Ecology: Study of Organisms and their Environment

Ecology

The study of how organisms interact with each other and their environment

Species

A group of organisms that can interbreed and produce fertile offspring

Population

A group of individuals of the same species that live in the same area and can potentially interbreed

Community

A group of different populations (different species) that live in the same area and interact with each other

Ecosystem

A community of organisms and their physical environment, including both living and nonliving components

Biome

A large-scale ecosystem characterized by a specific climate and dominant plant and animal communities

Biosphere

The part of the Earth where life exists, including the land, water, and atmosphere

Energy Flow

The transfer of energy through the ecosystem, primarily driven by the sun

Autotrophs (producers)

Organisms that can produce their own food using energy from the sun or inorganic chemicals

Photosynthesis

The process by which autotrophs use sunlight to convert carbon dioxide and water into glucose (food)

Chemosynthesis

The process by which certain bacteria use inorganic chemicals to produce food

Heterotrophs (consumers)

Organisms that obtain energy by consuming other organisms

Herbivores

Organisms that primarily eat plants

Carnivores

Organisms that primarily eat other animals

Omnivores

Organisms that eat both plants and animals

Decomposers

Organisms that break down dead organic matter and recycle nutrients back into the ecosystem

Food Chain

A linear sequence of organisms in which each organism is eaten by the next organism in the chain

Food Web

A complex network of interconnected food chains that shows the flow of energy and matter in an ecosystem

Trophic Level

Each level in a food chain or food web that represents a different position in the transfer of energy

Biotic

Living factors in an ecosystem, such as plants, animals, and microorganisms

Abiotic

Nonliving factors in an ecosystem, such as temperature, sunlight, and soil

Niche

The role and position of an organism within its environment, including its interactions with other organisms and its use of resources

Competition

The interaction between organisms of the same or different species as they compete for limited resources

Predation

The interaction in which one organism captures and feeds on another organism

Symbiosis

A close and long-term interaction between two different species

Mutualism

A type of symbiotic relationship in which both species benefit from the interaction

Commensalism

A type of symbiotic relationship in which one species benefits and the other is unaffected

Parasitism

A type of symbiotic relationship in which one species benefits (parasite) and the other is harmed (host)

Biogeochemical cycles

The cycling of elements and compounds through living and nonliving components of ecosystems

Water Cycle

The continuous movement of water between the atmosphere, land, and bodies of water

Carbon Cycle

The movement of carbon between the atmosphere, land, and living organisms

Nitrogen Cycle

The movement of nitrogen between the atmosphere, soil, and living organisms

Phosphorus Cycle

The movement of phosphorus between the land, water, and living organisms

Primary Succession

The process of ecological succession that occurs in an area where no soil exists, such as on bare rock

Secondary Succession

The process of ecological succession that occurs in an area where soil is already present

Quadrant Method

A method used to estimate the population size of stationary organisms by sampling a specific area

Mark and Recapture

A method used to estimate the population size of moving organisms by capturing and marking individuals, then recapturing a sample later

Census

A method used to directly count and estimate the population size of humans or other organisms

Population Density

The number of individuals of a population within a given area or volume

Exponential Growth

The rapid and unrestricted growth of a population under ideal conditions, resulting in a J-shaped curve

Logistic Growth

The growth of a population that initially follows exponential growth but then slows down as it approaches the carrying capacity of the environment, resulting in an S-shaped curve

Carrying Capacity

The maximum number of individuals of a species that the environment can support sustainably

Limiting Factors

Environmental factors that restrict the growth, abundance, or distribution of a population

Predation

The act of one organism hunting, killing, and consuming another organism

Ecological Succession

The gradual and predictable changes in the composition and structure of a community over time, resulting from natural and human disturbances