Ecology - Definitions

Ecology

The study of how living things interact with their environment.

Ecosystem

Groups of living organisms that interact with their environment (e.g., grassland).

Biosphere

The part of the planet containing living things.

Population

The number of organisms for one species living in an area.

Community

All the different populations living in an area (e.g., rabbits, snails and foxes).

Habitat

Where an animal or plant lives.

Biotic factors

Relate to living factors (e.g., food, competition, predation or humans).

Abiotic factors

Relate to non-living factors (e.g., temperature, soil, rainfall).

Edaphic factors

Relate to the soil (e.g., soil pH, soil temperature).

Climatic factors

Relate to the weather over a long period (e.g., wind, rainfall).

Consumers

Organisms that take in food from other organisms (e.g., rabbits).

Producers

Make their own food (e.g., all plants).

Food chain

Shows a sequence of organisms showing the transfer of energy when one is eaten by the next.

Key

Used to identify plants or animals.

Qualitative study

Records if a plant or animal is present or absent.

Quantitative study

Records the number of organisms present.

Trophic level

A feeding stage in the food chain.

Primary consumer

Eats a producer.

Secondary consumer

Eats a primary consumer.

Tertiary consumer

Eats a secondary consumer.

Decomposer

Breaks down dead organic matter (e.g., bacteria, fungi or earthworm).

Herbivore

Eats plants only.

Omnivore

Eats both plants and animals.

Carnivore

Eats other animals only.

Detritus feeders

Feed on dead leaves and dead organic matter.

Food web

Two or more inter-linked food chains.

Niche

The functional role an organism plays in the ecosystem.

Pyramid of numbers

Represents the number of organisms at each trophic level of a food chain.

Pollution

The release of any harmful substances into the environment.

Pollutant

The substance that is causing the pollution.

Conservation

The wise management of our environment and the preventing of organisms becoming extinct.

Competition

The struggle between two organisms for a resource in short supply (e.g., food, shelter or mates).

Contest competition

The physical contest between two organisms and only one gets the resource (e.g., two male deer's fighting for a female).

Scramble competition

Where a number of organisms struggle for a resource but they all get some of the resource but not enough (e.g., all young seedling plants competing for light and space).

Intra-specific competition

The struggle for a resource between the same species.

Inter-specific competition

The struggle for a resource between different species.

Predation

The catching, killing and eating of another organism.

Predator

Catches and kills another organism.

Prey

The organism being killed and eaten.

Symbiosis

Occurs when two organisms living in close association with each other and at least one of them benefits.

Parasitism

Occurs when one organism lives on another (the host) and causes it harm.

Exoparasites

Live on the host on the outside causing harm.

Endoparasites

Live on the host on the inside causing harm.

Adaptation

A feature of the organism that increases its chance of survival and reproduction.

Nitrogen fixation

The conversion of nitrogen gas into nitrates.

Nitrification

The conversion of ammonia to nitrite and then nitrate.

Denitrification

The conversion of nitrates into nitrogen gas.

Nutrient recycling

When carbon or nitrogen are exchanged between living and non-living parts of the environment (allows nutrients to be reused).