ALL OF THEM ARE…..

THE ANIMAL KINGDOM

The animal kingdom is made up of multicellular eukaryotic organisms. Animals are classified into two groups:

Invertebrates: animals without backbone. Some of them have no skeleton, and others have an external skeleton (Exoskeleton).

Vertebrates: animals with backbone. All of them have a internal skeleton or Endoskeleton.

Activity 1. Are they vertebrates or invertebrates?

PORIFERA

Porifera (Sponges) are the simplest invertebrates.

They live in the sea.

They have no organs.

They don’t move, they are attached to rocks.

Their body is full of pores and channels, so water can circulate.

They feed by filtration: water enters through the Pores to a Central Cavity, deposit nutrients, and leaves through a hole called Osculum.

Activity 2. Answer these questions….

a. Do all animals have a backbone?

b. Do some invertebrates have a skeleton? Is it internal or external? Do you remembre the name?

c. Why do you think sponges are called “Porifera”?

d. Where do sponges live?

e. Do sponges move?

f. Water enters in a sponge through the_______, deposit nutrients in a ________ ___________, and leaves through the __________.

Activity 3. Label this picture.

CNIDARIA

There are three groups in Cnidaria:

Jellyfish Corals Polyps

Cnidaria have a mouth surrounded by Tentacles, and a Gastrovascular Cavity.

They are carnivorous, and use their tentacles to capture preys.

They live in the sea.

Jellyfish can float. Corals and Polyps are attached to the floor.

Some Jellyfish produce their own light.

Cnidaria have special cells called “Cnidoblasts”. This cells have a poison dartlike microscopic hairs used to capture preys.

When a prey take contact with a cnidoblast, the poison hair is shooted.

The result is a quite urticant sting.

Reproduction: cnidaria usually pass from polyp to jellyfish stages:

Polyps reproduce asexually.

Jellyfish reproduce sexually.

Activity 4. What do you know about Cnidaria…?

a. How many groups are in Cnidaria?

b. Do you remember their names?

c. Cnidaria eat animals or plants?

d. Where do they live?

e. Can all cnidaria move?

f. What is a cnidoblast?

g. How do they reproduce?

WORMS

Worms have a soft body, and they don’t have skeleton. There are three groups of worms:

Nematodes Platyhelminthes. Anelids.

1) Nematodes:

Their body is cylindrical.

They have no segments or rings.

They have no respiratory system: they breathe through the skin.

They live on water or soil.

Some of them are parasites.

They are heterosexual: male and female specimens.

Example: intestinal worm.

2) Platyhelminthes:

They are long and flat.

Their body is divided into rings.

They live in water.

Lots of them are parasites.

They have no respiratory system: they breathe through the skin.

They are hermaphrodites: every specimen have male and female sexual organs, and they can fertilise themselves.

Example: Taenia, Planaria.

Planaria can reproduce by regeneration.

Planaria Regeneration

3) Annelids:

Their body is soft, cylindrical, and

divided into segments.

Each segments have the same organs.

They have tiny hairs for movement.

They have a digestive system.

They live in water and in the soil. Some are parasites.

Aquatic ones breathe through gills.

Terrestrial ones breathe through the skin.

Some are heterosexual and some are hermaphrodites.

Activity 5. Those lovely worms….

1. Which are the three groups of worms?

2. Which group includes flat worms?

3. Which group have tiny hairs for movement?

4. Which group includes only heterosexual especimens?

5. Which groups breathe only through the skin?

6. Which group have regeneration?

ECHINODERMS

They live on the sea bed. Some are fixed to the surface, but most of them can move.

They have an internal skeleton made of plaques.

They have a mouth on the underside.

There are three groups:

Seastar Sea Urchin Sea Cucumber

The ambulacral apparatus (a system of tubes filled with water) and the ambulacral feet, enables movement.

Most of them breathe through the skin, and some of them have simple gills.

Thay are carnivorous.

They are heterosexual: male and female specimens, but some are hermaphrodite.

Fertilisation is external.

Activity 6. What do you know about echinoderms?

1. Where do they live?

2. How can they move?

3. Do they have a mouth?

4. How can they breathe?

5. Do they eat plants?

6. Are they heterosexual or hermaphrodite?

7. Do they have internal fertilisation?

8. How many groups do you know?

MOLLUSCS

Snails, mussels, slugs, squids…are molluscs.

Their body has these characteristics:

Is soft, and divided into three parts:

Head, with sensorial organs and the mouth.

Body Mass, with the main organs.

Muscular Foot, to move around.

The body is covered by a fine membrane, the Mantle.

The mantle produces a protective Shell, made up of one or two valves. Some species have no shell.

Respiration:

Aquatic molluscs breathe through gills.

Terrestrial molluscs breathe through lungs.

Nutrition: some are carnivorous, and some are herbivores.

Reproduction: most are hermaphrodite, and oviparous

There are three groups of molluscs:

Gastropods: snails and slags. They may have no shell,

or may have a spiral-shaped shell.

Bivalves: their shell has two valves.

Cephalopods: they have tentacles, but no shell.

Activity 7. True or false?

1. Molluscs have four main parts in their bodies.

2. These parts are: head, body mass, and foot.

3. Annelids are a group of molluscs.

4. Bivalves have a single, spiral shell.

5. Cephalopods have a shell.

6. Snails are an example of gastropods.

7. All molluscs live in water.

8. All molluscs breathe through lungs.

9. Molluscs are viviparous.

ARTHROPODS

Arthropods are the most varied group of living things. They live in the sea water, fresh water, and on land.

Their body has these characteristics:

It is divided into three parts: head, torax and abdomen.

They have an exoskeleton.

In some arthropods,the head and the torax are joined, forming a cephalotorax.

The head contains the sensorial organs: antennae and eyes (simple or compound).

They have articulated legs.

Some of them have wings.

Nutrition: they can be carnivorous or herbivorous.

Respiration: aquatic breathe through gills, and terrestrial breathe through trachea.

Reproduction: most are heterosexual, and oviparous, with internal fertilisation. The larvae undergo metamorphosis to became adult.

As they grow, arthropods shed the old exoskeleton and produce a new one. This is called moulting.

There are four groups of arthropods:

Crustaceans: they usually have 10 legs, and are aquatics. Ex. Crab, Lobster.

Myriapods: they look similar to a worm, they have many legs, and are terrestrial. Ex. Centipede, Scolopendra.

Arachnids: they have eigth legs, and are terrestrial. Ex. Spider, Scorpion, Opilion.

Insects: they have six legs, two antennae. They usually have wings, but not always. Most are terrestrial, but some are aquatic.

Activity 8. Answer these questions...

1. How many parts has an arthropod’s body?

2. Do you remember their names?

3. Why do you think we call these animals “arthropods”?

4. Do arthropods have skeleton? Is it external or internal?

5. What is the cephalotorax?

6. Do all arthtopods have wings?

7. After metamorphosis, larvaes became....

8. How many groups of arthropods do you know?

9. What is the moulting?