MEA 100 Lecture Notes - Lecture 5: Cosmic Dust, Earth Structure, Radiometric Dating
31 Jan 2019
School
Department
Course
Professor
Document Summary
How did life emerge on earth? from the evidence scientists have hypothesized that life developed in two phases over the past 4. 7-4. 8 billion years two phases: 4. 6-4. 7 billion years ago a cloud of cosmic dust condensed into the earth the heat produced by the radioactive decay of chemical elements in its interior. Comets pierced crust, allowing products and energy to erupt. Gases released from earth"s interior formed the atmosphere this turned molten from. Most widely believed hypothesis: organic molecules form from inorganic molecules from inner parts of earth. Building block organics formed from formation over many years. How do we know what organisms lived in the past? fossils, primary source of knowledge of extinct organisms. What they looked like represent only 1% of species that ever lived. Material in cores drilled out of buried ice. Major driving of adaptation or evolution (the change in a population"s genetic makeup) 1st step of evolution: the development of genetic variability in a population.
