Ecosystems Definitions

Question	Answer
Decomposer	Organisms that break down dead organic matter. An example is a worm.
Consumer	Living organisms that get their energy by feeding off other living organisms. An example is a cow.
Producer	Autotrophic organisms that convert light energy to chemical energy. An example is a tulip.
Trophic level	The level at which an organism feeds in a food chain. An example is a tertiary consumer.
Autotroph	Organisms that synthesise complex organic molecules from simple inorganic molecules in the process of photosynthesis. An example is algae.
Ecosystem	The living organisms and the non-living components of a habitat and their interactions. An example is the Lake District.
Abiotic factor	The non-living or physical conditions of the ecosystem which affect an organism. An example is soil pH.
Biotic factor	The living components of the ecosystem that affects an organism. An example is disease.
Niche	The role of a species in its habitat. An example is an oak tree which grows to dominate a forest canopy.
Community	All the populations of different species that live in the same place at the same time, and who can interact with each other. An example is a lake with populations of insects, birds and fish.
Habitat	The place where an organism or population of organisms live. An example is a coral reef.
Population	The number of individuals of one species within a defined area at a given time. An example is the Galapagos Giant Tortoise.
Heterotroph	Organisms that acquire complex organic molecules by the ingestion of other organisms (feeding). An example is yeast.
Succession	A directional change in a community over time, starting with bare rock.
Net Primary Productivity (NPP)	The total amount of energy transferred from sunlight to chemical potential energy (biomass) less any used in respiration.
Gross Primary Productivity (GPP)	The total amount of energy transferred from sunlight to chemical potential energy (biomass) by plants.
Ecology	The study of the interactions between the environment and the organisms that inhabit it.
Succession	When changes to the environment causes the plant and animal species to change.
Pioneer Species	They come into an area after disturbance.
Primary Succession	No soil after disturbance
Secondary Succession	Soil after disturbance but no plants or animals.
Plagioclimax	Deflected succession means climax is not reached.
LAG Phase	A period of slow growth. This is because the small population reproduce to increase the population. The birth rate is higher than the death rate.
Log Phase	It is the period of rapid growth. The population increases exponentially. Here there are no limiting factors.
Stationary Phase	It is a stable state. The population growth is restricted by external factors. The population fluctuates.
Carrying capacity	It is the maximum number of species an environment can support.
Limiting factors	Abiotic factors: light, pH and water availability. Biotic factors: predators, disease and competition.
Immigration	Movement of individual organisms into an area.
Emigration	Movement of individual organisms away from a particular area decreasing the population size.
Density Independent Factors	Factors that have an effect on the whole population regardless of its size.
Density Dependent Factors	A factor which affects the size or growth of a population due to its intensity.
Exponential Growth	Populations of many organisms follow this trend during initial expansion.
Logarithmic Scale	Non-linear scale. The data spans several orders of magnitude.
Carnivore	Eats only animals
Herbivore	Eats only plants
Omnivore	Eats plants and animals
What percentage of light is captured by plant or algae?	1-3%
What happens to the remain percentage?	90% is reflected by the clouds/dust or absorbed by the atmosphere. All light is absorbed apart from the green wavelength. Also light may not fall on the chlorophyll molecule. Limiting factors to photosynthesis will mean that the light isn't used for photosynthesis.

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Ecosystems Definitions

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	Created by Chloe Drewery over 7 years ago