Fossils - Mrs. Salem 7th Grade Science

Fossils What is a fossil? Fossils are the preserved remains or traces of living things Most fossils form when living things die and are buried by sediments The sediments slowly harden into

rock and preserve the shapes of the organisms What is a paleontologist? A scientist who studies fossils

Sedimentary Rock The type of rock that is made of hardened sediment This is also where fossils are usually found How a fossil forms:

1. Surface Erosion 2. Layers form from Sediments. 3. Sed. Rocks form 4. Fossils form

Shells

Bones Teeth Trees tracks Kinds of Fossils 1. Petrified fossils 2. Molds and casts

3. Carbon films 4. Trace fossils Petrified Fossils Petrified means turning into stone Fossils in which

minerals replace all or part of an organism (Example: Petrified wood) Molds and Casts Mold: a hollow area in sediment in the shape of an organism or part of an organism

Forms when the hard part of the organism such as a shell, is buried in sediment Later, water carrying dissolved minerals and sediment may seep into the empty space of a mold, creating a cast. Cast: a copy of the shape of an organism

Carbon Films Another type of fossil is a carbon film, which is an extremely thin coating of carbon on rock. This process can preserve delicate parts of insects, flowers or plant leaves.

Trace Fossils This type of fossil provides evidence of the activities of ancient organisms Fossilized foot print Animal activities, diet, where it hunts,

and how it obtained food. Preserved Remains Tar Ice Amber

Tar Sticky oil that seeps from Earths surface Amber A hardened resin, or sap, of evergreen trees 1.Preserved 2.Dies, covers, destruction, body

Freezing Another way in which remains can be preserved What is the purpose of studying fossils?

What is the purpose of studying fossils? Fossils are used to determine what past events Were like, how organisms lived, what happened them, and in what environment they lived. Paleontologists also use fossils to build a picture of Earths environment in the past, such as elephants.

Fossil Record Provides evidence about the history of life on Earth. Also shows that different groups of organisms have changed over time.

Evolution is the gradual change in living things over long periods of time Law of Superposition In any undisturbed sequence of rocks deposited in layers,

the youngest layer is on top and the oldest layer is on the bottom Film Facts 1. 2.

3. 4. 5.