![Page 1: Fossils - 7th Grade Electionskellywms.weebly.com/uploads/5/4/9/0/54901139/fossils_-_2015.pdf · Fossils are used for examining Earths History. • The fossil record provides evidence](https://reader033.vdocuments.net/reader033/viewer/2022052017/60307bc74da0f716ef22850c/html5/thumbnails/1.jpg)
Fossils
![Page 2: Fossils - 7th Grade Electionskellywms.weebly.com/uploads/5/4/9/0/54901139/fossils_-_2015.pdf · Fossils are used for examining Earths History. • The fossil record provides evidence](https://reader033.vdocuments.net/reader033/viewer/2022052017/60307bc74da0f716ef22850c/html5/thumbnails/2.jpg)
HOW IS A FOSSIL FORMED?
1. SedimentAn animal is buried by
sediment, such as
volcanic ash or silt,
shortly after it dies. Its
bones are protected
from rotting by the
layer of sediment.
4. ErosionErosion from rain,
rivers, and wind wears
away the remaining
rock layers. Eventually,
erosion or people
digging for fossils will
expose the preserved
remains.
2. LayersMore sediment layers
accumulate above the
animal’s remains, and
minerals, such as silica
(a compound of silicon
and oxygen), slowly
replace the calcium
phosphate in
the bones.
3. MovementMovement of tectonic
plates, or giant rock
slabs that make up
Earth’s surface, lifts
up the sediments and
pushes the fossil
closer to the surface.
![Page 3: Fossils - 7th Grade Electionskellywms.weebly.com/uploads/5/4/9/0/54901139/fossils_-_2015.pdf · Fossils are used for examining Earths History. • The fossil record provides evidence](https://reader033.vdocuments.net/reader033/viewer/2022052017/60307bc74da0f716ef22850c/html5/thumbnails/3.jpg)
Formation of Fossils
![Page 4: Fossils - 7th Grade Electionskellywms.weebly.com/uploads/5/4/9/0/54901139/fossils_-_2015.pdf · Fossils are used for examining Earths History. • The fossil record provides evidence](https://reader033.vdocuments.net/reader033/viewer/2022052017/60307bc74da0f716ef22850c/html5/thumbnails/4.jpg)
5 types of Fossils
• Petrified
• Mold and Cast
• Carbon film
• Trace
• Preserved remains
![Page 5: Fossils - 7th Grade Electionskellywms.weebly.com/uploads/5/4/9/0/54901139/fossils_-_2015.pdf · Fossils are used for examining Earths History. • The fossil record provides evidence](https://reader033.vdocuments.net/reader033/viewer/2022052017/60307bc74da0f716ef22850c/html5/thumbnails/5.jpg)
Petrified
• Water fills spaces in bones with minerals
![Page 6: Fossils - 7th Grade Electionskellywms.weebly.com/uploads/5/4/9/0/54901139/fossils_-_2015.pdf · Fossils are used for examining Earths History. • The fossil record provides evidence](https://reader033.vdocuments.net/reader033/viewer/2022052017/60307bc74da0f716ef22850c/html5/thumbnails/6.jpg)
Cast and Mold
• An imprint is left in the rock, and then filled in with minerals
![Page 7: Fossils - 7th Grade Electionskellywms.weebly.com/uploads/5/4/9/0/54901139/fossils_-_2015.pdf · Fossils are used for examining Earths History. • The fossil record provides evidence](https://reader033.vdocuments.net/reader033/viewer/2022052017/60307bc74da0f716ef22850c/html5/thumbnails/7.jpg)
MOLDS AND CASTS• A mold forms when hard parts of an
organism are buried in sediment,
such as sand, silt, or clay.
• The hard parts completely dissolve
over time, leaving behind a hollow
impression with the organism’s
shape.
MOLD FOSSILThis mold, or imprint, is of
an extinct mollusk called
an ammonite.
• A cast forms from a mold.
• Water with dissolved minerals and
sediment fills the mold’s empty
spaces.
• Minerals and sediment that are left
in the mold make a cast.
CAST FOSSILThis ammonite cast was
discovered in the United
Kingdom.
![Page 8: Fossils - 7th Grade Electionskellywms.weebly.com/uploads/5/4/9/0/54901139/fossils_-_2015.pdf · Fossils are used for examining Earths History. • The fossil record provides evidence](https://reader033.vdocuments.net/reader033/viewer/2022052017/60307bc74da0f716ef22850c/html5/thumbnails/8.jpg)
Carbon Film
• Only the carbon is left from the organism
![Page 9: Fossils - 7th Grade Electionskellywms.weebly.com/uploads/5/4/9/0/54901139/fossils_-_2015.pdf · Fossils are used for examining Earths History. • The fossil record provides evidence](https://reader033.vdocuments.net/reader033/viewer/2022052017/60307bc74da0f716ef22850c/html5/thumbnails/9.jpg)
Trace
• Evidence left by the animal
![Page 10: Fossils - 7th Grade Electionskellywms.weebly.com/uploads/5/4/9/0/54901139/fossils_-_2015.pdf · Fossils are used for examining Earths History. • The fossil record provides evidence](https://reader033.vdocuments.net/reader033/viewer/2022052017/60307bc74da0f716ef22850c/html5/thumbnails/10.jpg)
Preserved remains
• Organism remains close to what it was in life (Usually preserved in amber, ice, etc.)
![Page 11: Fossils - 7th Grade Electionskellywms.weebly.com/uploads/5/4/9/0/54901139/fossils_-_2015.pdf · Fossils are used for examining Earths History. • The fossil record provides evidence](https://reader033.vdocuments.net/reader033/viewer/2022052017/60307bc74da0f716ef22850c/html5/thumbnails/11.jpg)
How do we know how old fossils are?
• Relative dating – Use rock layers to determine which are older and younger
• Absolute dating – Find the actual age of the fossil. One way we do this is carbon dating. All organisms have some radioactive carbon in them and after they die this starts to decay. We can determine how much is left and this tells us the approximate age.
![Page 12: Fossils - 7th Grade Electionskellywms.weebly.com/uploads/5/4/9/0/54901139/fossils_-_2015.pdf · Fossils are used for examining Earths History. • The fossil record provides evidence](https://reader033.vdocuments.net/reader033/viewer/2022052017/60307bc74da0f716ef22850c/html5/thumbnails/12.jpg)
Geologic Time
![Page 13: Fossils - 7th Grade Electionskellywms.weebly.com/uploads/5/4/9/0/54901139/fossils_-_2015.pdf · Fossils are used for examining Earths History. • The fossil record provides evidence](https://reader033.vdocuments.net/reader033/viewer/2022052017/60307bc74da0f716ef22850c/html5/thumbnails/13.jpg)
How fossils give us clues about
Earth’s history• Fossils are a part of that existing ecology that are also
left behind. It can tell us much about its environmental settings.– Includes plant material, animal remains, rocks and minerals.
![Page 14: Fossils - 7th Grade Electionskellywms.weebly.com/uploads/5/4/9/0/54901139/fossils_-_2015.pdf · Fossils are used for examining Earths History. • The fossil record provides evidence](https://reader033.vdocuments.net/reader033/viewer/2022052017/60307bc74da0f716ef22850c/html5/thumbnails/14.jpg)
Fossils are used for examining
Earths History.• The fossil record provides
evidence about the history of life and past environments on Earth.
• The fossil records also show how different groups of organisms have changed/evolved over time.
• Fossils of many different
kinds of organisms were
formed in this ancient
lakeshore environment that
existed in Wyoming about
50 million years ago.
![Page 15: Fossils - 7th Grade Electionskellywms.weebly.com/uploads/5/4/9/0/54901139/fossils_-_2015.pdf · Fossils are used for examining Earths History. • The fossil record provides evidence](https://reader033.vdocuments.net/reader033/viewer/2022052017/60307bc74da0f716ef22850c/html5/thumbnails/15.jpg)
IMPORTANT IDEA!!!
The deeper we dig,
the farther back in time we see. (IF the rocks
have not been changed)
![Page 16: Fossils - 7th Grade Electionskellywms.weebly.com/uploads/5/4/9/0/54901139/fossils_-_2015.pdf · Fossils are used for examining Earths History. • The fossil record provides evidence](https://reader033.vdocuments.net/reader033/viewer/2022052017/60307bc74da0f716ef22850c/html5/thumbnails/16.jpg)
Geologic Column- Everywhere in the world we see similarities in fossils.
• Mammals• Reptiles / Dinosaurs• Amphibians• Fish
• Insects• Land Plants
• Primitive Marine Animals• Trilobites
• Single-celled organisms
Life started as just bacteria and evolved from there into the species we see today.
![Page 17: Fossils - 7th Grade Electionskellywms.weebly.com/uploads/5/4/9/0/54901139/fossils_-_2015.pdf · Fossils are used for examining Earths History. • The fossil record provides evidence](https://reader033.vdocuments.net/reader033/viewer/2022052017/60307bc74da0f716ef22850c/html5/thumbnails/17.jpg)
Where would we find fossils most like those alive today? Why?
![Page 18: Fossils - 7th Grade Electionskellywms.weebly.com/uploads/5/4/9/0/54901139/fossils_-_2015.pdf · Fossils are used for examining Earths History. • The fossil record provides evidence](https://reader033.vdocuments.net/reader033/viewer/2022052017/60307bc74da0f716ef22850c/html5/thumbnails/18.jpg)
![Page 19: Fossils - 7th Grade Electionskellywms.weebly.com/uploads/5/4/9/0/54901139/fossils_-_2015.pdf · Fossils are used for examining Earths History. • The fossil record provides evidence](https://reader033.vdocuments.net/reader033/viewer/2022052017/60307bc74da0f716ef22850c/html5/thumbnails/19.jpg)
MASS EXTINCTION
MASS EXTINCTION
MASS EXTINCTION
MASS EXTINCTION
Range of Global Biodiversity PeriodEra
QUATERNARY
TERTIARY
CRETACEOUS
JURASSIC
TRIASSIC
PERMIAN
CARBONIFEROUS
DEVONIAN
SILURIAN
ORDOVICIAN
CAMBRIAN
We can tell from the fossil record that 90% of all species that have lived are now extinct. There have been MANY major extinctions over time.
![Page 20: Fossils - 7th Grade Electionskellywms.weebly.com/uploads/5/4/9/0/54901139/fossils_-_2015.pdf · Fossils are used for examining Earths History. • The fossil record provides evidence](https://reader033.vdocuments.net/reader033/viewer/2022052017/60307bc74da0f716ef22850c/html5/thumbnails/20.jpg)
MASS EXTINCTION
MASS EXTINCTION
MASS EXTINCTION
MASS EXTINCTION
Range of Global Biodiversity PeriodEra
QUATERNARY
TERTIARY
CRETACEOUS
JURASSIC
TRIASSIC
PERMIAN
CARBONIFEROUS
DEVONIAN
SILURIAN
ORDOVICIAN
CAMBRIAN
![Page 21: Fossils - 7th Grade Electionskellywms.weebly.com/uploads/5/4/9/0/54901139/fossils_-_2015.pdf · Fossils are used for examining Earths History. • The fossil record provides evidence](https://reader033.vdocuments.net/reader033/viewer/2022052017/60307bc74da0f716ef22850c/html5/thumbnails/21.jpg)
Why do you think there have been so many extinctions? What can we learn from extinct species?
Why do animals change over time? Why are the animals of today different from the animals of the past?
![Page 22: Fossils - 7th Grade Electionskellywms.weebly.com/uploads/5/4/9/0/54901139/fossils_-_2015.pdf · Fossils are used for examining Earths History. • The fossil record provides evidence](https://reader033.vdocuments.net/reader033/viewer/2022052017/60307bc74da0f716ef22850c/html5/thumbnails/22.jpg)
Index Fossil dating
• Some types of organisms only live for a short period of time. If we know when and how long they lived then if we see fossils of them we know the time period of the rock.
416 to 359 million years ago
540 million years ago 145.5 to 65.5 million years ago
![Page 23: Fossils - 7th Grade Electionskellywms.weebly.com/uploads/5/4/9/0/54901139/fossils_-_2015.pdf · Fossils are used for examining Earths History. • The fossil record provides evidence](https://reader033.vdocuments.net/reader033/viewer/2022052017/60307bc74da0f716ef22850c/html5/thumbnails/23.jpg)
Where is the index fossil?
Find the layer with afossil that only
appears in that one layer
Here it is!!!
***The yellow spiral shell fossil only appears
in this single layer. If we know when this
critter lived, when know exactly when this
layer was deposited! And we can make
estimates of when the layers above and below
were deposited as well!
The layers of strata are numbered along this side
The types of fossilsAre indicated here