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1/22/09 Fossil Records Fossil: are the preserved remains or HYPERLINK "http://en.wikipedia.org/wiki/Trace_fossil" \o "Trace fossil" traces of animals, plants, and other organisms from the remote past. Unaltered: similar or the same structure to when it was alive. E.G. Animals in Ice, Insects in amber, Tar pits, mummified. Don?t occur very often. 1% of fossil record Altered: 99% of the fossil records, fossils that are scattered bones that have been preserved differentially particulated. Filled with mineral deposits to show us what was once there. Land dwelling animals were not really fossilized because it was much less likely for his to happen. Neither are humans, much less likely to get entrapped in tar pits, etc. Lucy was an unusual example. Humans haven?t been around long, have a lower fossil record Sites and settlements helped caused fossils to be preserved, but didn?t happen right away Paleoanthropologist have to place things in time Helps show what other creatures were around at the same time Also tract evolution of societies and behaviors Because of this, Anthropologists date fossils and objects Relative Dating: things are placed around/relative to in time. Problems encouraged Chronometric Dating and Techneques. Stratigraphy: refers to the layers of the earth and the order they are layed down, based on super position principle, the layer that is layed down first, is older than the one about it. Requires stratia that represent a long period of time Fluorine Dating: fluorine contents are fond in fossils and artifacts that give it a relatively idea when it died and lived. This is because fluorine is found in the ground Chronometric Dating: Dating method that provides an actual age in years for a defined piece of material or event. Because all such dates are, in statistical terms, estimates, the results are usually reported with a measure of probability, typically expressed as a standard deviation. Measured in B.P. (Before present, considered 1950). Radio Carbon: C14 is absorbed by an organism throughout lifetime, and kept in equilibrium with C12. It ceases to absorb C14 (5,730 half-life) when dies, and turns into C12. Occurs at constant rate/half-life , and measuring the ratio. Measures up to 70,000 b.p. Potassium-Argon : K( Ar, Lava that cools over time has this. Half life (1.3 billion years). Useful in dating things that lived a long, long time ago (500,000-( 3 billion years). Paleomagnetism: study the ancient magnetic field by measuring the orientation of magnetic minerals in rocks and sediments, acquired at the time of their formation. Biostratigraphy: Biostratigraphy is the branch of HYPERLINK "http://en.wikipedia.org/wiki/Stratigraphy" \o "Stratigraphy" stratigraphy which focuses on correlating and assigning relative ages of rock HYPERLINK "http://en.wikipedia.org/wiki/Stratum" \o "Stratum" strata by using the HYPERLINK "http://en.wikipedia.org/wiki/Fossil" \o "Fossil" fossil assemblages contained within them. Usually the aim is correlation, demonstrating that a particular horizon in one geological section represents the same period of time as another horizon at some other section. Evolution: Theory that change happens in the HYPERLINK "http://en.wikipedia.org/wiki/Heritability" \o "Heritability" inherited HYPERLINK "http://en.wikipedia.org/wiki/Trait_%28biology%29" \o "Trait (biology)" traits of a HYPERLINK "http://en.wikipedia.org/wiki/Population" \o "Population" population of organisms from one generation to the next. Developed by Darwin to help explain the ?how we are here??, but not the ?why?? How Evolution came to be Renaissance discoveries Humanists sparked interesting in other countries (Dilettanti) Discovery of the New World, discovery of new cultures Scientific discoveries (showed that there were natural laws) Industrial Revolution, transition to agriculture to manufacturing. Have lots of large gloomy factories, moved things via water and canals. Quarrying caused the ability to discoveries of bones and dinosaurs Geological Influences: the quarrying of coal and iron ore helped to find bones, need to know topography. Understood there was a change and had an ancient past 650 Usher had though it was the earth started in 4004 B.C. Essentialism Earth was changeless Great chain of being