Unit 7: The Animal Kingdom: Invertebrate Animals

No distinct head

The three large groups of annelids are:

These have a very large foot which contains the stomach.

Trunk: the thorax and abdomen are fused.

Describe the body of Molluscs

Some are parasites, others are free-living.

These have four pairs of legs.

They move contracting their bodies or being pushed by ocean currents.

The largest group of living things

The marine animals that live on the ocean floor or near the coast.

Describe the body of Porifera

Cnidaria have which symmetry

Earthworms are

They have stinging cells.

They live in aquatic or damp terrestrial places.

Benefits obtained from invertebrate animals

The front legs are claws.

Motile means

Most live in the intestines of animals, including humans.

Rings that carry out the life functions because some internal organs are repeated in each rings

They have a thin cylindrical body with pointed ends.

Invertebrates live in __________ environments.

Describe the body of Annelids

The marine animals that live on the ocean floor or near the coast.

They are found in the sea, in fresh water and in damp soils.

Characteristics of echinoderms include:

The head: one pair of antennae, simple eyes, and a pair of chewing mouthparts.

The head has one pair of sensory antenae.

The long visceral mass gives the animal a hydrodynamic shape. Most have an internal shell.

Abdomen: most are balloon shaped, but not segmented.

Sac-shaped body surrounded by a hard skeleton of calcium carbonate.

The abdomen is segmented with no appendages.

The head is well-developed. It has two large eyes with excellent vision.

The segments of the abdomen are thin and flexible.

The shell consists of one piece and is spiral shaped.

This group consists of the sponges.

Platyhelmithes, nematodes and annelids share this characteristic:

Thorax: three pairs of articulated legs. One or two pairs of wings.

The body is divided into rings called metameres.

These are the simplest invertebrate animals. They have no organs.

The long, soft, flat body is divided into segments.

Annelids have no legs, but they move about by using rigid, hair-like structures called

Jointed appendages enable this animal to have more mobility.

The telson, the last segment of the abdomen, has a pair of tail fins.

The visceral mass is protected by a shell formed by two parts.

Spiders are

Most invertebrates have

There are five pairs of legs on the thorax.

More than 95% of the known animal species are intertebrates.

Flatworms are