• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month
  1. 1
  2. 2
  3. 3
  4. 4
  5. 5
  6. 6
  7. 7
  8. 8
  9. 9
  10. 10
  11. 11
  12. 12
  13. 13
  14. 14
  15. 15

Biology coursework investigation: Comparing the length of ivy leaves (Hedera helix) in areas of greater illumination and shade

Extracts from this document...


Biology coursework investigation: "Comparing the length of ivy leaves (Hedera helix) in areas of greater illumination and shade" Abstract The aim of this study was to compare the length of leaves of ivy plants (Hedera helix) climbing on two Hornbeam trees (Carpinus betulus) in two different light intensities. The hypothesis was that the lengths of Hedera helix exposed to a higher light intensity ("sun leaves") would be shorter than Hedera helix exposed to a lower intensity of light ("shade leaves"). The light intensity was measured using a light meter and the lengths of the midrib vein of 30 leaves were measured from each of the two trees. The method describes how leaves were chosen to ensure that they were approximately the same age. The results were analysed using a students t statistical test and it was concluded that there was a significant difference between the lengths of the two groups of leaves. The main reason for this was concluded to be the structural differences in the Hedera helix in the sun and shade. Background information on Hedera helix Previous investigations have shown that there are structural differences between the leaves of ivy in areas of high light intensity and areas of low light intensity. Shade leaves of ivy are typically thinner than sun leaves and also have a larger area in comparison. This is due to them having a thinner cuticle and one layer of palisade tissue cells whereas sun leaves usually contain two or three layers of palisade cells that are often longer and also have a thicker cuticle. Low light intensity causes the shade leaves to grow rapidly producing long internodes thus helping the leaves to catch any light in the plant's surroundings. This rapid growth helps the shoot to reach light subsequently helping the plant to survive in an area where light levels are low. The large leaves of the shade plant provide a larger surface area for trapping light energy for photosynthesis for maximum absorption. ...read more.


5.9 25 5.9 146.5 5.9 26 5.7 152.2 5.9 27 7.5 159.7 5.9 28 5.3 165 5.9 29 4.0 169 5.8 30 6.5 175.5 5.9 Table 2: Measurements of Hedera helix in the shaded area Leaf number Length (cm) Cumulative total (cm) Cumulative mean (cm) (1 d.p.) 1 12.0 12 12.0 2 8.2 20.2 10.1 3 10.5 30.7 10.2 4 9.5 40.2 10.1 5 9.0 49.2 9.8 6 8.0 57.2 9.6 7 9.0 66.2 9.5 8 9.4 75.6 9.5 9 9.7 85.3 9.5 10 8.6 93.9 9.4 11 7.3 101.2 9.2 12 10.8 112 9.3 13 10.7 122.7 9.4 14 11.0 133.7 9.6 15 9.5 143.2 9.5 16 9.2 152.4 9.5 17 9.0 161.4 9.5 18 8.5 169.9 9.4 19 8.5 178.4 9.4 20 12.0 190.4 9.5 21 9.7 200.1 9.5 22 9.0 209.1 9.5 23 9.6 218.7 9.5 24 9.9 228.6 9.6 25 7.5 236.1 9.4 26 10.5 246.6 9.5 27 10.0 256.6 9.5 28 10.0 266.6 9.5 29 9.7 276.3 9.5 30 9.5 285.8 9.5 The results displayed in the tables above have also been recorded in a tally chart as shown below: Length of Hedera helix (cm) Number in brighter area Number in shaded area 1.0 - 1.9 2.0 - 2.9 3.0 - 3.9 4.0 - 4.9 111 5.0 - 5.9 111111111111111 6.0 - 6.9 11111111 7.0 - 7.9 1111 11 8.0 - 8.9 11111 9.0 - 9.9 11111111111111 10.0 - 10.9 111111 11.0 - 11.9 1 12.0 - 12.9 11 The results in the tally have been displayed in the graph below to compare the two sets of data: Results The results table and graph clearly display evidence to support my hypothesis. The tally chart shows that the lengths of the Hedera helix in the shade were greater than Hedera helix in the sun. From the graph it can be seen that there appear to be notable differences in the lengths of the two sets of leaves, in particular between the ranges of 5.0-5.9 cm and 9.0-9.9 cm, where the majority of the sun and shade leaf lengths lie respectively. ...read more.


It can be seen from the graph that the measurements of the two groups show considerable variation with very little overlap. There is only overlap in the size class of 7.0-7.9 cm. The shade leaves cover a wider range of measurements thus showing more variability than the sun leaves. This is also apparent in the size differences in some of the sun leaves and shade leaves with some shade leaves measuring double the length of some sun leaves, e.g. 3 sun leaves fell into the size class of 4.0-4.9 cm whereas 5 shade leaves measured between 8.0-8.9cm. Therefore the difference in size between the two groups of leaves is indeed very significant as shown by the t test. A limitation of this study is that it only measured the length of leaves and not the area which may have produced different results. However, this is not likely to be the case as length is proportional to area so it is likely that the results would be very similar to those obtained in this study. Furthermore, working out the area is time consuming as opposed to working out the length which is a faster method as only a ruler is needed. Instead, time was allocated to studying a larger sample of leaves in order to have a normal distribution of data for which the t test could then be used. For further research into this topic, the area of leaves could be compared instead of length to produce results which may confirm those obtained by the investigation into length of leaves or may generate results suggesting otherwise. Leaves could also be compared for their thickness. This may be a difficult method as there is no simple technique to measure thickness of leaves as there is with length. However, the thickness of a leaf should be proportionate to its weight and area so the leaf could be measured for its area and weight after which the thickness could be estimated. Once again, this may confirm the findings of the investigation into length of leaves or may produce results suggesting otherwise. ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our AS and A Level Energy, Respiration & the Environment section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Here's what a teacher thought of this essay

4 star(s)

****A very good A-level experiment report, in which the key elements of a scientific paper are clearly attempted. To improve:
1)Give a more detailed explanation of the biology behind plant growth towards light and, the process of photosynthesis, and the role of chloroplasts and leaf structure in shade adaptation. Details should be concise, but illustrate understanding of the background biology
2)Reference all sources used in the text
3)Address sources of error and limitations of the procedure thoroughly and suggest solutions that could improve the method. This section lacks substance currently
4)Use standard format for the bibliography and evaluate sources

Marked by teacher kerry Jackson 27/03/2012

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related AS and A Level Energy, Respiration & the Environment essays

  1. Marked by a teacher

    effect of temperature on the rate of respiration in yeast

    5 star(s)

    All the fermentation is done anaerobically. Dehydrogenase enzymes: This is an alcohol enzyme which plays an important part in fermentation of yeast. Pyruvate resulting from glycolysis is converted to acetaldehyde and carbon dioxide, and the acetaldehyde is then reduced to ethanol by an alcohol dehydrogenase called ADH1.

  2. Marked by a teacher

    An investigation into the effect of different sugars on respiration in yeast.

    5 star(s)

    These were to determine firstly, the most effective ratio of yeast: sugar and secondly, the optimum temperature to use in the experiment. This was so that in the real experiment, I would gain the most accurate results from all the different sugars and get a more detailed picture of how different sugars affect the respiration of yeast.

  1. Marked by a teacher

    To make sure we have plenty of energy in the future, it's up to ...

    4 star(s)

    In a chain reaction, particles released by the splitting of the atom go off and strike other uranium atoms splitting those. Those particles given off split still other atoms in a chain reaction. In nuclear power plants, control rods are used to keep the splitting regulated so it doesn't go too fast.

  2. Describe the concept of homeostasis and the homeostatic mechanisms that regulate heart rate, breathing ...

    It increases each heartbeat in strength and in heart rate. The parasympathetic nervous system is active when the body is at peace, or resting and contentment. This system calms down the heart output. The main parasympathetic nerve is called the vagus nerve and this is cut off the heart starts to beat faster.

  1. the effect of bile concentration on the activity of the enzyme lipase during the ...

    The lipase enzyme I will be using in my experiment has an optimum pH of 8 as this is the pH of the small intestine where it is released. Concentration - If all other conditions are held constant, the rate of the reaction should increase with increasing concentrations of substrate.

  2. Compare and Contrast the Interactions Between a Forest and a Grassland Biome

    supporting over 40 species of large herbivore such as wildebeest, zebra and antelope, as well as several carnivores; both predators such as cheetahs and scavengers such as hyenas. Most of the animals on the savanna have adapted to the climate in some way; many burrow underground to avoid the heat

  1. The Pancreas is a large gland that forms part of the Endocrine System, but ...

    (Information from handout called Liver and pancreas, page 279.) On the next page is a table showing not only pancreatic enzymes but also ones that are found in the body. It is on the next page because it is too big to fit here Enzyme: Substrate: Product: Comments: Trypsin (endopeptidase)

  2. Effects of exercise on tidal volume and breathing rate

    One of the exercised induced challenges to the body is a lowering of the body?s pH level (acidic). Firstly to increase the energy available to the muscles the body increases its oxidation of fats and carbohydrates. During the oxidative phosphorylation of these compounds hydrogen molecules are removed to link with oxygen to produce energy.

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work