1 / 10

Chapter 9 The Mollusks

Chapter 9 The Mollusks. Abalone. Mollusks. Soft bodied Include the shipworm, snail, clam, mussel, oyster, scallop, abalone, squid, octopus, cuttlefish, chambered nautilus May or not have a shell 100,000 species. More Mollusk Characteristics. Soft, bilaterally symmetrical bodies

lars-valenzuela
Download Presentation

Chapter 9 The Mollusks

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. Chapter 9The Mollusks Abalone

  2. Mollusks • Soft bodied • Include the shipworm, snail, clam, mussel, oyster, scallop, abalone, squid, octopus, cuttlefish, chambered nautilus • May or not have a shell • 100,000 species

  3. More Mollusk Characteristics • Soft, bilaterally symmetrical bodies • Head, foot, coiled visceral mass (internal organs) • Coelom (body cavity), brain (like the worms)

  4. 9.1 Class Bivalvia • Clams, oysters, scallops, mussels • 2 shells held together by adductor muscles • Clams are the most common and are fed on by sea stars and predatory snails • You can learn the age of a clam by counting the bands on its shell • Little lines make up the bands and 1 band = 1 year

  5. Clam Age

  6. Clam Shells • Wider age bands mean a better year with more favorable conditions. • Made of CaCO3 which is secreted by the mantle

  7. Life Activities • Siphons – Incurrent siphon takes in water and food and waste is excreted through the excurrent siphon. • Clams filter food out of the water and O2 diffuses into gill membranes and CO2 diffuses out into waste water. • Clams filter and clean great quantities of seawater

  8. More Life Activities • Open circulatory system with colorless blood • One way digestive tract • Mussels excrete byssal threads to keep them anchored to rocks – very strong • Oysters excrete cement

  9. Movement • Clams dig into sand using muscular foot and extend their incurrent siphon into the water above them • Scallops clap shells together and move by jet propulsion

  10. Reproduction • Separate sexes • Females excrete eggs into the water and males excrete sperm. • Fertilization is external and larva lives as part of zooplankton population until it forms a tiny shell and settles to bottom

More Related