Evolution. Darwin’s theory.

This species' bones developed through the natural selection of small, inherited variations that increase the individual's ability to compete, survive, and reproduce.

Explanation:

Darwinism is a theory of biological evolution developed by the English naturalist Charles Darwin and others, stating that all species of organisms arise and develop through the natural selection of small, inherited variations that increase the individual's ability to compete, survive, and reproduce. Individuals in a species show variation in physical characteristics. As a consequence those individuals most suited to their environment survive and, given enough time, the species will gradually evolve.

from the original order (top to bottom) the new order will go

1 (founder)

4 (hawk)

2 (mutate)

3 (next generation)