Key Terms
Ecology
The study of interactions between living organisms and their environment. Central goal: understand distribution and abun
Mutualism
Long-term coevolved relationship where both species benefit.
Biogeography
The study of the geographic distribution of living things and the abiotic factors that affect that distribution.
Biome
A large area of land characterized by similar climate, flora, and fauna. Biosphere: all parts of Earth inhabited by life
Endemic species
Naturally found only in a specific, usually restricted geographic area. Generalist species: live in a wide variety of ge
Terrestrial light
Understory plants adapt to capture light filtered through the canopy above. Spring ephemeral plants grow and reproduce e
Aquatic light
Water absorbs most light wavelengths. Only shortest blue wavelengths penetrate deepest.
Adaptation to no-light environments
Chemosynthetic bacteria at hydrothermal vents use inorganic chemicals (hydrogen sulfide) instead of sunlight to produce
Thermocline
Water layer with temperature significantly different from surrounding layers. Photic zone: ocean layer where light penet
Terrestrial organisms
Lose water continuously; adaptations include leaf hairs, waxy cuticles, reduced foliage, deep roots. Freshwater organism
Net primary productivity
Total carbon fixed per year minus carbon oxidized during cellular respiration. Measured in terrestrial systems by above-
Pelagic realm
All open ocean water not near the bottom or shore.
Benthic realm
Ocean bottom from shoreline to deepest floor. Photic zone: depth where light can penetrate; approximately 200 m (650 ft)
Aphotic zone
Below 200 m; no light; no photosynthesis.
Intertidal zone
Between high and low tide. Neritic zone: intertidal edge to continental shelf (~200 m).