What evolutionary force causes adaptive evolution?

Answer 1

Adaptive evolution is caused by natural selection.

Natural selection means that some individuals leave more offspring than others. On average, the individuals which are best adapted to their environment will survive and leave more offspring than others.

In this way the genes for the useful adaptations will become more common and genes for less useful characteristics will become less common ie the species will become better adapted to its environment.

See this excellent website:

http://evolution.berkeley.edu/evolibrary/article/0_0_0/evo_14

Answer 2

There are three main mechanisms that can cause changes in allele frequency.

These include natural selection, genetic drift, and gene flow.

Answer 3

Gene frequencies in a population change because of some change or pressure on that population. For example, snowshoe rabbits have a high frequency of white fur genes and low frequency of black or brown genes, because the presence of dark fur would make them more likely to be eaten by predators. Dark rabbits would therefore not be as likely to pass on their dark fur genes. If the climate were to warm over a long period of time and snow was no longer camouflage but instead, shrubs, trees, or grasses were dominant, the gene frequency for darker fur may become more prevalent since they would provide a selective advantage and white fur genes would become less frequent. Gene frequencies change due to changes in the survival of the organism over many generations.

Answer 4

Genetic drift or population isolation can cause gene frequencies to change.

Answer 5

natural selection.

Answer 6

natural selection and genetic drift.

Answer 7

Natural selection and genetic drift.