Presentation on theme: "Paleontology The study of ancient life! Fossil Picture Here."— Presentation transcript:
Paleontology The study of ancient life! Fossil Picture Here
Paleontology Fossils are any evidence of ancient organisms. What can we learn from them? –They can help us study how evolution has created and changed life forms on Earth. –They can be used to determine relative geologic ages. –They tell us about ancient climates and sedimentary environments Sedimentary environments can include lakes, rivers, beaches, deep oceans, etc. –They can help determine the positions of Earth’s lithospheric plates during the geologic past.
How is evidence of life preserved? Body fossils Trace fossils Trace Fossil Picture Here Body Fossil Picture Here
Body Fossils Body fossils are any direct evidence of prehistoric life: –This includes whole bodies of animals, plants, or other organisms –Or any parts of bodies such as shells, bones, or teeth Petrified wood picture here Shark tooth picture here Fossilized Shells picture here
Trace Fossils Trace fossils are any indirect evidence of prehistoric life. This includes tracks, trails, burrows, boreholes, bite marks, and coprolites Trace fossils are useful for studying the behavior of ancient organisms.
COPROLITES (fossil poop) Coprolite picture here
Fossilization What is necessary to preserve a body fossil? 1.Hard parts! (bone, teeth, shell, wood)… Hard parts stand a greater chance of preservation than do soft tissues (skin and muscle) because soft parts readily decay or decompose after death.
2. Rapid burial Rapid burial helps to prevent decomposition, erosion, and disarticulation (separation of the body parts or bones). Picture of disarticulation here
Fossilization Body fossils are preserved as: –Unaltered remains Calcified skeletons Mummification Fossils in amber Frozen fossils Fossils in tar –Altered remains Petrification (Replacement) Permineralization or Recrystallization Dissolution Carbonization
Unaltered remains Many marine organisms build their skeletons with the mineral calcite, which is stable over geologic time. Unaltered fossil picture here
MUMMIFICATION An organism may dry out so fast that their soft parts don’t have time to decay Mummy picture here
FOSSILS IN AMBER Amber is fossilized tree sap. If an insect gets caught in the sap, it may become part of the fossil. Insect in amber picture here
FROZEN FOSSILS Animals may get trapped in ice and preserved. Wooly mammoths have been found preserved this way. Frozen animal (wooly mammoth) picture here
FOSSILS IN TAR Animals may have been stuck in naturally occurring pools of tar. A famous example is the La Brea tar pits in CA. Fossil in tar picture
Altered: Petrification or Replacement This is the removal of the original skeleton material and replacement by another mineral. –Example: calcite shells that are replaced with pyrite. Fossil replaced by pyrite
Altered: Permineralization and Recrystallization This is the filling of pore spaces in porous material such as wood or bone by the precipitation of minerals from water. –Example: petrified wood, or dinosaur bones Petrified wood picture here
Altered: Dissolution This is the dissolving of the original skeleton, leaving a hollow impression called a mold. A cast of the object is formed when the sediment fills in the mold and becomes rock. Mold and Cast pictures
Altered: Carbonization This is where the only compounds left of the organism is a carbon film in rock. Carbon film fossil picture here
INDEX FOSSILS Fossils of organisms that lived during a relatively short time. They help to give a relative age to rock layers. –Ammonites and Trilobites are examples of index fossils. Ammonite and Trilobite fossil here
Stratigraphic column Picture of a real stratigraphic column, preferably with fossils labeled