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AP ENVS. THURS DEC 19 2013. 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 THURS DEC 19 2013
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
BIODIVERSITY • The extent of either geneticvariation 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).
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
SPECIATION • # 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
SPECIATION ON EARTH VARIES # SPECIES = SPECIATION RATE - EXTINCTION RATE
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 • MAN-MADE “Extinction rate is now documented to be about 2 species per year or 0.01% per year.”
SPECIES ON THE BRINK • http://content.time.com/time/photogallery/0,29307,1888702_1863780,00.html
U.S. ENDANGERED SPECIES ACT • 1973 • Richard Nixon • Protects habitat
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.
K-T EXTINCTION https://www.youtube.com/watch?v=ubBebEywNmE
NASA JPL NEO PROGRAM • http://neo.jpl.nasa.gov/