Biology Terms - Google Docs

Autotrophs

Organisms that capture energy from non-living sources and convert it into forms living cells can use.

Primary Producers

Another name for autotrophs.

Photosynthesis

The process in which autotrophs make their own food using energy from sunlight.

Chemosynthesis

A process in which chemical energy powers the production of carbohydrates.

Heterotrophs

Organisms that must acquire energy from other organisms, usually by eating them.

Consumers

Another name for heterotrophs.

Detritus

Trash or debris.

Food Chain

A series of organisms in which energy is transferred from one organism to another.

Phytoplankton

Tiny floating algae that are often eaten by small animal zooplankton.

Food Web

A network of feeding interactions through which both energy and matter move.

Trophic Level

Each individual step on the food web.

Ecological Pyramids

Models that represent the relative amount of energy or matter contained within each trophic level in a food chain or food web.

Biomass

The total amount of living tissue within a given trophic level.

Biogeochemical Cycles

Cycles that involve the flow of chemicals powered by energy.

Nutrients

Elements that organisms need to sustain life.

Carbon Reservoirs

Places where carbon is stored for short or long periods of time.

Nitrogen Fixation

The process by which certain bacteria convert nitrogen gas into ammonia.

Denitrification

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

Limiting Nutrient

Any nutrient whose supply limits productivity.

Population Density

The number of individuals per unit area.

Population Distribution

Describes how individuals are spaced out across their range.

Age Structure

The distribution of individuals of different ages, including males and females.

Immigration

When individuals move into a population's range from elsewhere.

Emigration

When populations move out of the population's home range.

Exponential Growth

Growth pattern in which individuals in a population reproduce at a constant rate.

Logistic Growth

Growth pattern in which a population's growth slows and then stops following a period of exponential growth.

Carrying Capacity

The largest number of individuals of a species that a particular environment can support.

Limiting Factor

A factor that causes population growth to decrease.

Density-Dependent Limiting Factor

A limiting factor that depends on population density.

Density-Independent Limiting Factor

A limiting factor that affects all populations in similar ways, regardless of density.

Demography

The scientific study of human populations.

Demographic Transition

Change in population from high birth and death rates to low birth and death rates.

Habitat

The area an organism lives, including biotic and abiotic factors.

Tolerance

The ability of an organism to survive and reproduce under conditions that differ from their optimal conditions.

Niche

The full range of physical and biological conditions in which an organism lives and how it uses those conditions.

Resource

Any necessity of life, like water, nutrients, light, food, or space.

Competitive Exclusion Principle

The principle that states no two species can occupy the same niche in the same habitat at the same time.

Keystone Species

A species that is not usually abundant in a community but exerts strong control over its structure.

Symbiosis

A relationship in which two species live close together.

Commensalism

A symbiotic relationship in which one organism benefits while the other is neither helped nor harmed.

Mutualism

A symbiotic relationship in which both species benefit.

Parasitism

A symbiotic relationship in which one organism lives on or inside another and harms it.

Ecological Succession

Series of gradual changes that occur in a community following a disturbance.

Primary Succession

Succession that occurs in an area with no trace of a previous community.

Pioneer Species

The first species to populate an area during succession.

Secondary Succession

Type of succession that occurs in an area that was only partially destroyed.

Biodiversity

The total variety of organisms in the biosphere, also called biological diversity.

Ecosystem Diversity

Variety of habitats, communities, and ecological processes in the biosphere.

Species Diversity

The number of different species that make up a particular area.

Genetic Diversity

The sum of all different forms of genetic information carried by a species or all organisms on Earth.

Resilience

The ability to recover after a disturbance and deal with changes.

Ecosystem Services

The benefits for humans provided by healthy ecosystems.

Conservation Biology

The discipline focused on preserving and protecting natural resources, including species, ecosystems, biodiversity, and ecosystem services.