extinction

• vestigal traits

  • reduced or incompletely developed structure
  • has no function or reduction function
  • similar to functioning structures in closely related species
  • Ex. tail bone in humans vs monkeys
• Archaeopteryx

  • example of transitional form
  • between dinosaurs and birds
  • some relation to both other species
• Tiktaalik

  • example of transitional form
  • sea to land
• Transitional Fossils

  • difficult to find
  • rare and spare, haven't been found for every species
  • living fossils, things that did not transition, but fossil records show
• Coelacanth

  • example of living fossil
  • 400 million years old
  • thought to be extinct
  • rediscovered in 1938 and again in 1997
• 98% of all species have gone extinct

  • dead-end, no transition
  • no longer exist, even in newer species
• End Permian Extinction

  • 80-96% species gone extinct
  • 250 million years ago
• Late Triassic Extinction

  • 205 million years ago
  • amphibians and reptiles gone extinct
• End-Cretaceous extinction

  • 6.5 million years ago
  • dinosaur extinction
• Anthropocene Extinction

  • ongoing extinction
  • cause: CO2 levels, hunting, force movement and environmental change
  • wild animals declined by 80% since the rise of humans
  • 35% of know plant species are threatened
  • coastal chaparral of SoCal is the most threatened
  • 1/3 of freshwater fish are endangered