Difference between revisions of "SHELL"

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Most foraminifers construct tests (shells) covering the cell body. [[Composition]] of tests varies from [[Organic-walled foraminifera|organic]], through [[Agglutinated foraminifera|agglutinated]] (cemented foreign grains) [http://en.wikipedia.org/wiki/Calcareous calcareous] secreted from [http://en.wikipedia.org/wiki/Calcium_carbonate calcium carbonate]. Foraminiferal morphologies are extremely diverse, from simple single-chambered to multi-chambered, complex forms.
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Most foraminifers construct tests (shells) covering the cell body. Composition of tests varies from organic, through agglutinated (cemented foreign grains) to calcareous secreted from calcium carbonate.  
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The size of the test is associated with amount of the cytoplasm. "Feeding adds to the bulk of the cytoplasm" (Armstrong & Brasier 2005), therefore, the test has to enlarge. Foraminifera have developed several strategies for test enlargement during ontogeny (after Armstrong & Brasier 2005):
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- contained growth (see [[unilocular tests]] forms)
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- continuous growth (see [[unilocular tests|unilocular]] or [[bilocular tests]])
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- simple septate growth (see [[simple multilocular tests]])
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- complex septate growth (see [[complex multilocular tests]])
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These growth patterns result in a very diverse variety of [[shell architecture|test morphologies]].
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"The test is thought to reduce biological, physical and chemical stress" (Armstrong & Brasier 2005). See [[Function of the test]].
 
   
 
   
 
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Latest revision as of 20:26, 18 June 2006