Fossils I don’t have much of a voice today, so you are going to have to listen closely. Take notes, you will need this for your next test, hopefully Thursday!

What are fossils? Fossils are the petrified remains of ancient objects. Petrified – means turned to stone. Ancient – means very, very old.

Kinds of fossils? Fossils can be of animals, plants, or other objects.

Fossils, big or small….

Brought to you by the Corpus Christi Museum of Science and History Brought to you by the Corpus Christi Museum of Science and History 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… Paleontology and You Animals Plants Bacteria Fungus (Stromatolite)

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

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 three main types of fossils are… 1. body fossils 2. trace fossils (coprolite) 2. pseudofossils

1. Body Fossils are the actual body or body parts of an organism that has been preserved. The two main types of body fossils are (A) unaltered remains and (B) altered remains… Body Fossils A. Unaltered remains of fossils means that the remains have gone through little or no chemical or physical change. There are four main types of unaltered remains of fossils… (gastropod)

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

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.

A. Unaltered remains Body Fossils - Refrigeration: 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 Unaltered remains of fossils have gone through little or no chemical or physical change. Fossils must also be at least ten thousand years old. Let’s review the main types of unaltered remains of fossils… The types of unaltered remains of fossils are… - Original skeletal material Tar impregnation Amber Entombment Refrigeration

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? (dinosaur bone) (fossil pine cone) (fossil pine cone cut in half)

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

Body Fossils Stromatolites – a calcareous mound built up of layers of lime-secreting cyanobacteria and trapped sediment, found in Precambrian rocks as the earliest known fossils, and still being formed in lagoons in Australasia. B. Altered remains

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 - Carbonization: when the soft parts of organisms get buried in sediment, they can get squeezed and preserved. The soft parts of organisms might also get preserved. (fish) (cockroach) (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

They are the actual body or body parts of an organism that has been fossilized. Let’s review Body Fossils 1. Unaltered remains - fossils that have gone through little or no chemical or physical change. 2. Altered remains - 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 five main types of trace fossils… (gastropod cast)

- 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. Trace Fossils 2. Trace Fossils (Mold of a fossil seed) This fossil seed was found in Nueces County. (gastropod mold)

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) (trilobite tracks) (Dinosaur tracks) Do you see the people?

Trace Fossils 2. Trace Fossils - 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. Ok, now we’re going to talk about a fun trace fossil…

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 five types of trace fossils are? - Mold - Cast - Burrow - Track - Coprolite

Pseudofossils Pseudofossils (meaning “fake fossils”) are not fossils at all even though they may look like one. These fossils may look like many different things such as small branches. (dendrite made by a mineral) (fossilized raindrops that hit soft sediment)

Oolitic limestone - limestone consisting of a mass of rounded grains (ooliths) made up of concentric layers. Pseudofossils

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. How is a fossil made? In general, dead organisms that… get buried in soft sediment quickly… and have hard parts have a better chance to get preserved. 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. The soft parts of dead organisms that…

. 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 into supercontinents. It helps us to find out what animals, like dinosaurs, were like.