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Micro and Macroevolution

Micro and Macroevolution. Microevolution – deals with populations change from generation to generation Macroevolution – large, general changes in the Earth and the phylogeny of species. Formation of the Earth.

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Micro and Macroevolution

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  1. Micro and Macroevolution • Microevolution – deals with populations change from generation to generation • Macroevolution – large, general changes in the Earth and the phylogeny of species

  2. Formation of the Earth • 4.5 to 5 BYA – solar system formed from a swirling cloud of gases and dust with enormous pressure in the center – the sun • Planets formed held by the gravity of the sun. • Earth was probably very cold, with nickel and iron settling to the center and forming the core • Hydrogen gas made up the atmosphere • VERY VIOLENT ENVIRONMENT!!! • Carbon dioxide, nitrogen gas, and methane gas • No ozone layer – lots of UV radiation • No oxygen

  3. Primordial Seas • Earth cooled, gases condensed

  4. Early Earth

  5. Organic molecules • Organic from inorganic – primordial soup • UV light, radioactivity • Amino acids formed – building blocks of polymers • Nitrogenous bases form • RNA and DNA – argument as to which came first

  6. Origin of the first cells • The synthesis of Organic Molecules on early Earth were stimulated by the UV radiation and lightning. • Miller and Urey in 1924 – took water vapor and a mixture of gases and observed amino acids and nitrogen bases ATCG

  7. Miller-Urey Experiment

  8. Protocells – protobionts, liposomes, coacervates • The first “cell-like” microspheres • Hydrophobic outer layer • Like a plasma membrane

  9. Early life forms – 3.5-3.9BYA • Prokaryotes (bacteria) are the earliest fossils known • These were mostly anaerobic bacteria – live without oxygen • Eventually when oxygen entered the earth, it killed many of these early bacteria.

  10. Early Prokaryotes

  11. Oxygen and ozone • Early autotrophs release oxygen into atmosphere • Ozone is created, UV light is absorbed • This makes the environment favorable for prokaryotes that photosynthesize (like cyanobacteria)

  12. Cyanobacteria

  13. Endosymbiosis • Large bacteria “eats” small bacteria and they become the chloroplast and mitochondria • Mitochondria have their own DNA • Mitochondrial and chloroplast ribosomes resemble that of bacteria • Mitochondria and chloroplasts reproduce by binary fission • They have phospholipidbilayer • Thylakoid membranes resemble that of photosynthetic membranes of cyanobacteria

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