A student was investigating the populations of organisms in a garden - Edexcel - GCSE Biology - Question 2 - 2019 - Paper 1
Question 2
A student was investigating the populations of organisms in a garden.
Figure 2 shows the estimates of the number and biomass of some of the organisms in the garden.
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Worked Solution & Example Answer:A student was investigating the populations of organisms in a garden - Edexcel - GCSE Biology - Question 2 - 2019 - Paper 1
Step 1
Calculate the biomass of the population of earthworms in the garden.
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Answer
To calculate the biomass of the earthworms, we use the formula:
extBiomass=extNumberimesextMeanBiomassperOrganism
Plugging in the values from Figure 2:
extBiomass=620imes3.4
Calculating:
extBiomass=2108extgrams
Thus, the biomass of the population of earthworms in the garden is 2108 grams.
Step 2
Explain how killing the slugs would affect the population of earthworms in this garden.
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Answer
Killing the slugs would likely lead to a decrease in the population of earthworms for two main reasons:
Increased Predation: With slugs removed from the ecosystem, hedgehogs, which previously consumed slugs, may switch their diet to include more earthworms. This increased predation pressure would lead to a reduction in the earthworm population.
Food Source Availability: Earthworms are part of the food web, and if more hedgehogs are consuming them due to fewer slugs, the earthworm population will have less chance to thrive. Moreover, the balance of food sources can shift, meaning earthworms may compete more for the remaining food resources.
In summary, the death of slugs could indirectly reduce the population of earthworms due to increased predation and food competition in the ecosystem.