1. Exploring Invertebrates Biology Notes: Unit 7

2. I. General Characteristics of Animals A. Heterotrophic- Must take in food B. Mobility- Most animals can perform rapid, complex movements C. Multicellularity- Made of more than one cell D. Eukaryotic- Made of true cells with nucleus and organelles

3. II. Invertebrates Animals without a backbone

4. III. Invertebrate Characteristics A. Internal Body Cavities 1. coelom- body cavity A. acoelomates- animals with no body cavity B. pseudocoelomates- animals with a false body cavity C. coelomates- animals with a true body cavity

5. B. Skeletons 1. hydrostatic- use water contained under pressure 2. exoskeleton- a rigid external skeleton 3. endoskeleton- an internal skeleton exoskeleton endoskeleton

6. C. Body Symmetry 1. asymmetrical- irregular in shape 2. radial- body parts arranged around a central axis Bilateral- right and left sides that are mirror images

7. Body Symmetry

9. D. Feeding and Digestion 1. intracellular digestion- digestion within special body cells 2. gastrovascular cavity- a digestive sac with only a single opening 3. extracellular digestion- food is digested by special organs

10. E. Circulatory System 1. open system- blood is not contained in vessels 2. closed system- heart circulates blood inside blood vessels

11. F. Methods of Respiration 1. respire through the skin (earthworm) 2. use gills (crayfish, fish) 3. book lungs (spider) 4. trachea (insects)

12. Methods of Respiration gills Book lungs

13. F. Methods of Excretion 1. flame cells 2. nephridia 3. malpighian tubules

14. Methods of Excretion

15. H. Response 1. centralization- concentration of nerve cells at anterior end 2. cephalization- anterior developed into a definite head

16. I. Types of Reproduction 1. asexual-clone of the parent regeneration: can regrow lost body parts Budding :seperation of a parent into 2 or more individuals 2. hermaphrodites- contains male and female parts 3. sexual- fusion of egg and sperm

17. IV. Invertebrate Phyla A. 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