Transcript Phylum Mollusca (soft

Phylum Mollusca
Phylum Mollusca
(soft - bodied)
I.
Characteristics
A. Marine, freshwater, land
B. Body includes:
1. Head/foot - contains mouth, sensory
organs and locomotion
2. Visceral Hump - contains digestive,
excretory , circulatory and
reproductive organs
3. Mantle - thin membrane surrounding
visceral mass provides respiration,
excretion and sensory reception as
well as secreting the shell
C. Bilateral symmetry
Classification
(according to shells or foot)
1. Class Bivalvia - two piece shell
(A.K.A. - Pelecypoda - hatchet foot)
A. Movement * places foot in sand
*spreads out to form an anchor
*muscle contracts pulling animal forward
Bivalvia cont.
B. Feeding - filter feeder
*water enters through incurrent
siphon, rushes over the gills
*O2 and CO2 are exchanged; food is
caught in mucous
* cilia sweeps food into mouth- moves into
stomach for digestion
C. Economic Importance
1. Food
2. Jewelry
Bivalve Examples
Clams, Scallops, Oysters
2. Class Univalvia - one piece shell
(A.K.A. - Gastropoda - belly foot)
A.
B.
Movement - muscles in foot contract
in a wave-like motion pulling animal
along a slime layer
Feeding - uses a radula to scrap food
off of leaves
Economic Importance
1. Food source
2. Damages crops
Univalve Examples
Snails, slugs, conch, sea slug
More Univalves
Blue dragon sea slug
3. Class Cephalopoda - head foot
(reduced internal shell or no shell
present)
A. Movement
1. By jet stream of water
forced out of a siphon or by
tentacles
B. Feeding
1. Food is located by eyes
and captured by tentacles
2. Food is ingested
through a beak in center of
tentacles
Cephalopoda
C. Nervous System
1. Large, complex brain (similar to fish)
2. Eyes with lens and retina
Protection
1. Excrete ink cloud
2. Change colors to blend with
environment
D. Economic Importance
1. Food source
Cephalopod Examples
Cuttlefish
More Cephalopods
Click to see giant squid vid!
Squid
More Cephalopods
Octopus
Click to learn about the
Blue-Ringed Octopus
Click pic for cool octopus article

Click picture to
another great
link with video

Nautilus
Click above picture for video