Define the term species.
The image shows a woodland food web.
State the term used to collectively describe all the interbreeding foxes in the woodland.
Identify all the primary consumers from the forest food web.
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7 marksDescribe how a quadrat could be used to study the abundance of a species of clover plant in a meadow compared to a woodland.
2 marksIn a quadrat study, clover was found in 5 quadrats. Each quadrat was divided into 100 squares.
The numbers of squares containing clover in those 5 quadrats were 12, 39, 35, 85 and 27.
Calculate the average percentage cover of clover in the 5 quadrats. State your answer to the nearest whole number.
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Elodea canadensis (Canadian pondweed) is a species of aquatic plant from North America. A student grew Elodea canadensis, along with a pondweed species native to the UK, in water tanks both separately and together. The graphs below show their results.
State two abiotic factors the student should have controlled throughout the experiment.
1 markCalculate the difference in biomass between native pondweed grown separately and native pondweed grown in a tank together with E. canadensis after 15 days.
Explain the results for native pondweed when both species of pondweed are grown together.
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Ecologists studied several barnacle species, purple topshell snails (Gibbula umbilicalis), seaweeds, and lichens in a rocky shore habitat.
State, with a reason, which of the organisms listed above make up a single population.
The ecologists wanted to find out whether there was an association between the distributions of purple topshell snails and the common rock barnacle, Semibalanus balanoides.
Outline how the ecologists would collect and record data to determine whether or not such an association existed.
A chi-squared test was carried out to determine whether or not there was a significant association between purple topshells and common rock barnacles on a rocky shore.
When the calculated chi-squared value was compared to values in a critical values table it was found to be smaller than the critical value at a 0.05 probability level.
Deduce what can be concluded from this analysis?
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7 marksRed squirrels have declined in number in the UK and are now found in relatively few locations. Smardale Gill, a nature reserve in Cumbria, supports a population of red squirrels.
A researcher wants to estimate the size of this population to inform conservation efforts.
Describe a method the researcher could use to estimate the red squirrel population size at Smardale Gill.
The sampling took place over several days and in three different locations across Smardale Gill, known as sites A, B and C.
Area of Smardale Gill | First sample population size | Second sample population size | Number of marked individuals in the second sample |
A | 39 | 43 | 12 |
B | 51 | 48 | 20 |
C | 18 | 31 | 7 |
Total | 108 | 122 | 39 |
(i) Using the data in the table above, estimate the size of the red squirrel population in Smardale Gill.
[2]
(ii) List three assumptions that are made when making this estimation.
[3]
Suggest two limitations of this sampling method for the purpose of red squirrel conservation in Smardale Gill.
The decline in the number of red squirrels is due to interspecific competition with non-native grey squirrels.
The data below shows an example of how the numbers of each species of squirrel has changed since the grey squirrels were first introduced in the 1800s.
(i) Define the term interspecific competition.
[1]
(ii) Explain why the red and grey squirrels were not able to coexist together in the same location.
[3]
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