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Lewis Life 4e
Life, 4/e
Ricki Lewis, University of New York at Albany
Mariƫlle Hoefnagels, University of Oklahoma
Douglas Gaffin, University of Oklahoma
Bruce Parker, Utah Valley State College

Evidence for Evolution

Testing Your Knowledge

1. What was especially significant about the discovery of:

  • a. Thousands of dinosaur eggs in Patagonia?
  • b. Phosphatized algae and animal embryos in the Doushantuo formation in south central China?
  • c. Theropods with very similar skeletons from different continents, even though their ancestor, Allosaurus, left fossils all over the world?
  • 2. A geneticist aboard a federation starship must determine the evolutionary relationships among Human, Klingons, Romulans, and Betazoids, Each organism walks on two legs, lives in complex societies, uses tools and technologies, looks similar, and reproduces in the same manner. Each can interbreed with the others. The geneticist finds the following data:

    Klingons and Romulans each have 44 chromosomes. Humans have 46 chromosomes. Human chromosomes 15 and 17 each resemble part of the same large chromosome in Klingons and Romulans. Humans and Klingons have 97% of their chromosome bands in common. Humans and Romulans have 98% of their chromosome bands in common, and Humans and Betazoids show 100% correspondence. Humans and Betazoids differ only in an extra segment on chromosome 11, which appears to be a duplication. The cytochrome c amino acid sequence is identical between Humans and Betazoids. It differs in Humans and Romulans by one amino acid and in Humans and Klingons by two amino acids. The gene for collagen contains 50 introns in Humans, 50 introns in Betazoids, 62 introns in Romulans, and 74 introns in Klingons. Mitochondrial DNA analysis reveals many more differences among Klingons and Romulans than among Humans or Betazoids.

  • a. Hypothesize how chromosome differences among these organisms may have arisen.
  • b. Which are our closest relatives among the Klingons, Romulans, and Betazoids? What evidence supports your answer?
  • c. Are Klingons, Romulans, Humans, and Betazoids distinct species? What information supports your answer?
  • d. Which of these molecular tree diagrams is consistent with the data (refer to art in text)
  • 3. What assumptions underlie the following:

  • a. Relative dating based on a fossil’s position in rock strata.
  • b. Absolute dating based on radiometric data.
  • c. The mitochondrial clock.
  • 4. An elephant uses its trunk to bring food to its mouth; a human uses his or her hand. What information would help to distinguish whether an elephant’s trunk and a human’s hand are analogous or homologous structures?

    5. Cite a limitation of comparing chromosome-banding patterns to define species relationships.

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