Friday November 16, 2012 (Quiz 12; Complete Lab – The Geologic Time Scale)

The Launch Pad Friday, 11/16/12 What are the names of the eons if we consider there to have been only two in Earth’s history? If the Earth is millions years old, how many years did each eon occupy? What percentage of Earth’s history did each occupy? The Precambrian Eon and the Phanerozoic Eon Precambrian – 3958 million years Phanerozoic – 542 million years Precambrian – 88%, Phanerozoic – 12%

The Launch Pad Friday, 11/16/12 Name an important factor that caused the Precambrian Eon to change to the Phanerozoic Eon. First organisms with shells and other hard body parts Name an important factor that caused the Paleozoic Era to change to the Mesozoic Era. Great Permian extinction Name an important factor that caused the Mesozoic Era to change to the Cenozoic Era. Extinction of dinosaurs and many other species

Assignment Currently Open Summative or Formative? Date IssuedDate Due Date Into GradeSpeed Final Day Quiz 10S511/2 11/16 Video Activity – Fearless Planet – Earth Story F111/611/911/16 Quiz 11S111/9 11/30 WS – Origin of the Atmosphere and Oceans F211/1311/16 Lab – The Geologic Time Scale F311/1411/16

Recent Events in Science Scientists Discover Possible Building Blocks of Ancient Genetic Systems in Earth's Most Primitive Organisms /2012/11/ htm Read All About It! Scientists believe that prior to the advent of DNA as Earth's primary genetic material, early forms of life used RNA to encode genetic instructions. What sort of genetic molecules did life rely on before RNA? The answer may be AEG, a small molecule that when linked into chains forms a hypothetical backbone for peptide nucleic acids, which have been hypothesized as the first genetic molecules. Synthetic AEG has been studied by the pharmaceutical industry as a possible gene silencer to stop or slow certain genetic diseases. The only problem with the theory is that up to now, AEG has been unknown in nature. A team of scientists from the United States and Sweden announced that they have discovered AEG within cyanobacteria which are believed to be some of the most primitive organisms on Earth. Cyanobacteria sometimes appear as mats or scums on the surface of reservoirs and lakes during hot summer months. Their tolerance for extreme habitats is remarkable, ranging from the hot springs of Yellowstone to the tundra of the Arctic.

Quiz 12 After you finish your Quiz, please complete your Lab on the Geologic Time Scale.

Complete Lab- The Geologic Time Scale

Figure The Geologic Time Scale