Fossils index

Insects

Insects are six legged animals that mostly live on land. They are now extinct. Their name is derived from insectum (Latin) meaning 'cut into sections'. Insects have a head, thorax and abdomen, which are clear to see. So they are 'cut into' three parts.

Kingdom: Animalia
Phylum: Arthropoda
Subphylum: Hexapoda
Class: Insecta
Insects are arthropods. So are crabs and woodlice. Trilobites were arthropods.
Dragonfly larva

Timescale: Insects appeared about 325 million years ago. They are, of course, still with us.



Insect in amber

Insects live on land rather than water, so they are less likely to be covered with silt when they die, to be made into fossils. Also, they have no hard parts such as shells or bones or teeth which will survive better. However, some insects have been preserved in amber. Amber is fossilised resin. Fresh resin is sticky, and as resin oozed from the trunk of the tree, flies and other insects got stuck it. The resin preserved them, and once it had fossilised, if the amber is clear enough, you can still see them (see left - perhaps a fly). Pliny the Elder managed to work this out. Size of amber: 11mm

The film 'Jurassic Park' imagined that you could remove an ancient mosquito from amber and extract its latest meal of blood, which was from a dinosaur. Using the DNA from this, you could clone a living dinosaur. A good story, but unfortunately impossible! You wouldn't get enough good quality DNA.



While most insects live on land, there are some water insects. Dragonflies, like many insects, have more than one form through their lives. The adult lays eggs under water, and these hatch out as larva. The larva live under water. This makes it more likely that a dead larva will fall to the bottom and get covered in silt before it gets eaten or rots away. Then it might get fossilised.

This fossil shows a dragonfly larva from the Tertiary period, about ten million years ago. It came from Italy.
Size of fossil: 15mm

Below is a modern dragonfly.

Dragonfly

Dragonfly larva