Unit 4

A scientist who studies fossils to learn about organisms that lived long ago.

Remains; impression, track; or other evidence or ancient organisms.

Fossils of widely distributed organisms that lived during only one short period.

Mark or track of an ancient animal preserved in sedimentary rock.

A type of fossil consisting of an extremely thin coating of carbon on rock.

Remains of living things that have been replaced by minerals and thus turned to stone.

A space in a rock that has the shape of the remains of a living thing that once occupied that space.

A model in the shape of a living thing or its remains.

Method of describing the age of one object or even compared to another object or even.

Age in years of a geologic even fossil, or rock, usually found by radioactive test.

An igneous rock layer formed when lava flows onto Earth’s surface and hardens.

An igneous rock that forms when magma hardens beneath Earth’s surface.

A place where an old, eroded rock surface is in contact with a newer rock layer.

The process at work today happened the same way in the past.

In undisturbed layers, older rocks will be under younger rocks.

Over time, elements breakdown by releasing particles and energy.

The time it takes for half of the radioactive atoms to decay.

A random change in a gene.

Theory, based on scientific evidence, that describes how organisms change over many generations.

Condition in which there are no more living members of a species.

An organism that has not suffered extinction- still living.

Animals with backbones- fish, amphibians, reptiles, mammals, birds.

An animal without a backbone.

Role that a species plays in a living community or ecosystem.