BIO120H1 Lecture Notes - Lecture 19: Survivorship Curve, Net Reproduction Rate, Fecundity
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BIO120H1 Full Course Notes
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Lecture 19 - age-structured populations and life histories. Typical life history for higher plants & animals. Get bigger so you can handle the challenges from the environment. Sexual maturity: when have enough resources, become mature, start spending resources on reproduction. Organisms show various lifestyles after sexual maturity. Need to consider age structure of populations to: But now, fecundity and survivorship vary with age. Variation summarized by life tables of age-specific rates. Without age structured, population models assume individuals equal in capacity to contribute to population size change. If birth & deaths rates stay constant, pyramid shape is stable but human rates are always changing. 1961: pyramidal structure; high mortality age structure changes as life expectancy goes up. 1931: chipped at the base - wwi death. 1961: gap from 40-50 yrs because of ww1; post war baby boom dependency ratio: # of children divided by the # of producers.
