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264 Cards in this Set
- Front
- Back
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1. Does the rigorous use of logic set science apart?
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NO!
It is the use of the scientific method that makes something scientific |
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2. What drives modern science?
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Observations
Belief that the natural world is inherently understandable (natural,rational explanation) |
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3. To assume something is miraculous means what?
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There is no point in understanding how it works
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4. How does scientific progress proceed?
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Create and test ideas called hypotheses
They should be as simple as possible and add complexity only as demanded by future observations |
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5. What does a hypothesis have to be consistent with?
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Should be consistent with a rational understanding of other aspects of science
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6. What must a hypothesis be?
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TESTABLE
Other must be able to independently determine a hypothesis' veracity |
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7. If a hypothesis makes a prediction that is contradicted by new observations what happens?
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1. Modify hypothesis to include new factors
2. Reject hypothesis a false: then develop new one or evaluate other competing hypotheses |
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8. What happens if a hypothesis makes a prediction that is supported by new observations?
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It gains further credibility
*can't rigorously prove most hypotheses right, can either prove them as false or consistent with existing data |
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9. When does a hypothesis become a scientific theory?
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After it survives many attempts at falsification and has become widely accepted
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10. What is a scientific theory?
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They are the backbone of science
They are the most widely accepted ideas we have Most new work assumes they are true Can be disproved by new observations |
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11. Testability enforces what two key contrasts with other ways of thinking about the world?
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1. Science deals with the physical world b/c we can reproducibly observe and measure things only in the physical world
2. Science cannot investigate the metaphysical world |
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12. What about questions that cannot be resolved due to a lack of measurable data or testable hypotheses?
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They must be left to other fields that incorporate values-based considerations
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13. What is one of the major hallmarks of science?
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Peer Review
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14. How does peer review work?
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1. Give one or more talks on results at national meetings
2. Audience (experts on topic) evaluate 3. If survive meeting, submit paper to professional journal for publication 4. 3 or 4 world experts review manuscript 5. They write review that's sent to editor along with recommendation as to whether work is worthy of publication 6. If deemed worthy, incorporate comments and submit for publication |
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15. Since most scientific work is funded by government agencies how do you get money?
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Write proposals which are also reviewed by experts in your field
Thus, peer review acts to improve scientific process from beginning to end |
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16. What role does testability, peer review, and publication serve?
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Weed out bad ideas and produce a growing body of knowledge that most everyone agrees on
*scientists are in a common pursuit of the truth |
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17. Where does controversy exist in science?
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Only at the cutting edges of science
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18. What was the pre-19th century Christian assumption?
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God created all life
Each species was a separate act of creation |
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19. What did Aquinas say?
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Any conflict between theology and natural philosophy (natural science) was due to a mistaken interpretations of one or the other, no contradictions were expected
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20. What motivated early research into geology?
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Motivated by the natural assumption that the events of Genesis would be discovered in the rock record (i.e. Garden of Eden, Noah's flood)
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21. What was the first hint that Genesis may not be literally true?
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Discovery of fossils of extinct animals
Noah brought two of everything on arc, hmm... |
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22. How did they explain unknown fossils?
What happened though? |
Fossil organisms not known in Europe were assumed to be alive and somewhere else in Europe
As large organisms were recovered and the Earth become more explored, it was clear that things did go extinct despite Genesis recordings |
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23. Why was the fact that fossil record was dominated by marine creatures prove as a puzzling fact?
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Noah's flood should have wiped out huge numbers of land animals, but relatively few marine creatures
The reverse was found (fossils of land animals are much rarer) |
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24. What does catastrophism believe?
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The fossil record contains a succession of flood-related extinction events that wiped out more and more of the species originally created by God
*this is what fossil record first gave rise to |
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25. Later, what did D'Orbingy realize?
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That new species appear in the fossil record
So partial extinctions were followed by new creations |
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26. What does uniformitarianism believe?
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The scientific laws and processes that we observe today are all that is necessary to explain the entire geologic record
*not allowed to call upon supernatural forces but must think and come up with logical explanations consistent with natural laws |
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27. What is a religious geologists view?
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The forces and processes of nature were created by God's hand, and they thus illustrate His divine will
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28. What is one of the main ideas of Uniformitarianism?
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Slow acting forces, working over great expanses of time, can create amazing geologic wonders and, in fact, the entire geologic record
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29. What's the background on Darwin?
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A naturalist on board the H.M.S. Beagle
Took more geology notes than biology notes Convinced Uniformitarianism was correct |
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30. What was Darwin's key idea?
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Small changes acting over long times bring big changes
He applied uniformitarianism to biology |
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31. How were his ideas presented?
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Alfred Wallace and Darwin presented ideas at same meeting
Darwin published "On the Origin of Species" in 1859 Book thoroughly documented the case for evolution and proposed a mechanism by which it occurred |
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32. What is the Grand Unifying Theory of biology and medicine?
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Evolution
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33. Why is Darwin more famous than Wallace?
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1. Thoroughly documented arguments
2. Recognized ramifications of his ideas 3. Was often right |
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34. What was Darwin's main goal of writing "On the Origin of Species"?
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Overthrow the dogma of separate creations of each and every species
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35. What are the two parts evolution is broken into?
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1. Evolutions as historical fact
-Includes all the evidence that documents that evolution has in fact taken 2. Evolution as a Theory -How does it work, what are the mechanisms *data documents the facts, theory tries to unite the fact using processes with observable, testable results or predictions |
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36. What is the most important theoretical underpinning of evolution?
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Natural Selection
-It imposes severe constraints on how evolution must work *In principle these constraints make it easier to find evidence disproving evolution |
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37. Evolution is based on what three undeniable facts, one basic inference, and one inescapable conclusion?
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1. Individuals w/in a species vary
2. These variations are passed along to the offspring 3. More offspring are produced than can survive 4. Thus, a struggle to survive must ensure 5. Those best suited to survive are most likely to live long enough to breed and pass along their superior characteristics to their offspring |
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38. What else is natural selection known as?
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Survival of the Fittest
'Fittest' means those with characteristics best suited for their environment |
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39. What are creationists take on natural selection?
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They accept that natural selection is a potent force
However, most believe that some barrier prevents a new species from evolving |
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40. What limit is imposed on evolution due to natural selection?
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The maximum rate of evolutionary change of physical attributes has to be within the normal generation to generation variations within broods of offspring
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41. How does evolution occur?
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Gradually, step by step
Each step along the way must be advantageous to the individual possessing the feature |
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42. What are the constraints on evolution?
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Takes place by small steps and each tiny step MUST convey an advantage to the living individual (no foresight is allowed)
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43. Why do rates of evolution vary?
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Difference in rates of evolution depend largely on selection pressures
On the other hand, if an animal fits nicely into its environment and its environment never really changes, it ma show no outward signs of evolution at all |
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44. What are the three broad categories of evidence that have firmly convinced biologists that evolution is a historical fact?
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1. Anatomy of living organisms (Darwin relied only on this)
2. The fossil record 3. Genetic and molecular evidence |
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45. What are the five general categories of anatomy-based evidence?
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1. Hierarchical classification of life
2. Homology 3. Embryology 4. Vestigial structures 5. Biogeography |
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46. What is a "natural hierarchical classification"?
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A series of nested groups that are defined according to the shared characteristics of various organisms
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47. What are the units of the hierarchical classification of life?
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Specie
Genus (genera) Family Order Class Phylum (phyla) Kingdom Domain |
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48. Who established this hierarchical classifications and what is its importance?
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Established by Carolus Linnaeus
Each step in the hierarchy goes to a larger more inclusive group |
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49. What does the hierarchical classification resemble?
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A family tree
A family tree specifies ancestor-descendant relationships and these are testable |
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50. What happens if you try to connect things are not bound by the past?
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Cannot create an objective nested hierarchical classification
Linnaeus tried and failed to erect hierarchical classification schemes for rock and minerals (form independently so not possible) |
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51. When a single objective classification arise?
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Only when things that stem from ancestor-descendant relationships are considered
These family-tree like patterns can arise only if they are in fact family trees |
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52. What is homology?
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When organs, structures, or biochemical features in different organisms are strikingly similar in their underlying structure or composition
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53. What is an example of homology?
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Forelimbs of all vertebrates are built from same base bones, muscles, nerves, etc.
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54. Do homologous structures have similar functions?
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No, they have strikingly different functions but similar structure
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55. What do the many variations on the same forelimb suggest?
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All terrestrial vertebrates and their marine relatives evolved from one common ancestor
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56. Why is this suggested?
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Because evolution has to work with pre-existing structures
Cannot create a major structure from scratch |
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57. What prediction would be made based upon homologous structures?
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In the fossil record, we'd expect to find examples of limbs making transitions from one type to another
*each step must convey a competitive advantage |
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58. Would we find a tree of life to be organized functionally?
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No, we wouldn't expect it to show that function dictates the similarity of structures
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59. What are vestigial structures?
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Remnants of features that are either useless or perform functions that are much simpler than the same fully developed feature found in similar organisms
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60. What is an example of a vestigial structure?
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Wings of an ostrich
They are useless for flying, which is the normal function of wings They may aid in other stuff but they serve a reduced function compared to full flight |
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61. What do creationists say about vestigial hip bones in whales that are separated from the spine?
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They are not hip bones but some other structure of unknown function
Biologists say yes they are hip bones supported by those whales born with legs |
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62. How do vestigial structure affect evolution?
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Evolution predicts vestigial structures
As a species evolves from one lifestyle to next, some feature may become unnecessary Inessential features will gradually become lost b/c those born w/ smaller ones are more likely to survive b/c they will spend less NRG growing them |
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63. Based upon evolution what happens to vestigial structures gradually?
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Depending on the severity of the selection pressures, vestigial structures should fade away
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64. What is embryology?
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The study of developing embryos
In 1800's embryologists discovered that embryos in early stages of development are similar and share a number of features that me be lost later in development |
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65. What do human embryos have that we would not expect?
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Gill slits and tails
These are developmental leftovers from earlier generations rather than spare parts that never had a function |
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66. What are some widely shared embryonic features?
What do they suggest? |
Amphibians, reptiles, birds, and mammals have gill slits as embryos
*Suggests common ancestor was some sort of fish that needed gills Dolphin and whale embryos have rear leg buds *Suggests ancestor of dolphins and whales once had rear legs |
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67. What is biogeography?
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The study of the geographic distribution of life
Many, many species are found in only very restricted areas Few, if any, species are global in distribution |
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68. What's up with marsupials and Noah's flood?
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Marsupials of Australia are distantly related to placenta mammals and have similar lifestyle
Following the flood why would marsupials go to Australia and not other placental mammal since both have similar body forms |
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69. What did Darwin propose?
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This is extremely unlikely so he reasoned that remote Australia was colonized by primitive marsupials eons ago
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70. What is this called?
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Convergent evolution
Evolutionary change in two or more unrelated organisms that results in the independent development of similar adaptations to similar environmental conditions |
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71. What are atavistic features?
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Those that were possessed by an ancestor, are not normally present in a modern population, but that on rare occasions appear in modern individuals
*Whales born with small rear legs, babies born with tails |
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72. What are the five kingdoms?
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1. Plants
2. Animals 3. Fungi 4. Protists (large single-celled organisms) 5. Monera (bacteria) |
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73. What are eukaryotes?
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Larger cells with nucleus and organelles (mitochondria, chloroplasts)
Plants, animals, fungi, protists |
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74. What are prokaryotes?
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Tiny simple cell with no nucleus, no organelles
Bacteria (Monera) |
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75. Similarities of the cells of all four of the eukaryote kingdoms suggest what?
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They could share a common ancestor
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76. Since the prokaryote cells are much simpler, what two hypotheses can be made?
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1. Prokaryotes were first life
2. A single-celled eukaryote evolved from a prokaryote ancestor in the distant past |
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77. What is some biochemical evidence for a universal common ancestor?
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All life is built on the following biochemistry:
Carbohydrates Lipids Proteins Nuclei Acids |
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78. What are carbohydrates?
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Sugars and starched that provide energy to cells and form important structure-building compounds such as cellulite
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79. What are lipids?
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Fats that store energy and major ingredient in the cell membrane
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80. What are proteins?
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Made of amino acids and do a variety of things
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81. What are nucleic acids?
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Make DNA and RNA which carry host of instructions that together define heredity
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82. What are some molecular similarities shared by all life?
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1. We are all carbon-based
2. Molecular Handedness 3. Life uses a small subset of all available amino acids |
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83. How is molecular handedness shared by all life?
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All life on Earth uses the life-handed versions of AAs to make proteins
Use mainly the right-handed version of sugars The limited handedness observed suggests that there was one or at most a few independent origins of life |
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84. How does the use of only 20 amino acids (out of 70)among most organisms suggest one or a very few common ancestors?
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If life had originated independently multiple times, we would expect each groups to use at least a somewhat different set of amino acids
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85. What does DNA tell us about ancestral relations?
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Comparison of DNA can tell us if some or all of life can be traced by ancestor-descendant relations to one or more common ancestors
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86. How is DNA arranged?
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Four bases:
Adenine Guanine Cytosine Thymine Two bases pair and sequences of these carry hereditary instructions |
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87. What is the genetic code?
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A set of 3 bases makes a 'word', a particular instruction (64 'words')
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88. What are genes?
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Specific portions of the DNA molecule that carry the instructions for specific functions
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89. What is junk DNA?
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Stretches of DNA that are apparently never called upon to do anything
Some turns out to have a regulatory function |
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90. What is a genome?
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Complete sequence of DNA bases in an organism, including genes and 'junk' DNA
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91. What is a mutation?
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An error in the copy work about once per billion bases copied
*Human genome has ~3 billion base pairs and 25,000 genes |
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92. Why do most mutations produce change that has no real impact?
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Many AAs are specifiec by just the first 2 or 3 letters of the DNA 'words'
Mutation affecting the third letter has no impact at all |
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93. What are some neutral mutations?
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1. Mutations that change a single AA in a complex protein (slightly impact chemistry on protein in most cases)
2. Mutations that affect junk DNA 3. Mutations that duplicate a whole gene which is never activated |
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94. Are mutations beneficial?
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A very small number turn out by pure chance to be beneficial
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95. What are homologous genes?
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99% of human genes are detectably homologous w/ the genes of mice
50% of our genes are detectably homologous w/ those of yeast *our genome is more different |
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96. What is the interpretation of this?
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These homologous genes are copies of ancient genes that were possessed by ancient common ancestors
Organisms sharing more homologous genes share more recent ancestors, those sharing fewer share more ancient ancestors |
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97. What are paralogous genes?
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Homologous genes that have been duplicated within a single species' genome one or more times
Once duplicated, each can evolve (change) independently as a result of mutations |
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98. Which genes does natural selection act upon?
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Only those genes that are expressed (used) and that are important for survival
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99. How does genes accumulate mutations at different rates?
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Those that are crucial to survival change very slowly b/c more mutations are harmful
Other genes can change rapidly w/o making changes that really affect the survival of the organism |
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100. How does this fact help us establish a molecular tree of life?
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Slowly evolving genes allow us to find and compare homologous genes in organisms that diverged from a common ancestor
Rapidly evolving genes are great for exploring recent evolutionary events |
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101. Only about 5,000 species of bacteria were known as of the late 1900's. Why so few?
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1. They all are very small and look like unremarkable rods, disks, or spheres
2. Many are very difficult to culture in labs |
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102. On the tree of life what are the three main clusters called?
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Domains: Bacteria, Archaea, and Eucarya (eucaryotes)
All three domains share a single origin: DNA points to one single common ancestor |
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103. What is an unrooted tree?
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It does not say when the three main branches split
It just clusters by similarity and measures differences |
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104. What are the big 3 kingdoms on the tree of life?
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Only TINY branches
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105. What does genetic data suggest about eukaryotes and prokaryotic Archaea?
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They are more closely related than are the two prokaryote groups (bactera, archaea)
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106. What is key to evolution?
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Genes
Need to get the genes that provide the favorable traits to become widely distributed throughout a population |
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107. What is the biological species concept?
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A species is a population of individual who have the potential to naturally and successfully interbreed in nature and to produce healthy, fertile offspring
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108. What is the morphological species concept?
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A population of individuals that share similarities in body size, shape, and other physical features
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109. What types of organisms does the morphological species concept work with?
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1. Asexual organisms
2. Living organisms whose breeding preferences are largely unknown 3. Fossil records for which breeding preferences are unknown |
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110. What are lumpers and splitters?
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Lump similar forms into one species
Detail obsessed scientist can split one species into several |
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111. What does the struggle between lumpers and spliters mean?
What do paleontologists do? |
The definition of a particular species is not always based on reality
Paleontologists generally avoid species and even genera as being potentially too biased Measure diversity of families or even order instead |
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112. What is the fossil recored for species like?
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It is rarely so complete as to provide a nice, continuous series of fossils recording the step by step transformation of one species to the next
*1 in 30,000 species are actually preserved in fossil records |
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113. At the core a species if defined by what?
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GENES
DNA controls the size, shape, color, and even behavior of organisms The DNA of two individuals determines whether they will be able to mate |
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114. So in order to get a new species what do we have to do?
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Figure out how to get the genes of an entire population to change over time until appearances change enough to be distinct or reproductive incompatibility is achieved
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115. What causes selection pressures to change?
What does this in turn do? |
Change due to a change in climate, food supply, competition from others for the same food resources, new or more or fewer predators
By natural selection these changing selection pressures should cause a species to gradually change |
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116. How we talk of new species forming?
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1. One species gradually, over time, evolving into what becomes recognized as a new species
2. Parent population splitting into two or more distinct species, with parent species surviving or not after X years of time |
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117. How can selection pressures drive evolutionary change in large populations?
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Only if the selection pressures change similarly over their whole home area
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118. What are sub-populations?
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They are much more likely to experience a consistent change in selection pressures that pushes them in a consistent direction
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119. What are small populations to biologists?
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They are the natural laboratories of evolution
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120. What is an example of this?
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Small populations may be in a marginal territory w/ different climate or new vegetation
As they adapt to these marginal surroundings they can evolve away from the parent species in the home setting |
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121. What about with sexual organisms?
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Any mechanism that induces a reproductive isolation between sub-populations of one species can result in the development of new species
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122. How can reproductive isolation be achieved?
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Geographic isolation
Habitat isolation Temporal isolation Behavioral isolation |
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123. What is geographic isolation?
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The geographic range of a species is split with a mountain range forms, an ocean opens us, or a deep canyon forms, or it can be split just by a patchy distribution of woods, grasslands, lakes, etc.
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124. What are ring species?
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Species with a geographic distribution that forms a ring and overlaps at the ends
Where two subspecies meet, they can interbred and produce hybrids |
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125. What is allopatric speciation?
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The formation of species under the condition of geographic isolation
Thought to be the most important pathway of speciation |
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126. What is sympatric speciation?
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The formation of new species without geographic isolation
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127. What is habitat isolation?
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Sub-population can live within different niches within the same area
They just don't meet enough to exchange genes so two populations are reproductively isolated |
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128. What is temporal isolation?
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Different sub-populations can breed at different times of the day, season, or year
Thus, when they meet they ignore each other |
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129. What is behavioral isolation?
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Courtship rituals and other behaviors unique to a group can be attractive only to members of that group
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130. How can the genetics of one isolated population diverge from those of the source population in order to form a new species?
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Natural selection
The Founder Effect Mutations |
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131. What is the Founder Effect?
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If a population begins with a small numbers of individuals, their genetic peculiarities can become widespread in the descendant population
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132. For the few mutations that are good how do we get them to spread through a population?
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Key is small population
With a small population a genetic novelty has a much greater change spreading through the population and changing it *Big populations dilute novel genes |
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133. As species diverge genetically what happens?
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They become less and less able to produce viable offspring
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134. What is hybrid breakdown?
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Some first-generation hybrids of diverging species can be healthy and fertile, but when they mate with each other or with a parent species, the second generation offspring are feeble or sterile
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135. What is hybrid sterility?
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When a horse and donkey mate, they produce a mule
Mule is healthy and strong but sterile |
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136. What is hybrid viability?
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Offspring either do not develop fully or are very frail
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137. At what point is genetic variation enough to establish reproductively isolated species?
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In general, enough genes have to be different that when the sperm and egg genes combine, they just don't work together
It's generally true that species w/ differing numbers of chromosomes cannot successfully mate |
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138. Many small groups that become reproductively isolated are likely to perish. What creates opportunities for successful speciation?
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Very helpful pre-condition is ecological opportunity in a allopatric area
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139. What does ecological opportunity mean?
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Few competitors for food, living space, or other vital resources, and no increase in predators
Gives isolated group time to adapt and evolve |
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140. What is key to speciation?
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Reproductive isolation
Needed to accumulate enough changes to make species look different and/or reproductively incompatible *ring species and various hybrids emphasize that one species can blur into the next |
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141. How do creationists differ from scientists?
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Creationists do not use the scientific method or peer review
Thus, haven't developed a single consensus view of what is meant by 'creationism' |
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142. What are the creationist ideas like?
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They are mutually exclusive, so this creates some tensions and flare-ups between creationists
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143. What are the four young-Earth creationist groups?
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Flat Earth Creationists
Geocentric Creationists Young Earth Creationists Appearance of Age Creationist |
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144. What do Flat Earth Creationists believe?
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1. Very literal interpreters of the Bible
2. Accept Genesis as being literally true: Earth ~6,000 years, each species created separately, no evolution |
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145. What do Geocentric Creationists believe?
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1. Little less literal interpretation
2. Accept that the Earth is a sphere 3. Reject idea that Earth goes around the Sun 4. Earth is at center of solar system 5. Genesis is literally true |
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146. Geocentricism is not so common but who is one influence geocentric?
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Tom Willis
Instrumental in revising Kansas state elementary school standards to remove all references to evolution, Earth history, and the scientific method |
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147. What do Young Earth Creationists believe?
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1. Earth is 6,000 to 10,000 yrs old
2. Earth and all life were created as separate species in 6 literal days 3. Death and decay are direct result of the Fall of Adam and Eve 4. Geologic and fossil records must be interpreted in terms of Noah's flood 5. Most politically influential group today |
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148. What do "Appearance of Age" Creationists believe?
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Universe and the Earth were created with the appearance of great age
Otherwise, they favor a literal interpretation of Genesis to explain the origin of the Earth and of life on Earth |
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149. What are Old Earth Creationists?
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Accept the scientifically determined age of the Earth (4.5 Byr)
Believe God was to varying degrees involved in creating life |
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150. What are the four types of Old Earth Creationists?
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Gap Creationists
Day-Age Creationists Progressive Creationists Intelligent Design Creationist |
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151. What do Gap Creationists believe?
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There is a huge gap in time between the first two verses of Genesis
We have a very ancient Earth established before a second phase of creation accomplishes its work in 6 days |
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152. What are the six days of creation according to Genesis 1?
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Day 1: Heavens, Earth, light
Day 2: Firmament (heavens,sky) Day 3: Dry land, plants Day 4: Sun, Moon, stars Day 5: Sea monsters,sea life, birds Day6: All land creatures, men & women |
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153. How does the time not fit right in Gap Creationism?
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Accept that Earth itself is very ancient (4.57 Byr) but the 6 days of creation force the Moon, Sun, and stars to be much younger (6,000 yrs)
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154. What do dated rocks say though?
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Dated rocks from the Moon as being up to 4.4 Byrs
Oldest rock on Earth is 4.0 Byrs Sun should be just a bit older than the chondrite meteorites (4.57 Byr old) |
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155. What do Day Age Creationists believe?
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Each day of creation was much longer than a standard 24 hour
day They see parallel between the order of life's appearance in 6 days & order of appearance in geologic record (isn't so parallel though) |
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156. What do Progressive Creationists believe?
|
They find the fossil record to be compelling evidence that life was different in the past
But they believe God created each species in sequence over all geologic time *Evolution did not occur |
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157. Who are the most common Old Earth Creationists?
Why? |
Progressive Creationists
They accept modern science except for evolutionary biology and even accept the Big Bang Theory |
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158. What are some theological questions for Progressive Creationists?
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Do fossils imply God is indecisive or incompetent?
Did past animals die due to bad design or terrible sin? |
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159. What do Intelligent Design Creationist believe?
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Life is so amazingly complex and so well-designed that it could not have evolved by chance
All life must have been designed by an intelligent being |
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160. What is ID's explicit purpose?
What is their primary motivating factor |
Unite all creationists against evolution
Idea that evolution and other scientific advances have brought w/ them a materialist philosophy (devoid of God) |
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161. How id ID part of a culture war?
|
Rise of Marxism and Freud allowed materialist philosophy to invade the West
Humans (cultural elite) saw themselves as animals driven by biology, chemistry, and physics, and NOT divine will *Biology drives us, not God's laws |
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162. What did the materialist world view lead to?
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Loss of personal responsibility and to the evils of moral relativism
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163. What do ID proponents want to primarily do?
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Overthrow materialism and all of its cultural legacies
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164. How does evolution factor into this?
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The fight against evolution makes ID creationism a weapon of mass materialist destruction against all things liberal
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165. Where do the ideas behind ID rise from?
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Not from a scientific dispute with evolution
Fight against perceived cultural side-effects of evolution *kill evolution, kill the side-effects |
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166. What is Theistic Evolution?
|
Hold that God creates through the process of evolution
Belief in how much God directs evolution varies Invokes God to explain things outside the scientific realm |
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167. What do Methodological Materialist Evolutionists believe?
|
There is a god, and this god created the Universe, the laws of nature, and evolution
From the view point of actually doing science these scientists assume that God has take no active role in shaping biological evolution |
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168. What do Philosophical Materialist Evolutionists believe?
|
Methodologically they are the same as methodological materialist evolutionists
They differ in personal religious beliefs in that they believe there is no god (atheists) |
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169. What did Behe propose?
|
Certain biochemical processes or biochemically produced cellular structures cannot function (or have any useful function) unless each piece of biochemical process is in place
Irreducibly Complex: nothing can be removed w/o rendering them useless |
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170. What does Behe argue?
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There is no step by step way to assemble these irreducibly complex structures as required by natural selection
Truly irreducibly complex is evidence of intelligent designer b/c such things cannot evolve step by step |
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171. What does arguing through personal incredulity mean?
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"I can't imagine it, so it can't be true!"
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172. What does it mean to say that the building blocks (organic compounds) are produced abiotically?
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They are produced without any assistance from life in the natural environment
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173. What was the famous Miller-Urey experiment?
|
It stimulated the effects of lighting on an atmosphere of CH4, NH3, and H2O
Mini 'ocean' in experiment became brown after week of electrical discharge b/c amino acids and other organics were made |
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174. Now we think the atmosphere was dominated by CO2 (not CH4 & NH3) so what have experiments using better approximation of atmosphere produced?
|
Using UV light (fake sunlight) and electrical discharge (fake lightening):
1. All AAs in most living organisms 2. Several complex carbs and lipids 3. All five chemical bases in DNA and RNA *yields are low though |
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175. What do Carbonaceous chondrites contain?
|
1. >74 amino acids
2. Some nucleic acids 3. Variety of other organic compounds |
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176. When did these organics forms?
|
In space during condensation and accretion in early Solar System
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177. How could organic compounds survive flaming hot passage through the atmosphere
followed by collision on the ground? |
Rock is a great insulator!
Even when outside is white hot the inside stays cold during brief time it takes to pass through atmosphere |
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178. What is a third source of organic compounds?
|
Hydrothermal vents (hot springs) in early oceans
High temp provides energy and various minerals aid the chemical reaction |
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179. In sum what were the three sources of simple organic compounds?
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1. Atmosphere
(sunlight plus lightening) 2. Outer Space (meteorites and comets) 3. Hot springs on sea floor |
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180. How can we make complex molecules?
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Lab experiments show that dilute organic solutions in contact w/ hot sand, clay, or rocks spontaneously produce a variety of complex organic molecules
No life required, just add heat |
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181. What complex organics have clay minerals helped produce?
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RNA strands up to 100 bases long have been produced in hot solutions in contact w/ clays
*mud is made of clay minerals, extremely abundant |
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182. How does pyrite play a role in producing complex organics?
|
Pyrite attracts organic molecules to its surface
Pyrite formation releases NRG that maybe helped drive the formation of organic compounds |
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183. Where is pyrite produced?
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At sea floor hot springs where many primitive bacteria today live
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184. So can complex organics be made abiotically?
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Yes, near hot springs
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185. What are the four steps in DNA replication?
|
1. Start w/ full DNA helix
2. Strands separate 3. Bases of each strand then bond w/ a series of new bases 4. End w/ 2 identical DNA molecules |
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186. What does RNA carry?
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Can carry hereditary information b/c RNA also carries four bases
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187. Can RNA self-replicate?
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RNA needs enzymes to replicate, but the enzymes cannot be made w/o RNA
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188. What are rybozymes?
|
RNA catalysts
They have catalyzed partial replication of other RNA molecules |
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189. What is the idea behind an "RNA world"?
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Self-replicating RNA molecules became the first step on the pathway to life
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190. What are the four steps in the RNA world?
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1. Start with free-floating nucleotide bases that make up RNA
2. Spontaneously linked up to form short strands (in hot springs in contact w/ pyrite or clay minerals) 3. Rybozymes catalyze production of a complementary strand of RNA 4. With more rybozyme help, the complementary strand then reproduces the original strand |
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191. What happened to those duplicated RNA strands?
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They would soon become more abundant than those produced spontaneously
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192. What is the efficiency of RNA replication?
|
More copying error than DNA replication
Mutations would produce a wider range of successful molecules |
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193. Why move from RNA to DNA?
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Both similar so plausible that DNA evolved from RNA
DNA took over job of duplication b/c: -more flexible -less prone to copying errors -more durable |
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194. What does RNA do today?
|
Helps make proteins
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195. Why are cells crucial to life?
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1. Molecules enclosed in a cell are kept close, where they can react w/ one another
2. Cells keep molecular innovations from benefiting other RNA located outside the cell |
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196. How can lipids be seen as the origin of cells?
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Lipids are fatty molecules that rise to the surface of water and form a thin film
Crashing waves then cause these thin fatty films to form little enclose spheres termed 'pre-cells' |
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197. What do lipid sphere trap?
|
DNA
If simple proteins are present in this solution, the amount of DNA trapped increases 100-fold |
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198. How can amino acids be seen as the origin of cells?
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If a warm-water solution of AAs cools, the AAs can bond w/ each other to form pre-cells
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199. What amazing life-like properties do these pre-cells display?
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1. Absorb short chains of AAs grow
2. When they get large enough, they split to form daughter spheres 3. They selectively allow some types of molecules to enter the spheres, and other to exit 4. Some store an electrical voltage that is used to metabolize starch inside the cell |
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200. What do relative ages establish?
What do absolute ages establish? |
Relative ages establish the order in which events occurred, but do not give numerical dates
Absolute ages fix numerical dates on events |
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201. What is the principle of superposition?
|
In a sequence of sedimentary rock layers, the layers at the bottom are older than those on top
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202. What is the principle of original horizontality?
|
Loose sediment drapes the bottom of lakes and oceans. Lake bottoms and sea floors are not strictly horizontal, but are roughly horizontal
Sediments are also deposited as horizontal layers on flood plains along rivers, on river deltas, and in swamps |
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203. What do changes in depositional conditions cause?
|
Changes in sediment deposition
This produces visibly different layers |
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204. If the beds are not horizontal, what can we generally infer?
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Some sort of geologic event has titled the beds from their originally horizontal position
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205. What is the principle of lateral continuity?
|
Sedimentary layers generally accumulate in sheets that cover broad areas and do not abruptly end until they hit the edge of a basin
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206. What does the principle of lateral continuity allow us to do?
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1. Trace distinctive rock layers over considerable distances
2. Recognize faults as faults (b/c they cause beds to abruptly end) |
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207. What are faults?
How are they recognized? |
Faults are fractures that cut through rock layers and offset these rock layers
Recognized b/c they violate the principle of lateral continuity |
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208. Why do faults form?
|
Form in response to squeezing, stretching, and shear caused by tectonic plate movements
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209. What is the principle of cross-cutting relations?
|
If on geologic feature cuts another, the feature that is cut is older (had to exist first in order to be cut)
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210. What is a dike?
|
An igneous intrustion
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211. What are the four principles in summary?
|
Sedimentary beds were
1. Originally horizontal 2. Originally laterally continuous (not faulted) 3. Oldest beds are on bottom 4. Faults are younger than beds |
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212. Who was the first to recognize the principle of superposition?
|
Nicholas Steno
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213. What is the principle of Faunal Succession?
|
Fossil species always occur in the same order in sedimentary rocks
Each species defines a unique interval of time (it never reappears) and over time a whole series of unique geologic moments are defined |
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214. How can isolated sedimentary successions be dated if their general age cannot be determined by superpositioning?
|
Recognize their distinctive sequence of fossil species
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215. What is the principle of faunal succession?
|
Correlating sequences of fossil species across widely separated rock sequences to build a global geologic time scale
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216. What are the geologic time scales used?
|
Epochs, Periods, Eras, and Eons
All defined by a series of species that came and went over time |
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217. How is the base of each geologic period defined?
What characterizes each period? |
Defined by the first appearance of a particular species
Characterized by a distinct suite of species |
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218. How can radiometric dating be used to see if relative dating really works?
|
Many sedimentary sequences contain volcanic ash layers
These can be radiometrically dated (uranium-lead and potassium-argon) Absolute ages perfectly confirm the relative ages inferred by superpositioning and correlation using fossils |
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219. Why is the fossil record a very biased sample of life?
|
Soft-bodied fossils are very rare, biased toward those w/ hard parts
To get preserved as a fossil, quick burial is essential (most dead things are ripped apart by scavengers and eaten) |
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220. At what placed is quick burial most likely to place?
|
Lakes and oceans
Flood plains of rivers & deltas Swamps |
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221. So fossil records are biased toward....
|
Organisms w/ hard parts that live in or near water
1 in 20,000 extinct species is thought to have any fossil record |
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222. How can we reconstruct the history of life?
|
Anatomy of living organisms and genetic data allow us to reconstruct the family tree of life
Fossil record offers an independent test of the predictions based on anatomy and biochemistry Gaps in fossil record are filled w/ inferences |
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223. What does Phanerozoic time contain?
|
All of the fossil sea shells, fossil fish, fossil vertebrate, fossil land plants
Base is dated at 542 +/- Myr |
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224. What does Precambrian contain?
|
Mostly fossil bacteria and algae up until the very end
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225. What are Archean rocks?
|
Very old and pretty rare
Upper age defined as 2.5 Byr *we start w/ rock in mid-Archean (3.46 Byr) |
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226. What are the world's oldest (probable) fossils?
How old are they? |
Microscopic fossils from the Apex Chert of Australia
3.46 Byr |
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227. What do these fossils represent?
|
Filaments of bacteria (prokaryotes)
Fossil bacteria are rare, but can be found in chert |
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228. In general, most Precambrian fossil bacteria are well accepted. Why?
|
1. Display the same size, shape, and geometry of living cyanobacteria
2. Contain appropriate organic compounds |
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229. How old are the oldest well accepted bacterial fossils?
|
2.4 Byr
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230. What are stromatolites?
|
Finely layered limestones whose layers form a variety of characteristic mound forms
Found in rocks 3.43 Byr and younger They form as a result of the activity of cyanobacteria |
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231. How are modern stromatolies arranged?
|
Top Layer: photosynthesizing cyanobacteria
Next Layer: purple bacteria (photosynthesize using bacteriochlorophyll) Next: Anaerobic bacteria (eat dead bacteria from above) |
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232. How does bacteriochlorophyll work?
|
It absorbs wavelengths of light not absorbed by regular chlorophyll
Purple bacteria are anaerobes (live w/o using oxgen) |
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233. How was oxygen built up in the Precambrian atmosphere?
|
Stromatolites and other cyanobacteria
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234. What hampers the search for older fossils?
|
1. Rocks older than 3.5 Byr are quite rare
2. Rocks older than 2.5 Byr have all been recrystallized by metmorphism 3. Late Heavy Bombardment that ended 3.8 Byr (extremely unlikely we'll find fossils older than 3.8 Byr) |
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235. What are the basic constraints on when life on Earth originated?
|
1. End of heavy bombardment at 3.8 Byr
2. First fossils: 3.46 Byr or 3.4 Byr at the latest 3. Geochemical evidence: back to 3.8 Byr *took like between 0 and 400 Myr to appear following the end of life extinguishing heavy bombarment |
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236. What it as the base of the family tree?
|
Prokaryotic bacteria (based on genetic data)
Fossil records confirms that some form of bacteria was the first to evolve and give rise to all other life on Earth |
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237. What are acritarchs?
|
First fossils large enough to be eukaryotes
Date to be about 1.75 Byr |
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|
238. What are arcritarchs most closely related to?
|
Dinoflagellate (marine organism)
Organic walls contain same distinctive organic compound |
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239. What do geochemical fossils reveal about eukaryotes?
|
Pushes record back 1 billion yrs further than normal fossil record
|
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240. How did eukaryotes evolve?
|
Symbiosis
When one organism lives within another and both benefit from the relationship |
|
|
241. How were mitochondria believed to originate?
|
Purple non-sulfur bacteria thrived in larger bacteria
It got food and return generated ATP for cell |
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|
242. What was incorporated to give rise to chloroplast?
|
Incorporated cyanobacterium
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|
243. The first fossils of multicellular life date to about what?
|
580 myr ago
All members of first animal fauna had no hard parts |
|
|
244. What were their bodies like?
|
Made of a firm jelly-like flesh (like jelly fist)
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|
245. What do they seem to be related to?
|
JELLY FISH
sea anemone and corals as well |
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|
246. Abundant fossils of multicellular life are found in rocks of what age?
|
Phanerozoic age
|
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|
247. Precambrian includes what percent of all geologic time?
|
88%
Dominated by single-celled life |
|
|
248. Phanerozoic last what percent of history?
|
12%
Start with Pre-Cambrian |
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|
249. What is the earliest period of the Paleozoic
called? |
Cambrian
|
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|
250. When was the Cambrian Explosion?
What is this? |
Started 542 Myr ago after 3 Byr of single-celled life
Within 20 to 50 Myr of the Precambrian-Cambrian boundary, get appearance of almost all of important marine phyla w/ preservable hard parts |
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|
251. Why did life wait 3 Byr before becoming multi-cellular?
|
Tentative answer: oxygen in atmosphere reached high enough levels to allow large body size and ability to secrete hard parts
|
|
|
252. How do we go from single celled eukaryotes to multicellular life?
|
Based on the anatomy of
modern organisms, plus now with DNA data indicating how closely related various animals are we get a reasonable set of steps that amount to a hypothesis |
|
|
253. What are the five steps in the origin of multicellular life?
|
1. Simple association of individuals
2. Sponges are association of about 10 different specialized cells 3. Phylum Placozoa (just Trichoplax adhaerens) 4. Animals get a gut 5. Develop bilateral symmetry so you can get out and crawl around |
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254. What happened in simple associations of individuals?
|
Choanoflagellates (protists) either swim freely or sometimes join together to make simple stalked colonies
|
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|
255. What are sponges life?
|
Cooperative confederation of cells (all related, but specialized)
No real tissue or organs |
|
|
256. How many species are in the phylum Placozoa?
|
ONE specie
Trichoplax adhaerens |
|
|
257. What is Trichoplax adhaerens?
|
Tiny flat mat of irregular shape w/ cilia on top and bottom
Has only 4 different cell types (truly multicelluar) Simplest DNA of animal |
|
|
258. Does it have a gut?
|
It enfolds to a create a temporary very simple gut cavity
|
|
|
259. What are trace fossils?
|
They include foot prints, feeding trials, and a whole variety of vertical and horizontal burrows that were made in soft sediments
In order to make trace fossils, an animal has to be large enough to burrow through sediment. ALSO needs have muscles and body firm enough for muscles to attack |
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|
260. Do they indicate an earlier
diversification than the body fossils? |
They do not predate the fossil record of multicellular life
Closely follow the pattern that defines the Cambrian Explosion |
|
|
261. When do geological records suggest most the major marine animal diversified?
|
Between about 600 and 500 Myr ago
|
|
|
262. What about molecular dating?
|
Use "molecular clocks" to date the time of divergence of major groups
Based on mutations accumulating at constant rates |
|
|
263. Does molecular dating work?
|
Consistent results for estimating the timing of genetic divergence of recent splits
Results are all over the place for really old divergences like corals from sponges |
|
|
264. Does molecular dating confirm fossil records?
|
Yes
Big boom between about 580 and 520 Myr (only 60 Myr) |
