Download Mollusks and segmented worms

Chapter 6, Section 3
 Soft-bodied
invertebrates that usually have a
shell (ex. Snails, mussles, octopus)
 Have mantle and large muscular foot

Mantle: thin layer of tissue that covers the
mollusk’s soft body
 Water-dwelling

Gills: organs in which carbon dioxide from the
animal is exchanged for oxygen in the water
 Land-dwelling

mollusks have gills
mollusks have lungs
Lungs: carbon dioxide from the animal is
exchanged for oxygen in the air
 Have
digestive systems with two openings
 Have scratchy, tonguelike organ called
radula
 Radula: has rows of fine, teethlike
projections used to scrape off small bits
of food
 Have open circulatory system
 Do not have vessels to contain blood
 Blood washes over organs
Gastropods
 Largest
group of mollusks
 Have one shell
 Live in water or on land
 Move about on a large,
muscular foot
 Secretion of mucus allows them
to glide
Bivalves
Has
two shells joined by
a hinge
Large, powerful muscles
open & close shell
Gills filter water for food
 Cephalopods
 Most
complex type
 Have internal plate instead of shell
 Closed circulatory system
 Adapted for quick movement in
ocean
 Have mantle surrounding internal
organs
 Annelids
(earthworms, leeches, marine
worms)- body made of repeating
segments or rings that make worm
flexible
 Each segment has nerve cells, blood
vessels, part of digestive system, coelom
 Internal body cavity, separates internal
organs from body wall
 Closed circulatory system
 Complete digestive system with two body
openings
What
are the
characteristics of
annelids?