1) What is the name given to scientists who study fossils? 2) Why are fossils made mostly of hard parts? To the left is a picture of the Grand Canyon (AZ) 1)The lines, different colors and textures in the rock are representation s of different rock layers. How would you describe the age of the rock from top to bottom Hint: As you go down the layers, the age of the rock _________________

Ch4. Lesson 1

 Fossils are the preserved remains or traces of all living things.  Most fossils form by habitats where animals and plants once lived in, particularly near quiet waters such as: swamps, lakes or shallow seas where sediment builds up.  Generally, only the hard parts of an organism remains and become fossilized. This is because an organisms soft tissue / parts decay or are eaten by other animals.  These hard parts include: bones, shells, teeth, seeds and woody stems. Most fossils form when living things die and are buried by sediment. The sediment slowly hardens into rocks and preserves the shapes of the organisms.

Describe the events below: The fish is alive its habitat The fish eventually dies and sinks to seafloor Soft parts removed (decay / eaten) Fish is covered under sediment Over time soft sediment turns to hard rock Rock is distorted and uplifted Scientist recognizes and extracts Fish skeleton is preserved in rock as a fossil

There are different kinds of fossils based on the substance from which they are preserved from:  Rock  Molds & Casts  Petrified fossils  Carbon films  Trace fossils  Other Substances, such as: Ice, tar or amber:

 Molds and Casts – Most common type. A mold forms when organism is buried in sediment and is a hollow are in the shape of organism or part of organism. A cast is a solid copy of the shape of organism and is formed from molds. Molds and casts can preserve fine details  Petrified Fossils – Where minerals replace all of organism or its parts. Petrified simply means “turned into stone”. An example would be seen in dinosaur bones.  Carbon Films – Extremely thin coating of carbon on rock. This type of process can preserve delicate parts of plant leaves and insects.

 Trace Fossils – A print is fossilized by sediment, such as footprints. Trace fossils provide evidence of activities of ancient organism  Preserved Remains – Some processes can preserve entire organism. Example, when an organism is trapped in ice or is frozen, or sticky substances like tar or tree resin.

 Scientists who study fossils are called palenotologists.  All of the information gathered about past life is called a fossil record. Fossil Record This provides evidence about the history of life and past environments on Earth. It shows how different groups of organisms have changed over time.

Wyoming, 50 million years ago Today, Wyoming has areas of dry plateaus, but 50 million years ago it was very different Fossils also provide evidence about past climate of a region. Coal, a fossil fuel that comes from plants and animals which grows in warm climates, has been found in Antarctica. The presence of coal shows that the climate of Antarctica was once warmer than it is today.