structural:expansion
Evolutionary processes

Evolution is a central organizing concept in biology. It is the change in heritable characteristics of populations over successive generations. In artificial selection, animals were selectively bred for specific traits. Given that traits are inherited, populations contain a varied mix of traits, and reproduction is able to increase any population, Darwin argued that in the natural world, it was nature that played the role of humans in selecting for specific traits. Darwin inferred that individuals who possessed heritable traits better adapted to their environments are more likely to survive and produce more offspring than other individuals. He further inferred that this would lead to the accumulation of favorable traits over successive generations, thereby increasing the match between the organisms and their environment.