Studies on Limpets
A. Variation with position on shore
Limpets are found at quite a range of locations on the shore, from within the upper, right down to the lower shore.
One species (Patella vulgata) is most common, although others should be looked for.
This species, like many other organisms, shows a PLASTICITY in its development and form depending on environment. This study looks at variation in SHELL SHAPE and TONGUE LENGTH, with position on shore, in Patella.
Shell Shape.
A sample of 15 limpets was taken from each of three levels on a shore, low, mid and upper shore.
The three sample are shown by clicking the localities above.
Measurements were made of length, width and height of each limpet.
The data are available here as an EXCEL file, or here as a web page (this has further links to analyses of the data if you are not going to do these yourself on the Excel Sheet)
Some questions to consider
1. Consider variations in shell height, width and length and any ratios that you think might be important.
2. Bearing in mind what you have learned about limpet biology (here), suggest reasons for the results you have analysed.
Tongue Length
Limpets rasp the algae off rocks with their file like tongue but they only do this when covered with water. Those lower down the shore might be expected to have longer to feed and, maybe, shorter tongues (due to wear).
Tongue lengths of limpets from the low, mid and upper shore were measured. Again, the data are given in an excel file, click above on the shell size one again, or here.
Some questions to consider
1. Is the average tongue length different at different levels of the shore? You might like to consider a T Test.
2. If so, what explanation can you come up with for any differences.