BIO120H1 Lecture Notes - Lecture 19: Survivorship Curve, Evolutionary Ecology, Net Reproduction Rate
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BIO120H1 Full Course Notes
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Typical life history for higher plants and animals. When have enough resources, become mature, start spending resources on reproductio. Some expend all resources at once, some spread them out. Need to consider age structure of populations to: But now, fecundity and survivorship vary with age. If birth and death rates constant, pyramid shape stays constant. Arbitrary units of time chosen to give a reasonable number of age classes for the organism in question. Humans, typically 5-year intervals, therefore about 20 age classes ction anism. Data that summarize the life events that are statistically expected for the average individual of a specified age in a population. Lx = probability of being alive at age x. Survivorship curve = a graph of lx vs. x. Shape of lx curve is characteristic of species. If mortality is constant with age, get exponential decline with half-life (type ii) usually graph lx curves as log plots, where type ii is a straight line.
