Fossils Mr. Morris Science

What is a fossil? A fossil is the naturally preserved remains of a once living organism.

A fossil may be: an original skeleton or shell; a mold or cast; material that has replaced the once living thing; traces such as footprints or worm tubes

What conditions promote fossilization? Hard body parts such as skeletal bones or exoskeletons

What conditions promote fossilization? Rapid burial and/or lack of oxygen

Paleontology is much more than finding dinosaur bones like Dr Paleontology is much more than finding dinosaur bones like Dr. Grant did in the movie Jurassic Park. Fossils can be found on all seven continents and even right here in North Carolina.

Paleontology and You Paleontology is the scientific study of the fossilized remains of early life on Earth. The remains can be from different types of life, such as… Animals Plants Bacteria Fungus (Stromatolite)

Paleontology and You Paleontologist Archeologist VS. A Paleontologist is not the same as an Archeologist. Paleontologist Archeologist Studies fossilized remains of early life Studies prehistoric people and their culture VS.

What is a Fossil? A fossil is any remains, traces, or imprints of life that has been preserved at some time in the geologic past. Fossils must be at least ten thousand years old. Only a very small number of organisms get fossilized. The two main types of fossils are… 1. body fossils 2. trace fossils (coprolite)

What are the fossil types? Body fossils – actual parts of an organism, unaltered or altered bones, shells, leaf imprints Trace fossils – evidence of life that is not a body fossil tracks, burrows, casts

Body fossils

Body Fossils 1. Body Fossils are the actual body or body parts of an organism that has been preserved. These fossils may or may not be altered (fossils that have gone through a chemical change or physical change). The two main types of body fossils are (A) unaltered remains and (B) altered remains… (gastropod) A. Unaltered remains of fossils means that the remains have gone through little or no chemical or physical change. There are seven main types of unaltered remains of fossils…

Body Fossils Let’s look at the seven main types of unaltered remains of fossils… Unaltered remains of fossils have gone through little or no chemical or physical change. Fossils must also be at least ten thousand years old. The types of unaltered remains of fossils are… - Original skeletal material - Tar impregnation - Amber Entombment - Refrigeration/Ice - Desiccation/Mummification - Volcanic ash - Bogs

Body Fossils A. Unaltered remains - Original skeletal material: this means that the hard parts of the organism are preserved as the original material. (Ammonite) (gastropod)

(saber-toothed cat skull) Body Fossils A. Unaltered remains - Tar impregnation: tar pits are excellent areas to preserve life as a fossil. La Brea tar pits in California is one of the most famous areas because of the large number of preserved life forms found in it. (saber-toothed cat skull)

Body Fossils A. Unaltered remains - Amber entombment: some trees make a sticky and thick liquid called “pitch” or “resin.” Small animals such as insects and spiders or plant seeds and spores can get trapped in the pitch and become preserved. If this gets buried it can become amber.

Body Fossils A. Unaltered remains - Refrigeration or frozen in ice: doesn’t mean putting it in the fridge. Animals can get trapped in cracks of ice sheets, called glaciers, and freeze. Mammoths have been found frozen in ice. (This mammoth died in ice 39,000 years ago)

Body Fossils A. Unaltered Mummification - quickly dried material Frozen in ice – material is trapped inside ice and tissue is preserved

Body Fossils A. Unaltered -Volcanic Ash Gas – ash – lava from a Stratovolcano

Body Fossils – A. Unaltered Bogs – dark color

What are the modes of fossil preservation? Altered Permineralization – pores in tissue are filled by minerals Replacement or petrification – replacement of tissue with minerals

What are the modes of fossil preservation for body fossils? Altered Carbon film or imprint – tissue material is decomposed or reduced to a film of carbon Recrystalization – minerials recrystalized to rock

Body Fossils B. Altered remains of fossils means that the organisms have gone through chemical or physical change. - Permineralization: means that the hard parts of bones, shells and plants have microscopic (too small to see with our eyes) holes in them. When these hard parts are buried, water that has dissolved minerals in it can soak into the hard parts and collect on them. Can you see the how well the pine cone is preserved? (fossil pine cone cut in half) (fossil pine cone) (dinosaur bone)

Body Fossils B. Altered remains - Replacement or petrification: means that groundwater with dissolved minerals in it can replace the hard parts of buried organisms with minerals. (ammonite) (log)

Body Fossils B. Altered remains - Recrystallization: means that there is a chemical change of the atoms that make up the hard parts of the organism. In this ammonite, the hard parts have been changed to Calcite, a mineral.

Body Fossils B. Altered remains The soft parts of organisms might also get preserved. - Carbonization or Carbon Imprint: when the soft parts of organisms get buried in sediment, they can get squeezed and preserved. (cockroach) (fish) (leaf)

Body Fossils Let’s review the four main types of altered remains of fossils… Altered remains of fossils means that the organisms have gone through chemical or physical change and must be at least ten thousand years old. The types of altered remains of fossils are… - Permineralization - Replacement - Recrystallization - Carbonization

Let’s review Body Fossils Do you remember what body fossils are? They are the actual body or body parts of an organism that has been fossilized. Do you remember what the two types of body fossils are? The first type is the unaltered remains of fossils that have gone through little or no chemical or physical change. The second type is the altered remains of fossils that have gone through chemical or physical change. Now, we are going to talk about trace fossils.

Trace Fossils 2. Trace Fossils are not the actual body or body parts of life that has been preserved. These fossils show how an organism lived, how it moved, what its feet looked like, how it raised its offspring (its children), what it ate and what its shape was. There are six main types of trace fossils… (gastropod cast) Track trail tube burrow nest eggs, life activities

Trace Fossils 2. Trace Fossils - Mold: This isn’t the green fuzzy stuff that grows on old food. In paleontology, a mold is the imprint that an organism makes in the sediment as it is fossilized. When you push your finger into clay, the hole you made is the mold. (Mold of a fossil seed) (gastropod mold) This fossil seed was found in Nueces County.

Trace Fossils 2. Trace Fossils - Cast: A cast is the same shape as the original organism. Not all organisms will have these. Casts are formed when the original parts are all dissolved away and the empty space is filled with sediment or minerals. None of the original material is in the cast. (Cast of a fossil seed) (gastropod cast)

Trace Fossils 2. Trace Fossils - Burrows: These trace fossils show how an animal such as a worm (an annelid) moved through the soft sediment. This worm tube trace fossil is hollow (the hole goes all the way through it).

Trace Fossils 2. Trace Fossils - Tracks: can show how an animal moved and what its footprint looked like. These tracks can tell us a lot about the animal that made them in the geologic past. (trilobite tracks) (Dinosaur tracks) Do you see the people? (trilobite)

Trace Fossils 2. Trace Fossils Ok, now we’re going to talk about a fun trace fossil… - Coprolite: This is fossilized poop, called dung. Don’t worry, it’s ok to touch it because it has been turned to stone. Coprolite can tell a lot about how an animal ate and what it hunted.

Do you remember what trace fossils are? Let’s review Trace Fossils Do you remember what trace fossils are? They are not fossilized body or body parts. Trace fossils help us find out what prehistoric life was like. Do you remember what the six types of trace fossils are? - Mold - Cast - Burrow - Track - Coprolite

Trace Fossils

More on trace fossils Mold – reproduction of the inside or outside surface of a living thing Cast – duplicate of the original organism; usually formed by replacement of inside of living thing

More on trace fossils Burrows or borings – Spaces dug out by living things and preserved as is or filled in

More on trace fossils Gastroliths – smooth stones from abdominal cavity of dinosaurs Coprolites – fossilized excrement; usually preserved by replacement

More on trace fossils Tracks – impressions of passage of living things

Paleontology and You Why should we study paleontology? Paleontology helps us to find out what Earth was like in the geologic past. Studying fossils helps us to find out the age of rocks. Paleontology also helped to prove that the continents move and were all connected together about 300 mya (Pangaea). . It helps us to find out what animals, like dinosaurs, were like. The study of paleontology also made it possible to make the movies “Jurassic Park” and “Walking with Dinosaurs.”

How is a fossil made? Ok, now that we have talked about body fossils, trace fossils and pseudofossils, let’s talk a little bit about how a fossil is made. Only a small number of organisms get fossilized. This is because they must be preserved under special conditions. In general, dead organisms that… get buried in soft sediment quickly… and have hard parts have a better chance to get preserved. The soft parts of dead organisms that… get buried in soft sediment with little or no oxygen help to preserve those soft parts. Little or no oxygen means that there will not be many bacteria to eat the soft parts.

So lets study geology and paleontology!!! (turtle)