For example, the cactus finch has a long beak ... The Grants had documented natural selection in action. While beak size is clearly related to feeding strategies, it is also related to reproduction.

This is because natural selection acts to increase the prevalence of highly advantageous alleles, over time generating common resistance alleles of especially strong effect. For example ...

In natural selection, genetic mutations that are beneficial to an individual’s survival are passed on through reproduction. This results in a new generation of organisms that are more likely to ...

Note that this change was not due to pollution making the moths darker. The dark variety had always existed in small numbers, but only had a selective advantage when the selection pressure changed.

For example, if heterozygotes at a locus have higher fitness than homozygotes (a scenario known as heterozygote advantage or overdominance), natural selection will maintain multiple alleles at ...

unpredictable fray of natural selection. With two partners combining varied genes, a species has more flexibility to adapt to changing environments. There are, however, rare examples of asexual ...

The proportion of well-adapted organisms in a population can increase over the generations by the process of evolution by natural selection.