Chapter 53

Cards (25)

  • Population Ecology
    Explores how biotic and abiotic factors influence the abundance, dispersion, and age structure of populations
  • Population Density Factors
    Biotic and abiotic factors affect population density, dispersion, and demographics
  • Dispersion
    The pattern of spacing among individuals within the boundaries of the population
  • Mark-Recapture Method
    Capture, tag, and release sample of individuals in a population.(s) Capture second sample of individuals(n) and note how many are marked. (x) N=population size
    N= sn/x
  • Emigration
    The movement of individuals out of a population
  • Patterns of Dispersion
    Most common pattern is CLUMPED, this is when individuals aggregate in patches.
  • Benefits of clumped
    • resource availability
    • Mating Behavior
    • Group defense against predators
  • Uniform dispersion
    Individuals are evenly distributed. Influenced by territoriality, the defense of other individuals.
  • Random Dispersion
    The position of individual is independent of other individuals
  • Demography
    Study of these vital statistics of a population and how they change over time
  • cohort
    group of individuals of the same age
  • Survivorship curves
    Graphic way of representing the data in a life table
  • Survivorship Curves
    • Type 1: low death rates during early & middle life and an increase in death rates among older age groups
    • Type 2: A constant death rate over the organism's life span
    • Type 3: High death rates for the young and a lower death rate for survivors
  • Reproductive Rates 

    Reproductive output for sexual organisms is measured as the average number of female offspring produced by the females in an age group
  • population growth rate equation
    N/t=N/t =BDB-D
    N is the change in population size, t is the time interval, B is the number of births, and D is the number of deaths
  • Exponential Population growth
    Population increase under idealized conditions
  • Carrying Capacity
    (K) is the maximum population size the environment can support
  • Logistic model
    describes how a population grows more slowly as it nears its carrying capacity
  • The logistic Model and real populations
    S-shaped curve. These organisms are grown in a constant environment lacking predators and competitors
  • Organisms life history
    • The age at first reproduction (maturity)
    • How often the organism reproduces
    • How many offspring reproduced
  • Semelparity
    Reproduce one and die
  • Iteroparity
    repeated reproduction, produce offspring repeatedly
  • Density-independent
    populations, birth rate, and death rate don't change with population density
  • Density-dependent
    populations, birth rates fall, and death increase with rising population density
  • Factors of density-dependence
    • Competition for resources
    • Disease
    • Predation
    • Territoriality
    • Toxic wastes