Vertebrates are animals with backbones. There are five groups of vertebrates: fish, amphibians, reptiles, birds, and mammals. Fish live in water and breathe through gills. Amphibians can live on land or in water, undergoing metamorphosis from tadpoles to adults. Reptiles are terrestrial and have dry scaly skin, laying amniotic eggs. Birds are warm-blooded and have feathers and wings, laying eggs with hard shells. Mammals are warm-blooded and feed their young with mammary glands.

1. VERTEBRATES

2. What is a vertebrate?
 Vertebrates are animals with backbone.
 They have a bony endoskeleton.
 Their body is made up of a head and a trunk,
with articulated limbs.
 Many of them have a tail.

3.  There are five groups of vertebrates. Starting
letters are:
 A
 F
 R
 B
 M

4. FISH
 Fish are aquatic vertebrates, so they have gills
to breathe. Gills are protected by the operculum.
 Are cold-blooded: they cannot regulate their
temperature.
 They have fins: dorsal, pelvic, pectoral, anal and
caudal.
 Their skin is covered with scales.
 The lateral line is a sensory
organ that detects vibrations.

6. Gills and Operculum

8.  Most of them are carnivorous.
 They have external fertilisation, and are
oviparous. Eggs are laid in water because they
have no shell.

9.  They have swim bladder which fills with air to
control buoyancy.
 Sharks have a cartilagenous endoskeleton.
 Sharks have internal fertilisation and are
ovoviviparous.

10.  Activity 1. Complete these sentences:
1. Animals with backbone are called….
2. There are five groups, which are called.....
3. They have an endoskeleton made up of ….
4. Fish live in ….. , so they breathe through ….
5. Fish cannot regulate their temperature, so they are
called….
6. Their skin is covered with …..
7. Gills are protected by the ……

11.  Activity 2. True or false? Correct the false
ones.
1. Fish have fins to swim.
2. Fish don’t have caudal fin.
3. The lateral line is used to smell.
4. Gills take the carbon dioxide from the water.
5. All fish have external fertilisation, and lay eggs.
6. Their eggs have a protective shell, so they can be laid
on the terrestrial surface.
7. The swim bladder is filled with air to control buoyancy.

12. AMPHIBIANS
These are amphibians
Salamanders Newts Frogs

13.  Are cold blooded.
 Tadpoles live in water: they have gills to
breathe.
 Adults live in terrestrial wet places: they have
lungs to breathe.
 Have four limbs. Frogs have strong back legs.
 Their skin is wet, and
some produce toxins.
 They are carnivorous.

14.  They have external fertilisation. Most of them
are oviparous, except salamanders, which are
ovoviviparous.
 They undergo metamorphosis: adults do not
look like the tadpoles.

15. REPTILES
These are reptiles
Turtles Snakes
Crocodiles Lizards

16.  They are terrestrial, so they have lungs to
breathe.
 They have four legs (except snakes, which have
no legs).
 They are cold-blooded.
 Their skin is dry, hard, and covered with scales.
 Turtles have a carapace.

17.  Most of them are carnivorous and have teeth to
capture preys. Turtles have beaks, and snakes
have fangs connected to glands that produce
poison.

18.  Reptiles are oviparous. They lay eggs filled with
liquid (amnion), and a bag full of air (allantois).
Eggs have a hard shell to prevent dehydration, so
they can be layed on the land.
This kind of egg is called
“Amniotic Egg”.

19. Activity 3. Complete this comparative chart about
amphibians and reptiles.
SKIN EGGS
BREATHE
THROUGH
METAMORPHOSIS EXAMPLES
AMPHIBIANS
REPTILES

20. BIRDS
 A bird’s body is adapted for flight (aerodynamic).
 Birds have four limbs:
 Frontal limbs are wings.
 Back limbs are legs.
 Their body is covered with
feathers.

21.  Some of their bones are holow, so that it makes
them lighter.

22.  They have a beak, but not teeth. The beak has a
different shape depending on how they feed.

23.  They breathe through lungs, which are
connected to air sacs.
 They have internal fertilisation, are
oviparous, lay amniotic eggs, and
incubate them until the chicks hatch.
 Birds are warm-blooded.

24. Activity 4. Answer these questions about birds…
1. What characteristics enable birds to fly?
2. Why do we say that birds are warm-blooded?
3. Where are the air sacs connected to?
4. What depends the beak’s shape on?
5. Is it true that bird’s bones have no air inside?
6. Do all birds fly?
7. Why do we say that their body is
aerodynamic?

25. MAMMALS
 All mammals have mamary glands, to feed the babys.
 Most mammals are terrestrial, but some are aquatic,
and only one can fly. All of them are warm-blooded.
 They have three parts in their body:
 The head. It is joined to the trunk by the neck.
 The trunk.
 Four limbs.

26.  Their body is covered with hair, which keep
them warm.
 They have teeth, and the shape depends on the
food they eat (they may be carnivorous,
herbivorous or omnivorous)

27.  They breathe through lungs. Aquatic mammals
come up to the surface to breathe.
 They have internal fertilisation,
and are viviparous.
The baby grows in the mother’s
womb.

28. Activity 5. Answer these questions for birds and
mammals.
1. What is their skin like?
2. What kind of limbs do they have?
3. Can they control their temperature?
4. Do they have a beak? And teeth?
5. What kind of fertilisation do they have?
6. Where do the babys grow?
7. How do they breathe?

29. Activity 6. This is the Ornithorrhynchus, possibly
the strangest animal in the world. Look up for
information about it.