Unit 6Ecology Study Guide

-Behavioral ecology: study of interaction between animals and their environments.

-Ethology: study of animal behavior

-Imprinting: innate behavior learned during critical period early in life (baby ducks imprint to mama ducks)

-Migration: cyclic movement of animals over long distances according to the time of year.

-Taxis: reflex movement toward or away from a stimulus

-Coefficient of relatedness: statistic that represents the average proportion of genes two individuals have in common. The higher the value, the more likely they are to help one another.

-Chemical: communication through the use of chemical signals, such as pheromones

-Visual: communication through the use of visual cues, such as the tail feather displays of peacocks

-Auditory: communication through the use of sound, such as the chirping of frogs in the summer

-Population: collection of individuals of the same species living in the same geographic area

-Community: collection of populations of species in a geographic area

-Ecosystem: community + environment

-Biosphere: communities + ecosystems of the planet

-Biotic components: living organisms of ecosystem

-Abiotic components: nonliving players in ecosystem

-Dispersion patterns:

  • Clumped dispersion: animals live in packs spaced from each other (e.g. cattle)
  • Uniform distribution: species are evenly spaced out across an area (e.g. birds on a wire)
  • Random distribution: species are randomly distributed across an area,( e.g. trees in a forest)

-Biotic potential: maximum growth rate for a population

-Carrying capacity: maximum number of individuals that a population can sustain in a given environment

-Limiting factors: factors that keep population size in check

  • Density dependent (food, waste, disease)
  • Density independent (weather, natural disasters)

-Population growth

  • Exponential growth (J shaped curve, unlimited growth)
  • Logistic growth (S shaped curve, limited growth)

-Life history strategies:

  • K-selected populations (constant population size or growth, low reproductive rate, extensive parental care – kangaroos)
  • R-selected population (rapid population growth, J curve style, little parental care, quick reproduction, high death rate – roaches)

-Survivorship curves: show survival rates for different-aged members of a population

  • Type I: live long life, until age is reached where death rate increases rapidly – humans, large mammals
  • Type II: constant death rate across the age spectrum – lizards, small mammals
  • Type III: steep downward death rate for young individuals that flattens out at certain age – fish, oysters, sea turtles

-Parasitism: one organism benefits at another’s expense (ticks and humans)

-Commensalism: one organism benefits while the other is unaffected (clownfish and anemones)

-Mutualism: both organisms benefit from the interaction (acacia trees and ants)

-Competition: both species are harmed by the interaction

-Predation: one species, the predator, hunts the other, the prey

-Primary succession: occurs in area devoid of life that contains no soil

  • Pioneer species come in, add nutrients, and are replaced by future species which attract animals to the area, thus adding more nutrients
  • Constant changing until the climax community is reached and a steady-state equilibrium is achieved

-Secondary succession: occurs in area that once had stable life but was disturbed by major force (fire)

-Trophic levels: hierarchy of energy levels on a planet; energy level decreases from bottom to top; primary producers (bottom)  primary consumers (herbivores)  secondary consumers  tertiary consumers  decomposers