Study Guide


Sponge - one type of animal that filters the water it lives in to get food.

Example - Venus-Flower Basket,


- reproduce asexually

- can’t move once they attach as adults

- gets food from environment around it.

- between inner and outer layer there is a jelly-like layer

- grow at almost any depth

- grow on hard surfaces

- shaped like fingers, tree branches or round

- filters water to get its food

- 5000 known species

-no real digestive system

Adaptation - body is a network of tiny pores and canals that allow water to filter through to obtain food because they don’t move.

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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

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

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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.


Echinoderms - are invertebrates that have internal skeletons and spines sticking out from their bodies

examples: starfish, sand dollars, sea urchins, sea cucumbers


Interval skeletons and spines

live only in the ocean

get oxygen from seawater

most adults appear to have radial symmetry

spiny skin


no head or brain

tube feet

Adaptation - Mouth is at the center of underside with powerful jaws and hidden among their spines and poison glands. They also have tube feet for moving, feeding and sensing respiration

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