midtermreview

midtermreview - additional layer from the external covering...

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19/02/2008 19:09:00 Ways of classifying organisms Cells, tissues and organs o Can be differentiated but no tissues o Can have tissues but no organs o Can have tissues arranged into organs Forms of symmetry o Radial: can be cut along multiple planes and produce the same  segment i.e. a starfish o Bilateral: can only be cut along one plane to produce two identical  segments i.e. an arrow worm Segmentation o Unsegmented o Segmented Appendages o No appendages o Simple appendages o Jointed appendages Body covering o No cuticle and no ecdysis o Cuticle with ecdysis Digestive cavity o No gut o Gut with a “blind mouth” i.e. a mouth and no anus o Complete gut with mouth and anus Early development o Radial cleavage o Spiral cleavage
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Larvae o Different forms exist Body cavity o Acoelomate: gut floating in medium surrounded by external covering o Pseudocoelomate: gut floating in medium which is separated by an 
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Unformatted text preview: additional layer from the external covering o Coelomate: gut attached to additional layer which is separate from the external covering • Two grades of coelomate bilateria o Deuterostomes: the anus develops from the blastopore o Protostomes: the mouth develops from the the blastopore ← ← Kingdom-Phylum-Class-Order-Family-Genus-Species • Kids Play Cricket Or Football Games in Summer ← ← Hydrostatic skeleton is a fluid-filled cavity resistor surrounded by two sets of muscles (circular and longitudinal) Benefits of being bilateral • Have a distinct head region which makes locomotion easier and more efficient • Have a one way gut • Are able to go to the food source so able to eat more 19/02/2008 19:09:00 ← 19/02/2008 19:09:00 ←...
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This note was uploaded on 04/26/2008 for the course BIOL 305 taught by Professor Green during the Spring '08 term at McGill.

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midtermreview - additional layer from the external covering...

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