It occurs through genetics or when something becomes more popular or when it starts to go extinct. The change in genetics can be caused by many different reasons, which include inbreeding, hybridization, and mutation. Humans can cause the evolution to change, by size of human population.
The three things that are going to get talked about are The Fossil Records, Molecular Biology, and Structure Similarities. Fossil records are organisms from the past that have changed. Which with a fossil you can determine which period of life that the organism was alive. Molecular biology deals with the changes of structure and functions in macromolecules needed for the creation of life. Structural similarities is comparing organisms to see the relationship between them. It shows evolutionary relationship between the organisms, that will be able to determine common