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Sponges, Cnidarians and Unsegmented Worms

Sponges, Cnidarians and Unsegmented Worms. Sponges. Sponges are the most primitive of all living multicellular animals, make up the phylum of Porifera . Sponges are relatively independent, and they live together for mutual benefits.

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Sponges, Cnidarians and Unsegmented Worms

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  1. Sponges, Cnidarians and Unsegmented Worms

  2. Sponges • Sponges are the most primitive of all living multicellular animals, make up the phylum of Porifera . Sponges are relatively independent, and they live together for mutual benefits. • Phylum Poriferan meaning “pore bearing’’ this allow sponges to filter food from the water that passes through these pores

  3. Sponge structure • Collar cells: have whiplike flagella that beat water through the body wall and into the central cavity • Amebocytes: cells to digest and distribute food, as well as to produce the components of the sponge skeleton. • Spicules: small crystallike spikes to help support their bodies. • Spongin: a protein that help the sponges to support their bodies .

  4. Sponge life cycle • Sponges reproduces sexually by producing sperms and eggs however like other animals can reproduce asexually too, by two ways. • One way sponges do this is by producing ball-shaped structures called Gemmules they behave like seed by waiting until they ready to grow into big sponges. • A process called budding is another way sponges reproduces in this process a piece of sponges falls off and grow into new sponges

  5. Cnidarians • The phylum Cnidarians contain the corals, jellyfishes and sea anemones . • All Cnidarians live in water and nearly all live in the sea • Cnidarians have layers of differentiated cells that are organized into three specialized layers of tissues: endoderm (inner layer), mesoglea (middle layer), and ectoderm (outer layer).

  6. Cnidarian Structure • Ocelli: simple eyespots that detect presence or absence of light. • Statocyts: provide info on which way is up, helping them to balance themselves . • Nematocysts: structures that are made for defense and to catch prey. • Gatrovascular cavity: where most digestion take place

  7. Life cycle • Cnidarians alternate between two stages – a free-living stage stage called medusa and a sessile (attached) stage called a polyp Many cnidarians also alternate between sexual and asexual reproduction. • Jellyfishes: most are harmless to humans but several have stings than can cause allergic reactions to people. • Coral and Sea anemones: include many of the most beautiful and amazing animals in the sea and with the biggest ecological importance

  8. Unsegmented worms • Platyheminths: Flatworms are the simplest worms and are the simplest animals to show bilateral symmetry meaning they have a right and a left side. Three types • Planarians: are either carnivores that feed on more small aquatic animals or scavengers that feed on dead. • Flukes: flukes are parasites that live in the blood and tissues of various hosts. • Tapeworms: tapeworms live in the intestines of their host. So they eat the food already digested of the host.

  9. Nematodes • Roundworms: the nematodes are the simplest animals with a digestive tract similar to a humans, with a mouth end and an anus at the other. • Parasitic nematodes: like the parasitic flatworms nematodes typically have life cycle that are quite complex often involving more than one host.

  10. Videos and Diagrams • http://videos.howstuffworks.com/hsw/17128-science-of-the-sea-a-closer-look-at-sponges-video.htm • http://videos.howstuffworks.com/hsw/17105-animals-without-backbones-phylum-cnidaria-video.htm • http://www.enchantedlearning.com/subjects/invertebrates/sponge/sponge_bw.GIF

  11. Sources • Miller, Kenneth R., and Joseph S. Levine. Biology The Living Science. Upper Saddle River: Pearson Prentice Hall, 1998. • ADW: Porifera: Information." Animal Diversity Web. 26 May 2009 <http://animaldiversity.ummz.umich.edu/site/accounts/information/Porifera.html>.

  12. Cited work • Images • http://higheredbcs.wiley.com/legacy/college/levin/0471697435/chap_tut/images/nw0250-nn.jpg • http://www.arcodiv.org/watercolumn/cnidarian/images/Chrysaora_melanaster_400x300.jp • http://www.mccullagh.org/db9/10d-12/sea-anemone-4.jpg • http://davidbyrne.typepad.com/photos/uncategorized/12_05_06_b_diver_jellyfish.jpg • http://www.mermaid-liveaboards.com/images/PJ/MMI1707/Tube-Anemone-pink.jpg • http://entomology.ifas.ufl.edu/creatures/misc/land_planarians_photo1.jpg • http://www.starfish.ch/Fotos/worms-Wuermer/plathelminthes-Plattwurm/Pseudobiceros-gloriosus3.jpg • http://www.parasitecleanse.com/images/flukes02.jpg

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