Communities

Population Genetics

Gene Pools

All alleles in every gene in a population make up a gene pool

Allele Frequency: # alleles of one type divided by total # of alleles

Genotype Frequency: # genotypes of one type divided by total # of individuals

Hardy Weinberg Equation:predicts an equilibrium-unchanging allele and genotype frequencies from generation to generation

Assumptions of HW:

  1. No selection
  1. No mutation
  1. No migration
  1. Large population
  1. Random Mating

Microevolution: changes in pop. gene pool from generation to generation

Genetic Drift: random loss of alleles

Mutation: Change in one of nucleic acids.

Nonrandom Mating: plants choose their mates.

Gene Flow: movement of alleles into and out of a population.

Exponential Growth: dN/dt=rN

Logistic Growth: dN/dt=rN (1-N/K)

Life History: predicting whether a population will grow or shrink

Life tables summarize birth and death rates for organisms at different stages in their life.

Population Growth

x = age

Nx= number of individuals alive at age x

Sx= proportion of individuals of age x that survive to age x+1;
Nx+1/Nx

lx= proportion of individuals that survive from birth (age 0) to age x;Nx/N0

Fx= average number of offspring born to a female while she is age x

lx(Fx) = average number of offspring per capita at age x

lx(Fx)x = average number of offspring per capita at time x, weighted by age x

Species Interaction within a community

Community:a group of actually or potentially interacting species living in the same location.

Growth models:r = intrinsic growth rate
N = population size
K = carrying capacity
dN/dt = population change over time

Lotka-Voltera: explains how predator and prey fluctuate around one another populations

Prey: dN/dt=rN-aNP

Predator: dP/dt=faNP-qp