LIFESCI 1 Lecture 28: wk #10 ecology (complete)
Document Summary
Study of relationships of organisms to each other & to environment (distribution, abundance, causation); patterns & processes at ecological levels. Interactions between biotic & abiotic factors -> distribution & abundance. Key features: abundance: number of individuals, biomass: amount of living material. Population distribution (dispersion: clumped: gather around main resource, uniform: individuals battling for their own territory, random: no strong competition for resources. Logistic growth: as n approaches k (carrying capacity), intraspecific competition increases. Size & density: mobile: mark & recapture (assume: randomly distributed, captured, marking not fatal & not lost) Dangers at each growth stage (egg, larva, pupa, adult) Survivorship curves: type i: most mortality late in life, type ii: consistent mortality, type iii: high mortality early in life (once established, always there) Life history continuum: high survivorship, low reproductive capacity or vice versa, can"t do both. Effects on pop size: density independent factors. Physiological (some secrete hormones that repress reproduction)
