APES Unit 1: Introduction to Ecosystems

Community Ecology

The study of interactions among species in a community.

Symbiosis

A close biological interaction between two different biological organisms.

Biosphere

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

Competition

The struggle between individuals or species for limited resources.

Competitive Exclusion Principle

The principle stating that two species competing for the same limiting resource cannot coexist.

Resource Partitioning

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

Predation

An interaction in which one organism kills and eats another.

Parasitoid

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

Parasitism

A relationship between two organisms where one benefits and the other is harmed.

Pathogen

An organism that causes disease.

Herbivory

An interaction in which an animal consumes plants or algae.

Mutualism

A type of interspecies interaction where both organisms benefit.

Photosynthesis

The process by which green plants use sunlight to synthesize foods with carbon dioxide and water.

Commensalism

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

Native Species

Species that naturally occur in a specific ecosystem.

Exotic Species

Species that are not native to a particular region.

Invasive Species

An exotic species that spreads rapidly, often harming native species and ecosystems.

Biome

A large geographic biotic unit, a major community of plants and animals with similar life forms and environmental conditions.

Aquatic Biome

A biome that includes all water bodies that have different salinity, depth, and water flow.

Terrestrial Biome

A biome characterized by distinct climates and ecosystems on land.

Carbon Cycle

The process by which carbon is recycled in the ecosystem.

Nitrogen Cycle

The process by which nitrogen is converted into multiple chemical forms.

Phosphorus Cycle

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

Hydrologic Cycle

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

Primary Productivity

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

Trophic Levels

The hierarchical levels in an ecosystem, comprising producers, primary consumers, secondary consumers, and tertiary consumers.

Food Chain

A linear sequence of organisms through which nutrients and energy pass.

Food Web

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

10% Rule

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

Ecosystem Services

Benefits that humans freely gain from the natural environment and from properly-functioning ecosystems.

B horizon

Subsoil layer in soil profiles, containing minerals leached from the A horizon.

A horizon

The top layer of soil, containing a mixture of organic material and minerals.

Abiotic

Non-living chemical and physical factors in the environment.

Accuracy

How close a measured value is to the actual value.

Acid

A substance that increases the concentration of hydrogen ions in a solution.

Mutualism

An interaction between two species that increases the chances of survival or reproduction for both species.

Biodiversity

The variety of life in the world or in a particular habitat or ecosystem.

Biogeochemical Cycle

The movement of elements and compounds through the biological and geological parts of the ecosystem.

Bioaccumulation

The accumulation of substances in an organism.

Biomagnification

The increasing concentration of a substance, such as a toxic chemical, in the tissues of organisms at each successive level of the food chain.

Detritivore

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

Chemosynthesis

The process of converting carbon compounds and nutrients into organic matter using the energy derived from reactions involving inorganic chemicals.

Oligotrophic

Describes a lake or body of water that is nutrient-poor.

Eutrophication

The process by which a body of water becomes enriched with nutrients, leading to excessive growth of algae.

Desalination

The process of removing salt from seawater to make it suitable for drinking water.

Pollution

The introduction of contaminants into the natural environment that cause adverse change.

Wastewater

Water that has been used and contains waste matter.

Sustainable Development

Development that meets the needs of the present without compromising the ability of future generations to meet their own needs.

Climate Change

A long-term alteration in temperature and typical weather patterns in a place.

Renewable Resources

Resources that can be replenished naturally over time.

Nonrenewable Resources

Resources that do not renew themselves at a sustainable rate.

Urbanization

The increasing number of people that live in urban areas.

Industrial Agriculture

Agriculture that applies the techniques of mechanization and standardization to the production of food.

Agribusiness

The business of agriculture, including farming, seed supply, and distribution.

Bycatch

The unintentional capture of non-target species while fishing.

Regenerative Agriculture

Farming practices that regenerate the health and biodiversity of the soil.

Monoculture

Cultivating a single crop over a wide area.

Crop Rotation

The practice of alternating the species or varieties of crops grown on a particular piece of land.

Organic Farming

Farming that emphasizes the use of natural processes and excludes synthetic fertilizers and pesticides.

Ecosystem Diversity

The variety of ecosystems in a given place.

Population Density

The number of individuals per unit area.

Biomass

The total mass of organisms in a given area or volume.

Habitat Diversity

The variety of habitats in a given area.

Invasive Species

Non-native species that spread rapidly and disrupt local ecosystems.