Evolutionary History

1. Evolutionary History • Evolution does not occur in a vacuum; it depends on: • Geology – distribution of land and water • Climate – temperature, precipitation, latitude, ocean currents • Chemistry – water, atmosphere, soil • Other organisms • Predation, parasitism, mutualism, competition, habitat changes • Fate • Extraterrestrial (and earth-bound) caused extinction events • Probabilities of dispersal, gene change, etc. • Mechanisms of evolutionary change

2. Geology • “Big” time - Geological time periods • Plate tectonics & continental drift

3. Time - Geological time periods Eons Eras • Hierarchical units of geological time • Defined by changes in fossils • Eras named after the animal fossils • Extinctions occur at boundaries Recent animals Middle animals Visible animals Old animals 540 mybp → First animals

4. Geological time Know eras (named after animal life as fossilized) absolute timing of eras relative timing within the eras of important events (see our timeline) you don’t need to remember the periods, but if you want to, learn them Mnemonics UC Berkeley Time Machine 65 mybp → 245 mybp → 540 mybp →

5. Mechanism New crust at mid-ocean ridges Sea floor spreading, carries continents Subduction under continents Christopher Scotese Web Sites Walk Thru Time – 580 concept frame Plate tectonics & continental drift