Fossils, Geological Age and Superposition

A fossil is

• and dead organism

• a perfect copy of a rock

• the preserved remains or traces of an organism

• an unusual type of rock

How do most fossils form?

• living things die and their remains are buried by sediments

• the hard parts of an organism dry out in the air

• the soft parts of an organism change to stone

• freezing preserves the remains of an organism

A fossil formed when minerals replace all or part of an organism is called a(n)

• mold

• petrified fossil

• cast

• trace fossils

Can provide clues about the activities of ancient organism

• trace fossils

• preserved remains

• carbon films

• molds and casts

Radioactive decay occur when atoms of an unstable element

• become part of a fossil

• join with atoms of another element

• break down to form atoms of another element

• are exposed to chemical weathering

The Paleozoic, Mesozoic and Cenozoic are divisions in the geological time scale called ________

• Centuries

• Periods

• Layers

• Eras

The geological time scale is arecord of

• the thickness of sedimentary rock layers

• the rate of fossil formation

• the life forms and geological events of history

• the time since the evolution of dinosaurs

The earliest life forms were

• dinosaurs

• single celled organisms

• fossils

• vertebraes

What is the order from oldest to youngest layer?

• G ,E, C, A ,F, B ,D

• E ,G, C ,A ,F ,B ,D

• A, C, D, B, E, F, G

• D, B, F, A, C, E, G

The relative age of a rock is

• its age compared to the ages of other rocks

• the number of years since the rock formed

• less than the age of the fossils the rock contains

• its age based on hoe much carbon-14 the rock contains