Origin Of The Biosphere - SCI 10 GEOL 3 PDF

**Origin of the Biosphere** **Biosphere** **What is the biosphere?** - The region, on, above, and below the Earth's surface where life exists. - Includes all living (biotic) and non-living (abiotic) organisms **Theories of Abiogenesis** - Suggests that life initially developed from n...

**Origin of the Biosphere** **Biosphere** **What is the biosphere?** - The region, on, above, and below the Earth's surface where life exists. - Includes all living (biotic) and non-living (abiotic) organisms **Theories of Abiogenesis** - Suggests that life initially developed from nonliving materials - Roots in Greek Philosophers - Theory of Spontaneous Generation - Some animals were spontaneously created from non-living substances - Primordial Soup - Alexander Oparin (1900s) - Simple elements complex elements - If energy is added to the gases that made up Earth's early atmosphere, the building blocks of life would be created - Amino acids **Lamarck and Darwin** **Jean Baptiste Lamarck** **The Theory of Use and Disuse** - If the environment changes, behavior changes - A more frequent and continuous use of any organ gradually strengthens, develops and enlarges that organ, and gives it a power proportional to the length of time it has been so used, while the permanent disuse of any organ imperceptibly weakens and deteriorates it, and progressively diminishes it functional capacity until it finally disappears. - Elongated limbless body of the snake, vestigial organs of living animals **Theory of Inheritance of Acquired Characteristics** - Changes in anatomy are inheritable - If an organism changes during life in order to adapt to its environment, those changes are passed on its offspring **Charles Darwin** Geographical location was determining factor for characteristics of species Survival of the fittest - Coined by the Herbert Spencer - All descendants of a progenitor are modified **Fossil Record** - Provides clues on how creatures evolved, how the environment changed, and how creatures are related to one another - Radiometric dating - It is imperfect - The number of species known about through fossils less than 1% of all species that have ever lived - Gaps **Romer's Gap** - an apparent gap in the Paleozoic tetrapod fossil record used in the study of evolutionary biology, which represent periods from which excavators have not yet found relevant fossils. - The biological reality of reality of Romer's gap in both terrestrial vertebrates and arthropods, and has correlated it with a period of unusually low atmospheric oxygen concentration. **Miller-Urey Experiment** - Simulation in 1953 that attempted to replicate the conditions of Earth's early atmosphere and hydrosphere - Test if organic molecules can be created abiogenically - Documented the production of amino acids demonstrating that chemical evolution is possible **Design** - Matter can change phases between liquid and gas - 2 large flasks - 1 filled with water and boiled - 1 equipped with an electrode - Condenser with liquid could fall into a collection trap where samples are taken - Researched would introduce ammonia, hydrogen, and methane gas to cycle in the experiment After a week, the water in the flask simulating the ocean turned brown - Amino acids Proving organic molecules could form under the conditions laid out in the **Oparin-Haldane hypothesis** Scientists now think that the early atmosphere composed mainly of CO2 and N2. Recreating the experiment with this knowledge only produced a few amino acids **Hydrothermal Vents** Hydrothermal vents are the result of sweater percolating down fissures in the ocean crust in the vicinity of spreading centers or subduction zones (places on Earth where two tectonic plates move away or towards one another) - Similar to geysers or hot springs - Occur along mid-ocean ridges - Seawater becomes super-heated by magma - As pressure builds, it dissolved minerals and rinse towards the surface - Hot mineral-rich water exit and mix with the seawater - Minerals cool and solififyy into vent structures **Black Smokers** - Emit the hottest, darkest plumes - High in sulfur **White Smoker** - Emit cooler plumes - Rich in Barium, Calcium, Silicon **Seeps** - Vents with even cooler and weaker flow - "Shimmery" due to temperature or bubble do to gases such as CO2 **Panspermia?** - Suggests that life came from outside Earth - Carried to Earth via meteoroids or other space bodies - Heavily debated - No signs of life elsewhere - Bacteria should be coming from nearby space bodies - Space is hostile to life