Fossils are the remains of plants and animals that lived a long time ago that scientists about a plant or animals' life. Many fossils are the remains of plants and animals that are extinct. Extinct means they are no longer living and none are left on Earth. Fossils have been found on every continent in mountains, under water, in valleys, ice, and many more places. Paleontology is the study of fossils and about life from long ago. Paleontologists estimate that only a small percentage of dinosaurs and other animals or plants that ever lived have been or will be found as fossils.
One type of fossil is the remains of the dead organism or the imprint left by the remains. A second type of fossil is something that was made by the animal while it was living but has turned into stone.
The bones and teeth are hard mineral parts of an animal that become fossils after an animal dies. The animal's body is buried in mud or other sediment and the teeth and bones do not rot like the rest of the animal's body. After a long time, the chemicals in the buried animals' bodies undergo many changes. As a bone slowly decays, water filled with minerals seeps into the bone and replaces the chemicals in the bone with other minerals that are as hard as a rock. Fossilization is the name of this process.
Fossils come in many colors and are made of many different types of minerals, depending on where fossilization took place. Most fossils are dug up from sedimentary rock layers. Sedimentary rock is rock that has formed from sediment, like sand, mud, and small pieces of rocks. Small pieces of an animal's remains become squeezed between the layers of this sediment. Over long periods of time, they are buried under more and more layers of sediment that piles up on top of it.
Fossils are usually heavier than the original item since they are formed entirely of minerals. Most fossils are made of ordinary rock material. Fossils do have the same shape that the original item had, but their color, thickness, and surface may be different.
Trace fossils may be something that was made by an animal while it was living, but has turned into a stone. There are many types of trace fossils. Dinosaur tracks are an example. By studying fossil footprints, a paleontologist can study the speed, stride, number of feet an animal walked on, and the bone structure of the foot. They can also learn about the behavior of a dinosaur, whether they lived in herds, and how the tail was carried. The waste from an animal is an example of a trace fossil, which can lead to learning about the foods an animal had eaten. Dinosaurs laid eggs of a wide variety of shapes and sizes, and can be from 3 inches to 21 inches. Sometimes they have preserved parts of the beginnings of a dinosaur, which can help to match an egg with a type of dinosaur.
The best way for a fossil to be formed, which does not happen often, is inside ice. The animal must be continually frozen from the time of death until discovery. The wooly mammoth and rhinoceros are examples of fossils found in ice.
Finally, mummification occurs when the soft tissues of animals' skin and organs are preserved for thousands of years and are completely dried. Mummified bodies of animals, including humans, have been discovered in arid or dry parts of the world.
In summary, fossils are formed in many different ways, but the most common method of preservation is minerals filling the empty spaces of plants or animals, and after a long period of time, become hard as rock, but the shape of the original plant or animal is preserved.