Paul Andersen explains how natural selection is a major mechanism in evolution. The video begins with a discussion of Charles Darwin and the details of natural selection. The data of the peppered moth during the industrial revolution is used to show the process of adaptation. Allele frequencies are calculated before and after the selection. The adaptation of cichlids in African lakes is also included.

Paul Andersen details examples of natural selection in the world. He starts by explaining how changes in global temperatures are causing plants to adapt. He explains how mutations cause changes in phenotype which give organisms varying levels of fitness. Two specific examples of natural selection; sickle cell disease and multi-drug resistant tuberculosis are also included.

Crash Course Biology #14: Hank guides us through the process of natural selection, the key mechanism of evolution.