BIOL 1104 Lecture Notes - Lecture 2: Big Bang, Semelparity And Iteroparity, Microclimate
4 Sep 2018
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Type i: flat at the start, reflecting low death rates during early and middle life, and then drops steeply as death rates increase among older age-groups (humans) Type ii: i(cid:374)ter(cid:373)ediate, (cid:449)ith a (cid:272)o(cid:374)sta(cid:374)t death rate o(cid:448)er the orga(cid:374)is(cid:373)"s life spa(cid:374) (squirrels) Logistic population growth: per capita population growth rate approaches zero as carrying capacity is reached: semelparity: reproduction in which an organism produces all of its offspring in a single event, also known as big bang reproduction (salmon) Iteroparity: reproduction in which adults produce offspring over many years, also known as repeated reproduction (humans: k-selection: selection for traits that are sensitive to population density and are favoured at high densities. Populatio(cid:374)"s gro(cid:449)th rate = (cid:271)irth rate (cid:373)i(cid:374)us death rate. Logistic model: describes how a population grows more slowly as it nears its carrying capacity. Exponential growth cannot be sustained for very long. It is more realistic to incorporate the carrying capacity (k), the maximum population size the environment can support.
