Natural Selection Natural selection: organisms with favorable traits for a particular environment survive, reproduce, and pass these traits on to the next generation (those with less favorable traits are less likely to survive).

Adaptation- inherited trait that has become common in a population because the trait provides a selective advantage

4 Rules of Natural Selection All populations have genetic variation.

The environment presents challenges to successful reproduction.

Individuals tend to produce more offspring than the environment can support.

Individuals that are better fit their environment tend to live longer, reproduce more, and spread their genes throughout the population.

Evolution of a Species = Speciation Species = group of organisms that look alike and have the ability to interbreed and produce fertile offspring in nature Speciation occurs when Interbreeding is prevented Production of fertile offspring is prevented

Causes of Speciation Isolation of populations - Two populations of the same species do not mate because of some form of separation If populations can’t interbreed due to isolation, their allele frequencies can become more and more different from each other Each population will adapt to its environment, eventually preventing breeding with members of other populations (reproductive isolation)