By: Sara smith

Some invertebrates are :


Sponges are animals

Characteristics of a sponge

* Live mostly in the ocean, but can be found in freshwater rivers and lakes.

* Adult sponges are attached to hard surfaces they can not move.

* Water currents carry food and oxygen to them and take away their waste.

Sponges structure

* Invertebrates no body symmetry and never have tissue or organs!

* Pores- water moves into central cavity of the sponge through pores all over the sponges body.

* Collar cell- whiplike structures that move back and forth to push water through the sponge and traps food.

* Spicules (spikes)- they have no skeleton, but a system of a spikes that keep sponges very hard.


* Sponges can reproduce sexually and asexually.

* During asexual reproduction small new sponges grow from the sides of the adult sponge.

* When they fall off they begin their own life.

* Sponges also have sperm and eggs cell, so they can complete sexual reproduction.

These are also some invertebrates.


Cnidarian have the same whole to eat and digest food in and out of.


* Have tentacles with stinging cells used to protect themselves and gather food.

* Central body cavity

* Bodies have radial symmetry (symmetrical around a central point.)

The two different types of Body structures.


Polyp- vase shaped body. Mouth opens at the top with tentacles that spread out around the mout.h adapted for life attached to an underwater surface.


Medusa- bowl shaped body. Mouth opens downward with tentacles that trail down around the mouth. Adapted for life swimming underwater.
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Most cnidarian shave muscle like tissue that lets them move to avoid danger and to capture food.

Capturing food

They use stinging cells to capture prey. Some stoning cells release venom into the prey. The cnidarians use their tentacles to pull food. Into the mouth.
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Cnidarians can reproduce Asexually and sexually.

Reproduction asexual

Food asexual reproduction most polyps (corals,hydras,sea anemones) budding is Mormon this means they pull apart to form new polyps.


There are three types of worms.

Characteristics of worm

* All worms have long,narrow bodies with no legs.

* All worms have to tissue, origans, and body systems.

* Worms are the simplest organisms with a brain. There brain is a knot of nerve tissue located in its head end, because of this the worm can detect objects, food, mates and predators quickly


* Some worms reproduction sexually and others asexually.

* Some worms have members of both genders (male and female).

* Other worms have both male and female sex organs, but usually don't fertilize their own eggs.

* Some reproduce asexually breaking into pieces.

Flat worms

Many flat worms are parasites.

Characteristics of flat worms

* Flatworms are flat and soft as jelly. They are the simplest of all the worms.

* Many flatworms are parasites. Parasites are organisms that live inside another. Others are free living ( not in another organism) in ponds and oceans.

* It takes food in and gets rid of wastes through the same opening.

Round worms

They live in salt and fresh water.

Characteristics of round worms

The hook worm, pin worm and trichinelle are part of this group.

* They are more advanced than flatworms, with thin round bodies and digestive system that opens at both ends.

* Roundworms live in salt water, fresh water, and the soil (even in Antarctic sands). Many of them are harmful to man as they are parasites.

Segmented worms

Segmented worms have bodies made up of many linked sections called segments.

Characteristics of segmented worms

* Segmented worms include earthworms,leeches Nd some sea floor worms.

* Segmented worms have bodies made up of many linked sections called segmented.

* Segmented worms have nerve tissue and digestive tract that runs the length of the worm's body with a mouth and anus. A closed circulatory system, meaning blood moves within blood vessels. Blood carries oxygen and food to cells.



"Soft bodied"
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Characteristics all mollusks share.

* Commonly have 1 or 2 shells, but there are some that don't have one.

* Thin layer of tissue called the "foot" is used for movement.

* Bilateral symmetry (same on both sides).

* Mollusks that live under the water have gills.

3 major groups:


Snails and slugs.

Characteristics of Gastropods

* Live in oceans, rocky shores, fresh water, and land.

* Can have a shell or no shell

* Can be herbivores or carnivores.

* Move by creeping along on a broad foot which can ooze mucus.


Oysters and mussels attach to rocks

Characteristics of bivalves

* 2 shells held together by a hinge and muscles.

* Omnivores

* Clams can move! They even dig into the sand.

* Oysters can form a pearl when a grain of sand enters the shell.


Lives in the ocean

Characteristics of cephalopods

* Foot has adapted to form tentacles around the mouth.

* Carnivores

* Capture prey with their tentacles suckers on the tentacles taste and touch.

* Large eyes for good vision.

* Large brains and can remember things they have learned, some have even escaped captivity!

* Swim by jet propulsion ( current of water).