Fossils How Fossils Form How fossils show that

Fossils! How Fossils Form How fossils show that life on Earth has changed

What are Fossils? ? ? �Fossils are things that have lasted from living things that died long ago. �Traces of ancient animals and plants left as molds, casts, and prints. �Some fossils show us the shapes of plants and animals of the past. �Some fossils are also remains, which show actual bones, shells, or teeth.

Mold, Cast, Imprint �A mold is the shape of a plant or animal left in sediments when the rock formed. �A cast forms when mud or minerals fill a mold. The cast has the exact same shape of the animal that made the mold. �Imprints are molds of leaves or other thin objects. Some imprints are of animal wings or feathers.

How fossils form… �Fossils often form in sedimentary rocks, such as limestone and shale. �Steps: � 1. The soft parts of an animal decompose � 2. Hard parts of the animal, such as shells or bones, are slowly buried under layers of sediment. � 3. Over a long time the sediment turns into rock. � 4. Movement of the Earth’s crust brings the rock and fossils closer to the surface. Wind and rain wear away the rock on top of the fossils. � http: //www. youtube. com/watch? v=n. HJDi 4 v. Rv. XA

Mold & Cast

Fossils �Plant fossils are much less common than animal fossils. This is because plant parts are more easily destroyed as rocks form.

Dragonfly Fossil

Dinosaurs: �Dinosaurs became extinct long before there were any scientists to study them. But today scientists can use fossils to learn how dinosaurs looked and lived. �Scientists use fossils to put together dinosaur skeletons. The skeletons show large the dinosaurs were, and the teeth fossils show what kind of food they ate.

Paleontologist: A Scientist who studies fossils.