How do allele frequencies change over time?

Answer 1

If this happens then Natural Selection occurs because Natural Selection is the increase or decrease in allele frequencies due to the impact of the environment.

The above answer is partially true. An allele's frequency may also change due to genetic drift.

Answer 2

If you believe that Darwin might have been correct in his theory of Natural Selection, one answer will be when something changes in the environment.

For example, consider a gene that promotes thick hair and layers of fat that will help an animal in a cold climate . If the climate warms, the animals lacking such a gene will have an advantage over their peers, and will produce more offspring, that in turn will be better able to compete and have offspring of their own in the changed environment.

Anything that promotes selective breeding will allow gene frequencies to change.

Humans select animals and plants that exhibit certain characteristics as breeding stock, and cull animals and plants from breeding if they do not show the desired characteristics.

Organisms compete for shelter.

Answer 3

Genetic drift is the spread of specific random variations throughout the gene pool in the absence of specific selection pressures. There's always random variation in the population, but there aren't always changes in the environment for the population to adapt to. So natural selection, in stead of moving the population towards adaptation, might select from that random variation to move 'sideways', as it were, to a state that's equally well-adapted to the environment as what came before, but different. As random variation may produce many variants that are, more or less, equally well-adapted to their environment, the direction of evolution that results is more or less random.

Answer 4

Tall people in a population preferentially marry other tall people and do not marry people who are short or average height.

Answer 5

Evolution is the change in allele frequency in a population of organisms over time.

Answer 6

Under ideal circumstances, the dominant allele will appear more often.

Answer 7

Evolution.