PAG 3.1

Question 1

equipment

Answer 1

• Quadrat
• 2 tape measures (20 m long)
• Recording sheet with clear folder/plastic bag to cover it in case of rain
• Key or method of identifying species in area of study
• Method of generating random numbers e.g. calculator

Question 2

method

Answer 2

1. Your teacher will tell you about the two areas of habitat that you are going to compare. Area 1 Habitat:
   Area 2 Habitat
2. Lay down the two tape measures at right angles to each other in the first area of study as directed by your teacher. The length for each ‘axis’ should be 20 m.
3. Randomly generate a number between 0 and 20 as an x-coordinate (read this along the horizontal tape measure) and then one as a y-coordinate (read this along the vertical tape measure).
4. Carefully place the quadrat so that the left hand corner is approximately where the coordinates meet.
5. Identify the species present in the quadrat using the key and then count the number of each species present. Record this information in a suitably designed table.
6. Generate a new set of coordinates and repeat the process at least 9 more times in the first area.
7. Repeat steps 2-6 in the contrasting area.
8. Look at your results. Which species was most abundant in each area? Area 1 species:…………………………………. Area 2 species:……………………………………………….. Find an example of each of these species again and carefully draw, label and annotate each one.
9. Draw a graph to display the data (total numbers of individual species) from the two contrasting areas.
10. Use Simpson’s index of diversity to calculate the species diversity (D) for each area using the formula:

D = 1 - S (n / N)2

where N = the total number of organisms of all species and
n = the total number of organisms of a particular species.
11. Comment on the species diversity of the two areas you sampled.

Question 3

notes

Answer 3

Note: The bigger the number calculated for species diversity, the more diverse and stable the habitat is considered to be and the more able to withstand change. It is a place where there are many species which interact together. Whereas a smaller number for species diversity indicates fewer species that dominate and even a small change could potentially harm the habitat significantly and cause widespread destruction.

Question 4

1. Why would a climax community such as oak woodland have high species diversity?

Answer 4

Why would a climax community such as oak woodland have high species diversity? Many different species, variety of habitats, variety of food sources, many different food chains, inter-related food webs, loss of a species has little effect on the ecosystem.

Question 5

2. How does farming reduce species diversity?

Answer 5

How does farming reduce species diversity? Farmers tend to plant one crop species – low diversity. Fewer habitats for other species. The use of pesticides has an impact. Removal of hedgerows leads to fewer habitats for species. .

Question 6

3. If farmers plant hedges around their fields, explain what effect this might have on species diversity around their land.

Answer 6

If farmers plant hedges around their fields, explain what effect this might have on species diversity around their land? Species diversity will increase as there will be more habitats/niches and so more variety of species with more complex food webs.