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Ecology Terms
Autotroph (Producer): an organism that can make its own food from inorganic materials.
Abiotic factors: These are the non-living features of an ecosystem that affect the community. They
consist of the physical and chemical conditions, and they vary between ecosystems that are
terrestrial or aquatic. They include: temperature, light intensity, air speed, water current,
humidity, pH, dissolved oxygen, salinity, nitrate, phosphate and other plant nutrients.
Acid rain: Acid rain refers to very acidic rain with a pH of 4.5 or less. Sulphur dioxide (SO2)
dissolves in rainwater to form sulphurous acid (H2SO3) or reacts with particles in the air to form
sulphuric acid (H2SO4).
Biosphere: the narrow zone of the earth and its atmosphere inhabited by living organisms.
Biological magnification: Pollutants tend to concentrate as they are passed through food chains.
The organisms at the ends of the chains suffer the highest concentrations – biological
magnification.
Biotic factors: are the living features of an ecosystem that affect the other members of the
community. These include: plants for food and shelter, predators, prey, parasites and pathogens,
competitors and pollinators.
Carnivore: an animal that feeds exclusively or mainly on animal flesh, a meat eater.
Climax Community: the last community of a succession in dynamic equilibrium with its
environment, without loss or gain of species and the population of each remaining relatively
constant.
Commensalism: Where one organism obtains benefit from another and leaves it completely
unaffected – neither harmed nor helped, e.g. the bacterial population in the intestines of humans
and other animals.
Community: a group of interacting populations of different species living in the same area.
Competition: the struggle between organisms to obtain a sufficient supply of a resource of limited
quantity.
Conservation: is the protection and wise management of the environment
Benefits include: existing environments are maintained, endangered species preserved for
reproduction, the balance of nature is maintained, and pollution and its effects are reduced.
Consumer (Heterotroph): an organism that cannot make its own food - they need a supply of
organic material.
Contest competition: involves an active physical confrontation between two organisms e.g. two
dogs fighting over a bone. One may have stronger muscles and sharper teeth and so win the
bone.
Decomposer (Detritivore): an organism that feeds on dead organic matter. Detritus = dead organic
matter.
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Ecology Terms
Dependence: the reliance of one organism on another for a resource essential for its survival or
reproduction.
Detritivore (Decomposer): an organism that feeds on dead organic matter. Detritus = dead organic
matter.
Detritus food chain: is one where the chain begins with dead organic matter and animal waste
(detritus) e.g. Detritus  edible crab  seagull
Fallen leaves  earthworms  blackbirds  hawks
Ecosystem: the community of living organisms interacting with each other and their environment
within a particular area.
Edaphic Factors: the physical, chemical and biological characteristics of the soil that influence the
community – the major edaphic factors available are water, mineral content, pH, humus, soil
texture and structure.
Energy Transfer: the flow of energy into the ecosystem from the sun, within the ecosystem
through the different trophic levels including detritus and finally out of the ecosystem into the
atmosphere as heat loss due to respiration.
Food Chain: a list of species such that each is food for the next species in the list.
Food Niche: the feeding habits of a species within its community (includes producers - they are
self-feeders.)
Food Web: a chart showing all the feeding connections in the habitat - made by showing the links
between all the food chains in the habitat.
Grazing food chain: is one where the initial plant is living e.g.
Grass  grasshoppers  frogs  hawks
Honeysuckle  aphids  ladybirds  thrushes
Seaweed  winkles  crabs  herring gulls
Phytoplankton  zooplankton  copepod  herring
Habitat: the particular place where an organism lives and to which it is adapted.
Herbivore: an animal that feeds exclusively or mainly on plants, a plant eater.
Heterotroph (Consumer): an organism that cannot make its own food - they need a supply of
organic material.
Hydrophyte: a plant that is adapted to an aquatic or very wet environment, e.g., water lily, elodea.
Hydrosere: a succession that began in an aquatic or very wet environment.
Interdependence: the reliance of organisms of different species on each other for an essential
resource.
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Ecology Terms
Intraspecific Competition: the struggle between organisms of the same species for a limited
resource.
Interspecific Competition: the struggle between organisms of different species for a limited
resource.
Mesophyte: a plant adapted to normal soil water conditions, not too wet and not too dry, e.g., daisy,
dandelion.
Mutualism: Describes two organisms of different species, both of which benefit from a close
relationship e.g. a lichen is composed of an alga and a fungus intertwined.
The alga obtains support and a mineral supply from the fungus; the fungus obtains food from the
alga.
Niche: in ecological terms, a niche is the functional role of an organism in an ecosystem.
Omnivore: an animal that feed on plants and animal flesh.
Parasite: a living organism that lives with and feeds off another living organism causing it harm.
Pollution: is any human addition to the environment that leaves it less able to sustain life. It is the
most harmful human impact and affects air, fresh water, sea and land.
Chemicals of human origin that harm the environment are called pollutants.
Population: is a group of organisms of the one species.
Predator: an animal that hunts and kills another animal for food.
Prey: an animal that is hunted and killed by another animal for food.
Producer (Autotroph): an organism that can make its own food from inorganic materials.
Pyramid of Numbers: a diagram, in block form, showing the number of individuals at each trophic
level in a food chain, the size of each block indicates the number of individuals.
Saprophyte: bacteria and fungi that feed on dead organic matter.
Scramble competition: is where each organism tries to acquire as much of the resource as possible
e.g. an ivy plant and a hawthorn tree may compete for light. The ivy uses adventitious roots to
grip the hawthorn and climb higher.
Succession: the ongoing change in the composition of a community from initial colonisation of the
bare area towards a climax community.
Symbiosis (Mutualism): different species living together and each benefiting from the relationship.
Trophic Level: the position of a species in a food chain.
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