Wildlife Facts: All About Fish

The Arthropods

Insects and spiders belong to the group of animals known as arthropods. These are segmented invertebrate (in-VUR-ta-bret) animals, which means that they have an external skeleton and no backbone. Four out of five animals are arthropods. There are over one million species (kinds) of insects, and 50,000 species of spiders, scorpions, mites and ticks. For every person there are 200 million insects.

Insect bodies are divided into three parts: the head, the thorax and the abdomen. The head has two antennae (an-TEN-ee), eyes and mouth parts. The thorax has three segments, each with a pair of legs, so insects always have six legs. Nearly all insects have wings, and they are the only invertebrate group that can fly.

Spiders and their relatives have bodies that are divided into two parts. The head and thorax together care called the cephalothorax (SEF-a-la-THOR-ax), and then comes the abdomen. Instead of antennae on their heads, spiders have two jaw-like appendages. Most have four pairs of legs.

Fast Facts:

	All arthropods are invertebrates.
	There are 200 million insects for every person on Earth.
	Insect bodies are divided into three parts: the head, the thorax, and the abdomen.
	All insects have six legs.
	Spider bodies are divided into two parts: the cephalothorax and the abdomen.
	Most spiders and their relatives have eight legs.

Arthropod Diversity

Arthropods are divided up into groups of related animals, called Orders. Below you'll find the name of some orders and some examples.

Photo	Class	Examples
	Scorpionida (SKOR-pe-ah-NI-dah)	scorpions
	Araneae (ah-RAN-a-e)	spiders
	Opiliones O-pi-LE-on-es)	daddy longlegs
	Acarina (AK-ar-EE-nah)	mites and ticks
	Isopoda (ICE-o-po-dah)	pill bugs
	Decapoda (DEK-a-po-dah)	true shrimps, lobsters, crayfishes, crabs

Activity:

GRASSHOPPER GAZE (Grades 2-7 and older)

People don't often think of insects as animals and they hardly ever think of grasshoppers as wildlife. Pretend you are a scientist, and let's study grasshoppers. Have some paper and a pencil handy.

1. Collect some grasshoppers and grass in a plastic jar. Please do not hurt the grasshoppers! Remember to be gentle.

2. Examine the grasshoppers in your jar, and answer some of these questions:

What are some of the most interesting features of the grasshopper?

How many legs does it have?

Are all the legs alike or different?

Which legs are the jumping legs?

Can you see any wings? (You may not if the grasshopper if young.)

Look at the head. How many eyes do you see?

Why do you think they have so many eyes?

Do you see a mouth? Try to describe the mouth parts and how they move.

Is the grasshopper the same color all over?

Are the colors, shapes and sizes the same on both sides?

Are all the grasshoppers in your jar alike or different?

2. Let the grasshoppers escape from the jar right where you found them.

3. Did you think there were so many interesting things about a grasshopper? Do you think other insects might be as interesting? What other insects or small animals might be interesting to look at and learn more about?