Populations, habitats and ecological studyEdexcel International A Level Biology: Flashcards

Exam questions on Populations, habitats and ecological study

1. A coastal sand dune system contains marram grass, rabbits, beetles, bacteria and many other species. The sand is salty, dry and low in nutrients, and the wind speed is high.
   Distinguish between the habitat and the niche of marram grass in the dune system.2 marks
2. A student estimates the population of daisies in a rectangular field measuring 40 m by 25 m. She places 20 quadrats, each 0.5 m by 0.5 m, at positions chosen using random coordinates. She counts a total of 85 daisies in the 20 quadrats.
   Suggest two ways in which the student could make her estimate of the population more reliable.2 marks
3. A student lays a 30 m line transect running from the lower shore to the upper shore of a rocky beach and places a quadrat at 2 m intervals along it. The percentage cover of the seaweed Fucus falls from 90% at the lowest position to 5% at the highest position. Going up the shore, the length of time each position is covered by seawater each day falls and the temperature of the rock surface on sunny days rises.
   Explain why a line transect is more suitable than random sampling for this investigation.3 marks