Evidence Chart Key
Evidence
What it tells us:
Past Lives
1. growth rings in fossil trees Growth rings tell us the number of years that
or shells
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
These animals probably lived in herds.
of the same species together
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
There was once an ocean covering this area.
desert
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
This would indicate a mass extinction caused
fossil species at the same time by a wide-ranging catastrophe.
4. the extinction of one group
of organism, like corals, on
The extinction of one kind of organism often
which other organisms
causes the extinction of others.
depend