Key stage 3 (page 9)

Select one of the following questions aboutenvironmental variation to investigate.
1. Investigate differences in the shape and colour of holly leaves at different heights above theground and in different locations. Are theleaves low on a tree different from those higher up, and if so, why? A pupil sheet is providedfor use in this.
2. Record the surface areas of bramble or nettle leaves under different light conditions. Makethis a fair test by choosing an equivalent leaf on each plant e.g. for bramble, the terminalleaf of the third leaflet down. 3. Measure the variation in height and differences This unit of work relates to the first part of QCA Science Unit 7D ‘Variation and Classification’. honeysuckle and ivy under different lighting conditions. N.B. Ivy leaves will only mature ifthere is enough light. Juvenile leaves have lobes and all face in the same direction. Adult leaves are either only slightly lobed or unlobed Know that individual members of a species and spiral around the stem and face in variations are inherited and others caused byenvironmental differences. Help pupils with the design of their investigation, including the choice of a suitable sample size.
Design an investigation, choosing a sufficiently Ensure that the investigation involves the measurement of environmental factors and plant t Use a spreadsheet to store and analyse data, characteristics rather than relying just on observation. Measure light levels using a light meter, humidity using a whirling hygrometer, t Present ideas about causes of variation.
windspeed using an anemometer, and soilmoisture content by weighing before and after Show pupils photographs of a variety of animals of one species and ask them to point out thedifferences between them. Extend to humans and Use a spreadsheet to store and analyse the data elicit examples of differences. Collect data about obtained. Correlate the measurements of plant individuals, (e.g. height, hand span) and enter into characteristics against light levels, height above ground, etc, using scattergraphs. An alternative correlations, saying how strong they think these and simpler method is to compare the area of 30 leaves from one location with that of 30 leavesfrom a contrasting location.
Study one individual of a tree, shrub or plant. Are investigation, identifying the causes of any all of its leaves of the same size and shape? What variations found and stating how strong a link might account for any variations? Compare two there is between the plant characteristics identifying variations and speculating on possible Study secondary sources illustrating other examples of environmental variation e.g. treesgrown in windy and non-windy environments. Review the work on variation within a species. It isimportant at this stage to establish that somevariation is due to inheritance, some toenvironmental factors and some to both.
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plants to change?Use these boxes to draw Holly leaves fromdifferent locations and heights above the ground.
For each, record the height above ground ( to the nearest metre) and the light level (preferablymeasured using a lightmeter or data logger). Also,measure the length and width of each leaf.
Height above ground . . . . . . . . . . . . .
Height above ground . . . . . . . . . . . . .
Light level . . . . . . . . . . . . . . . . . . . . .
Light level . . . . . . . . . . . . . . . . . . . . .
Height above ground . . . . . . . . . . . . .
Height above ground . . . . . . . . . . . . .
Light level . . . . . . . . . . . . . . . . . . . . .
Light level . . . . . . . . . . . . . . . . . . . . .
Height above ground . . . . . . . . . . . . .
Height above ground . . . . . . . . . . . . .
Light level . . . . . . . . . . . . . . . . . . . . .
Light level . . . . . . . . . . . . . . . . . . . . .
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Source: http://www.heritagewoodsonline.co.uk/schools/pdfs/plant-changes.pdf