Review for a test


Mollusk - an animal with a soft body and no bones.

Example: clams, oysters, slugs, snails, squids and octopods


some have a hard shell that protects their body

Mantle - shell of mollusk, produces material to harden shell, grows as animal grows

some the mantle is a tough layer of skin

muscular foot - helps move and burrow into ocean floor

reproduce sexually

some have bivalves like oysters and clams

Radula - organ in snail that acts like a tongue with sharp teeth

octopus and squid have well developed brains and nervous systems

Adaptations - octopus and squid have jet like motion and squirt ink, snail has has a hard shell that protects itself.

Types of Mollusks

Some Mollusks are Octopuses, Snails, Squid, Slugs


Roundworm - a worm with a round, tube like body. Most are too small to be seen.

Example: hookworm


digestive system with 2 openings

take in food and eliminate waste

muscles that run length of body

reproduce sexually

nervous system with brain and simple sense organs

Adaptation - parasitic roundworms live in other animal’s body to get food and protection.

How do roundworms and flatworms differ? Roundworms have a digestive tract with two openings, muscles running lengthwise; flatworms can regenerate and have eyespots.



Flatworm - has a flattened body, a digestive system with only one opening, and a simple nervous system. Example: Planarian


flattened body

digestive system with only 1 opening and simple nervous system

live in both freshwater and saltwater

bilateral symmetry

sense organs and nerve cords

a mouth and digestive system

can regenerate body parts that have been cut off.

Adaptation - Planarian can regenerate body parts

What characteristics do all flatworms share? They have flattened bodies, digestive system with only 1 opening, simple nervous system.

Segmented worms

Segmented Worms

Segmented Worms - These are worms whose bodies are made up of connected sections, or segments. Example: earthworm.


body made up of connected segments

circulatory system - 5 enlarged tubes that act like hearts

nervous system - brain and main nerve

breath through skin

two sets of muscles that allow it to move

takes in food through mouth

reproduce sexually

Adaptation - breath through skin in the soil

What is the major difference between an earthworm and other worms? An earthworm has body systems that are more complex than those of other worms.