1 / 12

Learning Intentions

Learning Intentions. By the end of this lesson, you will be able to: Identify general characteristics of Phylum Cnidaria Describe functions of major structures in terms of life functions and explain their evolutionary significance (adaptations) Recall key ecological roles of cnidarians.

deanne
Télécharger la présentation

Learning Intentions

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. Learning Intentions By the end of this lesson, you will be able to: • Identify general characteristics of Phylum Cnidaria • Describe functions of major structures in terms of life functions and explain their evolutionary significance (adaptations) • Recall key ecological roles of cnidarians

  2. Phylum Cnidaria

  3. General Characteristics • Two life forms (polymorphism): swimming medusae and sessile polyps • All cnidarians have cells called cnidocyteswhich contain poisonous threads called nematocysts. • Bodies consist of mesoglea, a non-living jelly-like substance, sandwiched between two layers of epithelium (ectoderm) that are mostly one cell thick. • Radial symmetry with mouths surrounded by tentacles that bear cnidocytes.

  4. Structure Cont’d…

  5. Structure Endoderm Ectoderm

  6. Structure Cont’d…

  7. Feeding • Capture organisms by using nematocysts • Tentacles push food into mouth • Endoderm develops into gastrodermis (the cells that line the interior digestive cavity and secrete enzymes to digest food extracellularly) • Final digestion happens intracellularly (within cells located in mesoglea)

  8. Gas Exchange/Excretion • Diffusion of gases from water into epithelial cells • Diffusion of wastes from mesoglea into water (pushed out through mouth)

  9. Nervous System • Nerve net: interconnected nerve cells spread out through mesoglea • Allows for coordination of muscles and tentacles, firing of nematocysts

  10. Circulation • None: Diffusion

  11. Reproduction

  12. Ecological Roles • Corals provide diverse habitat for other organisms • Food for other organisms (turtles, fish) • Active predators • Protection – sea anemones & clown fish

More Related