24 8 Biodiversity can be reduced by management of habitats. (a) A study of plant species, other than grasses, found in two lawns was completed. Lawn A was cut every 14 days. Lawn B was cut every 7 days. The table shows the number of plants of each species identified. Plant species Number of plants Lawn A Lawn B Daisy 18 5 Bee orchid 1 0 Dandelion 12 0 Clover 4 0 Bird’s-foot trefoil 6 0 Biodiversity can be compared in different habitats using a formula to calculate an index of diversity (D). Σ − = − ( 1) ( 1) N N D n n n = total number of organisms of a particular species N = total number of organisms of all species (i) Calculate the index of diversity for lawn A. (3) Answer .............................................................. Turn over 25 (ii) Herbicides are sprayed on lawns to kill unwanted plants. Explain how the calculated value would change if a herbicide was used on this lawn. 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(b) The bee orchid, Ophrys apifera, is pollinated by a species of bee, Eucera longicornis, that is found in parts of the UK. Males of this species of bee mistake the flower for a female bee. The bee orchid can also self‑pollinate. The niche of E. longicornis is that it (1) A feeds on the orchid B is found in the same location as the orchid C looks like the orchid flower D pollinates the orchid 26 *(c) The graph shows the changes in the relative abundance of pollinating wild bee species in the UK. The original sample in 1980 represents a value of 100%. 1980 1984 1988 1992 1996 2000 2004 2008 2012 2016 110 100 90 80 70 60 50 Year Relative abundance (%) Explain how the changes in the relative abundance of bee species in the UK may result in the development of a new species of bee orchid. 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(Total for Question 8 = 12 marks) TOTAL FOR PAPER = 80 MARKS 28 BLANK PAGE