chapter 4 pre-test
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section 4.1
introduction to ecology video
biological levels (amoeba sisters)
BECPO pyramid
penguins and polar bears
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section 4.2
limiting factors and carrying capacity video
crash course population ecology video
exponential growth image
overshoot and dieback image
degraded carrying capacity image
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section 4.3
interactions among living things video (move to ch 5)
video 3
video 4
