BIOLOGY 3SS3 Lecture Notes - Lecture 4: Paramecium, Exponential Growth, Models 1
10 Mar 2015
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Introduction: in linear population models, per capita rates are independent of popu- lation size, now we"ll discuss why large and small populations might have di erent birth or death rates. And what this implies about population dynamicss. The rst law of population dynamics: if individuals are behaving independently: The population-level rate of growth (or decline) is proportional to the population size. The second law of population dynamics: exponential growth (or decline) cannot continue forever, something is changing the average rate at which populations we observe grow. Population regulation: all the populations we see are regulated. On average, population growth is higher when the population is lower. Lots of populations don"t look like they are regulated. Sometimes regulation is apparent: some species seem to ll a niche (mangroves, or deplete their own food resources (gypsy moths) Sometimes regulation is not apparent: other species seem like they could easily be more common (pine trees)
