8
Living things
The Animal Kingdom: invertebrates
What do invertebrate
animals have instead
of a backbone?
R E A D & T H I N K
They have a soft
muscular
body, often protected by a
hard
shell
. Some, such as
snails, live on land. But most,
like mussels and octopuses,
live in the sea.
They live in the sea. They’re
protected from
predators
by hard skin or
spikes
and
are often brightly coloured.
Starfish are echinoderms.
They usually have five arms
but can have up to 40!
They live in the sea. They
have a soft body called the
umbrella
and often have long
tentacles
. There’s a hole under
their umbrella that is both
mouth and anus.
Some of them live in the sea.
They have a long, soft body
divided into
segments
. A
very important annelid is the
earthworm
. The earthworm
helps to get air and nutrients
into the soil. Can you say how?
They live in the sea. They have
soft bodies covered with little
holes. They stay on the
seabed
and take in oxygen and food
through the holes. There are lots
of known species of sponges.
Almost all animals on Earth are
arthropods. The biggest group
is
insects
. They live in water, on
land, in the air and underground.
They have a head, thorax and
abdomen,
jointed
legs
and a
protective
exoskeleton
.
97% of all animals are invertebrates and they live almost everywhere! Scientists are still finding new
species of invertebrates, but here are the six most common groups.
1
Read and find out:
a)
Which groups have a hard protective part?
b)
Which groups live only in water?
c)
Which is the biggest group?
Molluscs
Echinoderms
Jellyfish
Annelids
Sponges
Arthropods
