1. INVERTEBRATES

2. Characteristics of Animals (Invertebrates)
Eukaryotic
Heterotrophic
Multi-cellular
No backbone (invertebrates only)
Reproduce sexually and/or asexually

3. Phylum Porifera
“Pore-bearer”
Ex. Sponges
No tissues or organ systems

4. Porifera Systems Asymmetrical
Mechanism for digestion, excretion, respiration, and circulation- movement of water through body
Reproduction-
sexual: egg/sperm asexual: budding or gemmules

5. Phylum Cnidaria “Nettle” or “Stinger”
Ex. Hydras, Jellyfish, Sea anemones, Corals
Cells organized into tissues

6. Cnidarian Life Cycle Two different stages of life cycle:
Polyp: usually sessile, mouth points up
Medusa: motile, mouth points down
Radial Symmetry

7. Cnidarian Systems
Digestion- stings prey, in through mouth, into gastrovascular cavity
Respiration, Circulation, Excretion- Diffusion through body
Nervous system- nerve net, special cells

8. Cnidarian Systems cont’d
Reproduction-
Sexual: external fertilization of eggs
Asexual: budding

9. Worms- 3 Phyla Phylum Platyhelminthes
Ex. Flatworms (planarians, flukes, tapeworms)

10. Worms- Platyhelminthes
Bilateral symmetry
Tissue layers- ectoderm, mesoderm, endoderm
Digestion- mouth, gastrovascular cavity

11. Platyhelminthes Systems
Respiration, Circulation, and Excreation- rely on diffusion through body
Nervous- ganglia, nerve cords, eyespots
Reproduction-
Sexual: hermaphrodites
Asexual: fission

12. Worms- Nematoda Ex. Roundworms Bilateral symmetry Tissue layers
Digestion- mouth and anus
Respiration, Circulation, Excretion- diffusion

13. Nematoda Systems cont’d
Nervous- several ganglia, nerves
Reproduction
Sexual: internal fertilization of egg

14. Worms- Annelida Phylum Annelida
Ex. “Segmented” worms: earthworms, leeches, bristleworms
Bilateral symmetry
Tissue layers

15. Annelida Systems Digestion- mouth and anus, pharynx
Circulation- closed system (blood contained in vessels)
Respiration- some gills, skin
Excretion- Nephridia, anus

16. Annelida Systems cont’d
Nervous- brain and nerve cords
Reproduction-
Sexual: (most), separate sexes, hermaphrodites

17. Phylum Mollusca Mollusks
Ex. Gastropods (snails), Bivalves (clams), Cephalopods (squid)
Internal or external shell
Bilateral symmetry
Tissue layers

18. Mollusk Systems Digestion: Variety, mouth and anus
Respiration- gills or skin
Circulation- open system (except squid/octopi- closed)
Excretion-Nephridia

19. Mollusk Systems cont’d
Nervous- small ganglia, nerve cords brains
Reproduction-
Sexual: internal/external fertilization

20. Phylum Echinodermata Echinoderms- “Spiny skin”
Ex. Sea Stars, Sea Urchins, Sand Dollars
Internal skeleton
Water vascular system (tube feet)
Radial symmetry

21. Echinoderm Systems
Digestion- pushes out stomach through mouth, digests prey with enzymes
Respiration, Circulation- water vascular system
Excretion- water vascular system and anus

22. Echinoderm Systems cont’d
Nervous System: Nerve ring, sensory cells
Reproduction: external fertilization, most are separate sexes

23. Phylum Arthropoda Arthropods- “Jointed foot”
Ex. Insects, crustaceans, spiders
Segmented body, exoskeleton, jointed appendages

24. Arthropod Systems
Respiration- tracheal tubes & spiracles, book lungs, gills
Circulation- open circulatory system
Excretion- Malpighian tubules or diffusion

25. Arthropod Systems cont’d
Nervous system- Brain, nerve cord, ganglia, sense organs
Reproduction- Internal fertilization, some (aquatic) external
Growth requires molting

26. Phylum Chordata Characteristics: Two invertebrate subphyla:
Notochord (stiff flexible rod)
Nerve cord (hollow cord)
Gill slits
Post-anal tail
Two invertebrate subphyla:
Urochordata: tunicates
Cephalochordata: lancelets