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Invertebrates & Joint-Legged Animals. SBI 3U October 18 th , 2012 Ms.Zafar. Invertebrates. Animal grouping No backbone Heterotrophic Why don’t they have cell walls?. We will be studying…. Phylum Mollusca Phylum Echinodermata. Phylum Mollusca. Shell Marine or terrestrial
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Invertebrates & Joint-Legged Animals SBI 3U October 18th, 2012 Ms.Zafar
Invertebrates • Animal grouping • No backbone • Heterotrophic • Why don’t they have cell walls?
We will be studying… • Phylum Mollusca • Phylum Echinodermata
Phylum Mollusca • Shell • Marine or terrestrial • Annelid-like ancestors
Body Plan • Foot • Mantle • Visceral Mass
3 Classes • Bivalva • Cephalopoda • Gastropoda
Class Bivalva • Shell-fish • Two-part shell • Why do they not need an anterior end? • Gills
Class Gastropoda • Diverse • Big foot • Radula • Gills • Which mollusks have a lung?
Class Cephalopoda • Shell movement • Brain development • What has happened to the cephalopod’s shell?
Phylum Echinodermata • Marine • Symmetry shift • Why might Echinoderms have radial symmetry as adults? • Endoskeleton
Joint-Legged Animals • Arthropods
Phylum Arthropoda • Segmented body • Exoskeleton • Hemocoel • Coelom • Gas exchange – gills & trachea
Moulting in Arthropods • Exoskeleton limits size
Open Circulatory System • Hemocoel • Ancient annelids developed blood instead of body fluid