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The accelerating loss of species

The accelerating loss of species. The Sixth Extinction. Mass Extinctions. A mass Extinction is: - When at least half of all species (including animals and plants) die within a relatively short time. We know these extinction occurred -Through the fossil record

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The accelerating loss of species

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  1. The accelerating loss of species The Sixth Extinction

  2. Mass Extinctions • A mass Extinction is: • - When at least half of all species (including animals and plants) die within a relatively short time. • We know these extinction occurred • -Through the fossil record • -Fossils of plants and animals in early layers are suddenly not present in later rock layers. • Scientist believe that 99% of all plant and animal species that have ever lived are now extinct.

  3. The First Extinction • Ordovician-Silurian • 440 million years ago • Caused by: sudden global cooling • Extinction of marine organisms • This was a time when the Earth was covered with land plants.

  4. Second Extinction • Devonian Extinction • 370 million years ago • Caused by: possible climate change • Extinction of tropical marine species

  5. The Third Extinction • Permian – Triassic Extinction • 245 million years ago • Caused by: climate change, plate tectonic movement or possible comet or meteor impact. • Largest mass extinction – so far • Killed a range of species, including vertebrates • Only 10% of species survived.

  6. The Fourth Extinction • Triassic – Jurassic Extinction • 210 mya • Unknown cause • Extinction of land vertebrates

  7. The Fifth Extinction • Cretaceous-Tertiary • 65 million years ago • Caused by: collision of comet or meteor and/or volcanic eruption • Extinction of dinosaurs, marine life, and many other plant and animal species • 50 – 75% of animals extinct • Global temperature decreased • Rise of the primates

  8. The Sixth Extinction • The sixth extinction is happening today. • All other mass extinctions were caused by natural disasters. • The sixth, however is being caused by modern humans.

  9. When did the sixth extinction begin? • When modern homo sapiens began to radiate to different parts of the world. • Only in places where early hominids lived (Africa, Europe and Asia) did native plant and animal species survive in the beginning. • Some paleoanthropologists believe that the Neanderthals became extinct due to warfare or competition from modern humans.

  10. Quickly after the arrival of modern humans, native species began to disappear North America – 12,500 years ago • - butchering killed off mammoths, mastodons, and ancient buffalos Caribbean – 8000 years ago • Lost all larger native species Madagascar – 2000 years ago -lost larger lemurs elephant birds, a species of hippo, etc.

  11. How are modern humans causing the sixth extinction? • 1. Pollution • 2. Warfare • 3. Exploitation of Species • 4. Overpopulation • 5. Unnatural rates of consumption

  12. What can we do?

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