Ecosystems

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Define community
All populations of different species living together in the same place at the same time, who can interact with each other
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Define population
All organisms of 1 species living in the same place at the same time
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Define ecosystem
Any group of living or non-living things occuring together and the interrelationship between them. They are dynamic (constantly changing).
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Define biotic factors and give examples
Biotic factors are the LIVING factors such as predators, food supply and disease
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Define abiotic factors and give examples
Abiotic factors are the NON-LIVING factors such as pH, humidity and temperature
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Define niche
The niche of a species is its role in the community including its habitat, food sources and its use of abiotic resources.
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Explain why organisms cannot possess the same niche.
If they did, there would be competition and one species would out compete the other.
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Define producer and provide examples
A producer is an autotroph which makes its own food from light energy such as plants and algae.
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Define consumer
An organism that feeds off another and obtains its energy by feeding - a heterotroph.
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Define decomposers
Fungi and bacteria which chemically break down or digest material.
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Define detritivores
An example of these is worms, they physically break down material into smaller pieces.
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Disadvantages of pyramids of numbers
They do not take size into account and it is hard to work out exact numbers.
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Describe pyramids of biomass
Te horizontal bar represents the dry mass of the organism. However, it is difficult to calculate without killing the organisms. Biomass at each trophic level can vary over time resulting n an inverted pyramid e.g. aquatic ecosystems.
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Description of pyramids of energy
More informative. They represent the energy flow into each trophic level over a given time. They are destructive and a snapshot as populations fluctuate.
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Equation for calculating efficiency of energy transfer.
Energy available after the transfer/energy available before the transfer x 100
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Why do plants only convert 3% of sunlight into chemical energy for photosynthesis?
Some light reflects off the leaf. It may miss the chlorophyll molecules, some wavelengths may not be absorbed, all the area may not be covered by plants and it may pass through.
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Give examples of limiting factors
Carbon dioxide concentration, amount of water, oxygen and the temperature
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How is energy lost when transferring to consumers on different trophic levels?
Through respiration, movement, excretion and maintenance of body temperature. Not all is eaten and not all is digested.
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Define productivity
The rate at which organisms convert the energy received into chemical energy.
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Define primary production
The energy converted from light energy to chemical energy
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Define secondary production
The energy converted from the plant.
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Define gross productivity (GGP)
The total amount of energy transferred into the organisms/into chemical energy.
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Define net productivity
The amount of energy left after respiration (GPP-R)
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Define gross priamary productivity (GPP)
Total fixation of energy by photosynthesis.
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Define net primary production (NPP)
The difference between gross primary productivity and respiration.
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Other cards in this set

Card 2

Front

All organisms of 1 species living in the same place at the same time

Back

Define population

Card 3

Front

Any group of living or non-living things occuring together and the interrelationship between them. They are dynamic (constantly changing).

Back

Preview of the back of card 3

Card 4

Front

Biotic factors are the LIVING factors such as predators, food supply and disease

Back

Preview of the back of card 4

Card 5

Front

Abiotic factors are the NON-LIVING factors such as pH, humidity and temperature

Back

Preview of the back of card 5
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