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INVERTEBRATES. I) Phylum: Porifera (sponges) A) Characteristics 1) asymmetrical bodies 2) 2 body layers 3) specialised cells i) but no tissues ii) won’t die if seperated from organism iii) porocyte, spicules, collar cells,amoebocyte 4) porous body
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I) Phylum: Porifera (sponges) A) Characteristics 1) asymmetrical bodies 2) 2 body layers 3) specialised cells i) but no tissues ii) won’t die if seperated from organism iii) porocyte, spicules, collar cells,amoebocyte 4) porous body i) cells in direct contact with environment
5) filter feeders 6) sessile as adults
II) Phylum: Cnidaria (hydra,jellyfish, sea anemones, corals)
A) Characteristics 1) marine 2)radial symmetry 3)2 cell layers 4)simple nervous system (net-like) a) tentacles with nematocysts
6) 2 body forms a) polyp: attached to surface, tentacles up or down and/or b) medusa: flat, mouth down, moves (contractions or currents)
III) worms: flatworms (Platyhelminthes) round worms ( Nematoda) segmented worms (Annelids) A) characteristics (ex.planaria, tapeworm) 1) bilateral symmetry (definite head!) 2) acoelomate (no body cavity)
B) characteristics (nematodes) 1) fluid-filled body cavity 2) one-way digestive system: ANUS!!!
C) characteristics (segmented worms) 1) segmentation a) division of body into sections b) animals can increase in size by adding more identical segments c) different segments can perform different functions ex. earthworm 2) coelom (fluid filled body cavity) a) room for complex internal organs
IV) Phylum: Mollusca A) characteristics 1) bilateral symmetry 2) 3 cell layers 3) coelom 4) 2 body openings 5) soft body, hard shell a) mantle surrounds internal organs and secretes calcium carbonate for shell 6) organ systems (circulatory, respiratory, excretory, reproductive, nervous)
B) 3 main groups 1) gastropods (snails, slugs) a) aquatic or terrestrial b) carnivorous or decomposers c) radula for feeding d) muscular foot e) sexual fertilisation i)gametes may meet in water
2) bivalves (clams, mussels) a) 2 shells (hinged) b) no cephalization c) muscular foot
3) cephalopods (squid, octopus) a) large brain b) grasp prey with arms, beak tears apart c)siphon for movement
V) Phylum: Echinodermata (ex. starfish, sea urchins, sand dollars, sea cucumbers) A) Characteristics 1) all marine 2) have coelom 3) have 1-way digestive system 4) most with radial symmetry
5) no cephalization (head) 6) internal skeleton for protection and support (endoskeleton)