Evidence
|
What it tells us:
|
|
Past Lives
|
|
1. growth rings in fossil trees or shells
|
Growth rings tell us the number of years that individual lived.
|
|
2. curled up fossil trilobites
|
Trilobites may have curled up to avoid predation just as pill bugs do today.
|
|
3. the contents of fossil nests
|
Some dinosaurs cared for their young while still in the nest.
|
|
4. fossils of many individuals of the same species together
|
These animals probably lived in herds.
|
|
5. a change in the shape of a feature over time
|
The function of that feature has also changed.
|
|
Geologic Time
|
|
1. layers in the rocks
|
The rocks were deposited at different times and represent part of the history of the Earth.
|
|
2. index fossils
|
These fossils can help us to date rock layers around the world.
|
|
3. fossil shells on mountain tops
|
What is now the top of the mountain used to be under the sea.
|
|
4. identical fossils on widely separated continents
|
The continents were once joined together.
|
|
Paleoecology
|
|
1. fossil marine animals in the desert
|
There was once an ocean covering this area.
|
|
2. shapes of leaf edges
|
The leaf edges tell us if the climate where the plant grew was generally cool or warm.
|
|
3. tooth marks in fossil shells
|
The animal living in the shell was preyed upon by another animal.
|
|
4. fossil pollen
|
Fossil pollen tells us what kinds of plants lived in past ecosystems.
|
|
Biodiversity
|
|
1. fossils of organisms no longer alive today
|
Living things in the past were different from those of today.
|
|
2. features that are shared by more than one species
|
These species are probably related to each other.
|
|
3. the extinction of many fossil species at the same time
|
This would indicate a mass extinction caused by a wide-ranging catastrophe.
|
|
4. the extinction of one group of organism, like corals, on which other organisms depend
|
The extinction of one kind of organism often causes the extinction of others.
|