Ecology Key Terms: Biomes, Cycles, and Ecosystem Dynamics

Climate

The long-term average of weather patterns in a particular area.

Weather

The short-term atmospheric conditions in a specific area.

Community ecology

The study of interactions among species in a community.

Symbiosis

A close and long-term interaction between two different species.

Biosphere

The global sum of all ecosystems; the zone of life on Earth.

Competition

The interaction between organisms or species in which both are harmed by their shared use of limited resources.

Littoral zone

The nearshore area of a body of water where sunlight penetrates to the bottom.

Limnetic zone

The open water area of a lake or pond that is well-lit and supports photosynthesis.

Phytoplankton

Microscopic plants that float in water and are a primary producer in aquatic ecosystems.

Profundal zone

The deep, dark part of a large lake where light does not penetrate.

Benthic zone

The ecological region at the lowest level of a body of water, including the sediment surface.

Oligotrophic

Describes a body of water that is low in nutrients and supports little plant life.

Competitive exclusion principle

The principle stating that two species competing for the same resources cannot coexist at constant population values.

Mesotrophic

Describes a body of water with a moderate level of nutrients.

Resource partitioning

The process by which competing species use the environment differently to coexist.

Predation

The act of one organism consuming another for food.

Parasitoid

An organism that lives on or in a host organism and ultimately kills it.

Parasitism

A relationship between two species where one benefits at the expense of the other.

Pathogen

An organism that causes disease in another organism.

Herbivory

The consumption of plant material by animals.

Mutualism

A symbiotic relationship where both species benefit.

Photosynthesis

The process by which green plants and some other organisms use sunlight to synthesize foods with the help of chlorophyll.

Commensalism

A relationship between two organisms where one benefits and the other is neither helped nor harmed.

Native species

Species that naturally occur in a particular region or ecosystem.

Exotic species (Alien species)

Species that are not native to a specific location and have been introduced.

Invasive species

Non-native species that spread widely and cause harm to the environment, economy, or human health.

Biome

A large ecological area on the Earth's surface with flora and fauna adapting to their environment.

Terrestrial biome

A biome that is located on land.

Aquatic biome

A biome that is located in water.

Habitat

The natural home or environment of an animal, plant, or other organism.

Tundra

A cold, treeless biome characterized by permafrost.

Permafrost

A thick subsurface layer of soil that remains frozen throughout the year.

Taiga (Boreal forest)

A biome characterized by coniferous forests, cold temperatures, and moderate precipitation.

Temperate rainforest

A biome characterized by high rainfall and moderate temperatures.

Temperate seasonal forest

A biome characterized by four distinct seasons and deciduous trees.

Shrubland (Woodland)

A biome characterized by shrubs and small trees.

Temperate grassland (Cold desert)

A biome characterized by grasses and few trees, with cold winters.

Tropical rainforest

A biome characterized by high rainfall and biodiversity.

Eutrophic

Describes a body of water that is rich in nutrients and supports a lot of plant life.

Freshwater wetland

An area where water covers the soil for part of the year, supporting aquatic plants.

Estuary

A coastal area where freshwater from rivers meets and mixes with saltwater from the ocean.

Salt marsh

A coastal ecosystem characterized by salt-tolerant plants.

Mangrove swamp

A coastal wetland found in tropical and subtropical regions, characterized by salt-tolerant trees.

Intertidal zone

The area of the shore that is exposed to the air at low tide and submerged at high tide.

Coral reef

A diverse underwater ecosystem held together by calcium carbonate structures secreted by corals.

Coral bleaching

The loss of color in corals due to stress, often from temperature changes or pollution.

Open ocean

The vast body of salt water that covers most of the Earth's surface.

Photic zone

The upper layer of a body of water that receives enough sunlight for photosynthesis.

Aphotic zone

The deeper layer of water where sunlight does not penetrate.

Chemosynthesis

The process by which certain organisms create energy from chemical reactions, often in the absence of sunlight.

Biogeochemical cycle

The cycle of chemical elements and compounds between living organisms and the environment.

Reservoirs

Natural or artificial lakes used to store water.

Carbon cycle

The series of processes by which carbon compounds are interconverted in the environment.

Aerobic respiration

The process of producing cellular energy in the presence of oxygen.

Steady state

A condition in which all state variables are constant in a system.

Greenhouse gases

Gases that trap heat in the atmosphere and contribute to the greenhouse effect.

Global warming

The long-term rise in the average temperature of the Earth's atmosphere.

Limiting nutrient

A nutrient that is in short supply and limits the growth of organisms.

Nitrogen cycle

The series of processes by which nitrogen and its compounds are interconverted in the environment.

Nitrogen fixation

The process of converting nitrogen gas from the atmosphere into ammonia or related compounds in soil.

Nitrification

The process by which ammonia is converted to nitrites and then to nitrates.

Assimilation

The process by which plants and animals incorporate nutrients from the environment into their bodies.

Leaching

The process by which nutrients are washed out of the soil by water.

Phosphorus cycle

The movement of phosphorus through the lithosphere, hydrosphere, and biosphere.

Algal bloom

A rapid increase in the population of algae in water bodies, often due to nutrient pollution.

Hypoxic

Describes an environment with low oxygen levels.

Dead zone

An area in a body of water where oxygen levels are so low that most marine life cannot survive.

Hydrologic cycle

The continuous movement of water on, above, and below the surface of the Earth.

Transpiration

The process by which moisture is carried from plants to the atmosphere.

Evapotranspiration

The sum of evaporation and plant transpiration from the Earth's surface to the atmosphere.

Runoff

Water that flows over the ground surface rather than being absorbed into the ground.

Producers (Autotrophs)

Organisms that produce their own food through photosynthesis or chemosynthesis.

Cellular respiration

The process by which cells convert glucose and oxygen into energy, carbon dioxide, and water.

Anaerobic respiration

The process of producing cellular energy without oxygen.

Primary productivity

The rate at which energy is converted by photosynthetic and chemosynthetic autotrophs to organic substances.

Gross primary productivity

The total amount of energy captured by photosynthesis in a given area over a specific time.

Net primary productivity

The rate of energy storage by photosynthetic organisms in a given area after accounting for energy lost through respiration.

Biomass

The total mass of living matter in a given area or volume.

Standing crop

The total biomass of living organisms in a given area at a specific time.

Consumer (Heterotroph)

Organisms that cannot produce their own food and must consume other organisms.

Herbivore (Primary consumer)

An organism that primarily eats plants.

Carnivore

An organism that primarily eats other animals.

Secondary consumer

An organism that eats primary consumers.

Tertiary consumer

An organism that eats secondary consumers.

Trophic levels

The hierarchical levels in an ecosystem, comprising producers and various levels of consumers.

Food chain

A linear sequence of organisms through which nutrients and energy pass as one organism eats another.

Scavenger

An organism that feeds on dead or decaying organic matter.

Detritivore

An organism that feeds on dead organic material, especially plant detritus.

Decomposers

Organisms that break down dead or decaying organisms, returning nutrients to the ecosystem.

Ecological efficiency

The efficiency with which energy is transferred from one trophic level to the next.

The 10% rule

The principle that only about 10% of energy is transferred from one trophic level to the next.

Food web

A complex network of feeding relationships among various organisms in an ecosystem.

Mineralization (Ammonification)

The process by which organic matter is decomposed into inorganic substances.

Trophic pyramid

A graphical representation of the distribution of biomass, numbers, or energy among trophic levels.

Savanna (Tropical seasonal forest)

A mixed grassland ecosystem characterized by trees and a seasonal rainfall pattern.

Denitrification

The process by which bacteria convert nitrates into nitrogen gas, returning it to the atmosphere.

Hot desert

A biome characterized by high temperatures and low precipitation.

Freshwater biomes

Aquatic biomes that include lakes, rivers, ponds, and wetlands.

Anaerobic

Describes processes or organisms that do not require oxygen.

Aerobic

Describes processes or organisms that require oxygen.