Fossils: Tales from the Past

What is a fossil?

Fossils are the remains of ancient animals and plants Fossils are the remains of ancient animals and plants. Fossils can also be________ or ___________ of animals and plants. Most fossils are found in _______________layers. The _____________________ cover the plants and animals after their death. traces impressions sedimentary sand, rocks, and pebbles Trilobite – an extinct marine arthropod. An arthropod is an invertebrate animal having an exoskeleton, a segmented body, and jointed appendages.

Over time more sand and rock cover the________ Over time more sand and rock cover the________. The parts of the dead animal that do not easily __________ become covered in the___________. These parts, such as bones or teeth, became fossils. remains decay sediment Mastodon – Ancient relative of the elephant that roamed North and Central America.

Plesiosaur fossil – fossil of a marine reptile found in Kansas As an _____________decays, water and _______seep into the bones and teeth and replace the original matter with a __________ substance. animal or plant minerals rock-like Plesiosaur fossil – fossil of a marine reptile found in Kansas

How are fossils formed? Fossil of a lizard.

Fossils are categorized by how they were formed Fossils are categorized by how they were formed. The most common types of fossils are _____ fossils, ______fossils, _____ fossils, and ______ fossils. body cast mold trace Fossilized fern

ice tar pits amber mummified Body fossils are created when all or part of animal becomes fossilized. This can occur in sedimentary rock but body fossils are also found in _____, _________, ______ fluids such as pine tree sap, and _____________. ice tar pits amber mummified Insects preserved in tree sap.

Cast fossils are formed when the original _________is dissolved by ground water and replaced by the _________ contained in the water. _________ wood is a good example of a ______ fossil. organism minerals Petrified cast

Mold _____ fossils are created when the original organism is destroyed or __________, and the space left by the organism is filled with sediment that ________ into a mold. Often mold fossils are formed from _______________ or animals with _______________. dissolved hardens shelled animals exoskeletons This mold fossil includes several species of marine animals.

sediment Trace fossils are formed when _________ fills or covers trace evidence left by animals or plants. ______________ include animal burrows, dung, foot ________, and gnawed areas on trees and _________. Trace fossils prints bones Coprolite is dung (a.k.a. poop) that has been fossilized. Scientists can study an animal’s diet by studying this alligator coprolite.

How are fossils excavated and studied?

Paleontologists are __________ that study fossils in order to understand both ________ and ________ organisms . A ______________ leads a team of scientists during _____________ of fossils. scientists extinct living paleontologist excavation One of the world’s most famous excavation sites for Ice Age fossils is the La Brae Tar Pits in Los Angeles, California.

Paleontologists excavate the remains, and then ________ the organism that was fossilized. They ___________ the animals and their _____________. These scientists also study the _________________ by comparing these fossils to the animals and plants that ________ today. identify reconstruct environment history of the earth exist Can you identify any of these fossils as organisms that exist today?

One of the important tasks that paleontologists do while completing ___________ at an excavation is to date the fossils. Sedimentary rocks and ________ lava flows are found in _____. The lower the layer of rock or ash the _______ the fossils are that were found in that layer. field work volcanic layers older Layered beds of limestone located on a canyon wall in Nevada.

Fossils help scientists understand the movement of the ___________ Fossils help scientists understand the movement of the ___________. When fossils that are the same ________ are found on two _________, scientists can identify movement of the _______ plates as the cause of the fossil placement. tectonic plates species continents earth’s Finding similar species on different continents is used as proof of the theory that the continents have drifted apart over time.