1. 1
   A group of students uses 1 m by 1 m quadrats to estimate how many dandelion plants are growing in two different areas of the school field: one area that is mown every week, and one area that has been left unmown all summer.

   (a)

   What term describes all the dandelion plants of this one species living together in the school field?

   [1 mark]

   • AA community
   • BA population
   • CAn ecosystem
   • DA habitat

   (b)

   Why is it important that the students place their quadrats randomly within each area, rather than choosing where to place them?

   [1 mark]

   • ATo make the investigation quicker to carry out
   • BTo make it easier to identify the dandelion plants
   • CTo ensure every dandelion plant in the area is counted
   • DTo avoid bias and obtain a representative sample of the area

   (c)

   Describe how the students could use their quadrat counts to estimate the total dandelion population size in the unmown area of the field.

   [2 marks]

   Total for question 1: 4 marks

2. 2
   A team of ecologists lays out a line of quadrats along a transect running from the edge of a dense woodland into an open meadow, recording every different plant species found in each quadrat, in order to compare how the vegetation changes across the transect.

   (a)

   What term describes the variety of different species living along the transect from woodland to meadow?

   [1 mark]

   • APopulation
   • BHabitat
   • CBiodiversity
   • DEcosystem

   (b)

   What term describes all the different plant and animal populations living and interacting together along this transect?

   [1 mark]

   • AA community
   • BA population
   • CA quadrat
   • DA species

   (c)

   Explain how the ecologists could use their quadrat data to compare the biodiversity of the woodland edge with the biodiversity of the open meadow.

   [2 marks]

   Total for question 2: 4 marks

3. 3
   Ecology students studying a patch of woodland floor count far more woodlice living under damp, shaded logs than on the nearby open ground, which receives direct sunlight for most of the day. The following year, a pair of thrushes (birds that feed on woodlice) begin nesting in a tree close to the same patch of woodland.

   (a)

   Explain how abiotic factors could account for the researchers finding far more woodlice under the damp, shaded logs than on the open, sunlit ground nearby.

   [3 marks]

   (b)

   The following year, thrushes begin nesting near the woodlice's habitat. Explain how this new biotic factor could affect the size and distribution of the woodlice population.

   [4 marks]

   Total for question 3: 7 marks

4. 4
   A severe summer drought affects a nature reserve. Wardens notice that many of the reserve's smaller ponds, important breeding sites for its frog population, have dried up completely, while the largest ponds still retain some water. At the same time, wardens carry out a biodiversity survey of the reserve's grassland using quadrats, both before the drought began and again after it ended.

   (a)

   Explain how the summer drought, as an abiotic factor, could change both the size and the distribution of the reserve's frog population.

   [6 marks]

   (b)

   Explain how the wardens could use quadrats to measure whether the drought reduced the biodiversity of the reserve's grassland, and why a fall in biodiversity would be a concern for the reserve.

   [6 marks]

   Total for question 4: 12 marks

End of questions