Ecology Rapid Review for AP Biology

By — McGraw-Hill Professional
Updated on Oct 24, 2011

For a more thorough review of the terminologies below, refer to these concepts:

The following terms are important for ecology review:

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 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—cattle), uniform distribution (animals are evenly spaced out across an area, e.g., birds on a wire), random distribution (animals 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 size, low reproductive rate, extensive postnatal care—humans); R-selected populations (rapid growth, J-curve style, little postnatal care, reproduce quickly, die quickly—bacteria).

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, hydra, small mammals.
  • Type III: steep downward death rate for young individuals that flattens out at certain age—fish, oysters.

Forms of Species Interaction

  • Parasitism: one organism benefits at another's expense (tapeworms and humans).
  • Commensalism: one organism benefits while the other is unaffected (cattle egrets and cattle).
  • Mutualism: both organisms reap benefits from the interaction (acacia trees and ants, lichen).
  • Competition: both species are harmed by the interaction (intraspecific vs. interspecific).
  • Predation: one species, the predator, hunts the other, the prey.

Defense Mechanisms

  • Cryptic coloration: coloring scheme that allows organism to blend into colors of environment.
  • Deceptive markings: patterns that cause an animal to appear larger or more dangerous than it really is.
  • Aposematic coloration: warning coloration adopted by animals that possess a chemical defense mechanism.
  • Batesian mimicry: animal that is harmless copies the appearance of an animal that is dangerous.
  • Müllerian mimicry: Two aposemetrically colored species have a similar coloration pattern.

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 of guards 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).

Biomes: The Special Facts

I recommend that you read the biome material in the above review concepts for more detail.

  • Desert: driest land biome.
  • Taiga: lengthy cold, wet winters; lots of conifers.
  • Temperate grasslands: most fertile soil of all.
  • Tundra: permafrost, cold winters, short shrubs.
  • Savanna: grasslands, home to herbivores.
  • Deciduous forest: cold winters/warm summers.
  • Tropical forest: greatest diversity of species.
  • Water biomes: freshwater and marine biomes of earth.

Trophic levels: hierarchy of energy levels on a planet. Energy level decreases from bottom to top (Figure 18.7). Primary producers (bottom) → primary consumers (herbivores) → secondary consumers → tertiary consumers → decomposers.

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