Biology3 ecology exam2

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  1. ecology
    the study of interactions between organism and environment
  2. population
    a group of organisms of the same species who live in a specific location and breed with one another
  3. species
    a type of organism
  4. population density
    the number of organisms of a particular population in a given area
  5. size (N)
    mean number of individuals in a population
  6. change in population equation
    (births - deaths) + (immigrants - emigrants) = change in population size
  7. growth rate equation
    r (growth rate) = b (births) - d (deaths)
  8. carrying capacity (K)
    • maximum number of individuals an environment can hold
    • S-shaped growth curve stabilizes at carrying capacity
  9. density
    density independent
    density dependent
    • density: number of individuals per given area
    • * independent: environmental factors that have nothing to do with population size (weather, temperature, etc.)
    • * dependent: environmental factors due to population size (predation, competition, etc.)
  10. dispersion
    3 types
    • how organisms are arranged in a population
    • clumped
    • uniform
    • random
  11. community
    a group of populations living close enough to potentially interact
  12. ecological niche
    • all the factors that affect or are affected by an organism
    • the role of a species in its community
  13. keystone species
    a species that plays a larger role in a community (starfish/muscles or beavers/dams)
  14. batesian mimicry
    harmless animals may evolve to resemble poisonous ones
  15. mullerian mimicry
    two unpalatable and harmful organisms resemble eachother
  16. symbiosis
    3 types
    • two organisms live together
    • commensalism: one species benefits and the other is unaffected
    • mutualism: both benefit
    • parasitism: one species benefits and the other is harmed
  17. competitive exclusion principal
    two species in the same area with same niche will compete for limited resources and one will out compete the other
  18. resource partitioning
    similar species in same area will usually occupy some slight differences in their niches (allows them to coexist)
  19. succession
    primary and secondary
    • a gradual change in a community in which one array of species replaces another
    • primary: ecological succession occurs in an area where there was previously no soil
    • secondary: ecological succession occurs in an area where a community previously existed and soil remains
  20. energy in the ecosystem
    energy enters ecosystem from sun, flows through it as food and exits as heat
  21. carbon cycle
    • CO2 in the atmosphere
    • taken in by plants during photosynthesis
    • consumed by herbivore => consumed by carnivore
    • carbon returns to atmosphere via organism's aerobic respiration
    • decomposition of wastes and the dead bring carbon to soil
    • soil bacteria and detritus feeders perform respiration
    • carbon diffuses between the atmosphere and the ocean
    • over time, sediments become carbon-rich rocks => fossil fuels
  22. nitrogen cycle
    • nitrogen in the atmosphere
    • nitrogen-fixing bacteria in legume roots and soil
    • they break N2 bonds and use nitrogen atoms to form ammonia => dissolves to form ammonium ions (NH4+)
    • plant roots take up ammonium which gets eaten by consumers and used in metabolic reactions
    • also, decomposers break down waste and remains to produce ammonium
    • bacteria convert ammonia to nitrates (nitrification) which plants can use
    • ecosystems lose nitrogen by denitrification, denitrifying bacteria use nitrate and give off nitrogen gas back to the atmosphere
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Biology3 ecology exam2
Biology3 ecology exam2
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