Animals Chapter 2

1. Animals Chapter 2 Sponges, Cnidarians, and Worms Sections 1 and 2

2. Definitions • Nerves – carry signals throughout the body • Ganglia – groups of nerves bundled together. Animals can have a brain and ganglia or just have ganglia depending on how advanced the animal is • Gut – pouch lined with digestive enzymes • Coelom – cavity that allows organs such as the gut, heart etc to work without interference from body movement

3. Coelom

4. Ganglion

5. Symmetry

6. Sponges • Phylum Porifera • 1st animals on earth

7. Phylum Porifera • Simplest of all animals • Asymmetrical • No head, nervous system, gut or coelom • Spicules are needle-like splinters that make up the skeleton • If cells are separated, they can come back together • Both asexual and sexual reproduction

8. Sponge Anatomy • Pores - used to pump water into sponge • Collar Cells – filters particles of food from water and digests them • Osculum – hole at the top of the sponge

9. Anatomy of a Sponge

10. Cnidarians • Jellyfish • Hydra • Sea anenome • corals

11. Phylum Cnidaria • Radial symmetry • Complex tissues • Gut • Nerve net and nerve ring in medusa form • If cells get separated, they come back together • Tentacles – covered with nematocysts • Nematocysts – stinging cells • Sexual and asexual reproduction

12. Body Forms • Medusa – free swimming, mushroom shaped • Polyp – vase shaped, attached to a surface • Most spend life as polyps but some are born polyps and turn into medusas

13. Flatworms - Platyhelmenthes • Planaria • Flukes • Tapeworms

14. Characteristics • Bilateral symmetry • Nervous system • Ganglia acts as a brain • Sensory lobes to detect light and food • Planaria have a gut • Fluke and tapeworms are parasites and have no gut

15. Reproduction of Fluke

16. Reproduction of Tapeworms • Sexual • Can go from uncooked meat to human

17. Roundworms - Nematoda

18. Roundworm • Pseudocoelom – tube within a tube • Bilateral symmetry • Can pick up through the soles of feet, through dirty hands, through some foods

19. Segmented Worms - Annelida • Includes earthworms, bristle worms and leeches • Can live in water or on land

20. Earthworms, Bristle Worms, Leeches Earthworms – aerate soil (makes tunnels) to allow water and air in, break down organic matter into elements that can be used Bristle Worms – all live in water Leeches – can be scavengers, predators or parasites, and can be used in medicine

22. Next… • Earthworm dissection • Earthworm questions powerpoint

23. Mollusks • Phylum Mollusca • Soft bodied usually with a shell or shells • Three classes: • Gastropods – snails and slugs • Bivalves – 2 shells- clams, mussels, etc. • Cephalopods – squid and octopus

25. Similarities Between Mollusks

26. Feeding • Different depending on species: • Gastropods have a radula which is like a really rough tongue and scraps algae, leaves etc. • Bivalves filter feed • Cephalopods use tentacles to grab prey

27. Circulatory System • Most mollusks have an open system • Open system - A simple heart pumps blood into sinuses • Cephalopods have a closed system • Closed system – blood is circulated through a closed loop

28. Brains • Most mollusks have ganglia spread throughout their body • Cephalopods have a brain where all of the ganglia are connected

29. Next • Squid Dissection