All About Ammonites

Ammonites were sea creatures that lived surpassing and at the same time as dinosaurs. They were a bit like a modern-day squid or octopus with a shell. Ammonite fossils have been found all over the world. The fossils resemble a curled-up snake, and for a while, people thought they were remains of snakes, earning them the nickname snakestones!

Ammonites made uneaten chambers in their shell as they grew, which gave the shell a unshared screw shape.

How did ammonites swim?

The hollow inner chambers of an ammonite’s shell helped them bladder and tenancy their buoyancy. Ammonites had a siphuncle system which unliable them to longish gas in and out of the empty shell to transpiration their buoyancy. Only the outermost chamber housed the soft body.

They squirted water to push themselves along. Modern cephalopods ( octopus, squid, cuttlefish and nautilus ) use this same jet propulsion method to move.

When did ammonites live?

It’s thought that ammonites first appeared virtually 400 million years ago and became extinct well-nigh 66 million years ago during the same extinction event that killed non-avian dinosaurs and many other species of animals and plants on Earth.

What did ammonites eat?

Ammonites are thought to have eaten plankton and small crustaceans and were eaten by dinosaurs such as mosasaurus, ichthyosaurus and plesiosaurus.

Ammonite fossils

Ammonites were hugely well-healed in the ocean for a very long time, so fossils are plentiful. Scientists use the number and type of ammonite fossils found in a particular layer of waddle to stage other fossils in the same layer. They are known as alphabetize fossils.

Ammonite fossils are found in marine sedimentary rock. If you’re in the UK, Lyme Regis in Dorset is a good place to go ammonite hunting.

Ammonite Investigation

How did ammonites tenancy their buoyancy?

The soft soul of an ammonite only lived in the outermost section of its shell. The other chambers were sealed off as the ammonite grew and used to tenancy its buoyancy.

Ammonites had a siphuncle system which unliable them to longish gas in and out of the empty shell to transpiration their buoyancy. The siphuncle moreover pumped water out of empty chambers as the soul grew.

We can demonstrate how waffly the density of the ammonite shell would have reverted its buoyancy with a simple demonstration.

You’ll need

A jar or a large snifter

Small test tube with a toss or air-tight lid

Buttons, plasticine or flipside small object

Water

Instructions

Fill the jar or snifter scrutinizingly to the top with water. The jar needs to be deep unbearable for the test tube to be completely covered with water when submerged.

Place the empty test tube with the lid on into the jar. It should bladder on the surface of the water. The test tube represents an ammonite.

Add buttons or plasticine to the test tube until it just starts to dip under the surface of the water.

Add a little bit of water to the test tube containing buttons and watch what happens. You should find the position of the test tube in the water changes the increasingly water you add.

Keep subtracting increasingly water to the test tube until it sinks to the bottom.

By subtracting water, you are waffly the density of the test tube. When the density of the test tube is greater than the density of the water it is placed in, the test tube will sink.

When water is widow to the test tube, its whole density changes, which ways its position in the water changes. This is how ammonites tenancy their buoyancy. The siphuncle pumped water out of the newly empty shell chambers and gases in to indulge the ammonites to bladder at the level they wanted.

More well-nigh ammonites

Find out how x-rays revealed what ammonites ate.