Bio 004,CH18, College of the Desert

  1. Abiotic components
    Nonliving chemical and physical factors.
  2. Biotic components
    Living factors.
  3. Organism
    The basic unit of cological systems. Organismal ecology – pertains to the evolutionary adaptations that enable organisms to meet the challenges posed by their abiotic environments.
  4. Population
    A group of individuals of the same species living in the same place at the same time. Population ecology – pertains mainly to factors that affect population density and growth.
  5. Community
    Consists of all organisms that inhabit a particular area; assemblage of populations of different species. Community ecology – pertains to how interactions between species affect community structure and organization.
  6. Ecosystem

    Includes all the biotic and abiotic factors within a specific area. Ecosystem ecology – pertains to energy flow and the cycling of chemicals among various biotic and abiotic factors.

  7. Biosphere
    The global ecosystem; the sum of all the planet’s ecosystems – all of the life and where it lives.
  8. Abiotic Components of
    the Biosphere
    • 1. Sunlight
    • 2. Water
    • 3. Temperature
    • 4. Wind
    • 5. Rocks and soil
    • 6. Periodic Disturbances
  9. Acclimation
    Physiological response to a situation that is long term, but still reversible.
  10. Anatomical Responses
    Acclimation that may become irreversible or reversible on a seasonal basis.
  11. Behavioral Responses
    Acclimation that is a change based in behavior rather than a physical adaptation.
  12. Population Density
    • Number of individuals of a species per unit area or volume.
    • Dependent on: Size and behavior of species.
    • a) Ant colonies - millions of individuals/acre
    • b) One mountain lion/territory of 100 sq. mi.
  13. Patterns of Dispersion

    Way in which individuals spread out within a population’s geographic range.

  14. Clumped
    • Individuals aggregated in patches.

    • a) Most common in nature.

    • b) Associated with uneven nutrient distribution (fungi) or social behaviors (wolves).

  15. Uniform
    Evenly spaced pattern of dispersion; direct result of individual interactions (gannets).
  16. Random
    • Position of each individual is independent of other individuals.
    • a) No strong attractions/repulsions
    • b) Least common in nature
    • c) Seeds (dandelions).
  17. Zero population growth
    Occurs when birth and death rates of a population are equal
  18. Exponential population growth
    Maximum increase of a species’ population under ideal conditions.
  19. Carrying capacity

    Maximum population size a particular environment can support.

  20. Logistic population growth
    Population increase levels off as carrying capacity is reached
  21. Density Dependent Factor
    Population-limiting factor whose effects intensify as population density increases. *Dwindling food supply *Buildup of toxic wastes *Decrease a population’s growth rate by increasing death rate, decreasing birth rate, or both.
  22. Intraspecific competition
    Competition between individuals of the same species for the same limited resources. A s population size increases, competition for resources increases and growth rate declines in proportion to intensity of competition.
  23. Density Independent Factor
    Population-limiting factor whose intensity is unrelated to population density. Mainly affected by abiotic factors (aphids).
  24. Snowshoe Hare and
    Two species whose population size is directly dependent on the other.
  25. Age structure

    The relative numbers of individuals at each age in a population.

  26. Human Population
    Growth - 3 categories
    • 1. Pre-reproductive juveniles
    • 2. Reproductive adults
    • 3. Post-reproductive adults
  27. Life History

    The series of events from birth through reproduction and death that affect an organism’s life schedule. Variable 1: At what age reproduction begins: Variable 2: How often reproduction occurs Variable 3: How many offspring are produced

  28. Cohort

    A group of individuals of the same age whose fate can be followed from birth to death.

  29. Survivorship curves
    Plot of the proportion or numbers in a cohort still alive at each age.
  30. Idealized
    Survivorship Curves
    • Type I: Low death rates during early and middle life, but steep death rates during late life. Few offspring with much care (humans).
    • Type II: Constant death rates during the entire life of an organism. More offspring with some care (birds).
    • Type III: High death rates during early life, but leveling off during middle and late life. Many offspring with little
    • care (alligators).
Card Set
Bio 004,CH18, College of the Desert
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