BIOL 1010 Lecture Notes - Lecture 6: Phanerozoic, Ocean Current, Relative Dating
Document Summary
Bio 1010 november 27th 2018: preserved remnants (traces) of past life. Trace fossils (footprints etc: more direct view of evolutionary history than from living organisms. Information about past ecosystems; climate; sea levels & dating of geological record. Common, widespread fossils characteristic of particular periods of earth"s history. Crucial for relative dating" in geological record. Fossils of animals & plants common in the last ~550 million years: phanerozoic eon . Phanerozoic divided into 3 eras": each era subdivided into several periods". Mass extinctions: many species extinct in very short time, causes: large environmental changes like volcanic activity, changes in ocean circulation patterns or impact by asteroid or comet, major importance in history of life. Extinction of ~90% of species on earth. Many large taxa went totally extinct (e. g. ~50% of families) Extinction of ~50% of species on earth (like dinosaurs and several marine invertebrate groups) Adaptive radiations rapid speciation and evolutionary change in underexploited habitats.
