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Explorations of the Universe

Explorations of the Universe

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Explorations of the Universe

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  1. Explorations of the Universe One Voice in the Cosmic Fugue

  2. What’s a Fugue? • From a Latin word for “flight” • From the same root as the word “fugitive” • Variations on a theme are played on top of one another, creates an aural impression of rapid flight • No true fugues anywhere in the episode!

  3. Artistic Conventions and Science • Anthropomorphism • Accelerating Events • Picturing the invisible • Bringing the past to life • Restoring Lost Details • What if?

  4. DNA • Deoxyribonucleic acid • Total length of human DNA in a single cell is about a meter • A human body contains about 20 trillion cells • The total length of DNA in a human body is thus 20 trillion meters, or twenty billion kilometers, the circumference of the orbit of Pluto.

  5. "Evolution is a Fact, Not a Theory - It Really Happened" • Here's Sagan at his in-your-face best. • Why is Evolution a Hot-Button Issue? • Science versus other modes of Knowledge • Ideological Abuses of Science • Dualistic nature of Western Culture (Fact vs. Fiction)

  6. “Of course, long before you mature, most of you will be eaten.”

  7. “The picture’s pretty bleak, gentlemen. The earth’s climate is changing, the mammals are taking over, and we all have brains the size of a walnut.”

  8. “Now this end is called the thagomizer, after the late Thag Simmons.”

  9. “Evolution’s been good to you, Sid.”

  10. The Cosmic Calendar • Human History = 5000 years • Dinosaurs = 150,000,000 years • Dinosaurs had: • 30,000 years for every year of human history • 80 years for every day • 8 hours for every second

  11. Prebiotic Evolution • The basic molecules of organic chemistry are easily made • The first self-replicating molecule was almost certainly not DNA • DNA assembles from simpler materials all the time

  12. Plants and Animals • CO2 + H2O + Energy = Sugars, Starches, etc. + O2 (toxic waste) - “The sky is made by life” • O2 is actually toxic (even to us!) • Idea: Take the sugars and starches (from somebody else) combine it with the waste O2, and get energy

  13. Amazing Events in Life History • “Invention of Sex” - Who Needs It? • We are a team - Mitochondria • The Great Freeze 900-600 m.y. ago • Mass Extinctions • Dinosaurs = 4th worst • Permian extinction (220 m.y. ago) took out 90% of all species

  14. Randomness, Order and Evolution • Are the following letter sequences random: crvn, smrt, vrlo, gdje, trg? • In Serbo-Croatian, the words mean, respectively, red, death, very, where and town square. • Moral: the fact that something looks random doesn't mean it is. It may convey meaning in a way you don't understand.

  15. Randomness, Order and Evolution • Is the following number sequence random: 592653589793238462643383279? • It not only looks random: it is random. • But lacking in meaning? No. These are the digits of pi beginning with the fourth decimal place. • Random does not mean “meaningless”

  16. The Scientific Meaning of Random • Something cannot be predicted with better accuracy than that predicted by statistics. • It takes as much information or effort to describe an event fully as it does simply to produce the event itself. The event is its own simplest description

  17. Randomness and Evolution • Biological systems are far too complex to describe or predict mathematically • We have incomplete information, • Significant events like climate change or asteroid impact are unpredictable.

  18. Randomness and History • Mongols in Europe, 1242 • In three months, the Mongols wiped out military opposition in the Balkans • Ordered to turn back to select a new Khan • Mongols never returned • Gallipoli, February 1915 • Object: force passage to the Black Sea and Russia • Intense artillery forced British fleet to retreat • Turks had 5 minutes’ ammunition left

  19. Can Order Arise Naturally? • The Second Law of Thermodynamics is often paraphrased as: • ”Things always go from bad to worse” • ”Disorder in the Universe is always increasing" • The core of the Second Law is entropy • Entropy can decrease locally if it increases elsewhere • Intuitive notions of disorder are of no relevance whatsoever

  20. Chemical Reactions are not Random Na Cl Na Cl Na Cl Na Cl Na Cl Na Cl Na Cl Na Cl Na Cl Na Cl Na Cl Na Cl Na Cl Na Cl Na Cl Na Cl Na Cl Na Cl Na Cl Na Cl Na Cl Na Cl Na Cl Na Cl Na Cl Na Cl Na Cl Na Cl Na Cl Na Cl Na Cl Na Cl Na Cl Na Cl Na Cl Na Cl Na Cl Na Cl Na Cl Na Cl Na Cl Cl Na Cl Na Cl Cl

  21. The Geologic Record • Physical evidence records mostly small-scale, gradual processes • Fossils show a gradual increase in complexity with time • Fossil forms intermediate between major groups are well documented • Over most of its history, life on Earth was simple

  22. Selection • Deliberate selection for desirable traits by humans (only since ca. 1700) • Unsystematic selection for desirable traits by humans (domesticated animals and plants) • Unconscious and unintentional selection by humans (self-domestication of animals) • Natural selection with no human intervention at all

  23. Lessons from Selection • Artificial selection has produced organisms radically different from their natural state • Natural selection has resulted in dramatic changes in natural populations with and without human intervention • Microorganisms and viruses change with dazzling speed (mutation of flu viruses, resistance to antibiotics)

  24. This Descended from Wolves?

  25. 1750 1800 1825 1850 Biology Linnaeus Selective Breeding Lamarck Voyage of Beagle Mendel - genes Origin of Species Prelude to Evolution Geology Hutton Lyell-Uniformitarianism Geologic Column

  26. Linnaeus • Classification of Organisms • Kingdom-Phylum-Class-Order-Family-Genus-Species • Included Man and Apes in the Primates • Encountered little opposition • System was viewed as descriptive only • Static, hierarchical, meshed with social prejudices of the day

  27. Classification of Dogs and Humans • Kingdom Animalia • Phylum Chordata • Class Mammalia • Order Carnivora (Dogs) Primates (Humans) • Family Canidae Hominidae • Genus Canis Homo • Species familiaris sapiens

  28. The Five Kingdom System • Animals • Plants • Protista (one-celled organisms) • Fungi • Bacteria* • Ediacaran Fossils? (ca. 700 m.y. ago)

  29. What’s Bigger Than a Kingdom? • Bacteria differ from all other kingdoms in lacking a cell nucleus • We need a bigger box • Superkingdoms or Domains • Monera (Bacteria) • Archaea • Eukarya (have cell nucleus) • Need electron microscopes and molecular biology to see differences

  30. 1750 1800 1825 1850 Biology Linnaeus Selective Breeding Lamarck Voyage of Beagle Mendel - genes Origin of Species Prelude to Evolution Geology Hutton Lyell-Uniformitarianism Geologic Column

  31. Jean Lamarck, 1795 • Animals change in response to their environment • Changes passed to offspring • Example: the Giraffe • First modern theory of evolution • Wrong, but contributed the idea that the environment shapes organisms

  32. 1750 1800 1825 1850 Biology Linnaeus Selective Breeding Lamarck Voyage of Beagle Mendel - genes Origin of Species Prelude to Evolution Geology Hutton Lyell-Uniformitarianism Geologic Column

  33. Why was Darwin on the Beagle? • British Navy SOP: ship’s surgeon (Dr. McKenzie) is the expedition naturalist • Rigid rules against fraternization • Depression ran in Captain Fitzroy’s family • Solution: hire an extra civilian naturalist • Real job: social peer and gentleman companion to the captain • Problem: Darwin and Fitzroy were ideological opposites

  34. Evolution By Natural Selection • Charles Darwin and Alfred Russell Wallace, 1859 • Organisms are adapted to their environments • Individuals vary • More organisms are born than can possibly survive • Variations best suited to the environment tend to survive and be passed on.

  35. Why the Furor over Evolution? • Pieces had been falling into place for over 100 years • All the main tenets of Natural Selection were well known • Seemed Cruel • Seemed purposeless (“random”) • Conflicts with Religion • Sexual Connotations • Ideological Abuses

  36. Sexual Connotations • This was the Victorian era, and you can’t discuss evolution without reproduction • For an allegedly prudish era, they produced a lot of undraped art and figure-exaggerating fashions • They weren’t so much prudish as mind-numbingly sentimental

  37. How Sentimental Were the Victorians?

  38. Conflicts with Religion • Death and the Fall • Traditional: Death due to Adam’s fall • Darwin: Death is intrinsic part of life • So where does Christianity fit? • Could a merciful God design Natural Selection? • The Paradox of Predestination • Does predation have any moral dimension? • How to Interpret the Bible? • Literal versus metaphorical and allegorical

  39. Ideological Abuses • Evolution Disproves Christianity • Atheism vs. Fundamentalism • Evolution Negates Purpose in Life • Nihilism vs. Religious and Marxist Schools • Evolution = “Survival of the Fittest” • Social Darwinism vs. Religious and Marxist Schools • Racist Applications

  40. “Evolution Disproves Christianity” • Where did all these atheists come from? • They were there all along, but keeping a low profile (compare resurgence of racism in recent years) • Moral: suppression is always more dangerous to the suppressor • Two final words: Soviet Union

  41. The Five Fundamentals (1910) • Literal Inerrancy of the Bible • Virgin Birth and Divinity of Christ • Atonement for sin at the Crucifixion • Resurrection of Christ • Second Coming

  42. How Fundamentalists See It

  43. The Scopes Trial, 1926 • Intended as a deliberate test of Tennessee’s anti-evolution law • Clarence Darrow (defense) vs. William Jennings Bryan (prosecution) • Climax came when Darrow grilled Bryan on the stand • Inherit the Wind, based on the trial, is good drama but very inaccurate history

  44. The Biggest Single Misconception About Religion • Many scientists consciously avoid saying “science believes” • Draw distinction between subjective beliefs and documented evidence • PROBLEM: EVERY RELIGION REGARDS ITS DOCTRINES AS PROVEN FACTS

  45. Lysenko (USSR 1930’s) • Rejected Darwin because of social darwinist abuses of evolution, “purposelessness” • Reverted to Lamarckian theories • Likened struggle for existence to Marxist class struggle • Was close friend of Josef Stalin • Effectively shut down Soviet biology 1930-1945

  46. Racism and Evolution(Ernst Haeckel, 1874)