15.3 Evolution in Action

Standards CLE Explain how evolution contributes to the amount of biodiversity CLE Explain how genetic variation in a population and changing environmental conditions are associated with adaptation and the emergence of new species.

How does evolution work? Natural Selection can work in several ways: Natural Selection can work in several ways: Convergent Evolution: the process by which unrelated species become more similar as they adapt to the same kind of environment Divergent Evolution: the process by which two or more related but reproductively isolated populations become more and more dissimilar Co-Evolution: the process by which two or more unrelated species evolve together because of a symbiotic relationship.

Convergent Evolution How it happens: How it happens: Example: Example: Two genetically different species adapt to the same environment in similar ways resulting in similar phenotypes.

Convergent Evolution Leads to analogous structures: Leads to analogous structures:

Divergent Evolution How it happens: Adaptive Radiation: One species branches off into two or more different species due to changes in environment or behavior. an evolutionary pattern in which many species evolve from a single ancestral species

Divergent Evolution Leads to homologous structures: Leads to homologous structures:

Co-Evolution How it happens: When two different species are dependent on each other; if one changes the other must adapt or go extinct.

Artificial Selection Natural Selection = environment determines desirable traits Artificial selection = humans determine desirable traits

Exit Ticket m.socrative.com Room: stewart348 Compare and contrast natural selection with artificial selection