Evolutionary HistoryEvolutionary 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

GeologyGeology

• “Big” time - Geological time periods

• Plate tectonics & continental drift

Time - Geological time periodsTime - Geological time periods

• Hierarchical units of geological time

• Defined by changes in fossils

• Eras named after the animal fossils

• Extinctions occur at boundaries

Vis

ible

an

imal

s

Old animals

First animals

Middle animals

Recent animals

ErasEons

540 mybp 540 mybp →→

Geological Geological timetime

• 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 Machi

ne

540 mybp 540 mybp →→

245 mybp 245 mybp →→

65 mybp 65 mybp →→

Plate tectonics & continental driftPlate tectonics & continental drift

• 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