Fossils

What are two things that scientists can learn from the fossil record?

-evidence to support theory of evolution -evidence to tell when an organism is extinct

What are the five different kinds of fossils?

Fossils found in rock include -molds -casts -petrified fossils -carbon films -trace fossils

In general, how does a fossil form?

Most fossils form when living things die and are buried by sediments. The sediments slowly harden into rock and preserve the shapes of the organisms.

How are petrified fossils similar to preserved remains? How are they different?

Same: both fossils - preserved with something (minerals, tar, amber, ice) Different: petrified fossils replace organisms with minerals and preserved remains preserve the organisms with little or no change

What does the fossil record show about how life has changed over time?

The fossil record provides evidence about the history of life and past environments on Earth. The fossil record also shows that different groups of organisms have changes over time.

mold

a fossil formed when an organism buried in sediment dissolves, leaving a hollow area

cast

a fossil that is a solid copy of an organism's shape formed when minerals seep into a mold

paleontologist

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

carbon film

a type of fossil consisting of an extremely thin coating of carbon on rock

trace fossil

a type of fossil that provides evidence of the activities of ancient organisms

scientific theory

a well-tested concept that explains a wide range of observations

fossil record

all the information that paleontologists have gathered about past life

extinct

describes a type of organism that no longer exists anywhere on Earth

petrified fossil

fossils in which minerals replace all or part of an organism

Which parts of an organism are most likely to be preserved as fossils? Why?

hard parts of an organism generally leave fossils - these hard parts include bones, shells, teeth, seeds, and woody stems. It is rare for soft parts of an organism to become a fossil because when an organism dies, its soft parts often decay quickly or are eaten by animals.

fossil

the preserved remains or traces of living things

evolution

the process by which all the different kinds of living things have changed over time

sedimentary rock

the type of rock that is made of hardened sediment; which is material removed by erosion. Sandstone, limestone, coal

What are the three ways in which the remains of an organism can be preserved with little change?

trapped in tar - sticky oil that seeps from Earth's surface amber - the hardened resin, or sap, of evergreen trees ice - freezing

How does a carbon film fossil form?

when sediment buries an organism, some of the materials that make up the organism evaporate, the gases escape from the sediment, leaving carbon behind. eventually only a thin film of carbon remains