Ecology Review

Ecology

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

Organism

An individual living being.

Population

A group of individuals of the same species living in the same area at the same time.

Community

All the different populations of species that live and interact in the same area.

Ecosystem

A community of organisms and their physical environment, including both biotic (living) and abiotic (non-living) components.

Biome

A large regional or global ecosystem characterized by its climate, plant, and animal life.

Biosphere

The sum of all the ecosystems on Earth; the global ecological system integrating all living beings and their relationships.

Biotic Factors

Living or once-living components of an ecosystem.

Abiotic Factors

Non-living physical and chemical parts of an ecosystem.

Producers (Autotrophs)

Organisms that produce their own food, primarily through photosynthesis or chemosynthesis.

Consumers (Heterotrophs)

Organisms that obtain energy by consuming other organisms.

Primary Consumers (Herbivores)

Consumers that eat producers.

Secondary Consumers (Carnivores/Omnivores)

Consumers that eat primary consumers.

Trophic Levels

The position an organism occupies in a food chain.

Energy Transfer Efficiency

Only about 10% of the energy from one trophic level is transferred to the next; the rest is lost as heat.

Food Chains

Linear pathways showing how energy is transferred from one organism to another.

Food Webs

Complex networks of interdependent food chains within an ecosystem.

Water Cycle

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

Carbon Cycle

The biogeochemical cycle by which carbon is exchanged among different Earth systems.

Nitrogen Cycle

The process by which nitrogen is converted into various chemical forms as it circulates among ecosystems.

Phosphorus Cycle

The biogeochemical cycle that describes the movement of phosphorus through the lithosphere, hydrosphere, and biosphere.

Exponential Growth

Population growth that occurs under ideal conditions with unlimited resources, resulting in a J-shaped curve.

Logistic Growth

Population growth that slows as it reaches the carrying capacity, resulting in an S-shaped curve.

Carrying Capacity (K)

The maximum population size that an environment can sustain indefinitely.

Limiting Factors

Environmental factors that restrict population growth.

Density-Dependent Factors

Factors whose effects intensify as population density increases.

Density-Independent Factors

Factors whose effects are not related to population density.

Ecological Niche

The role and position a species has in its environment.

Competitive Exclusion Principle

Two species competing for the same resources cannot coexist indefinitely.

Ecological Succession

The process of change in the species structure of an ecological community over time.

Primary Succession

Succession that occurs in an area devoid of life and soil.

Secondary Succession

Succession that occurs in an area where soil remains after a disturbance.

Ecosystem Services

Benefits that humans receive from ecosystems.

Biodiversity

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

Keystone Species

A species whose presence is crucial for maintaining the structure of an ecosystem.

Foundation Species

A species that plays a major role in structuring a community.

Indicator Species

A species whose health serves as an early warning of environmental changes.

Disruptions in Ecosystems

Changes in species composition and energy flow due to natural events or human activities.

Natural Disruptions

Short-term or long-term events that affect ecosystems, such as wildfires or climate shifts.

Anthropogenic Disruptions

Human activities that lead to changes in ecosystems.

Loss of Biodiversity

Reduction in the variety of life forms, impacting ecosystem stability.

Ecosystem Degradation

Severe and lasting damage to ecosystem health, reducing its ability to provide essential services.