Porifera and Cnidarians

1. Porifera and Cnidarians

2. Porifera • Sponges are the simplest found in this phylum • There are about 10,000 species of sponges and they are all aquatic • Asymmetrical and only have specialized cells

3. Sponges

4. Digestion and Feeding • Filter feeders • Sift plankton through collar cells • Food is digested in a central cavity • Clean up ocean floor • Amebocytes, which are crawling cells, also help in feeding by distributing nutrients throughout the sponge.

6. Respiration • All sponges perform respiration through their cell walls

7. Circulatory • Sponges handle transportation by moving things through their body wall. • Amebocytes (crawling cells) also distribute nutrients throughout the Porifera’s body

8. Excretion • Through an osculum(a large opening) • Amebocytes also transport CO2 and waste products through the osculum

9. Response • They release protective chemicals, like toxins, to discourage predators

10. Movement • Contain no nerves or muscles • They are sessile (meaning that they are attached to the floor) • Swimming larva are carried by currents before settling down and forming a new sponge. • Skeleton composed of spongin (soft) and spicules (hard)

11. Reproduction • Reproduce sexually (sperm and eggs) • Most sponges are hermaphrodites, and self fertilization is AVOIDED by producing sperm and egg cells at different times. • Reproduce asexually (regeneration) • budding

12. Cnidarians • jellyfish, coral, hydra, sea anemone • Named after the stinging cells found on their tentacles called CNIDOCYTES • Radial symmetry • Have two body forms: • Polyp (vase shaped) • Medusa (bowl shaped)

13. Jellyfish Sea Anome Coral Hydra

14. Feeding and Digestion • Most are carnivorous. • They have stinging tentacles called nematocysts. • Digestion takes place in their gastrovascularcavity.

15. Respiration • Passes nutrients through cells by diffusion

16. Circulatory • Their “skin” contains three layers; the epidermis, the mesoglea and the gastroderm. • They also have two germ layers

17. Excretion • Through their mouth • Done by diffusion

18. Response • Nervous system is build up of nerve nets • Corals produce poisons to protect themselves. • These poisons are used in cancer research and poison research.

19. Movement • Non-swimming larva and swimming medusa • Hydrostatic skeleton that allows the them to change shape

20. Reproduction • Sexual (medusa stage) • Release sperm, zygote develops on the females. • Hermaphrodites: they can fertilize themselves because they contain both male and female reproductive organs • Asexual (polyp stage) • Budding

21. Flatworms • Members of the phylum Platyhelminthes • First phylum to have three germ layers: • Ectoderm • Mesoderm • Endoderm • Simplest animal with bilateral symmetry • Three classes of flatworms

22. Feeding • Most are parasitic • Free-living : carnivores or scavengers; they have a digestive cavity, mouth and pharynx. Food is ingested through a muscular tube called the pharynx • Tapeworms have a hook and sucker that enables it to attach a host

23. Respiration and Circulation • Diffusion through the body wall • Thin bodies allow for materials to diffuse (respiration, excretion, etc) • Flame Cell – specialized cells that remove excess water

24. Response • Ganglia – group of nerve cells that control the body (like a brain) • Eyespot – group of cells that can detect light (like an eye)

25. Movement Flatworms move in 2 way: • Cilia helps them glide through the water • Muscle cells help them twist and turn

26. Reproduction • Sexual Reproduction – most flatworms are hermaphrodites (have both male and female sex organs) • Asexual Reproduction by fission  • flatworms can split in two and regenerate • Zygotes are passed out through the feces.

27. Roundworms • Members of the phylum Nematoda • Unsegmented worms • Pseudocoelom (false coelom)

28. Feeding and DIgestion • Can be: • Free-living – predators • Parasites - humans and animals • Digestive tract with 2 openings: mouth & anus

29. Respiration and Circulation

30. Excretion • Nitrogenous waste is excreted in the form of ammonia through the body wall

31. Response

32. MOvement

33. Reproduction • Sexual reproduction, Separate sexes