A horizon Proportion of population in each age class Pertaining to the physical environment The topsoil abioticAge structure

B horizon Species that don’t feed on any other species but are eaten by other species. The ecological zone at the bottom of the body of water. Sometimes called the subsoil Basal Species Benthic zone

C horizon Describes the type of woody vegetation that loses its leaves in fall. The process by which microbes create energy. The layer under the subsoil deciduouschemosynthesis

Ecological niche The smallest and highest elevation streams. The ecosystem where the river meets the ocean A set of optimal environmental conditions. First order streamsEstuary

Food web Atmosphere gases that absorb and reradiate the earths radiation The genetic makeup of a particular organism An interwoven set of relationships between trophic levels Greenhouse gasesgenotype

horizon Biotic interactions between members of different species An educated guess Each layer within the soil profile Interspecific interactionsHypothesis

Kinetic energy The rate of energy stored after accounting for the energy expended. Coastal ecosystems The energy of an object in motion Net primary productivityMangroves

Nitrogen fixation Ongoing fishing, hunting, or gathering beyond. The surface layer of soil The assimilation of nitrogen into organic compounds. OverkillO Horizon

Parent material The geographical area in which a particular species can be found The rock mineral substrate that underlies the soil profile Rangepathogen An organism that causes disease in host species

salinity Eats other species but is not a food source for any other species Vertical layering in the soil column A measure of dissolved salt content in water Top preditor Soil profile

theory Formed to collectively explain the results Organism that lives in association with another organism Symbiont Periods when deep, cold, nutrient rich ocean water Upwelling