years or more and we finally regain contact with them.

They'll be a different species from us, but there will still be a traceable ancestry.

Answer 4

It would depend on some more details that you really didn't state.
IF the two populations BOTH are in new environments (and these environments are different from each other), then they would both become new species eventually.
So, for example, if you take a population of humans and put one on Mars and one on Venus, then they would both become different species- one a Martian and the other a Venetuan (this is a ridiculous example, but hopefully you understand the main point I'm trying to make).
Now, if ONE population was put elsewhere (Mars) and the other stayed in its original environment (Earth), then one would become a new species (Martian) and the other would still be human. (Of course, the humans would probably still evolve, but we'd still call them humans).
I hope this makes sense now.

Answer 5

Divergent evolution is a collection of dissimilarities between groups which can form new species, usually a result of diffusion of same species adapted to different environs. This leads to natural selection defining the success of specific mutation. Basically, diffusion is the basis of molecular division that is visible in some characters of higher level of function and structure that are observable in organisms. Example Of Divergent Evolution- the limb of a vertebrate is a divergent evolution example. The limb has a common origin for different species, but has little diversion in overall structure and function. In divergent evolution, the reason for similarity is the common origin, as divergence from a common ancestral function or structure has not yet completely distinguished the underlying similarity. Convergent Evolution: There are many instances where different organisms that are not very closely related have developed similar adaptations for life in similar habitats. This phenomenon is often referred to as Convergent Evolution. The convergent evolution occurs when there are some type of physical or ecological drivers towards a similar method, even though the function or structure has occurred independently. Such as different specialities converging on a similar, common solutions from different origin of points. This includes analogous structures. hopefully you could arrange these quality sentences to however you like!

Answer 6

They would likely both be different from the common ancestor, but it's not absolute. One group or the other could remain pretty much the same depending on local environment and conditions.