Fossils and the Past
These are the remains or traces of living things from long ago.
What are fossils?
Most fossils form when a plant or animal is quickly ______________ by mud or sand.
What is buried?
Sedimentary rock often forms in these places over long periods of time.
What are oceans?
These fossils include bones, teeth, or shells.
What are body or true form fossils?
Fossils are most often found in sedimentary rock because ______________________.
What is because organisms can be covered and protected.
Scientists study fossils to learn about the ____________ and how life has changed.
past
Being buried protects an organism from this and from other animals.
What is weather?
These form as sediment builds up over time.
What are layers?
These fossils show movement, like footprints or burrows.
What are trace fossils?
This is an example of a trace fossil.
What is a footprint?
________________ are an example of this type of animal that lived long ago in the ocean.
Ammonites
Over time, layers of sediment harden into this type of rock.
What is sedimentary rock?
Each rock layer can tell scientists something about Earth’s ______.
What is Earth’s past?
This fossil forms when an organism decays and leaves a hollow space.
What is a mold fossil?
Ammonite fossils help scientists learn about these environments from long ago.
What are ancient oceans?
Fossils can be remains of these, such as footprints or marks left behind.
traces
Ammonite shells were buried and slowly turned into this.
What is rock?
Fossils in sedimentary rocks are easier to find when these can be seen clearly.
What are rock layers?
This fossil forms when minerals fill in the hollow space left behind.
What is a cast fossil?
Fossils are usually not found in igneous or metamorphic rock because _____________________
What is because heat can destroy fossils?