GASTROPODS

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Gastropods
Columella 1
A P 5 min
Students separate about 10 gastropods into those with and those without a columnella
Columella 2
D
Grind a Turretella down until the columella is exposed and show it to students
Columella 3
D
Some tourist shops sell slices of gastropod shells which can be placed on the overhead
projector to show the columella.
Evolute – involute
A P 5 min
Students put a number of gastropods into a line with the most evolute one a one end and
the most involute at the other end.
Siphonal canal
A P 5 min
Students must separate about 10 gastropods into those with entire apertures and those
with siphonal canals.
Apical angle
A P 5 min
Students put about ten gastropods in order of increasing apical angle and then measure the
angle using a simple goniometer or a protractor.
How many whorls
A P 5 min
Students are given a few gastropods and they must count the number of whorls on each.
Plasticene coils
D or P 5 min
A long, thin and tapering piece of plasticine is provided. This is coiled up to make an evolute
gastropod. Students are then given a fatter and more carrot-like piece of plasticine to
make an involute gastropod.
Parameters controlling the shape
D or P 10 min
There is computer programme designed by Dr. D. M. Raup, which used to be available, which
allowed one to vary the parameters and the computer would draw the gastropod shape.

Earth Science Activities and Demonstrations