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Summary Notes
National 5 – Life on Earth- Biodiversity
Biodiversity is the term used to describe the variety of life on earth.
A Biome is a region of the world that has a similar climate and similar
plant and animal species present. E.g. A desert or a rainforest.
A habitat is the place where an organism lives.
A population is all the animals or plants of one species living in a
particular habitat.
A community is all the plants and animals in a particular habitat.
An ecosystem is the habitat together with all the plants and animals
(communities).
A food chain is a diagram which shows simple feeding relationships
Clover
Rabbit
Fox
The arrows in a food chain show the direction of the flow of energy
sparrow
ladybird
greenfly
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wolf
weasel
sheep
rabbit
grass
clover
If the sheep are removed there may be a decrease in the size of the
wolf population as one of their food sources has been removed. There
may be a decrease in the rabbit and weasel populations as they will
have increased predation by wolves. There may be more clover as less
will be eaten by sheep.
As a prey species number increases the number of predators also
increases, until there are too many predators. Then the number of
prey species will begin to decrease resulting in the predator numbers
also decreasing. Then the cycle begins again.
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A niche is a role (job) an organism plays in an ecosystem.