Fossils

Fossils

Hello!I am Stephen Bornheimer Indiana EducatorYou can find me at:Twitter: @MrBornheimerWebsite: http://bclassroom.com

Topics1. Overview2. What are fossils?3. How are fossils formed?

a. Deathb. Decay and Burialc. Uplift and Exposured. Fossilized Amber

4. Discovery and Extractiona. Paleontology b. Animation

5. Types of Fossilsa. Petrificationb. Carbon Filmsc. Molds and Castsd. Impressionse. Amberf. Trace Fossils

6. Usesa. Fossil Record and Datingb. Principle of Fossil Succession & Index Fossils

7. Resources and Citations

Overview

2.What are Fossils?

What are Fossils?

▧ Fossils: the physical remains or traces of prehistoric life.

▧ Prehistoric refers to a time before recorded human history, however there is no defined age at which a life form or traces of that life form are considered fossilized.

3.How are fossils formed?

Death

Fossilization usually begins when an organic lifeform (like this fish) dies and settles to the ground (or aquatic floor).

Decay and Burial

Most organic life forms once they die, begin a process of decomposing. In order for fossilization to take place the remains need to be buried under sediment in a relatively short period of time. This way the skeletal remains will not be disturbed or scattered by scavengers.

Decay and Burial

Overtime, the skeletal remains become buried. Water and other gases are “squeezed” out of the remains due to increasing pressure. Many of the organic components of the original skeleton are dissolved and voids are left in the remains.

Decay and Burial

Minerals in the surrounding sediment migrate and fill in the voids in a process called permineralization. In time, increased pressure eventually results in lithification (the formation of sedimentary rock).

Uplift and Exposure

In time, the fossilized remains (which are now part of the rock) undergo tectonic activity and through uplift, weathering and erosion the fossil becomes exposed.

Fossilized Amber

Watch 1:20 - 1:47 for Relevant Clip (Note: Tree sap is used wrongly here. It should be tree resin).

4.Discovery and Extraction

PaleontologyOnce exposed, fossils are excavated by humans. Scientists that study prehistoric life and fossils to determine how organisms lived and interacted are called paleontologists.

It should be noted that while archeologists also extract and study remains from the ground. Paleontologists study prehistoric organisms and life forms whereas archeologists study past human activity.

Animation

5.Types of Fossils

Types of Fossils

PetrificationThe process by which organic matter exposed to minerals over a long period is turned into a stony substance.

Carbon FilmsA fossil formed when organic material is compressed, leaving only a carbon residue or film. This is also known as a carbonaceous film or compression.

Molds and CastsOrganisms trapped in layers of sediment may dissolve away leaving a preserved 3D cavity (mold) or if this cavity fills with sediment, a cast may be formed.

ImpressionsImpressions are shallow 2D molds that give insight into biological activity, however unlike compressions/carbon films, they contain NO organic material.

AmberAmber is fossilized tree resin. Some resins trapped organic lifeforms like insects before becoming fossilized.

Trace FossilsAre fossilized traces of animals like burrows, footprints, or feces (coprolites) that have been preserved in sediment.

PetrificationPetrified Forest National Park

PetrificationPetrified wood is unique. Unlike other fossilized plant remains, petrified wood is a 3D representation of the plant material with fossilized stem tissue. It is not just an impression or mold but instead exhibits amazing detail and structure.

Place your screenshot here

Carbon FilmsFossilized seed

fern leaves from northeastern Ohio

Place your screenshot here

Carbon Films/Compression FossilsOver time the remains of organisms (particularly small organisms like plants and insects) are compressed in the stone. AS a result much of the organic matter turns into a fine carbon film that is pressed into the stone. This is often a very shallow 2D fossil.

Molds & Casts

Ammonite Mold and Cast (Whitby,

Yorkshire, England)

Place your screenshot here

Casts and MoldsWhen organisms get buried in sediment they become entombed. Overtime, the organism decomposes leaving a cavity that can be filled by sediment to create a cast. Molds and casts are important because they can accurately portray surface anatomy which can tell scientists much about how the organism moved, behaved, and lived.

Impressionsand Trace Fossils

Impressions and Trace FossilsThese fossils are remnants of animal movement, and life

as imprinted on their surroundings at the time of their demise. These types of fossils give us a good indication of the way creatures lived, moved, and interacted with their

environment.

Amber

AmberAmber is fossilized tree resin that has encased and preserved small organisms like plants and insects. This is an ideal form of preservation because not only does it give us a look at prehistoric creatures but we have a clear three dimensional model of their anatomy.

6.Uses for Fossils

Fossil Record and Dating▧ Fossils occur in very specific rock strata.

▧ Fossils of the same species are found in rock of the same age.

▧ Rock layers are successive (layers further down are older)

▧ Fossils are collected and help to determine the age and former characteristics of prehistoric environments.

Index Fossils“These fossils are widespread

geographically and are limited to short geologic time spans.”

Principle of Fossil Succession

“Fossil organisms succeed one another in a definite and determinable order, and therefore, any time period can be recognized by its fossil content.”Page 448 (Text)

Thanks!

Any questions?

You can find me at:@mrbornheimer

http://bclassroom.com

Credits

Special thanks to all the people who made and released these awesome resources for free:▧ Busy Icons by Olly Holovchenko▧ Presentation template by SlidesCarnival▧ Photographs by Unsplash▧ Backgrounds by Pixeden

Cited Resources

Works Cited

"Amber." Wikipedia. Wikimedia Foundation, 30 Nov. 2014. Web. 30 Nov. 2014. <http://en.wikipedia.

org/wiki/Amber>.

"Carbonaceous Film." Wikipedia. Wikimedia Foundation, 29 Nov. 2014. Web. 30 Nov. 2014. <http://en.

wikipedia.org/wiki/Carbonaceous_film>.

"Fossils and Earth's History." Fossils and Earth's History. Desire2Learn.com, n.d. Web. 30 Nov. 2014. <https:

//gcps.desire2learn.com/d2l/lor/viewer/viewFile.d2lfile/15538/6268/FOSSILS_print.html>.

"Fossils." BBC News. BBC, 2014. Web. 29 Nov. 2014. <http://www.bbc.co.uk/nature/fossils>.

"Fossils: Window to the Past." Fossils. University of Berkeley, n.d. Web. 30 Nov. 2014. <http://www.ucmp.

berkeley.edu/paleo/fossilsarchive/permin.html>.

Cited Resources

"Paleontology." Wikipedia. Wikimedia Foundation, 30 Nov. 2014. Web. 30 Nov. 2014. <http://en.wikipedia.

org/wiki/Paleontology>.

Shepherd, Roy. "What Is a Fossil?" DISCOVERING FOSSILS. N.p., 2002. Web. 29 Nov. 2014. <http://www.

discoveringfossils.co.uk/whatisafossil.htm>.

"Trace Fossil." Wikipedia. Wikimedia Foundation, 29 Nov. 2014. Web. 29 Nov. 2014. <http://en.wikipedia.

org/wiki/Trace_fossil>.

Viney, Mike. "Molds & Casts." Molds & Casts. The Virtual Petrified Wood Museum, 2008. Web. 30 Nov.

2014. <http://petrifiedwoodmuseum.org/moldscasts.htm>.

Walters, A. "Main Menu." Modes of Fossil Preservation. University of Oregon, 19 July 2013. Web. 30 Nov.

2014. <http://blogs.uoregon.edu/geology304fossilpreservation/2013/07/19/compressionimpression-

2/>.