This document classifies animals into two groups: vertebrates and invertebrates. Vertebrates are animals with backbones and there are five types: fish, amphibians, reptiles, birds, and mammals. Invertebrates lack backbones and are divided into six groups including arthropods, mollusks, echinoderms, annelids, poriferans, and cnidarians. While only 3% of animal species are vertebrates, vertebrates include fish, birds, mammals, amphibians, and reptiles. The vast majority, 97%, are invertebrates such as arthropods like insects and shrimp, mollusks like snails and scal

2. C L A SS I F I C AT I O N
O F A N I M A L S :
V E R T E B R A T E S A N D
I N V E R T E B R A T E S

3. VERTEBRATES
• A vertebrate is an animal with a backbone or a spinal column, also called vertebrae.
• There are five types of vertebrates: fishes, amphibians, reptiles, birds and mammals.
1. Fish are animals that live in the water. They have gills that allow them to breathe under
water. They are cold-blooded. Example: trout fish, shark, whale, lionfish.
2. Amphibians are cold-blooded animals. They have gills just like fish to breathe under
water when they hatch but later, they develop lungs and move to the dry land. Example:
frogs, toads, salamanders.
3. Reptiles are cold-blooded animals which lay eggs. Their skin is covered with hard and
dry scales. Example: alligators, crocodiles, snakes, lizards and turtles.
4. Birds are warm-blooded animals that have feathers, wings, and lay eggs. Many, but not
all, birds can fly. Example: hawk, eagle, pigeon, ostrich.
5. Mammals are warm blooded animals that give birth and nurse their young with milk and
and have fur or hair. Example: humans, dolphins, giraffes, horses.

4. THERE ARE CURRENTLY AROUND 65,000 KNOWN SPECIES OF VERTEBRATE
ANIMALS, BUT ONLY AROUND 3% OF ALL THE ANIMALS ON EARTH ARE
VERTEBRATES.
• Vertebrate animals can either be
warm-blooded or cold-blooded.
1) Warm-blooded animals are able
to regulate their internal
temperature and have fur and
feathers to help keep them warm.
Only birds and mammals are
blooded.
2) Cold-blooded animals cannot
maintain a constant body
temperature. The temperature of
their body is determined by the
outside surroundings. Reptiles,
amphibians and fish are all cold-

5. Fish
Birds
Mammals
Amphibians
Reptiles

6. INVERTEBRATES
• An invertebrate is an animal without a backbone or a spinal column, also
called vertebrae.
• Invertebrates can be classified into six groups: arthropods, mollusks,
echinoderms, annelids, poriferas and cnidarians.
1. Arthropods is the largest invertebrate group. All arthropods have an external skeleton called
called an exoskeleton. For example: crustaceans, myriapods, arachnids, insects.
2. Mollusks are another large group of invertebrates. There are three subgroups: gastropod,
bivalves, cephalopod. For example: octopus, snail, slug, oyster.
3. Echinoderms live at the bottom of the sea. They are covered by a hard, spiny skin. For
example: starfish.
4. Annelids have a long, soft body with moist skin. Many annelids are parasites and live inside
the bodies of other animals. For example: tapeworm, earthworm, leeches.
5. Poriferas live in water. They are the simplest invertebrates with no muscles, nervous or
circulatory system. For example: sponges.
6. Cnidarians live in the sea. They have a soft, jelly-like body with one opening. For example:
jellyfish.

7. 97% OF ALL THE ANIMAL SPECIES ON
EARTH ARE INVERTEBRATES.
flatworm: annelids
sponge: sponges
jellyfish: cnidarians
starfish:
echinoderms
snail: mollusks
scallop: mollusks
shrimp: arthropods
spider: arthropods

12. TELL ME
4
VERTEBRATES
AND
4
INVERTEBRATES