Earthworms: live in soil feed on dead and decaying plant matter have soft, moist skin exchange gases through their skin 02.1 Give two abiotic factors and two biotic factors that could affect the size of an earthworm population - AQA - GCSE Biology - Question 2 - 2022 - Paper 1

Food availability: The amount of decaying plant matter present in the soil directly affects the earthworm population.

Predators: The presence of predators like birds can reduce earthworm populations.

Ensure the same concentration and volume of chemical X is applied to both areas A and B respectively.

Randomly select areas within each site to apply the chemical, ensuring they are of equal size, for example, 1 m².

Use a quadrat to mark off the sample area for consistent counting.

Apply chemical X, and after a predetermined timeframe, gently collect the earthworms from the surface without damaging them.

Count the number of earthworms collected from each area (A and B).

Repeat this process at least five times in each area for reliable data.

Analyze and compare the average number of earthworms per m² in areas A and B.