Oldest Rock Found on Earth

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1a) Where are the oldest rocks found on Earth? The oldest found whole rocks were found in the Nuvvuagittuq greenstone belt in northern Quebec along the east shore of the Hudson Bay. Samples taken from this site indicate an age of 3.8 to 4.28 billion years old, and were confirmed by measuring small variations in isotopic compositions of neodymium and samarium in the rocks. Older grains of minerals, called zircons, have also been found in Western Australia, with ages of 4.36 billion years. National Science Foundation (NSF) News – Oldest Known Rock on Earth Discovered: https://www.nsf.gov/news/news_summ.jsp?cntn_id=112299 1b) Are there other types of radiometric dating other than uranium to lead? There are many types of radiometric dating, such as radiocarbon dating which is based on the radioactive decay of 14C in organic materials, with an accuracy topping out at less than 70,000 years. Similar methods measure the decay of Potassium-40 to Argon-40, Thorium-232 to Lead-208, Samarium-147 to Neodymium-143, and others. Another way to date materials is by measuring the accumulation of electrons, dislodged by radiation, that have become trapped in imperfections in the crystal structure of the material being measured. Examples of this type of dating are Luminescence and electron spin resonance. Nature – Dating Rocks and Fossils Using Geologic Methods: http://www.nature.com/scitable/knowledge/library/dating-rocks-and-fossils-using-geologic-methods-107924044 2a) Have other important transitional fossils have been found? One set of transitional fossils details the evolution from reptiles to mammals. Dimetrodon lived between 280 million years ago (mya) and 265 mya, had a sail on its back which allowed for partial regula... ... middle of paper ... ...-resistant CCR5-Δ32 allele formed by a breakdown of the pathocenosis due to the historical Roman expansion?: http://sharc.sums.ac.ir/icarusplus/export/sites/sharc/unpload/6.pdf Evaluating plague and smallpox as historical selective pressures for the CCR5-Δ32 HIV-resistance allele: http://www.pnas.org/content/100/25/15276.long Detection of the CCR5-Delta32 HIV resistance gene in Bronze Age skeletons: http://www.ncbi.nlm.nih.gov/pubmed/15815693/ 6b) What type of mutation lead to this allele? The CCR5-Δ32 gene is the name of the allele discussed in the video, as eluded to by its name it resulted from a frameshift mutation that occurred in the CCR5 gene resulting in the deletion of 32 base pairs (Δ32). THURJ | Engineering recombinase enzymes to emulate the CCR5-Δ32 mutation conferring resistance to HIV-1 infection: http://thurj.org/research/2011/02/1238/

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