Diversity of Invertebrates: From Sponge to Roundworm

1. Biology IChapters 33-34 Porifera, Cnidaria, Ctenophora, Platyhelminthes, Nematoda, and Rotifera

2. Do Now • What are the two types of tissues found only in animals? • Nervous tissue • Muscle tissue

3. Do Now • What is the function of cilia and flagella? • Movement, trapping and removing materials from the body • What’s the difference between asexual and sexual reproduction? • Sexual: two parents, offspring genetically different from parents • Asexual: one parent, offspring genetically identical to parent

4. Phylum Porifera • “Pore bearer” • Nonsymmetrical • Lack organization into tissues and organs • Possess cells that are capable of recognizing other sponge cells. • Sessile-attach themselves firmly to a surface and do not move

5. Sponge Structure • Collar cells-draw water into the body of a sponge. • Ostia-pores that penetrate the body wall • Osculum-the opening at the top of the sponge through which water leaves

6. Sponge Structure • Spongin-tough, flexible protein fibers that provide support • Spicules-hard spike-like structures in the wall of a sponge. • Sponges obtain food by filtering small organisms from the water.

7. Sponge Feeding • Amoebocytes-The cells that move throughout the sponge’s body wall to deliver food to the organism’s cells

8. Sponge Reproduction • Sponges can reproduce: • By a breakup of the original parent into fragments that each become a new sponge. • By the budding of new sponges from the parent.(Regeneration)

9. Sponge Reproduction • By producing internal buds called gemmules that can withstand harsh conditions

10. Sponge Reproduction • Sexually, using sperm and eggs.

11. Phylum Cnidaria • Hydra, Box Jellies, Jellyfish, Sea Anemones, Coral • Radially Symmetric

12. Many cnidarians have two distinct life stages, the polyp and the medusa. • Medusa-bell-shaped; specialized for swimming • Polyp-vase-shaped; specialized for sessile existence

14. Body Plan • Have 2 cell layers: • Outer layer-Epidermis-Protection • Inner layer-Gastrodermis-Digestion • Mesoglea-Jelly layer

15. Tentacles-flexible extensions that surround the mouth

16. Feeding and Defense • Cnidocytes • Cnidocytes specialized for defense and capturing prey • Nematocysts-can spear a cnidarian’s prey. Jellyfish Sting

17. Hydra • Most are sessile as adults. • Portuguese man-of-war-not sessile as adult • The hydra is unique among the hydrozoans because it has no medusa stage. • Hydra • Man-of-War

18. Box Jellies • The cnidocytes of some species can inflict severe pain and even death among humans

19. Box Jellies Irikuji Syndrome

20. Jellyfish • Have both a polyp and medusa stage. • Spend most of their lives as medusa. • Have poisonous nematocysts that can cause severe pain

21. Sea Anemone • Spend most of their lives polyp. • Have a symbiotic relationship with the clownfish.

22. Coral • Spend most of their lives polyp. • Over thousands of years, these polyps build up large, rocklike formations known as coral reefs

23. Ctenophores • “Comb holder” • Comb jellyfish • Movement by means of beating cilia • Hermaphrodites • Bioluminescence • Comb Jelly • Crash Course

24. Phylum Platyhelminthes • “Flatworms” • Simplest animals with bilateral symmetry. • First to exhibit cephalization (have anterior end). • Flatworms have no need for circulatory and respiratory systems because their cells are close to the animal’s exterior surface. • Have nervous system. • Flatworms 1 • Flatworms 2 • Spanish Dancer

25. Planarians • Food is ingested through a muscular tube called the pharynx • Cerebral ganglia-two clusters of nerve cells serve as a simple brain. • Eyespot-sense the intensity and direction of light; located near the cerebral ganglia • Planarians can reproduce asexually by fission. • Planaria

26. Flukes • Parasitic • Endoparasites-live in blood, intestines, lungs, liver or other organs • Ectoparasites-live on the external surface of aquatic hosts, such as fish and frogs.

28. Tapeworm • They can infect a person who eats undercooked food. • They can grow to be large in human intestines. • They do not have a digestive system.

29. TapewormTapeworm Removal • Tapeworms attach to their hosts by the scolex.

30. Phylum Nematoda • Roundworms • Pseudocoelom-a hollow, fluid-filled cavity that is not a true coelom. • 2 opening digestive tract: mouth and anus

31. Ascaris • Live in the intestines of pigs, horses, and humans.

32. Hookworms • Feed on host’s blood-can cause anemia. • Face Hookworms

33. Trichinella • Trichinosis-causes muscle pain and stiffness and can lead to death if large numbers of cysts form in the heart muscle.

34. Pinworm

35. Rotifera • Cloaca-a common chamber into which the digestive, reproductive, and excretory systems empty