Ecology (IB)

Ecology

The branch of biology that studies interactions among organisms and their environment.

Interdependence

The idea that organisms and their environments are interconnected.

Holistic Approach

Studying ecological systems as a whole rather than in isolated parts.

Levels of Ecological Organization

The hierarchy of ecological units including individual, population, community, ecosystem, and biosphere.

Biotic Factors

The living components of an ecosystem that directly or indirectly affect other organisms.

Producers (Autotrophs)

Organisms that produce their own food using sunlight or chemical energy.

Primary Consumers (Herbivores)

Organisms that feed directly on producers.

Secondary Consumers (Carnivores)

Organisms that feed on primary consumers.

Tertiary Consumers (Top Predators)

Organisms at the top of the food chain that feed on secondary consumers.

Decomposers (Saprotrophs)

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

Competition

Occurs when organisms vie for the same resources within an ecosystem.

Predation

The interaction where one organism hunts and consumes another organism.

Symbiosis

A close, long-term interaction between different species.

Abiotic Factors

The non-living physical and chemical components of an ecosystem.

Climate

The long-term patterns of temperature, humidity, wind, and precipitation in a region.

Soil

The upper layer of the Earth's surface where plants grow, consisting of organic matter, minerals, gases, and liquids.

Water

A vital component of life, required for biochemical processes, nutrient transport, and temperature regulation.

Sunlight

The main energy source for life on Earth, driving photosynthesis in producers.

Nutrients

Essential chemical elements required by organisms for growth, reproduction, and survival.

Energy Flow

The movement of energy through an ecosystem, primarily from the sun to producers and then through various trophic levels.

Food Chain

A linear sequence of organisms where each is consumed by the next member in the chain.

Food Web

A more complex representation of energy flow that shows multiple interconnected food chains.

Trophic Levels

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

10% Rule

Only about 10% of the energy at one trophic level is transferred to the next level.

Water Cycle (Hydrological Cycle)

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

Photosynthesis

The process by which producers convert light energy into chemical energy stored in glucose.

Nitrogen Fixation

The conversion of atmospheric nitrogen into ammonia by bacteria.

Exponential Growth

Population growth that occurs when resources are abundant, resulting in a rapid increase.

Logistic Growth

Population growth that slows as it approaches the carrying capacity of the environment.

Carrying Capacity (K)

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

Density-Dependent Factors

Factors that have a greater impact as population density increases, such as competition and predation.

Density-Independent Factors

Factors that affect population size regardless of density.