Ecology: Distribution of animals

Ecology

scientific study of the interactions of organisms and their environments including distribution and abundance

Distribution

where they live

Dispersal ability

• species characteristics

• movement (can travel long distances)

• not picky on environments

Biogeographic realms

areas where animals can move relatively effectively within that realm

why are animals of Australia & south America different

separated from other continents earliest

biogeographic realms

different realms have ecologically equivalent species

• the same habitat may occur in several realms

analogous structure

similarity despite no common ancestry

Convergent evolution

ecologically equivalent species occur

results of convergent evolution

• 2 unrelated organisms evolve to look more similar

• similar environments = select for similar adaptive traits

Physiological tolerance

• range of abiotic conditions in which species can survive

• broad and narrow tolerances

abiotic

nonliving environmental conditions (temp, O2, H2O)

biotic

living components (food, competition, nesting areas)

biotic factors affecting disribution

• predators need prey

• parasites need hosts

• herbivores may require specific plants

• mutualists require each other

• competitors may exclude similar species