Ecology and Environmental Science: Key Terms and Concepts

Biosphere

part of Earth in which life exists, including land, water, and air (atmosphere)

Ecology

scientific study of interactions among organisms and between organisms and their environment

Species

a group of similar organisms that can breed and produce fertile offspring

Population

group of individuals of the same species that live in the same area

Community

assemblage of different populations that live together in a defined area

Ecosystem

all the organisms that live in a place, together with their nonliving environment

Biotic Factor

any living part of the environment with which an organism might interact

Abiotic Factor

physical, or nonliving, factor that shapes an ecosystem

Atmosphere

thin layer of gases that surround Earth

Hydrosphere

all water (salt and fresh) in liquid, ice, or vapor form above and below Earth's surface

Geosphere

all of the rock at and below Earth's surface

Climate

average year-to-year conditions of temperature and precipitation over a long period

Weather

day-to-day conditions of the atmosphere like temperature and precipitation

Greenhouse Effect

process where gases trap heat in Earth's atmosphere

Biome

group of ecosystems that share similar climates and organisms

Logistic Growth

growth slows and stops after a period of exponential growth

Carrying Capacity

maximum number of individuals an environment can support

Keystone Species

species with a large impact on its ecosystem despite low numbers

Exponential Growth

population grows rapidly at a constant rate

Density Independent Limiting Factor

affects populations regardless of size (weather, disasters)

Biodiversity

variety of organisms in the biosphere

Density Dependent Limiting Factor

affected by population density (competition, disease)

Niche

full role and conditions in which an organism lives

Genetic Variation

differences in DNA among individuals in a population

Habitat

place where an organism lives including biotic and abiotic factors