1. Origin of Life Origin of Universe Origin of Elements Origin of Sun & Solar System Origin of Living Systems Evolution of Living Systems

2. Arguments for Origin Divine Extraterrestrial Chemical evolution

3. In the beginning…a big bang About 15 billion years ago Evidence –Hubble Expansion –Big Bang Nucleosynthesis –Microwave background radiation

4. Big bang – Hubble Expansion Galaxies appear to be moving away from our galaxy Initially observed by Edward Hubble in 1927 Galaxies have a red shift in light produced by the Doppler effect similar to sound (also used in radar) The movement of galaxies away from us corresponds to an equation called "Hubble's Law" The time elements in Hubble's Law permit the estimation of the age of the universe – about 13 billion years (+ or – a few billion)

5. Big Bang - Nucleosynthesis Occurred during seconds 100 to 300 following big bang temperature cools allowing hydrogen to form Result of temperature of universe dropping below that required for nuclear fusion (4 H to He) forms Helium Produced a large amount of Helium which is very stable and cannot be converted easily into heavier elements Amount of background Helium measured in universe is consistent with Big Bang Nucleosynthesis

6. Big Bang – Background Radiation If big bang then there should exist remanentt heat The cosmic microwave background was predicted in 1948 1964-65Arno Penzias and Robert Woodrow Wilson measured the temperature to be approximately 2.725 K which translates to specific background radiation in the microwave range.Arno PenziasRobert Woodrow Wilson This radiation as a signature of the big bang. Penzias and Wilson received the 1978 Nobel Prize in Physics for their discovery.Nobel Prize in Physics Existence of this radiation inconsistent with steady state model that Einstein and others favored.

7. Origin of Elements Hydrogen fuses to form helium –Hydrogen & Helium most abundant –Sun’s energy drives life processes Stars become red giants as hydrogen runs low (about 10 billion years) Helium fuses into other elements Star goes nova (blows up) Heavier elements released into space

9. Sun and Planets Sun formed about 5 billion years ago –Gravitational attraction of gases –Gravitational field becomes great enough to initiate fusion reactions Accretion forms inner planets & moons from dust and debris of supernova Process occurs quickly-earth & moon about same age

11. Early Earth Earth 4.6 billion years old (U 238 dating) –Moon rocks & meteorites Early Atmosphere mostly non-oxidizing –Nitrogen –Carbon dioxide –Water (as water vapor) Lesser amounts –CO, H 2, NH 3, H 2 S and CH 4

12. Venus, Earth & Mars Comparison VenusEarthMars AtmosphereCO 2 (>98%) N 2 (1%) Ar (1%) O 2 (0%) CO 2 (0.03%) N 2 (79%) Ar (1%) O 2 (20%) CO 2 (96%) N 2 (2.5%) Ar (1.5%) O 2 (2.5%) Pressure91 atm1 atm0.006 atm Temperature740 K*290 K **240 K *** Gravity8.87 m/s 2 9.87 m/s 2 3.72 m/s 2 *870º F **70º F *** -30º F

13. Characteristics of Life Composed of Cells Reproduce in kind Metabolism / Energy Transformations Respond to stimuli

14. Abiogenesis The process of life from the inanimate Formation of organic monomers from inorganic molecules Formation of organic polymers from organic monomers Evolution of membranes Evolution of DNA based reproduction

15. Chemical Evolution Requires a non-oxidizing atmosphere –No oxygen initially Requires a source of energy –Lightening, UV light, Volcanoes & Meteorites Requires hydrogen, nitrogen, carbon, oxygen –Components of organic and biological compounds –water, ammonia, carbon dioxide/methane Requires time

16. Chemical Reactions & Chemical Reactions Need to speed up chemical processes Reactions are sped up by Increasing concentrations of reactants Temperature Common phases Solvent effects Catalyst

17. Molecular Clues to Origins The following suggest common origin: –Organisms use molecules based mostly on hydrogen, nitrogen and carbon present on early earth –Only L-amino acids found in proteins –DNA & RNA are universal in all organisms –ATP is energy intermediate in all organisms –All organisms initiate carbohydrate metabolism with similar steps –Genetic code is universal –All cells bound by a plasma membrane composed of a lipid bylayer

18. Organic Monomers Oparin & Haldane suggest organic molecules could form from precursors (1930) Miller & Urey test using an apparatus which simulates early earth (~1950) Stanley Miller

20. Organic Polymers Major Groups - Nucleic acid, proteins, lipids, polysaccharides - have been formed synthetically Information vs. Structural vs. Catalytic Protenoids will form spontaneously on clay D & L amino acids can be selected on calcite - a common crystalline mineral RNA - has all three capabilities

21. RNA “Life” Ribose, a component of RNA will form spontaneously from formaldehyde and HCN Some RNA’s have been found to have catalytic activity - ribozymes RNA has structural capability in ribosomes RNA’s have an information carrying capacity in viruses & RNA’s have been induced to take on new traits

22. RNA Life Book segment by B. Alberts http://www.ncbi.nlm.nih.gov/books/NBK26 876/ http://exploringorigins.org/timeline.html https://www.princeton.edu/~achaney/tmve/ wiki100k/docs/RNA_world_hypothesis.htm l

23. DNA Life Separation of functional roles of molecules related to constant input of energy Separation of information carrying capacity from other roles of molecules in cells RNA to DNA RNA to Protein - catalytic capacity Protein & polysacharides take on structural roles in cells

24. Membranes Why cells? –Inside vs. outside –Concentration effect on reactions Indications of process –Microspheres - hydrocarbons in water form microsperes which can contain other molecules –Liposomes - artificial lipid bilayers very similar to cell membranes but smaller - used for drug transport

25. Prokaryotic Cells Appear about 3.5 billion years ago Photosynthesis in blue-green algae begins to modify atmosphere Oxygen in atmosphere begins to modify types of organisms

27. Stromatolites

29. Eukaryotic Cells Begin to appear in fossil record about 2.5 billion years ago Considerable internal structure relative to prokaryotic cells Precursors to multicellular organisms

33. Fossil Record Dating –Stratographic analysis –Radiometric dating Geologic Time –Precambrian - 4.6 to 0.57 billion years ago Fossils all unicellular –Caambrian – 0.57 billion years ago to present Multicellular organisms Extinction Level Events

35. Evidence for Evolution Physical methods – radiometric dating Fossil record Anatomical comparisons DNA sequence analysis Laboratory experiments showing selection