Wild grasses growing beside a small island airfield release pollen on dry mornings. Fig. 1 shows one grass flower. The student placed identical sticky micro...
Question 1 Report
Wild grasses growing beside a small island airfield release pollen on dry mornings. Fig. 1 shows one grass flower. The student placed identical sticky microscope slides downwind for the same time. Table 1 gives the number of pollen grains caught on each slide. Wind carries the pollen through air containing oxygen, but much of it settles before reaching another plant. This can affect how many seeds are made by a rare grass species.
(a) Identify the structures labelled X and Y in Fig. 1. [2]
(b) Describe the pattern in the pollen counts in Table 1. [2]
(c) Calculate the percentage of the pollen count at 1 m that was collected at 10 m. [2]
(d) Explain how the structures of a wind-pollinated grass flower help it to transfer pollen between plants. [4]
(e) Suggest two ways a conservation worker could increase the chance of pollination between isolated grass plants. [2]
Answer Details
(a) X is anther. [1] Y is stigma. [1]
(b) The pollen count decreases as distance from the grass plants increases. [1] It falls from 1200 grains at 1 m to 240 grains at 10 m. [1]
(c) 240 / 1200 × 100 [1] = 20%. [1]
(d) Anthers are exposed outside the flower so wind can remove pollen. [1] Long filaments allow anthers to move in moving air. [1] Large amounts of light, dry pollen can be carried by wind. [1] The feathery stigma has a large surface area to trap pollen. [1]
(e) Any two from: plant individuals closer together; plant more individuals of the species; protect plants from mowing until after flowering; create a sheltered corridor of suitable habitat between plants; move pollen by hand between flowers. [2]
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