Table 2 shows the number of species recorded by scientists in two habitats on the same farm. Each habitat was searched on five dry mornings in June. The old...
Question 1 Report
Table 2 shows the number of species recorded by scientists in two habitats on the same farm. Each habitat was searched on five dry mornings in June. The old hedge had not been cut for eight years, whereas the grass verge was mown every three weeks. Organisms were identified using field guides and placed into groups. The results show the variety of animals, plants and fungi in each place.
| group of organisms | old hedge | mown grass verge |
|---|---|---|
| flowering plants | 18 | 7 |
| ferns | 4 | 0 |
| fungi | 11 | 3 |
| insects | 26 | 14 |
| arachnids | 9 | 4 |
| birds | 7 | 5 |
(a) Calculate the total number of species recorded in the old hedge. [2]
(b) Use Table 2 to describe three differences between the variety of organisms in the two habitats. [3]
(c) Explain why the scientists used the same number of searches in each habitat. [3]
(d) Suggest two changes to the management of the grass verge that could increase the variety of organisms there. [4]
(e) Describe two limitations of using these results alone to decide which habitat has the greater biodiversity. [4]
Answer Details
(a)
\[18+4+11+26+9+7=75\]
The total number of species recorded in the old hedge is 75 species. [2 marks]
(b) Three valid comparisons are:
- The hedge has more flowering plant species, 18 compared with 7. [1 mark]
- Ferns were found in the hedge, 4 species, but none were recorded on the verge. [1 mark]
- The hedge has more fungi, 11 compared with 3. [1 mark]
The hedge also has more insects, 26 compared with 14, and more arachnids, 9 compared with 4; bird species are only slightly higher, 7 compared with 5.
(c) Using five searches in each habitat gives equal sampling effort and makes the comparison fair. [1 mark] Differences are then less likely to be caused by one habitat being searched more often. [1 mark] Equal numbers of searches allow totals or mean results to be compared more reliably. [1 mark]
(d) Four suitable changes are: mow less frequently [1 mark]; leave some areas uncut [1 mark]; sow native flowering plants [1 mark]; avoid herbicides and pesticides [1 mark]. Leaving dead wood or leaf litter, creating a pond or damp area, and planting shrubs or a hedge are also acceptable.
(e) The surveys were carried out only in June. [1 mark] Some organisms are seasonal and may not have been present then. [1 mark] Five searches may not represent the entire habitat. [1 mark] Organisms may have been missed or misidentified, and species number does not show the number of individuals of each species. [1 mark] Weather and differences in habitat area are further limitations.
Download The App On Google Playstore
Everything you need to excel in your exams
