Le 2

• Hydrothermal Vent is a hotspring/geyser on the seafloor.
• Hydrothermal Vent continuously spews super-hot (~400ºC), mineral-rich water that helps support a diverse community of organisms
• Deep-sea hydrothermal vents form along mid-ocean ridges, the volcanic undersea mountain ranges where new seafloor is created.
• Vents may be 3.5 – 4 billion years old, but were discovered by scientists 30 years ago
• Process

  1.       Seawater seeps into the oceanic crust;

  2.       Oxygen, potassium and then calcium, sulfate and magnesium are removed from the water;

  3.       As water is heated up (underlying magma heats the water), iron, zinc, copper, and sulfur are dissolved;

  4.       Water rises back to the surface (upflow zone), where it mixes with the cold seawater, forming black metal-sulfide compounds.
• Black smokers

  -          Waters rich in sulfide minerals

  -          Superheated waters (approx. 400ºC)

  -          Contact between the superheated waters and frigid ocean water results to precipitation of minerals (massive sulfide ore deposits; sometimes gold)
• White smokers

  -          Waters depleted in sulfide minerals

  -          Water temperature less than that of the black smokers
• Vent Ecosystem is the center of unique ecosystems beneath the seafloor
• Vent Ecosystem depends on microbes that tap into the chemical energy in the vent water (Archaea and other extremophiles convert heat, methane and sulfur compounds into energy through chemosynthesis)
• Vent ecosystems derive their energy from chemicals in a process called chemosynthesis
• Photosynthesis and Chemosynthesis involve an energy source, carbon dioxide, and water to produce sugars
• photosynthesis gives off oxygen gas as a byproduct, while chemosynthesis produces sulfur
• amino acids formed short protein-like chains called peptides
• Life on earth began as a primordial soup in a lake or pond 4 bya
• Chemicals from the atmosphere combined with some form of energy necessary to make amino acids, the building blocks of protein, to create the first primitive organism and start the evolution of life
• A.I. Oparin (Russian) and J.B.S. Haldane (British): independently proposed similar hypothesis in the 1920s
• Reducing atmosphere (low oxygen) + abundant methane (CH4) and ammonia (NH3) = ideal primordial soup for the origin of life
• Miller-Urey Experiment is an experiment that simulated hypothetical conditions of the early Earth, testing earlier hypothesis that conditions on the primitive Earth favored chemical reactions that synthesized organic compounds from inorganic precursors.
• Ingredients in the Miller-Urey Experiment: Methane (CH4), ammonia (NH3) and hydrogen gas = primitive atmosphere (note no oxygen)
• Problems with the Miller-Urey Experiment

  -          Amino acids have to become protein

  -          Early atmosphere contains different gases than those used by Urey and Miller in their experiment
• Scientist have long believed meteorites and comets played a role in the origin of lie.
• Comets contain large amounts of complex carbon compounds and provided large supply of complex organic molecules along with water and other volatiles.
• Panspermia is the origin of life outside earth
• The creatures were found during a space walk to clean the surface of the space station. The organisms seem to be a type of sea plankton.
• A NASA scientist has discovered sugar and several related organic compounds in two meteorites, providing the first evidence that another fundamental building block of life on Earth might have come from outer space.
• The carbonaceous Murchison meteorite harbors sugar-related organic compounds.
• Glycolaldehyde contains 8 atom molecules of carbon, hydrogen, and oxygen
• Glycolaldehyde can combine with other molecules to form more complex sugars like ribose and glucose.
• Ribose are building blocks of nucleic acids such as RNA and DNA, which carry genetic codes of living organisms
• Glucose is important carbohydrate in biology and cells use it as primary source of energy
• Giant Molecular Cloud known as Sagittarius B2 is the cloud in which scientists detected the simple sugar molecule glycolaldehyde
• Titan is the only satellite in our Solar system that has a thick and extended atmosphere
• Titan resembles the very young Earth before the appearance of life, when oxygen probably existed in the form of carbon dioxide and methane was abundant
• Titan lacks the input from intense meteorite bombardment
• Europa would be the only place the solar system besides Earth where liquid water exists in significant quantities
• We can speculate that the mantle ocean of Europa hosts a modest biota
• Mars' lander sites are not ideal for sustaining living organisms
• Pathfinder is a small spacecraft dropped onto Mars and tumbled stop that will be sending signals back to Earth concerning the atmosphere and soil
• Noctis Labyrinthis or Labyrinth of the Night is a maze of short interconnected canyons on the western edge of Valles Marineris
• Olympus Mons is the largest volcanoes in the Tharsis Montes volcanic province, and probably the largest volcano in the solar system