Earth Science Chapter 12-13

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Geologic time is divided into units based upon types of organisms
This is produced when sediments fill in a cavity that was left when an object decayed cast
Remains, imprints, or traces of once-living organisms fossils
Today, many scientists think that dinosaurs evolved from reptiles and birds evolved from dinosaurs
The end of the Paleozoic Era was signaled by _______ of land and sea animals mass extinctions
A life-form that evolved during the Mesozoic Era dinosaur
One way to correlate rock layers is to use fossil evidence
A creature is _______ if there are no living members of its kind extinct
The longest division in geologic time is a (n) era
Humans appeared in the Cenozoic Era
Species today are becoming extinct at a greater rate than in the past because of activity by humans
A gradual change in life-forms through time is called evolution
Plate tectonic during the Mesozoic Era caused Pangaea to separate
A petrified bone is composed of minerals
Only a radioactive _______ will have a half-life isotope
Fossils of thin layers of carbon atoms and molecules are carbon films. True
A process that uses the properties of atoms in rocks and other objects to determine their ages is relative dating False, absolute dating
A mold is produced when sediments fill a cavity made when an object. False, cast
Gaps in rock records made when agents of erosion remove existing rock layers is an unconformity. True
A state of species that is no longer has any living members is extinct. True
Explain why a clay layer rich in iridium might explain why the dinosaurs became extinct? It is evidence of a large meteorite hitting the earth that sent up lots of ash and dust. This blocked out the sun and Earth cooled. So the dinosaurs became extinct
What happened to the continents at the end of the Paleozoic? They were all together Pangaea

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