Arthropods

While plants make up the vast majority of biomass on the planet, arthropods make up most of the animal biomass. Arthropods are invertebrates. They have no backbone, and for that matter no bones at all. They have a hard exoskeleton that protects them and allows them to move around on land. In addition, they have left/right symmetry and multiple jointed limbs.  Insects and spiders belong to this group along with crabs and lobsters. In this lesson we will discuss spiders and insects.

Spiders

Spiders have 8 legs, 2 body segments (the abdomen and cephalothorax), and no wings. Spiders have simple development. When the babies hatch they look basically like the adults, just smaller.

Insects

Insects have antennae, 6 legs, 3 body parts (head, thorax, abdomen), and may have wings. Different species of insects have different developmental cycles. Silverfish and spring tails have simple development  just like spiders. Cockroaches and dragonflies are examples of types of insects that undergo incomplete metamorphasis. This life cycle consists of nymphs that hatch from eggs and grow until they become adults. The in some species the nymphs look similar to the adults and for some species the nymphs do not look like adults at all, however in both cases nymphs do not have wings. Other insects like moths, butterflies, mosquitoes, and beetles undergo complete metamorphasis. This life cycle consists of an egg, a larva that eats and grows, a pupa, and an adult that ecloses from the pupa.

Models of Spiders and Insects

You can add lettuce wings to your insects and make the spider legs with raisins on toothpicks.

Here are some examples of the arthropods the kids made in class. You can put them on baking paper and the kids can label their models.