Nate Slow Change

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by nate457698
Last updated 5 years ago

Discipline:
Science
Subject:
Geostudies
Grade:
7

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Nate Slow Change

430 mya - 248 mya

Earths Slow Change

How Do Scientists Date Fossils?

570 mya - 430 mya

Mesozoic Era

240 mya - 150 mya

Cenozoic Era - 65 mya - today

Cooksonia plant 1st known plant fossil found in Ireland. Amphibians emerge from water. Tiktaalik fossil discovered in Canadian artic. Single supercontinent Pangaea. Earliest reptile fossil anapsid discovered in Nova Scotia.

Cambrian explosion occurs. First vertebrae,hardshelled molusks, fish evolve, In 1990, 530 mil yr old fossil discovered in shale bed in China. New Brunswick in Canada has oldest fish fossil found. Trilobite fossil found in Burgess Shale in BC.

picture of oldest Fossil found in China

150 mya - 65 mya

Dinosaurs first arrived. 1st dinosaur fossil later found in Madagascar. Panagea supercontinent breaks up. Europe separates from Africa. South America pushed away from North America.

Birds take flight. Flowering plants. In 1861 a fossil of Archaeopteryx was found in Germany. Dinosaurs go extinct. 50% of animals and plants disappear. Meteor or valcano?

Most major mammal groups emerge. 55 million years ago primates appear.

Trilobite

Dating FossilsLaw of superposition says that the oldest layers of rock are on the bottom and the youngest on the top. The rock surrounding the fossil is usually layered. Paleontologists or geologists look at the layer of rock on the fossil itself to figure out the age. Fossils are almost always found in ice, tar, amber and sedementary rock.Carbon or radiocarbon dating measures the decay of various isotopes like uranium- 238 and thorium-232 in rocks to determine their absolute ages.Fossils are abiotic meaning they were once living. You can only carbon date living things up to 70,000 years old. So thats why scientists started carbon dating the rocks surround the fossil itself. They learned that they could get the exact age of the fossil because there was no limitation to carbon dating for rocks.

Sources: http://science.nationalgeographic.com/science/prehistoric-world/prehistoric-time-linehttp://www.fossilmuseum.net/Fossil_Sites/Chengjiang.htmhttp://www.trilobites.info/Burgess.htmhttp://tiktaalik.uchicago.edu/meetTik.htmlhttp://humanorigins.si.edu/evidence/datinghttp://www.concord.org/~btinker/GL/web/geology/english/dating_rocks.htm

Types of Fossilsimprint fossils when an object or organism makes an imprint on sediment and that sediment hardens into a stone creating an imprint fossil.cast fossil when minerals fill the imprint an organism hast left behind creating a cast of the organisms imprint. actual remains when the intact body of an organism falls into ice amber or tar..petrified wood when minerals take the place of wood creating a harder lookalike of the original wood or a mineral fossil.

Paleozoic Era

Tiktaalik fossil

Largest extinction ever. 95% marine species, 70% of land animals wiped out.

Hominins

Paleontologists are scientists that study prehistoric life and preserved fossils they figure out the evolution of these animals from the fossils.

Paleontolgists use small tools as to not damage the fossil these tools are paintbrushes and dental picks and in the field they won't actually dig out the fossil itself they will dig out the rock around the fossil and ship it back to the lab in plaster sheets.

Archaeopteryx Fossil


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