Investigating populationsAQA A-Level Biology: Mind map

Exam questions on Investigating populations

1. An ecologist wants to estimate the number of dandelion plants in a meadow of area 2000 m². She places a 0.5 m × 0.5 m quadrat at 20 positions in the meadow and counts a total of 130 dandelion plants in the 20 quadrats.
   Calculate an estimate of the total number of dandelion plants in the meadow. Show your working.2 marks
2. A student investigates how the percentage cover of a moss species changes along a 20 m line running from the edge of a woodland into an open field. She suspects that light intensity affects the distribution of the moss.
   Suggest two other abiotic factors that the student should measure or control to be confident that light intensity is responsible for the distribution of the moss.2 marks
3. Ground beetles in a field were sampled using pitfall traps. On day 1, 86 beetles were caught, marked with a small dot of non-toxic paint on the underside of the body and released where they were caught. Three days later, 74 beetles were caught, of which 19 were marked.
   Calculate an estimate of the population size of the beetles. Show your working.3 marks