Evolution

Adaptive Radiation

Adaptive Radiation

• The speciation and adaptation of an array of species

• Species show different morphological and physiological traits

Galapagos

Darwin’s Finches

• Darwin noticed varieties of finches on the Galapagos

• Kept specimens, but didn’t record which islands they came from

• Back in England, recognized they were closely related, but different species

• Finches evolved from an ancestor that came from mainland S.America

Darwin’s Finches

Convergent and Divergent Evolution

Convergent• Pattern of evolution in

which similar traits arise because different species have independently adapted to similar conditions

Divergent• Pattern of evolution in

which species that were once similar to an ancestral species diverge, or become more distinct

Convergent

Divergent

Mass Extinctions

Mass Extinctions

• Large scale dying out of a large percentage of all living organisms in an area over a relatively short period of time

• There have been 5 global mass extinctions

The Big 5Era Time Extinction CauseCretaceous – Tertiary

65.5 Ma 50% of all Genera, 75% of all speciesDinos killed off, mammals and bird evolved as dominant

Asteroid or Comet, volcanic events

Triassic-Jurassic

205 Ma 48% of all GeneraLarge amphibians, other non-dinosDinos evolved as dominant (no competition)

Small impacts, gradual climate change, massive volcanic eruptions

Permian-Triassic

251 Ma 83% of all GeneraMany insects killed off, Archosaurs become dominantMother of all mass extinctions

Impact?Volcanism, climate change, Combination?

Late Devonian

360-375 Ma

50% of all Genera Many causes, ocean anoxia, global cooling caused by ocean volcanism

Ordovician-Silurian

440-450 Ma

57% of all GeneraMany invertebrates extinct

Movement of Gondwana

Co-evolution

Coevolution

• The change of a species triggered by the change of a related object