Download presentation
Presentation is loading. Please wait.
Published byJayson Sparks Modified over 9 years ago
1
Unit 8 Chapter 27 Mollusks and Segmented Worms
2
What is a Mollusk? Bilateraly symmetry, coelomates, and well-developed body systems Soft bodies covered by a thin mantle, which may secrete a shell
3
What is a Mollusk? Mollusks have a foot, a ventral structure for locomotion Some have an open circulatory system, blood moves through vessels & into open spaces around body organs Others have a closed circulatory system, blood moves through the body enclosed entirely in blood vessels
4
What is a Mollusk? Gastropods include snails and slugs One shell, “belly- footed” Radula = scraping tongue-like structure Radula magnified 1000X
5
What is a Mollusk? Bivalves include clams, oysters & muscles Two shells, “hatchet-footed” Filter-feeders
6
What is a Mollusk? Cephalopods include octopus, squid, cuttlefish, & chambered nautilus Little or no shell, foot divided into tentacles with suckers Use ink and jet propulsion to escape from danger
7
What is a segmented worm? Phylum Annelida Bilaterally symmetrical, segmented coelomates, with two body openings
8
What is a segmented worm? Earthworms have complex body systems: Digestive system includes a crop & gizzard for grinding food taken from soil Closed circulatory system includes 5 pair of “hearts” Reproductive system includes both ovaries & testes
9
What is a segmented worm? Leeches are freshwater, external parasites Some microsurgeons use leeches after surgery to improve blood flow
10
What is a segmented worm? Marine worms include bristle worms, fan worms and tube worms (below) Most have structures for swimming or crawling on the bottom of the sea
Similar presentations
© 2024 SlidePlayer.com Inc.
All rights reserved.