The document discusses the general characteristics and classification of invertebrate animals. It outlines that invertebrates lack backbones and covers their body structures like body cavities, skeletons, symmetry, and systems like digestion, circulation, respiration, excretion, and reproduction. The major invertebrate phyla described are porifera, cnidarians, platyhelminthes, nematodes, annelids, mollusks, echinoderms, and arthropods.

1. Exploring InvertebratesBiology Notes: Unit 7

2. I. General Characteristics of AnimalsA. Heterotrophic- Must take in foodB. Mobility- Most animals can perform rapid, complex movementsC. Multicellularity- Made of more than one cellD. Eukaryotic- Made of true cells with nucleus and organelles

3. II. InvertebratesAnimals without a backbone

4. III. Invertebrate CharacteristicsA. Internal Body Cavities1. coelom- body cavityA. acoelomates- animals with no body cavityB. pseudocoelomates- animals with a false body cavityC. coelomates- animals with a true body cavity

5. B. Skeletons1. hydrostatic- use water contained under pressure2. exoskeleton- a rigid external skeleton3. endoskeleton- an internal skeletonexoskeletonendoskeleton

6. C. Body Symmetry1. asymmetrical- irregular in shape2. radial- body parts arranged around a central axisBilateral- right and left sides that are mirror images

7. Body Symmetry

9. D. Feeding and Digestion1. intracellular digestion- digestion within special body cells2. gastrovascular cavity- a digestive sac with only a single opening3. extracellular digestion- food is digested by special organs

10. E. Circulatory System1. open system- blood is not contained in vessels2. closed system- heart circulates blood inside blood vessels

11. F. Methods of Respiration1. respire through the skin (earthworm)2. use gills (crayfish, fish)3. book lungs (spider)4. trachea (insects)

12. Methods of RespirationgillsBook lungs

13. F. Methods of Excretion1. flame cells2. nephridia3. malpighian tubules

14. Methods of Excretion

15. H. Response1. centralization- concentration of nerve cells at anterior end2. cephalization- anterior developed into a definite head

16. I. Types of Reproduction1. asexual-clone of the parentregeneration: can regrow lost body partsBudding :seperation of a parent into 2 or more individuals2. hermaphrodites- contains male and female parts3. sexual- fusion of egg and sperm

17. IV. Invertebrate PhylaA. Porifera- sponges

18. B. Cnidarian- jellyfish, corals, sea anemone

19. C. Platyhelminthes- flatworms-planaria, tapeworm

20. D. Nematodes- roundworms

21. E. Annelids- segmented worms-earthworms, leeches

22. F. Mollusks- clams, snails, squid

23. G. Echinoderms- starfish, sea urchin, sand dollar

24. H. Arthropods- spider, grasshoppers