History of Life - Fossil Record

To understand how life has changed over time

To predict future weather patterns

To learn about the structure of atoms

To improve computer technology

The techniques were not accurate enough.

There were no fossils in sedimentary rocks.

Sedimentary rocks are too young.

Scientists did not know about isotopes.

Radioactive dating

Carbonation

Evaporation

Photosynthesis

Isotopes have the same number of protons.

Isotopes have different atomic masses.

Isotopes have the same number of neutrons.

Isotopes have the same atomic number.

Radioactive isotopes undergo decay, releasing particles or energy.

Stable isotopes have more protons than neutrons.

Radioactive isotopes have the same atomic mass as stable isotopes.

Stable isotopes are only found in living organisms.

Carbon-12

Carbon-13

Carbon-14

Carbon-16

They are unstable isotopes.

Their half-lives are too short.

Living organisms do not incorporate these isotopes into their bodies.

They are only found in water.

The exact age of a fossil in years

The placement of a fossil in relation to other fossils

The chemical composition of a fossil

The environment where a fossil was found

There have been great changes in the kinds of organisms that dominated life at different times.

All organisms have remained the same over time.

Only plants have changed over time.

Fossils only show extinct organisms.

Many organisms did not die in the right place at the right time to be preserved as fossils.

Many fossils have been destroyed by geologic processes.

All fossils have been found.

Only a fraction of the fossils have been found.

Having hard shells or skeletons

Being rare and short-lived

Living only in one small area

Being soft-bodied