1 / 13

The Simplest Animals

The Simplest Animals. Phylum Porifera. Invertebrates Animals without tissues (Sponges) All are aquatic and sessile (stay in one place) The body plan is asymmetrical Made of a loose arrangement of cells with no defined cell layer. Sponges!. Sponges.

yorick
Download Presentation

The Simplest Animals

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. The Simplest Animals

  2. Phylum Porifera Invertebrates Animals without tissues (Sponges) All are aquatic and sessile (stay in one place) The body plan is asymmetrical Made of a loose arrangement of cells with no defined cell layer

  3. Sponges!

  4. Sponges • Have two germ layers, ectoderm and endoderm • They do have some specialized cells • Collar cells line the inside of the body cavity and have flagella that move water and food into the sponge through pores • Water exits via the osculum (the open end of the sponge • Digestion occurs in collar cells, or special cells called amoebocytes • Amoeobocytes wander around in a gelatinous mixture called mesenchyme

  5. Sponge Reproduction Sponges are hermaphrodites (produce both male and female gametes) They only produce one gamete at a time (they can’t fertilize themselves) Fertilized eggs turn into free-swimming larva The larva undergoes metamorphosis and develops into a full grown sponge They can also reproduce asexually, by budding or branching

  6. Role of Sponges • Important food source for snails, sea stars and fish • Provide shelter for smaller invertebrates inside their body cavity • Some clean up the ocean floor by releasing chemicals

  7. Phylum Cnidaria Include Hyrda, Jellyfish, Sea Anemones, and Corals Aquatic, have tentacles and possess true tissues Radiallysymmetrical Have endoderm and ectoderm, separated by jelly-like mesoglea Have nerve, muscle and digestive tissues Nerve nets encircle the body, so if touched, they can flatten out and pull tentacles inward

  8. Cnidarians!

  9. Cnidarian Body Structure • Either polyp or medusa form

  10. Cnidarian Feeding • Capture food using stinging cells containing nematocysts (stinging capsules) • Captured food is digested in the gastrovascular cavity (gut) which has only one opening

  11. Cnidarian Reproduction Hydra may reproduce asexually by budding Hydra and all medusae reproduce sexually by releasing eggs or sperm into the surrounding water

  12. Role of Cnidarian Food for fish, turtles and small animals Sea anemones and coral reefs form protective structures Coral reefs protect land along coastal areas from rough water

More Related