The preserved remains or traces of an organism that lived in the past.
The process of turning some plant material into stone by infiltration with water carrying mineral particles without changing the original shape.
A type of fossil formed when a shell or other hard part of an organism dissolves, leaving an empty space in the shape of the part.
A type of fossil that forms when sediments fill in the cavity left by a decomposed organism.
Yellowish brown fossil resin that often has particles trapped inside.
A type of fossil formed when an impression made in mud by a living thing is preserved when the mud is transformed into rock.
Tar pits are formed when a dark sticky form of oil seeps up from underground, causing animals to get stuck and their bones to be preserved as the material around them hardens.
A vertebrate with two pairs of limbs.
A scientist who studies fossils.
A type of fossil that provides evidence of the activities of ancient organisms. Some examples of trace fossils are footprints, tracks, trails, and burrows.
To develop gradually by process of growth and change.
An animal that walks on two legs.
geologic time scale
Earth's history organized into four eras: Precambrian, Paleozoic, Mesozoic, and Cenozoic.
Dating based on the decay of radioactive isotopes. This method is used for determining the age of fossils and rocks by the ratio of a radioactive isotope to the nonradioactive isotope(s) of the same element in the sample.
Structures in different species that are similar because of common ancestry.
An organism that has five fingers or toes to each hand or foot.