B9 - Ecosystems and material cycles

Ecosystem

The community of organisms (biotic) and non-living (abiotic) components of an area and their interactions.

Population

All organisms of the same species living with one another in a habitat.

Habitat

Place where an organism or population lives.

Community

All of the populations of different species living together in a habitat.

Interdependence

The dependence of different organisms on each other for survival, e.g. Plants depend on pollinators, herbivores depend on plants.

Abundance

Sum of total individuals from a given species in a given area.

Quadrat

A sample grid of known area used in sampling to determine the abundance and distribution of organisms in an ecosystem.

Sample

Transect

A line across a habitat or part of a habitat.

Belt transect

A line along a sampled area upon quadrats are placed at regular intervals to determine the abundance and distribution of organisms in an ecosystem.

Food chain

Describes the feeding relationships between organisms and the resultant stages of biomass transfer.

Food web

Diagram that shows the complex feeding relationships between organisms in an ecosystem.

Biomass

The total mass of organic material, measured in a specific area over a set period.

Trophic level

The position of an organism in a food chain.

Biotic

the living aspects of an ecosystem, e.g. Food availability, competition, predators and other species.

Abiotic

Non living aspects of an ecosystem, e.g. Temperature, light intensity and moisture.

Adaptation

The process by which a species becomes fitted to its environment.

Pollution

Contamination or destruction of the natural environment due to human intervention.

Biodiversity

The variety of living organisms in an ecosystem.

Indicator species

A species whose presence or absence in an environment provides and indication of environmental conditions, e.g. Pollution levels.

Lichen

A type of indicator species that is used to monitor air pollution.

Blackspot fungus

An indicator species that is found on rose leaves. It is sensitive to the concentration of sulfur dioxide, so its presence indicates clean air.

Sludgeworms and blood worms

Types of indicator species that are adapted to live in polluted water

Stonefly larvae

An indicator species sensitive to dissolved oxygen concentrations and only found in clean water.

Nymph

The immature form of some invertebrates, particually insects.

Eutrophication

The process in which pollution by nitrogen-containing fertilises results in algal blooms and subsequent oxygen level reduction in water bodies.

Parasite

Organism that lives on a host organism. The parasite benefits but the host does not.

Host

A living organism that harbours a smaller organism such as a parasite or a symbiont.

Mutualistic

A relationship between two organisms where both benefit as a result.

Deforestation

The destruction of forests due to human actions.

Reforestation

The replanting of forests in an effort to restore biodiversity.

Conservation

The maintenance of ecosystems and biodiversity by humans in order to preserve the Earth's resources

Endangered

A species that is at risk of extinction because of a sudden rapid decrease in its population.

Captivity

The containment and breeding of endangered animals in enclosures to increase the population numbers and increase biodiversity.

Food security

Ensuring that populations have access to adequate amounts of safe and nutritious food.

Yield

The amount of useful product that you can get from something.

Sustainability

The ability to maintain something for future generations

Biofuel

A renewable energy source produced from biomass.

Potable

Safe to drink.

Desalination

A process that removes salts from saline water to produce potable water.

Reverse osmosis

A method of desalinisation that uses a partially permeable membrane to remove impurities from drinking water.

Solar still

A device that uses the heat of the sun to evaporate water so that it may be cooled and collected, thereby purifying it.

Decay

Breakdown of dead matter.

Decomposers

Organisms that release enzymes which catalyse the breakdown of dead plant and animal matter into simpler organic matter.

Combustion

The process of burning something, which releases carbon dioxide.

Nitrates

Minerals needed for plants to produce proteins in order for growth. Contain nitrogen and oxygen atoms.

Ammonia

NH3

Nitrification

The conversion of ammonia into nitrites or nitrates by aerobic nitrifying bacteria.

Denitrification

The conversion of nitrate ions into nitrogen gas by anaerobic denitrifying bacteria in waterlogged soils.

Nitrogen fixation

The conversion of nitrogen gas into ammonia by nitrogen-fixing bacteria in the soil or root nodules of legumes.

Crop rotation

The practice of growing different crops each year in a cycle. This replenishes nutrients that may have been depleted by the previous crop.