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Spiny
Skinned Animals
Marine
Slow moving or sessile
Starfish, Sea Urchins, Sea
Cucumbers, Sand Dollars,
Feather Star
Coelom
One Way
Digestive Tract
Radial Symmetry
3 tissue layer
Tube Feet
• Locomotion, feeding, and gas
exchange
Endoskeleton
•Internal Skeleton
Nerve ring is centrally
located around the mouth
with radiating nerves
Asexual
• Regeneration
Sexual Reproduction
• External Fertilization
Starfish
Five
arms that project
from a central disk
Bottom Dwellers
Carnivorous
No
Excretory System
Water Vascular System
Water
is drawn in through
central disc
Water passes through canals
Water goes to bulb of tube
feet
When
bulbs contract:
•Water is forced into tube
feet
•Creates a suction
When
the bulbs relax:
•Water is pushed back
into canals
•Relaxes suction
Marine
or land dwelling
Have a soft body enclosed
by a shell or shells
• (Slugs have lost their mantle
and shells during evolution)
Bilateral
Symmetry
3 tissue layers
Coelom
Head is well developed
•Exception: clam
Radula:
Feeding Device
• Rasping organ that scrapes
food in snails
Muscular
Foot
Gills for aquatic species
One way digestive tract
Visceral
Mass
Digestive, reproductive,
excretory, and circulatory
systems
Mantel
( folded tissue )
• Forms shell
Open
Circulatory System
Snails and slugs
Largest group of molluscs
Found in fresh water, salt water, and
terrestrial environments
Eats plants, meat, or dead organisms
Terrestrial
Gastropods
• Only mollucs that live on land
• No gills
• Simple lung
Bivalves
• Valve = shell
Oysters,
Clams, Mussels,
Scallops
No Radula
Gills used for respiration and
feeding
Some are sessile (mussels)
Squids
and Octopuses
Most highly specialized mollusks
Have a large brain
• Eyes are among the most complex
organs in animal kingdom
Carnivorous
• Use beak like jaws and a radula to
crush or rip prey apart
Foot
has evolved into
large arms that project
form the head
Closed Circulatory
System