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) 4 types: porocyte, spicules, collar cells, amoebocyte 4) porous body i) cells in direct contact with environment

5) filter feeders 6) sessile as adults

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II) Phylum: Cnidaria (hydra,jellyfish, sea anemones, corals)

hydra

sea anemone *

coral

jellyfish

A) Characteristics 1) marine 2)radial symmetry 3)2 cell layers 4)simple nervous system (net-like) a) tentacles with nematocysts

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5) digestive system with 1 opening!

6) 2 body forms a) polyp: attached to surface, tentacles up and/or b) medusa: flat, mouth down, moves (contractions or currents)

III) worms: flatworms (Platyhelminthes) round worms ( Nematoda) segmented worms (Annelida) A) characteristics Platyhelminthes (ex.planaria, tapeworm) 1) bilateral symmetry (definite head!) 2) acoelomate (no body cavity)

planaria

tapeworm

B) characteristics Nematoda (ex. nematodes) 1) fluid-filled body cavity 2) one-way digestive system a) 2 openings (mouth & ANUS!)

nematodes

Parasitic worms:

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C) characteristics Annelida (ex. 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

earthworm

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)

a) aquatic or terrestrial 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

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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

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5) no cephalization (head) 6) internal skeleton for protection and support (endoskeleton)

7) tube feet for locomotion *

8) Sexual reproduction a) eggs/sperm meet in water b) also by regeneration in starfish

VI) Phylum: Arthropoda A) characteristics 1) exoskeleton a) growth ….. Molting b) prevents dehydration 2) jointed appendages 3) segmented bodies

4) cephalization a) highly developed nervous system 5) open circulatory system a) dorsal heart pumps blood from posterior to anterior end

B) 2 groups 1) Chelicerates a) 2 body parts i) cephalothorax - head - thorax (8 legs) ii) abdomen b) ex. arachnids, horsehoe crab, scorpions, ticks

2) Mandibulata a) have mandibles (jaws) for chewing b) have antennae c) >3 pairs ofwalking legs d) 3 groups i) crustaceans - marine Ex. copepods, barnacles, crab, lobster

ii) myriapods (centipedes and millipedes)

iii) insects ( bees, termites, buttterflies, beetles) - 3 body parts (head, thorax, abdomen) *specially adapted segments

- development = metamorphosis incomplete (ex. Grasshopper) or complete (ex. Butterfly)

- various types of feeding appendages

adaptations in appearance 1)camouflage

2)mimicry

reproductive adapatations 1) parthenogenesis (asexual repr., unfertilised eggs ex. aphid) 2) bodies adapted (ex. May fly)

3) pheromones

social behaviours ex. ants, bees, termites