Invertebrate Animals

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Invertebrate Animals
(MOST Animals -- gt95!)
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Animal Phylogeny
Porifera Cnidaria Platyhelminthes Nematoda Annelid
a Mollusca Arthropoda Echinodermata
Invertebrates
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Porifera (Sponges)

• Simple, ALMOST Colonial
• No Symmetry
• No Gut
• 2 Tissue Layers
• Acoelomate (Spongocoel)
• Sessile filter feeders

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Porifera (Sponges)
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Cnidaria (Jellyfish, Anemone)

• Simple
• Radial Symmetry
• Incomplete Gut Gastrovascular Cavity (GVC)
• 2 tissue Layers
• Acoelomate

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Cnidaria (Jellyfish, Anemone)

• Sessile (Polyp) or Mobile (Medusa) forms

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Cnidaria (Jellyfish, Anemone)

• Carnivores
• Tentacles with stinging cells
• Cnidocytes

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Platyhelminthes (Flatworms)

• Simple
• Bilateral Symmetry
• Incomplete Gut Gastrovascular Cavity (GVC)
• 3 tissue Layers
• Acoelomate
• Protostomes

http//www.biology.ualberta.ca/courses.hp/zool250/
Labs/Lab04/DugesiaCrawling.mov
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Platyhelminthes (Flatworms)

• Incomplete GVC is finely branched.
• Simple Nervous System
• Simple Reproductive System

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Platyhelminthes (Flatworms)

• Tapeworms

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Nematoda (Smooth Roundworms)

• More Complex
• Bilateral Symmetry
• Complete Gut
• 3 tissue Layers
• Pseudocoelomate
• Protostomes
• Many soil-dwellers
• Many parasites

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Nematoda (Smooth Roundworms)

• More complex Digestive System
• More complex Reproductive System
• No Circulatory system

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Nematoda (Smooth Roundworms)
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Annelida (Segmented Roundworms)

• More Complex
• Bilateral Symmetry
• Complete Gut
• 3 tissue Layers
• Coelomate
• Protostomes
• Many soil-dwellers
• Many marine
• Some parasites

Earthworms
Polychaetes
Leeches
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Annelida (Segmented Roundworms)

• Segmentation ? Specialization
• Basic central nervous system
• Complex reproductive system
• Complex digestive system
• Open circulatory system
• Simple kidney system

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Annelida (Segmented Roundworms)
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Mollusca (Snails, Clams, Squid)

• Even More Complex!
• Bilateral Symmetry (some modified)
• Complete Gut
• 3 tissue Layers
• Coelomate
• Protostomes
• Diverse!

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Mollusca (Snails, Clams, Squid)

• Soft bodies, often with a CaCO4 shell
• Complex systems (digestion, reproductive)
• Open circulatory system
• Simple respiratory system (gills)
• Modified Segmentation ? Specialization
• Foot (musclular, locomotion)
• Visceral Mass (organs, organ systems)
• Mantle (membranous covering shell secretion)

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Mollusca (Snails, Clams, Squid)

• CLASS Gastropoda (Snails, Slugs)

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Mollusca (Snails, Clams, Squid)

• CLASS Bivalvia (Clams, oysters, scallops)

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Mollusca (Snails, Clams, Squid)

• CLASS Cephalopoda (Octopus, Squid)

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Arthropoda (Insects, Crustaceans, Spiders)

• Rather Complex!
• Bilateral Symmetry
• Complete Gut
• 3 tissue Layers
• Coelomate
• Protostomes
• Very Diverse!

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Arthropoda (Insects, Crustaceans, Spiders)

• Hardened Exoskeleton (Protein Chitin)
• Molting to grow
• Jointed Feet
• Segmentation (often modified through fusion)
• Specialization
• Open circulatory system
• Simple respiratory system (gills, book lungs,
  tracheal system)
• Complex systems (digestion, reproductive)

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Arthropoda

• CLASS Insecta (grasshopper, fly, butterfly,
  ladybug, mantis, bee, wasp, etc.)

3 sets of walking appendages
Metamorphosis
15 Orders!
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Arthropoda

• CLASS Arachnida (Spiders, Ticks, Scorpions)

Chelicerae (jaws)
4 sets of walking appendages
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Arthropoda

• CLASS Crustacea (Crabs, Shrimp, Lobsters)

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Echinodermata(Sea Stars, Starfish, Sea Urchins)

• Somewhat Complex
• Radial Symmetry
• Complete Gut
• 3 tissue Layers
• Coelomate
• Deuterostomes

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Echinodermata(Starfish, Sea Urchins)

• Radial Symmetry is secondary
• Almost Radial
• Larvae are bilateral
• Endoskeleton (hardened calcium plates or spines)
• Spiny-skin
• Water Vascular System
• Hydraulic locomotion,feeding, gas exchange
• Complete Gut
• (Seems Incomplete)

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Echinodermata (Starfish, Sea Urchins)
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