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AP ENVS. WED DEC 18 2013. UNIT 3: THE LIVING WORLD. CHAPTER 3: EVOLUTION, BIODIVERSITY, AND POPULATION ECOLOGY. THE UNIT: CHAPS 3, 4, 5 (16). LEVELS OF ECOLOGICAL ORGANIZATION ECOSYSTEM COMMUNITY POPULATION INDIVIDUAL. CHAPTER 3: POPULATION LEVEL.
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AP ENVS WED DEC 18 2013
UNIT 3: THE LIVING WORLD CHAPTER 3: EVOLUTION, BIODIVERSITY, AND POPULATION ECOLOGY
THE UNIT: CHAPS 3, 4, 5 (16) • LEVELS OF ECOLOGICAL ORGANIZATION • ECOSYSTEM • COMMUNITY • POPULATION • INDIVIDUAL
CHAPTER 3: POPULATION LEVEL • A population is a collection of individuals of the same species, living within the same geographic location and within the same community and ecosystem. • For life-forms that reproduce sexually, there will be variability of traits within that population. • Individual variability will also arise out of genetic mutation
DARWIN: “THAT’S IT?! I THOUGHT IT WOULD BE.....WELL, BIGGER!
AS A YOUNG MAN... “I don’t feel too well!”
ONE BIG ISLAND-----TWO SMALLER ISLANDS • ISLAND A: Mountainous, Dry climate • ISLAND B: Exposed, Wet climate
ONE BIG ISLAND-------TWO SMALLER ISLANDS • ISLAND A: Mountainous, Dry climate, TOUGH SEED SHELLS • ISLAND B: Exposed, Wet climate, SOFTER SEEDS
DARWIN’S FINCHES DRY ISLAND A, TOUGH SEEDS WET ISLAND B, SOFT SEEDS
DARWIN • “BY JOVE! THE ENVIRONMENTAL CONDITIONS SPLIT ONE SPECIES INTO TWO!” • “IT CHANGED THE SMALL-BEAKED BIRDS INTO BIG-BEAKED!”
DARWIN • “WOULD THIS ALSO OCCUR ON THE SAME ISLAND?”
NATURAL SELECTION • “A significant change in the environment will “select” out of a population those individuals possessing a trait that gives them an advantage.” • “These individuals will die at a slower rate than individuals without this trait, and will tend to find one another for mating with more frequency.” • “Over time, and generations, the original trait will be strengthened, as reflected in a higher and higher % of individuals with that trait....until a new species is formed.”
ISLAND A • FINCH LIFE-SPAN: 5 YEARS • TIME ZERO: 95% small-beaked, 5% big-beaked • 20 YEARS: 90% small-beaked, 10% big-beaked • 10,000 YEARS: 99% BIG-BEAKED
DIVERGENT v CONVERGENT EVOLUTION • DIVERGENT: Closely related species in different environments with very different selective pressures • CONVERGENT: Unrelated species in similar environments
EVOLUTION WORKING AGAINST MANKIND • ANTI-BIOTIC RESISTANCE • PESTIC IDE RESISTANCE