How do geographic isolation, genetic drift, and mate selection contribute to evolutionary change?

Question

I need some help with this question. My book is very limited on this. Can someone explain?

How do geographic isolation, genetic drift, and mate selection contribute to evolutionary change?

What are some examples of each?

Thanks so Much! Please no *do your own homework stuff* I'm really good at biology...I just need some help with this. Thank You!

Answer 1

mate selection (probably the most important) contributes to evolutionary change because typically when selecting a mate, the animal will look for one who gives them the Best chance of having their genes represented. So if you have a choice between two mates and one is stronger (more fit), typically you'd go with the more fit one because it would have a better chance for survival. (hence the term survival of the fittest). The weaker animals die out due to this selection process. Also, mates will have to be representative of what the species as a whole values. My biology professor gave a stellar example of this: He likes very tall women, our society does not necessarily (typically men prefer women to be smaller and the proportions of a shorter woman are more conducive to childbearing and hence gene representation). Since he married a tall woman and now his daughters are very tall, he may have hurt his chances of having his genes represented--since other men may not want to court women over 6 feet tall..

Geographic isolation contributes as you'd imagine. If there were a species isolated in the wild, they'd only be able to breed amongst themselves. Thus animals with "abnormal" traits would be phased out as time went on (a smaller pool to draw from). After several generations this geographic isolation would become more and more prominent as this group became more and more unified.

As for genetic drift, that is a term that I'd have to see in the context to better understand. Good luck. (PS. The Selfish Gene, or anything by Dawkins are good sources for this kind of project)

Answer 2

Geographic isolation-
If animals can't mate, evolution can not occur.
Can't think of an example sorry


Genetic drift-
Bottleneck effect causes only certain organisms to survive in an envirornment and changes the gene pool which eventually causes evolution. Tribes in the himilyan mountains are blue skinned because of a diverse gene pool.

Mate Selection-

Sexual Dimorphism- The phenotypes of organisms change as a result of females being selective in their mates. Causes change in phenotype and eventually effects the population causing evolution.

Peacocks!
In peacocks the males are much more vibrant while the femals are brown and not showy in comparison to the males.

I think most of that's right

Answer 3

Here are a couple examples of the effects of geographic isolation since I don't see any other answers on that part or your question.

Camels are related to llamas and alpacas and have a common ancestor. At one time South America and Africa were connected. When the two continents separated, they carried the camel/llama/alpaca ancestors with them. Over eons of time, they became separate species because of physical separation. Llamas and Alpacas both evolved on the South American continent and remain more closely related than either are to camels which evolved on the African (and Asian) continent.

Polar bears and brown bears are related in the same way. If a brown bear moved too far north and had to live on year-around snow covering, it was hard to sneak up on seals and other prey because of color. Lighter colored bears fared better finding something to eat and over time this lighter color became white. At the same time other evolutionary changes happened so that now brown bears and polar bears no longer interbreed.