Notesale: Turn your study into money

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[2]
b) From your food chain,
write down the name of a:
i) top predator
ii) herbivore
iii) consumer
iv) producer
v) omnivore
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7 which organism
is both a secondary consumer
and a primary consumer?
[Total 1]
State two advantages of a
food web as opposed to a
food chain for showing
feeding relationships
between organisms
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Instead of one simple food chain there are many food chains
that share the same organisms
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7)
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A food web is usually arranged with the producers at the bottom
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This is not always possible since an organism might be at
different trophic levels in two different food chains
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These are animals that rely on both
plants and animals for food
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If you carefully study one area, for example a pond, you can draw a
food web and plot a pyramid of biomass for the whole area (Figure
1
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There are usually very few predators in the pond
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The biomass gets smaller at
each trophic level
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Decomposers
Simple food chains and food webs contain herbivores and carnivores
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Animals and plants also die from disease or
old age
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These are grouped together as
decomposers
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The main decomposers are bacteria
and fungi
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Although energy is
lost, decomposers allow material to be recycled
through an ecosystem
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Bacteria and fungi
Figure 1
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Food chains and webs

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8 A pond food web with the
pyramid of biomass
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A food
web should include decomposers as they are part of the community
but because they are small or microscopic they are often missed out
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9 Fungi feeding on a rotting
log
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A producer traps energy from its surroundings
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Energy is lost from food chains, mainly as heat
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Pyramids of number can be inverted if the organisms are of different sizes
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A food web shows all the feeding relationships in a community
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