CAS BI 107 Lecture Notes - Lecture 18: Species Pool, Species Richness, Life Table
14 Nov 2016
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Document Summary
Ecological efficiency the overall transfer of energy from one trophic level to the next: ratio of consumer production to producer production. Influences on immigration and extinction rates are distance from the species pool and size of island. N1=n0+(b-d)+(i-e: n1 =number of individuals at time 1, n0= number of individuals at time 0, b=births, d=deaths, i=immigration, e=emigration. Life history: a description of the life cycle of an organism that includes birth, development, reproduction, and death, the adaptations of an organism that influence its age-specific survival and fecundity. Intrinsic rate of increase (r: maximum rate of increase of a population per individual, r=b-d. Model for exponential population growth: change in number / change in time = intrinsic number, dn/dt=rn. Carrying capacity (k: dn/dt=rn * (k-n)/k. Density-dependent factors effects increase in proportion to population density: food supply, predators, pathogens. Density-independent limits per capita growth rate: usually abiotic factors, intense storms or cold periods.
