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| Home > Science > Notes on the Nobel Conference 2003, St. Peter, MN |
| Notes on the Nobel Conference 2003, St. Peter, MN | | Date Created: Oct 14, 2003, 08:57 PM |
 Nobel Conference, Oct 7-8, 2003
Dr. James Peters former Science Museum of MN president, now President of Gustavus Adolphus.
Panel:
- banquet speaker: Dr. Christian de Duve, 1974 Novel laureate in physiology/medicine
- Niles Eldredge, evolutionary theorist from the American Museum of Natural History, NY
- Peter Grant and Rosemary Grant, evolutionary biologists from Princeton University
- John Haught, Prof of Theology, Georgetown University, on God after Darwin
- Tim White, from UC Berkeley on Unearthing Human LIneage
- Philip Currie, Royal Tyrrell Museum Alberta, on feathered dinosaurs and origin of birds
- Sean Carroll, Univ. of Wisconsin-Madison on The Molecular Approach
Day 1
Lecture 1 -
Dr. Eldredge, paleontologist - First to convince world, but not first to come up with theory, that life evolved from single source. Review Richard Dawkins' book "The Selfish Gene". Changes in physical environment effect evolution. Happens when you get dramatic changes in environment. Darwin and George Gaylord Simpson are two key figures. Founding father of evolutionary synthesis. How do you do evolutionary biology with samples so old there is no genetic material left? Says there are repeated patterns in life than can be studied. Stromatolites are blue-green algae. There was a big die-off at end of Permian period (end of Paleozoic Era 230M years ago). Oxygen spiked at certain times of change, spurring growth of life on earth. Three evolutionary patterns include "stasis" (straight line), "speciation and stasis" (line, oblique break, line) and "lineages" (lots of lines and breaks). Also known as "turnover pulse" (stasis + speciation). If glaciers cover an area there is little local evolution because of little environmental change - until the glacier melts. Local adaptations happen, but unlikely to make a major evolutionary change if the environment is stable. "The sloshing bucket" theory of evolution. Reproductive success affects local population, local ecosystem , regional ecosystem, then the biosphere. Elizabeth Vrba's work on turnover pulses is the newest outlook on evolution theory and lineages.
Panel - change isn't rising from the genes but from the environment. Sixth extinction (present day). In 10K years we went from 5 million people on earth to 5 billion people.
Lecture 2 -
Peter and Rosemary Grant - The change in Darwin's Finches took place over 3M years. In the beginning there was a singular finch 3M years ago. Radiation (outward migration). Multiplication of species. Evolution happens when the environment changes. The reproductive barrier between species. Hybridization. The Galapagos Islands were never part of the mainland. Disbursement greatest after El Nino year because of overpopulation. First disbursement was due to volcanic eruptions burning Ecuadorian forests and finches flee out to sea. Fewer islands 3M years ago, but eruptions and sea-mount building caused many more to form. Temperature changes as well. Temperature lowered over time with greater ranges in fluctuation. Molecular data indicates radiation began with finch bill becoming more like warbler bill (short and thin). Another finch developed a short but stouter beak. Used micro-satellite DNA phylogeny. Mitochondrial DNA analysis would show the same phylogenic radiation. 14 species derived. Niches increased as islands increased. Has to be ecological separation (different food) and reprodutive separation (no interbreeding) for separation of species. In some niches finches feed on eggs and blood of boobies (they used to feed on flies that bled boobies, but now have shortened the food chain). Study of beak sizes over 30 years. Beak depth increases with rainfall (El Nino) as population increases and smaller seeds are "over grazed". Measuring evolution is done by taking measure in generation before replication and comparing it to second generation after replication (skipping a generation). Measured mean trait values across years. So natural selection on Daphne island is observable, natural, has morphogenic consequences. What is reproductive barrier between species and is it "leaky"? Birds only mate with their own species. They develop the same song sung by their father even if the father's singing of it is wrong. If they learn song of other species they will mate with member of that other species. This is called introgression and increases genetic variation on which selection can act. Perching birds all learn songs but doves and pigeons don't learn their songs.
Lecture 3 -
John Haught -
Richard Dawkins in a Materialist who believes that any religion is against the tenets of evolution. Separatists see science in one realm, religion (meaning and purpose) in another, but compatible. Evolutionary Theology tries to rethink theology to deeper insights into God. More accommodating and progressive than Materialism.
"Evolution and Divine Providence". Classical view of providence has a hierarchical universe. Contemporary picture of universe is 13.7 B years. Imagine 30 volumes of books with each volume at 450 pages. Each page = 1 M years. Earth begins at volume 21. Life begins at volume 22. Cambrian explosion volume 29 and modern humans on p450 of volume 30. Evolution's recipe: accidents + natural selection + deep time. How to map classic hierarchy onto this picture? Providence after Darwin? Approaches: Should we consider that providence is entirely unbelievable? or initial cosmic design? or hidden plan? or evolution as divine pedagogy? or we can see broad evolutionary trends suggesting divine influence? or Darwin's recipe itself that there is providence in evolution applied through randomness, natural selection and deep time.
- Natural selection: is cruel
- Dawkins says there is only pitiful indifference. Darwin suffices.
- Is providence hidden behind accidents of evolution? Alexander Pope says, chance is "direction which thou canst not see". Perhaps there's some wider divine plan. Human sense of order may only be a narrow view.
- Evolution as divine pedagogy? Guy Murchie, The Seven Mysteries of Life. Darwinian process is harsh but educational. Earth as a soul school: obstacles essential to life. What kind of work would you have created? Says God made a world that is educational, contrasty, thrilling, tantalizing and beautiful to develop spirit in. Writings by Pierre Teilhard de Chardin (priest and geologist). He noted that there is a gradual increase in organized complexity. Corresponding increase in consciousness. Sufficient to give meaning to evolution. Also increase in centration (search for center) from nucleus to central nervous system to more complex brain to self-awareness to religion. Called this final centration the "noosphere". Said suffering is inevitable in an unfinished universe. Ultimate explanation of evolution is an emergent hierarchy and God draws the world toward unity from "up ahead". Alfred N. Whitehead said the aim of evolution is toward more and more intense versions of beauty (balance of novelty and order) as derived from adventure. Balances the forces of ennui and chaos. God is persuasive as opposed to forcing, allows for chance, freedom and Darwinian evolution. God's will = maximizing of beauty.
- Or, evolution is God's Self-gift. Giving himself away to the universe. Only way the finite world can adapt to the infinite is to undergo self-transcendence (which is evolution). Universe is seeded with promise rather than design. In the bible providence is tied to the theme of promise. Because the world around us isn't that well designed. Promise is consistent with present ambiguity in the world. Darwin's 3-part recipe is consistent with promise.
- Contingency leads to to nature's openness to the future
- Laws of nature lead to a universe we can depend on
- Deep time is indicative of divine timeframe. Waiting is never disinterested passivity but the highest form of interest in the other. Awaiting keeps an open space for the other, gives the other time, and creates possibilities of life for the other.
Day 2
Lecture 4 -
Dr. Tim White in paleoanthropology. Human evolutionary studies at Berkeley. Spokesperson for research area in Ethiopia (Middle Awash). Funded since 1981 through the NSF and IGPP Los Alamos. There are dozens of creation myths across the world. Do any reflect the evidence? Lava dome in Ethiopia split and now opens to the Red Sea (great east African rift). Afar depression, near Addus Abba. Lots of clouds over dome and that leads to drainage and deposits into the rift. Fracture zone of rift creates volcanos, which play an important role since resultant ash horizons are datable by Argon/Argon dating. Eruptions in the past are larger then Mt. Pinatubo in Philippines. Ash deposits several meters thick. At 1.8M years ago hominids are leaving Africa. 1M years ago homo erectus has a range that stretched from China to Mediterranean. They used stone tool technology. Neanderthals: extinct or ancestral? About 100K years ago. National Geographic couldn't decide in mid 80s. Maternal DNA from mitochondria. High variation in chimps, small range of variation in humans. So there was some keyhole of lineage humans went through that resulted in limited genetic diversity. We had an "Eve" or lucky mother who led to all humans, about 100K years ago. After one season found hippopotamus bones and hand axes, plus marks on bones. Looking for fossils you walk toward the sun to see the reflections off bones because they're mostly silica. Uncovered nearly intact skull with cranium of a 7 year old nearby. Both had tool marks on them suggesting cannibalism. No other bones near by. Some form of mortuary practice. 400K years ago in Europe there was some glaciation and that led to the specialization of Neanderthals. Neanderthal craniums had greater breadth at the parietals but it was lower than for sapiens, no canine fossa. The more deeply we look back, ancestors seems more anatomically remote.
Panel - Eldredge said molecular biology is newer but paleontology gives different information including a context of other animals and flora. Tim, Neanderthal fossil record is broken. No clue as to where it ended. But knows that they disposed of dead in a cave where bear bones where found also. Men, women and children remains found there. Close to 30 remains. These were early Neanderthal, less facial ridge development. Persisted after it became more tropical as far north as Croatia (hippos found there). Seems like they were a glacial adaptation, supplanted by homo sapiens after the glaciers receded.
- Why did early man leave Africa? Well, they didn't all leave. It was an expansion.
Lecture 5 -
Philip Currie - studies vertebrates including dinosaurs, aquatic reptiles, and feathered dinosaurs and the origins of birds. From Alberta CA where there are lots of fossils. Found that small carnivorous dinosaurs had feet very similar to birds (ligatures, etc.). There are passive flying squirrels, fish and even flying snakes. Active flyers include birds, bats and pterosaurs. Pterosaurs are not dinosaurs, they are pre-dinosaurs and not ancestors to birds. Though some were as small as robins or wrens. Jeholopterus has been found in China and it was covered with fur. They now know that pterosaurs were fur-covered. Archaeopteryx closely related to dinosaurs. Feathers are preserved which is the only way discoverer knew they were related to birds. 1870 Thomas Huxley already said that dinosaurs are closest relative to birds. Fused clavicles of fish and amphibians = furcula (wishbone). Theilman (?) though more ancient ancestor to dinosaurs gave rise to birds. Later, crocodiles were suggested. How could dinosaurs have been precursors to birds since dinosaurs had no fused clavicles. Lontgisquama insignis is another reptile recently suggested as ancestor, but their feathers are structured differently. Turns out that dinosaurs do have a bird-like furcula. Turns out oviraptor has a furcula. Furcula have been misidentified until mid 1970s. Often placed improperly in reconstructions in museums. Many bird-like dinosaurs were larger than most birds, including Dromaeosaurus (child-size). Whole new types of dinosaurs still being discovered. Ornithomimus also looks birdlike (ostrich like). Even beak was preserved. Birds have lots of air sacs in body and air tubes that go through bones. Confuciusornis with short tail and long tail feathers was found in Colorado. Had spaces suggesting air sacs and had bone cross-sections bird-like. Farmer in China who discovered a new species sold one specimen impression to one
museum and the other half of the impression to another museum. That animal, about the size of a chicken, Sinosauropteryxis a dinosaur with "feathers". They are very small feather-like structures on head. Not hairs, but branching structures. Inside stomach was last meal: including jaws from two small mammals. Another had small lizard in it. Even dinosaurs the size of a man had feathers. Then a new one, Caudipteryx, found to have tail with long fan of feathers and fan of feathers behind short arms. It had feather barbs and barbs had barbules, just like modern feathers. Sat in intermediate position where it had real feathers and physiology of a dinosaur. Lately found that misidentified eggs likely belonging to this dinosaur on top of it (likely defending and protecting the nest). 9 species of feathered dinosaurs now known. Thought that early feathers gave a slightly aerodynamic edge for gliding. Some species are even larger than a man. So closely related to raptors and tyrannosaurus that maybe in some early stages of life TRex had feathers for heat retention, etc.
Panel. Did flight start from tree down or ground up? Some dinosaurs had feathers in back of hind legs and that might suggest it started with gliding from trees.
Lecture 6 -
Dr. Sean Carroll: evo/devo (evolutionary development) underlying mechanisms that allow animals to look vastly different from each other. NSF Young Investigator award. Butterflies, Zebras and Fairy-tales: Genetics and the Making of Animal Diversity. Early in genetics there were lots of questions regarding form. How do individual animal forms develop? How have so many different animal forms evolved? Evolution of form occurs through changes in development assimilated over many generations. Would evolution of new animals and parts involve new genes? Would humans have more genes than other animals? Is there a gene for every piece of anatomy ad trait - every finger, toe, muscle, etc.
Making animals:
Common features of animal design -
Modularity (snakes, worms) and serial homology (lobsters, butterflies and humans have repeating blocks that are modified through specialization). Williston's Law, "... the parts in an organism tend toward reduction in number, with the fewer parts greatly specialized in function."
Monsters and master genes -
Fruit fly mutations include the wrong number of wings (extra pair), extra legs (replacing antennae). Mutations that kill before maturation can effect the number of segments, their polarity (direction they face), distribution. Controlled by genes. How do these dramatic genes work?
Building animals -
Basic logic divides up the embryo through divisions like latitude and longitude marking on a globe. Coordinates include height and depth, like mountains with various elevations on a globe. Latitude divides up into north, mid and southern latitudes along the length of the organism, corresponding to the head, middle, tail. Longitudinal divisions are made into quadrants (NWSE) for dorsal-rt, dorsal-left, ventral-rt, ventral-left. All this happens in about 60 minutes of differentiation in the fruit fly embryo. Shown under fluorescent laser light. At certain intersections of latitudinal and longitudinal meridians it creates a little globe respond for complete development of legs, arms, etc.
Genetic toolkit for the animal kingdom -
The homeotic genes mark longitudes along the main body axis and the control of the identity of segment and body parts. 8 genes control this. In 1963 E. Mayr said "search for homologous genes is quite futile except in very close relatives" Not true. Sean found what applied to fruit flies also applied to mice and chickens. Evo/Devo applies to species through time (paleontology) systematics (species, variation and speciation), and genes in population (genetics). Embryology is no long a "black box". Eyes - you can turn off "eyeness" gene. Same gene for fruit flies or mice. "Distal-less" gene makes legs into nubs. Same gene for fruit flies, crustaceans, fish fin, chicken wing, or sea urchin.
Common ancestor of vertebrates and arthropods lived prior to Cambrian Explosion (>544 M years ago) Don't know what animal it is, though it was bilaterally symmetrical and has extensive toolkit of developmental genes.
Toolkit paradox -
If we share an extensive toolkit of body-building genes, mice and humans have virtual identical sets. Chimps and humans are >98% identical, so how do differences in form arise? Resolution: It's in the way that you use it" (a reference to E. Clapton). Differences in the time and place of gene expression. DNA contains both genes and control switches. 29,000 genes in human, mice , ape genome. Switches are regulatory, they don't control anything by themselves. The xrays causing mutations in fruit flies broke the switches, they didn't create or change the genes. Genetic switches act like GPS locators to determine where genes turn on and off. One ON switch might show up in stripes on an embryo, with OFF genes overlapping in large bands, making the area of no overlap the only place where ON switches allow genes to grow legs (for example). Insects evolved wings from respiratory structures in aquatic crustaceans. Only switches changes as to where wings were allowed to develop and not to develop. Butterfly wing spots use the "distal-less" gene in the wing for the center of the eye spot. The patterns of two other genes mark the outer rings of the eye spots. Evolved by adding switches. Switches may be the main thing differentiating between species (especially close species. Apes have speech centers in brain according to recent studies, so difference between them and man is just a matter of degrees ... one mediated by switches. |
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