Types of Fossils
This fossil forms when an organism is trapped in hardened tree resin.
What is an Amber Fossil?
This law states that deeper rock layers are older than layers above them.
What is the Law of Superposition?
Put these divisions in order from largest to smallest: Era, Eon, Period, Epoch.
What is Eon → Era → Period → Epoch?
Scientists found evidence of these earliest MOST simple life forms in ancient rocks.
What are single-celled organisms?
How did life forms change in terms of complexity over time?
They changed from simple organisms to more complex organisms over time.
These fossils form when organisms are trapped in sticky natural asphalt.
What are Tar Pit Fossils?
This method compares rock layers to determine which is older or younger.
What is Relative Dating?
Scientists believe this many major mass extinctions have occurred in Earth’s history.
What are five mass extinctions?
Traces of this element in ancient rocks suggest life once existed there. It makes up most living organisms.
What is Carbon?
This type of fossil shows traits of both older and newer groups of organisms.
What is a transitional fossil?
These fossils are created when minerals replace the original remains of an organism.
What is a Permineralized Fossil?
This type of age gives the exact number of years a rock or fossil has existed.
What is Absolute Age?
This is the oldest and longest division of Earth’s history.
What is the Precambrian Time?
These are fossils of some of Earth’s oldest bacteria.
What are Cyanobacteria?
This famous transitional fossil shows characteristics of both fish and early land animals. It had fins like a fish but also had a neck, strong ribs, and limb-like bones that helped it move in shallow water and onto land.
What is Tiktaalik?
These fossils form when pressure leaves a thin film of carbon behind.
What is a Carbonized Fossil?
Scientists use radioactive elements in this process to determine exact ages of rocks
What is Radiometric Dating?
This era is often called the “Age of Reptiles.”
What is the Mesozoic Era?
These layered rock structures were formed by ancient cyanobacteria.
What are Stromatolites?
This term describes an organism from which two or more different species evolved.
What is a common ancestor?
These fossils form when an organism leaves an impression that later fills with minerals.
What are Cast and Mold Fossils?
These fossils are used to identify and compare the ages of rock layers.
What are Index Fossils?
This era is known as the “Age of Mammals” and continues today.
What is the Cenozoic Era?
These gases in Earth’s early atmosphere were likely produced by ancient life forms through photosynthesis.
What is oxygen?
These two types of anatomy help scientists describe evolutionary relationships between organisms
homologous structure and embryo similarities