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AP ENVS

MON DEC 23 2013. AP ENVS. THE VOCABULARY OF EVOLUTION. Population Selection pressure Adaptation/Adaptive trait Genetic variation Mutation Directional selection Stabilizing selection Disruptive selection Divergent evolution Convergent evolution Artificial selection Speciation

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AP ENVS

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  1. MON DEC 23 2013 AP ENVS

  2. THE VOCABULARY OF EVOLUTION • Population • Selection pressure • Adaptation/Adaptive trait • Genetic variation • Mutation • Directional selection • Stabilizing selection • Disruptive selection • Divergent evolution • Convergent evolution • Artificial selection • Speciation • Extinction • Extirpation

  3. BIODIVERSITY • The extent of eithergeneticvariation of a population of individuals of one species... • ....OR, the extent of the variability of different species within the same community. • Community: A collection of individuals and species interacting and exchanging energy and materials via feeding relationships (food web).

  4. BIODIVERSITY • A HEALTHY EARTH = HIGH (RICH) BIODIVERSITY • PRESERVE THE RAINFORESTS! • Tree-fogger experiment! • “G_d must love beetles!” • There are many threats to maintaining rich biodiversity.....later

  5. SPECIATION • The act of generating new species as a result of selection pressure. • # Species on Earth? • # Known/characterized species? • Total # species ? • SAME...?? • http://news.nationalgeographic.com/news/2011/08/110824-earths-species-8-7-million-biology-planet-animals-science/ • http://bit.ly/1bVx6mO

  6. SPECIATION ON EARTH VARIES # SPECIES = SPECIATION RATE - EXTINCTIONRATE DYNAMIC

  7. EXTINCTION • NATURAL • Necessary to make room for improved versions! • Natural rate? • http://labs.russell.wisc.edu/peery/files/2011/12/7.-Extinction-a-Natural-and-Human-caused-Process.pdf • About 0.00001% to 0.0001% per year • MAN-MADE “Extinction rate is now documented to be about 2 species per year or 0.01% per year.” ??????

  8. MAN-MADE EXTINCTIONS

  9. SPECIES ON THE BRINK • http://content.time.com/time/photogallery/0,29307,1888702_1863780,00.html

  10. U.S. ENDANGERED SPECIES ACT • 1973 • Richard Nixon • Protects habitat

  11. MASS EXTINCTIONS • A sudden loss of multiple populations (extirpation) and/or multiple species (extinction) arising from some natural cataclysmic event: • Volcanic eruptions (“flood basalt”) • Sea-level falls • Sustained and significant global cooling (“ice ages”) • Sustained and significant global warming • H2S emissions • Ozone layer degradation (UV exposure) • Anoxic events • Gamma-ray burst (nova, supernova) • Ozone • Superquakes • Impacts from space

  12. FIVE MASS EXTINCTIONS

  13. IS MANKIND CAUSING THE “SIXTH”?!

  14. FOSSIL RECORD Paleontological dating methods: isotopic measurements

  15. IMPACTS FROM SPACE & MASS EXTINCTION EVENTS!

  16. THE K-T MASS EXTINCTION EVENT • 65 million years • Geologic horizons show abrupt drop in dinosaur fossil record, all over the world • These horizons are rich in iridium, a transition metal present only in trace levels on Earth, but abundant in asteroids/comets/meteors.

  17. IRIDIUM

  18. K-T EXTINCTION https://www.youtube.com/watch?v=ubBebEywNmE

  19. K-T EXTINCTION • Asteroid impacts land/sea (present-day Yucatan) • Local devastation, but worldwide extinctions?!

  20. COULD THIS HAPPEN....TO US?!

  21. NASA JPL NEO PROGRAM • http://neo.jpl.nasa.gov/

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