1. Invertebrate Animals
(MOST Animals -- >95%!)

2. Animal Phylogeny Porifera Cnidaria Platyhelminthes Nematoda Annelida
Mollusca
Arthropoda
Echinodermata
Invertebrates

3. Porifera (Sponges) Simple, ALMOST Colonial Sessile filter feeders
No Symmetry
No Gut
2 Tissue Layers
Acoelomate (“Spongocoel”)
Sessile filter feeders

4. Porifera (Sponges)

5. Cnidaria (Jellyfish, Anemone)
Simple
Radial Symmetry
Incomplete Gut = Gastrovascular Cavity (GVC)
2 tissue Layers
Acoelomate

6. Cnidaria (Jellyfish, Anemone)
Sessile (Polyp) or Mobile (Medusa) forms

7. Cnidaria (Jellyfish, Anemone)
Carnivores
Tentacles with stinging cells
Cnidocytes

8. Platyhelminthes (Flatworms)
Simple
Bilateral Symmetry
Incomplete Gut = Gastrovascular Cavity (GVC)
3 tissue Layers
Acoelomate
Protostomes

9. Platyhelminthes (Flatworms)
Incomplete GVC is finely branched.
Simple Nervous System
Simple Reproductive System

10. Platyhelminthes (Flatworms)
Tapeworms

11. Nematoda (Smooth Roundworms)
More Complex
Bilateral Symmetry
Complete Gut
3 tissue Layers
Pseudocoelomate
Protostomes
Many soil-dwellers
Many parasites

12. Nematoda (Smooth Roundworms)
More complex Digestive System
More complex Reproductive System
No Circulatory system

13. Nematoda (Smooth Roundworms)

14. Annelida (Segmented Roundworms)
More Complex
Bilateral Symmetry
Complete Gut
3 tissue Layers
Coelomate
Protostomes
Many soil-dwellers
Many marine
Some parasites
Earthworms
Polychaetes
Leeches

15. Annelida (Segmented Roundworms)
Segmentation  Specialization
Basic central nervous system
Complex reproductive system
Complex digestive system
Open circulatory system
Simple kidney system

16. Annelida (Segmented Roundworms)

17. Mollusca (Snails, Clams, Squid)
Even More Complex!
Bilateral Symmetry (some modified)
Complete Gut
3 tissue Layers
Coelomate
Protostomes
Diverse!

18. 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)

19. Mollusca (Snails, Clams, Squid)
CLASS Gastropoda (Snails, Slugs)

20. Mollusca (Snails, Clams, Squid)
CLASS Bivalvia (Clams, oysters, scallops)

21. Mollusca (Snails, Clams, Squid)
CLASS Cephalopoda (Octopus, Squid)

22. Arthropoda (Insects, Crustaceans, Spiders)
Rather Complex!
Bilateral Symmetry
Complete Gut
3 tissue Layers
Coelomate
Protostomes
Very Diverse!

23. 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)

24. Arthropoda
CLASS Insecta (grasshopper, fly, butterfly, ladybug, mantis, bee, wasp, etc.)
3 sets of walking appendages
Metamorphosis
15 Orders!

25. Arthropoda CLASS Arachnida (Spiders, Ticks, Scorpions)
Chelicerae (jaws)
4 sets of walking appendages

26. Arthropoda
CLASS Crustacea (Crabs, Shrimp, Lobsters)

27. Echinodermata (Sea Stars, Starfish, Sea Urchins)
Somewhat Complex
Radial Symmetry
Complete Gut
3 tissue Layers
Coelomate
Deuterostomes

28. 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)

29. Echinodermata (Starfish, Sea Urchins)