Evolution Unit 1: From Stars to Life

Unit 1: Evolution

• Formation of Elements in Stars:
  • Stars fuse hydrogen, helium, carbon, and other elements through fusion.
  • Iron is the endpoint of nuclear fusion.
  • Supernovae release energy to create elements beyond iron.
• Stanley Miller's Forgotten Experiments, Analyzed:
  • 1953 experiment simulated early Earth's atmosphere.
  • Spark (lightning) and water (oceans) created amino acids.
• RNA Enigma: Grand Challenge:
  • RNA is a single-stranded molecule (nucleotide).
  • RNA can switch genes on and off.
• Permeability of the Membrane:
  • RNA can pass through fatty acid membranes.
  • Fatty acids carry RNA into the membrane.
• Creating Artificial Life:
  • 2010 scientists created mycoplasma (cell) with 1,000,000 base pairs of DNA.
• Transiting Exoplanet Survey Satellite (TESS):
  • Sent data every two weeks (10 billion pixels).
  • Star's brightness change can indicate exoplanets.
• Life on Other Planets:
  • Comets may have delivered life's building blocks to Earth.
  • Possibility of life on Ganymede (Jupiter's moon) due to its oceans.
• Emergence:
  • Complex systems arise from simple interactions and rules.
• Are Viruses Alive?:
  • Viruses don't need food or metabolize. They need a host.
  • Viruses are simpler and evolve quickly.
• What Earth's Early:
  • Earth differentiated into layers (core, mantle, crust) billions of years ago.
  • The Hadean, Archean, and Phanerozoic eons.
  • Great Oxidation Event (2.8 billion years ago).
• Endosymbiotic Theory:
  • Pro and eukaryotic cells - Differences in the structure.
  • Scientific basis and evidence - Testable.
  • Mitochondria and chloroplasts (similar size and reproduction bacteria).
• Photosynthesis:
  • Formula for photosynthesis is:
  • Solar energy + 6CO2 + 6H2O → C6H12O6 + 6O2
• Snowball Earth:
  • Ice age that covered Earth due to the decrease of green house gases.
• Cambrian Explosion:
  • Increased oxygen levels enabled larger animals.
• Finding Tiktaalik: Neil Shubin:
  • Fossil discovery (transitional species).
  • Connection between fish and land animals.
• Overproduction of Offspring - Crabs:
  • Crabs produce numerous eggs.
• Mechanisms of Natural Selection:
  • Traits passed down based on reproduction or survival.
• Galapagos Finch Evolution:
  • Different Finch species on islands.
  • Example of natural selection (beak shape to type of food).
• Founder Effect, Bottle Necking, and Genetic Drift:
  • Small populations can lose genetic variety due to Random events.
• Evolution in Action: Ring Species:
  • Species that live in a geographic ring rather than a linear range. They are connected by interbreeding in a region.
• How Many Mass Extinctions Have There Been?:
  • Eight major mass extinctions identified in the fossil record.
• Homologous Structures vs Analogous Structures:
  • Homologous structures share similarity based on origin.
  • Analogous structures have similar function but different origins.
• Human Evolution:
  • Timeline of human ancestors (Homo habilis, Australopithecus afarensis, Homo neanderthalensis, etc.).
• Facts about Human Evolution:
  • Bipedalism, tools, care for the sick/dead.