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Life’s Diversity is a result of many speciation events

Life’s Diversity is a result of many speciation events . Earth’s Biodiversity is the result of Speciation & Extinction events . Until 10,000 years ago North America was home to large mammals such as mammoths, camels, giant sloths, saber-toothed tigers, etc.

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Life’s Diversity is a result of many speciation events

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  1. Life’s Diversity is a result of many speciation events

  2. Earth’s Biodiversity is the result of Speciation & Extinction events • Until 10,000 years ago North America was home to large mammals such as mammoths, camels, giant sloths, saber-toothed tigers, etc. • Nearly all of these animals went extinct with the arrival of first humans on continent

  3. Extinction • The disappearance of a species from Earth forever • Natural process…occurs gradually one species at a time… • “background extinction rate”

  4. Some species are more vulnerable than others… Discovered in 1963….none have been seen since 1989….

  5. Causes of Extinction • Rapid or severe change in environmental conditions….natural selection does not have enough time to work • At risk populations: • Endemic – occurs nowhere else in the world • Small populations • Specialized species - a species closely fit to a specific environment and able to tolerate little change in that environment

  6. Earth has seen 5 mass extinction events • Occurred at widely spaced intervals over Earth’s 4.2 Billion year history • Wiped out 50-95% of planets species at one time! • Most well known K-T event 65 million years ago…caused by giant asteroid…wiped out the dinosaurs

  7. Permian Period Mass Extinction Event • Wiped out 75-95% of all species on earth • Hypothesis…..massive volcanism released greenhouse gases “CO2”….inducing global warming…leading to severe climate change….and chemical changes in the oceans….loss of dissolved oxygen…bacteria producing toxic gases….killed all life in oceans….gases bubbled from oceans….killed all organisms on land as well…. Nova Video: Permian Period Mass Extinction Event

  8. 6th Mass Extinction Upon Us! Humans are to blame! Human population growth, development, and resource depletion are causing changes in Earth’s natural systems…. Destruction of natural habitats Hunting and harvesting of species Introduction of non-native species Could be one of the biggest environmental problem humans face….because the loss of species is IRREVERSIBLE

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