Graptolites The specification states that you need to be able to recognise and know the function of the following morphological features: Thecae (including the different shapes). Shape of rhabdosome. Position and number of stipes. In addition you need to be able to: describe and explain the morphological changes and evolution of graptolites in the Lower Palaeozoic. Also you need to be able to: describe and explain the factors which make a good zone fossil. Outline the principles of using graptolites as zone fossils .
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Graptolites The specification states that you need to be able to recognise and know the function of the following morphological features: Thecae (including.
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GraptolitesGraptolites The specification states that you need to be able to
recognise and know the function of the following morphological features:
Thecae (including the different shapes).Shape of rhabdosome.Position and number of stipes.
In addition you need to be able to:describe and explain the morphological changes and evolution of graptolites in the Lower Palaeozoic.
Also you need to be able to:describe and explain the factors which make a good zone fossil.Outline the principles of using graptolites as zone fossils .
The exoskeleton is made of organic protein material secreted by the soft parts of the animal.
Both orders consisted of small animals, which were mainly pelagic (planktonic) living in colonies.
The one skeleton is actually a colony containing several soft-bodied animals (zooids) which could extend out of the cups.
Found in Palaeozoic rocks only (middle Cambrian to the Carboniferous).
They are pelagic and planktonic. Graptolites are most commonly found
in deep water black shales, but do extend into shallow conditions.
They are nearly always carbonised. The process of carbonisation
combined with the highly compressible nature of shales made most graptolite fossils extremely flat and therefore difficult to study.
They are useful zone fossils.
Zone FossilsZone
FossilsWhat is a zone fossil?
A fossil species characteristic of a certain rock horizon and is restricted to this time span e.g. certain Monograptus, ammonites, goniatites and ceratites. Micraster...