CHAPTER 11.6

SECTION 1

• Evolution through natural selection is not random.
• Mutations + genetic drift can't be predicted, called random events.
• The environment controls direction taken by natural selection.
• Convergent evolution: evolution toward similar traits in unrelated species
• Divergent evolution: closely related species evolving different direction

SECTION 2

• Species can shape each other over time.
• Species interact with each other in many different ways.
• Coevolution: 2+ species evolve in response to changes within each other
• Can occur in competitive relationships
• Each species reacts to the actions in another; evolutionary change results

SECTION 3

• Species can become extinct.
• Extinction: elimination of a species on Earth
• Background extinctions: occur continuously at low rate
• Mass extinctions: occur suddenly

SECTION 4

• Specification often occurs in patterns.
• Punctuated equilibrium: occur suddenly; followed by long periods of little evolutionary change
• Adaptive radiation: diversification of one ancestral species into many descendant species
• In first 10 million years after dinosaurs, 4,000+ mammal species had evolved.
• The earliest mammals barely resemble the mammals today.