1. Núria Forns
Escola del Mar

2. Look at these animals.
Can you find the odd one out?
Frog
http://recursos.cnice.mec.es/bancoimagenes4/
Spider
http://recursos.cnice.mec.es/bancoimage
nes4/
Ladybird
http://recursos.cnice.mec.es/bancoimage
nes4/

3. Answer these questions:
Has the frog bilateral symmetry?
Has the frog many pairs of limbs?
Has the spider a segmented body?
Has it jointed legs?
Has the ladybird a hard exoskeleton?
Has it bilateral symmetry?

4. Well done!
The spider and the ladybird have:
•Bilateral symmetry
•Segmented body
•Hard exoskeleton
•Jointed legs
•Many pairs of limbs
Therefore, they are
arthropods.
Can you say the same about the frog?

5. Has the frog..
bilateral symmetry?
segmented body?
hard exoskeleton?
jointed legs ?
many pairs of limbs?
http://recursos.cnice.mec.es/bancoimagenes4/
So, is the frog an arthropod?
No,
it is not. You are right.
Brilliant!

6. Groups of arthropods
There are four groups of arthropods:
-
Arachnids
-
Crustaceans
-
Insects
-
Myriapods
Every group has got its own features. Let’s have a
look!

7. Arachnids
Observe these animals.
What do they have in common?
Their body has two parts:
Cephalothorax
Abdomen
They haven’t got any
antennae or wings.
They’ve got 8 legs.
They are mostly terrestrial.
Spiders, scorpions, ticks
and mites are arachnids.
http://recursos.cnice.mec.es/bancoimagenes4
/

8. Crustaceans
What do these animals have in common?
Their body has two parts:
Cephalothorax and abdomen.
They’ve got four antennae.
They’ve got ten or more legs.
They are mostly aquatic, few
terrestrial.
Crabs, shrimps, lobsters are
crustaceans.
http://recursos.cnice.mec.es/bancoimagenes4/

9. Myriapods
What do these animals have in common?
Myriapods have :
A clearly visible head with two
antennae.
A body with many segments.
Centipede
http://recursos.cnice.mec.es/bancoimagenes4/
In each segment there are two legs
(centipedes)or four legs (millipedes)
Centipedes and millipedes are
myriapods.
Millipede
http://en.wikipedia.org/wiki/Image:Millipede.jpg

10. Insects
Observe some virtual insects:
http://www.ento.vt.edu/~sharov/3d/virtual.html
As you can see most insects have:
Three body parts: Head, thorax and abdomen.
Six legs.
Two or four wings and two antennae.
Ants, bees, flies, grasshoppers, butterflies, beetles,.. are
insects.
To know more about insects we are going to visit this web:
http://www.urbanext.uiuc.edu/insects/01.html