QUIZ 7

Apuntes

QUIZ 7 Lecture 19: The History of Life on Earth: Part 2 Marked by Explosive Adaptive Radiations And Mass Extinctions The History of Life on Earth Cenozoic : Age of Mammals Mesozoic : Age of Reptiles Paleozoic : Age of Invertebrates Precambrian : Age of Single Cell Total extinction rate (families per million years): Time (millions of years ago) Number of families: Cenozoic Mesozoic Paleozoic Changes in physical environment • Estimated 99% of species in the history of Earth have gone extinct • What explains extinction and speciation over geological scale? • Environmental changes: ▪ Plate tectonics ▪ Climate change ▪ Volcanoes ▪ Meteorites ▪ Biotic - induced changes • Plate tectonics hypothesis only accepted in 1960s! • Plates converge, diverge, or slide • Movement and changes in sizes of continents Plate tectonics • Plate tectonics hypothesis only accepted in 1960s! • Plates converge, diverge, or slide • Movement and changes in sizes of continents affects: • ocean circulation • global climate • sea levels • Glaciation • Volcanoes • mountain and island formation Plate tectonics Volcanic Eruptions and meteoroids can dramatically chan...