17-4 Patterns of Evolution Macroevolution is a word meaning large-scale evolutionary patterns and processes that occur over long periods of time

Extinction Usually, extinctions happen for Darwinian reasons. Some species adapt and survive, Others gradually become extinct in ways that are caused by natural selection. Several times in the Earth’s history, however, mass extinctions wiped out entire ecosystems. Researchers have not yet determined the precise causes of mass extinctions.

Adaptive Radiation Adaptive Radiation is when a species or a small group of species has evolved, through natural selection, into diverse forms that live in different ways. The disappearance of the dinosaurs cleared the way for the great adaptive radiation of mammals.

Adaptive Radiation The radiation of mammals produced the great diversity of their species during the Cenezoic.

Convergent Evolution Convergent evolution is the process by which unrelated organisms come to look like eachother. Convergent evolution involving fishes, 2 groups of aquatic mammals, and swimming birds has resulted in sharks, dolphins, seals, and penguins whose streamlined bodies and swimming appendages look the same

Coevolution The process where 2 species evolve in responses to changes in eachother over time is called coevolution. Many flowering plants, for example, can reproduce only if the shape, color, and odor of their flowers attract a specific type of pollinator.

How is this an example of co-evolution?

How is this an example of coevolution?

Coevolution Some of the most powerful poisons in nature are plant compounds that have evolved in response to insect attacks.

Punctuated Equilibrium At several points in the fossil record, changes in plants or animals occurred over relatively short periods of time. Some biologists suggest that most new species are produced by periods of rapid change. Scientists use the term punctuated equilibrium to describe this pattern of long, stable periods interrupted by brief periods of more rapid change.

Punctuated Equilibrium Rapid evolution after long periods of equilibrium can occur when a small population becomes isolated from the main population, genetic changes can then spread in the small population very fast.