BIOL 1070 Lecture Notes - Fecundity, Density Dependence, Carrying Capacity

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Published on 26 Nov 2011
of 2
OCT 24th!
Population density variables: Population Size(N)
Population Density (N/area)
Birth and deathrates
Sex and age structure (#males vs. # females)
Fecundity (#eggs produced per female)
Fertility (% of eggs that are fertile!)
Production (Actual number of offspring produced by a population)
Recruitment (# of new individuals reaching breeding age, includes immigration)
How do species disperse? (Recruitment)
Natal: movement of young from their birthplace prior to reproducing (e.g MUSSELS!)
Breeding: movement of reproductively mature adults
Measuring pop. Density: top arrow – birth, immigration and bottom arrow- death,
PT2= Pt1 + (B-D) + (I-E)
Carrying capacity: Q1: food, space, predators
Density dependence: regulation of a population by changes in per capita birth or death
rates in response to density is said to be density dependent. Examplles of density
dependent: predators, space, ability to find a mate
- depletion of food supply that accompanies growth
- attraction of predators by high density prey
- increased infection by disease with higher density
Examples of density INDEPENDENCE:
- a rare extreme event
- hard freeze
- tornado
- flood
- landslide
density independent factors can intensify density dependent regulators
- a hard freeze