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.

Description: The tallest land mammal, with a neck as long as 6 feet, the giraffe is also well known for the unique brown and white pattern on its coat (“pelage”) and its lengthy eyelashes and legs.

Eventually, those traits — such as giraffes' long necks or polar bears' white fur — come to dominate and shape the evolution of the species. The theory of evolution by natural selection still ...

Aa Aa Aa Natural selection, genetic drift, and gene flow are the mechanisms that cause changes in allele frequencies over time. When one or more of these forces are acting in a population ...

The phrase "survival of the fittest" functions principally in evolutionary theory to describe the biological concept of natural selection. English naturalist, geologist, and biologist Charles ...

Today, with access to heretofore unprecedented data sets for the study of human genetic variation, researchers can exploit the genetic signatures of natural selection using novel analytical methods.

but it takes a different approach to natural selection. Lamarckism proposes that animals acquire characteristics based on use or disuse during their lives, rather than through hard-coded genetic ...