Biology-topic 9

  • Created by: xopriya
  • Created on: 23-03-18 17:50
How to calculate the efficiency of every transfer between levels?
(Energy transferred to next level / energy available at previous level) x100
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What is biodiversity?
The variety of living organisms in an ecosystem
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What is fish farming?
Growing fish in a contained area, usually to apply humans with food.
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what are non-indingous species?
species that have been introduced to an area where they haven't been before
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what are indigenous/ native species?
species that have always been in an area
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why can non-indigenous species cause problems for native ones?
they will compete for resources- sometimes they are better than the native at getting the resources so the native may eventually die out
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what is a problem with non-indigenous species?
They may bring new diseases to a habitat. These often kill lots of indigenous species, reducing the habitat's biodiversity.
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what is reforestation?
planting new forests where old forests have been cut down.
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why do forests generally have a high biodiversity?
because they contain a wide variety of trees & plants- these provide food & shelter for lots of different animal species.
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what is food security?
having access to enough safe and healthy food at all times
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why does a drought occur?
because there isn't enough precipitation
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name a method that can be used to produce potable water if there is a drought
desalination
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what does desalination do?
it removes salts (mineral ions) from salt water
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what do decomposers do?
decompose proteins and urea and turn them into ammonia
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what is nitrogen fixation?
the process of turning nitrogen from the air into nitrogen-containing ions in the soil which plants can use.
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two main ways of nitrogen fixation
lightning & nitrogen-fixing bacteria
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name the 4 types of bacteria involved in the nitrogen cycle
decomposers, nitrifying bacteria, nitrogen-fixing bacteria, denitrifying bacteria
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what does nitrifying bacteria do?
turn ammonia in decaying matter into nitrites and then into nitrates
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what does nitrogen-fixing bacteria do?
turn atmospheric nitrogen into ammonia, which forms ammonium ions.
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what does denitrifying bacteria do?
turn nitrates back into nitrogen gas. they're often found in waterlogged soils and are of no benefit to living organisms.
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what is crop rotation? how does it help increase the amount of nitrates in the soil?
Where different crops are grown each year in a cycle. It usually includes a nitrogen-fixing crop, which helps to put nitrates back into the soil for another crop to use the following year.
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what are fertilisers? how do they help increase the amount of nitrates in the soil?
spreading animal manure or compost on fields recycles the nutrients left in plant and animal waste and returns them to the soil through decomposition.
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if there are a lot of bloodworms or sludgeworms in water...
the water is polluted
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if there are a lot of freshwater shrimps or stonefly larvae...
the water is clean
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if there are a lot of lichen, blackspot fungus...
the air is clean
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what does the rate of decay depend on?
temperature, water content & oxygen availability
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explain temperature on the rate of decay
a warm temperature speeds up the rate of enzyme-controlled reactions in microbes. Enzymes nature if the temperature gets too high
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explain water content on the rate of decay
decay takes place faster in moist environments because the organisms involved in decay need water to survive and carry out biological processes.
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explain oxygen availability on the rate of decay
the rate is faster where there is plenty of oxygen available. Many microorganisms need oxygen for aerobic respiration.
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what is compost?
decomposed organic matter that is used as a fertiliser for crops and garden plants.
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Other cards in this set

Card 2

Front

What is biodiversity?

Back

The variety of living organisms in an ecosystem

Card 3

Front

What is fish farming?

Back

Preview of the front of card 3

Card 4

Front

what are non-indingous species?

Back

Preview of the front of card 4

Card 5

Front

what are indigenous/ native species?

Back

Preview of the front of card 5
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