Changes in DNA due to evolutionary influences?

Question

Describe changes in DNA due to evolutionary influences.

Answer 1

Through a variety of mechanisms, gene flow, mutations, etc... allele frequencies in populations change over time. Some genes are favored while others are not this is how selection and evolution, as it were, work.

Say that there is an organism that has two dominant phenotypes, one green and the other bright purple. If for some reason being one color or the other affects that organisms ability survive and reproduce, then organisms with the preferred phenotype will end up creating a larger percentage of the offspring that those without it. IN this way the population will be directionally selected towards the "preferred" phenotype, in this case say purple makes you more attractive to mates so therefore you reproduce more than others of your species that are green.

The interesting thing is that this is not a one way street and there is no end... this is because the environment is always changing and what was preferred before might be selected against in the future. In this way DNA is always and will always be changing and in that way evolving.

Answer 2

Ex. As we evolved we didn't need the use of all our teeth, because we invented accessories that assisted us in cutting of meat etc.. therefore, our (DNA) changed, wisdom teeth became weak and useless, and our mouths smaller. If you want more of a chemical composition, place your question under chem., not my forte. sorry

Answer 3

those who survived the changed environment get to pass on their DNA, those who didnt survive didnt, so soon, the population would be different than the origanal one before the environment changes, and each generation would be slightly different from the previous one.