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B7: Quiz 3 – Answers
B7: Quiz 3 – Answers
1)
a)
i) Biotic factors are living factors
ii) Any 3 from the availability of food, new predators, new pathogens, competition (one species outcompeting another)
b)
i) Abiotic factors are non-living factors
ii) Any 4 from light intensity, temperature, moisture levels, soil pH & mineral content, wind intensity & direction, carbon dioxide levels for plants, oxygen levels for aquatic animals
2) The tree’s leaves are blocking out light for the smaller plants underneath the tree. Plants need light for photosynthesis. So, less light reaching these smaller plants means that they will be photosynthesising less and will therefore have reduced growth and some will die. This results in a decrease in the population of smaller plants underneath the tree.
3) Soil pH and mineral content
4) Oxygen levels in the water. The oxygen levels in the water is important because the aquatic animals need the oxygen for respiration. If there wasn’t enough oxygen, the aquatic animals wouldn’t be able to respire and would die
5) The introduction of grey squirrels to the UK resulted in red squirrels and grey squirrels being in competition with each other. Grey squirrels are better suited to the UK than the native red squirrels. This resulted in the grey squirrels outcompeting the red squirrels for resources, which caused the population of red squirrels to decline
a)
i) Biotic factors are living factors
ii) Any 3 from the availability of food, new predators, new pathogens, competition (one species outcompeting another)
b)
i) Abiotic factors are non-living factors
ii) Any 4 from light intensity, temperature, moisture levels, soil pH & mineral content, wind intensity & direction, carbon dioxide levels for plants, oxygen levels for aquatic animals
2) The tree’s leaves are blocking out light for the smaller plants underneath the tree. Plants need light for photosynthesis. So, less light reaching these smaller plants means that they will be photosynthesising less and will therefore have reduced growth and some will die. This results in a decrease in the population of smaller plants underneath the tree.
3) Soil pH and mineral content
4) Oxygen levels in the water. The oxygen levels in the water is important because the aquatic animals need the oxygen for respiration. If there wasn’t enough oxygen, the aquatic animals wouldn’t be able to respire and would die
5) The introduction of grey squirrels to the UK resulted in red squirrels and grey squirrels being in competition with each other. Grey squirrels are better suited to the UK than the native red squirrels. This resulted in the grey squirrels outcompeting the red squirrels for resources, which caused the population of red squirrels to decline
Questions
1) The population and distribution of organisms in an ecosystem is affected by biotic and abiotic factors.
a)
i) What are biotic factors?
ii) Give 3 biotic factors.
b)
i) What are abiotic factors?
ii) Give 4 abiotic factors.
2) Some small plants live underneath a tree. The tree grows, which results in the tree’s leaves blocking out light for the small plants underneath the tree. Explain what effect this will have on the growth and population of the plants underneath the tree.
3) What are the two abiotic factors that relate to the soil?
4) Give an abiotic factor that affects the population of aquatic animals. Explain why this abiotic factor is important.
5) Red squirrels were the native squirrel in the UK. The grey squirrel was introduced to the UK from America. The introduction of grey squirrels resulted in the population of red squirrels declining. Explain why the population of red squirrels declined.
1) The population and distribution of organisms in an ecosystem is affected by biotic and abiotic factors.
a)
i) What are biotic factors?
ii) Give 3 biotic factors.
b)
i) What are abiotic factors?
ii) Give 4 abiotic factors.
2) Some small plants live underneath a tree. The tree grows, which results in the tree’s leaves blocking out light for the small plants underneath the tree. Explain what effect this will have on the growth and population of the plants underneath the tree.
3) What are the two abiotic factors that relate to the soil?
4) Give an abiotic factor that affects the population of aquatic animals. Explain why this abiotic factor is important.
5) Red squirrels were the native squirrel in the UK. The grey squirrel was introduced to the UK from America. The introduction of grey squirrels resulted in the population of red squirrels declining. Explain why the population of red squirrels declined.