A classic example of natural selection at work is the origin of giraffes’ long necks. The ancestors of modern giraffes were animals similar to deer or antelope, with necks of ordinary length.

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 ...

Many people are. In fact, the ability to digest lactose may be an example of adaptive evolution in the human lineage. Although the study of natural selection in humans is still in an early stage ...

The phrase "survival of the fittest" functions principally in evolutionary theory to describe the biological concept of ...