Chapter 6, Lesson 3 Resources from The Past Pages 272-280

One way people can learn from the past is from studying fossils One way people can learn from the past is from studying fossils. A fossil is evidence of an organism from long ago.

Fossils can be as small as a tiny insect Fossils can be as small as a tiny insect. Very large organisms can also be preserved.

Amber is hardened tree sap that can be a source of insect fossils.

There are several kinds of fossils: molds, casts, imprints, and stony fossils.

A mold is an empty space in rock that once held the remains of a living thing.

A cast is a fossil that is formed or shaped in a mold from minerals building up inside a mold.

An imprint is a mark made by pressing.

Wood and bone can turn into stone. These stony fossils are petrified.

Many fossils found show that the Earth has changed over time Many fossils found show that the Earth has changed over time. Some fossils of sea creatures are found on land and other fossils are from organisms that could not survive in climates where their fossil was found.

A fossil fuel is a source of energy made from the remains of ancient, once-living things.

People burn fossil fuels to use the energy stored in them People burn fossil fuels to use the energy stored in them. This creates pollution and acid rain.

Coal, oil, and natural gas are fossil fuels.

Fossil fuels are nonrenewable resources Fossil fuels are nonrenewable resources. Nonrenewable resources are useful materials that cannot be easily replaced.

Scientists are looking for other ways to produce energy Scientists are looking for other ways to produce energy. These are called alternative energy sources.

Renewable resources are materials that can be replaced quickly.

The sun, wind, and moving water are renewable resources that can be used to create energy.

Why do you think it is important for people to start using less fossil fuels to produce energy and more renewable resources? ?