1. 1
   A student used a 0.5 m by 0.5 m quadrat to survey daisy plants growing in a school playing field. They placed the quadrat randomly at ten locations across the field. The mean number of daisy plants per quadrat was 6. The total area of the field is 800 m2.

   (a)

   What is the area of the quadrat used by the student?

   [1 mark]

   • A0.25 m2
   • B0.5 m2
   • C1 m2
   • D2.5 m2

   (b)

   Why did the student place the quadrat at random locations rather than choosing the locations themselves?

   [1 mark]

   • ATo avoid bias in choosing sample sites
   • BTo make the survey take less time
   • CTo make sure every daisy plant is counted
   • DTo increase the size of the quadrat used

   (c)

   Calculate the estimated total number of daisy plants in the whole field. Show your working.

   [2 marks]

   Total for question 1: 4 marks

2. 2
   A group of students investigated how the percentage cover of marram grass changed with distance from the sea on a sand dune. They laid a 30 metre tape measure from the top of the beach to a fixed inland point and placed a 1 m by 1 m quadrat every 5 metres along the tape. At 0 m from the sea the percentage cover of marram grass was 5%. At 30 m inland the percentage cover was 65%.

   (a)

   What name is given to the sampling method used by the students in this investigation?

   [1 mark]

   • ABelt transect
   • BRandom quadrat sampling
   • CMark-release-recapture
   • DPooter sampling

   (b)

   Which abiotic factor most likely explains the increase in marram grass cover with distance from the sea?

   [1 mark]

   • AReduced exposure to salt spray and wind further inland
   • BIncreased competition from other species further inland
   • CIncreased predation by animals near the beach
   • DReduced availability of light further inland

   (c)

   Explain why the percentage cover of marram grass increased with distance from the sea.

   [2 marks]

   Total for question 2: 4 marks

3. 3
   In a woodland margin habitat, students recorded the number of buttercup plants in five 1 m by 1 m quadrats placed in a shaded area (counts: 0, 1, 2, 1, 1) and five 1 m by 1 m quadrats placed in an open sunny area (counts: 8, 10, 9, 11, 7).

   (a)

   Calculate the mean number of buttercup plants per quadrat in the shaded area and in the sunny area.

   [3 marks]

   (b)

   Explain why the mean number of buttercup plants differs between the shaded and sunny areas, and suggest one way the students could improve the reliability of their results.

   [4 marks]

   Total for question 3: 7 marks

4. 4
   A conservation group wants to assess how effective a new hedgerow planting scheme has been at increasing biodiversity on a farm. Before planting, ecologists recorded the species present using random quadrat sampling in the field margins. Five years after planting, they plan to repeat the survey using the same method in the same locations.

   (a)

   Evaluate the quadrat sampling method used by the ecologists before planting the hedgerow, and suggest how they could improve the reliability of the survey when they repeat it in five years.

   [6 marks]

   (b)

   Using ideas about interdependence and biodiversity, explain why increasing biodiversity in the field margins would benefit the stability of the wider farm ecosystem.

   [6 marks]

   Total for question 4: 12 marks

End of questions