Natural Selection

What is Natural Selection? Classic Peppered Moth Example Primary mechanism for evolution “Survival of the fittest” Individuals that have traits that are better suited to their environment will more likely survive and reproduce.

Natural Selection Affects… Populations – a group of organisms of the same species that live in the same geographic area and successfully interbreed.

Factors of Natural Selection 1. All populations have genetic variation.

2. Environment presents challenges to successful reproduction.

3. Individuals tend to have more offspring than the environment can support.

4. Individuals that are better able to cope with the challenges presented by their environment tend to leave more offspring than those individuals less suited to the environment do.

Adaptations A feature that is common in a population because it provides some improved function. They are produced by natural selection Can include: Behaviors Proteins that function at the cellular level Anatomical features

Examples of Adaptations Creosote bush producing toxins that prevent other plants from growing nearby thus reducing competition Mimicry of leaves by insects to evade predators

Example of Adaptations Echolocation of bats to capture insects

Natural Selection At Work Non-poisonous King Snakes mimic the poisonous Coral Snake Orchids “fool” wasps into mating with them to spread help spread their pollen

Natural Selection At Work Birds mating rituals can include a “dance” The male blue-footed booby, shown to the right, exaggerates his foot movements to attract a mate.

Natural Selection At Work Galapagos Island finches beaks are different shapes

Natural Selection at Work Human activity prompted the changes in the 19th century for the peppered moths