1 / 17

Phylum Molluska

Phylum Molluska. Over 50,000 species Coelomate , Protostomes , Bilaterally symmetrical Mostly marine, although some live in fresh water or land. Generally soft-bodied with a hard shell However, squid & octopi have internalized, reduced or lost their shells. Body Plan

devika
Download Presentation

Phylum Molluska

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. Phylum Molluska Over 50,000 species Coelomate, Protostomes, Bilaterally symmetrical Mostly marine, although some live in fresh water or land. Generally soft-bodied with a hard shell However, squid & octopi have internalized, reduced or lost their shells. Body Plan Although phenotypically diverse, mollusks share 3 common features A muscular foot - usually for movement A visceral mass - including internal organs A mantle - envelopes visceral mass and secretes a shell

  2. Molusk General Anatomy

  3. Class Polyplacophora (chitons) • Marine animals - shells divided into 8 plates • Move using a muscular foot and graze using a scraping mouthpart called a radula

  4. Chiton Anatomy

  5. Chitons

  6. Class Bivalvia • Include clams, oysters and mussels • Have shells divided into 2 halves, connected by strong muscles • Has hatchet shaped foot for digging and anchoring • Are typically filter feeders drawing in water end expelling it through a siphon tube • Generally sessile, however, some species can quickly move by rapidly closing it's shell

  7. Bivalve Anatomy

  8. Bivalves

  9. Class Gastropoda • Include snails, abalone, and slugs • Largest class of mollusks ~40,000 species • Exhibit embryonic process of torsion • Visceral mass twists 1800 during development • Most species are herbivores, but some have modified radullas for boring into other mollusks • Some species have successfully colonized land

  10. Gastropods

  11. Giant African Land Snail

  12. Class Cephalopoda • Unlike other mollusks, these are quick predators • Have beak-like jaws and poison to catch & immobilize prey • Beak is located @ the center of several long tentacles • Foot has been modified to form a siphon which allows most species to move quickly using a jet of water. • Only mollusks with a closed circulatory system (blood is always contained in vessels) • Very highly developed nervous system • Can learn complex behaviors • Octopi have learned to open jars to retrieve prey • May have rudimentary communication • Cuttlefish and octopi may communicate by skin coloration

  13. Cephalopod Anatomy

  14. Octopus

  15. Squid

  16. Cuttlefish

  17. Cambered Nautilus

More Related