Descent with Modification: A Darwinian View of Life

1. Chapter 22 Descent with Modification: A Darwinian View of Life Questions prepared by Janet Lanza University of Arkansas at Little Rock Michael Dini Texas Tech University

2. Lamarck’s Hypothesis of Evolution Lamarck thought evolution had occurred. Lamarck’s proposal that individuals evolve by the principle of use and disuse is well supported by evidence. Lamarck was wholly wrong. Lamarck published his ideas only after Darwin published his. Which of the following statements about Lamarck is/are accurate?

3. Darwin’s Knowledge Darwin thought individuals varied. Darwin thought the Earth was a few thousand years old. Darwin thought fossils in a given area were similar to the animals that were still living there. Darwin thought organisms produced many offspring. Darwin thought few offspring of a pair survived. Which of the following statements about Darwin following the voyage of HMS Beagle is incorrect?

4. The Unity and Diversity of Life Which of the following statements can be associated with the concept of the “unity of life” and which can be associated with the concept of the “diversity of life”? • The amino acid sequences of cytochrome c (an enzyme in mitochondria) differ between humans and chimps by one amino acid. • If the gene for human insulin is inserted into bacteria, the bacteria can make human insulin. • Medium ground finches (Geospiza fortis) have beaks that are similar in shape but smaller than large ground finches (Geospiza magnirostris). • The basic forelimb structure of horses and moles is similar. • Scientists interested in curing human cancer may study cell division in yeasts.

5. Adaptation If an adaptation is defined as a trait that promotes survival or reproduction, which of the following traits would qualify as an adaptation? • Hemoglobin is one color (bright red) when oxygenated and another color (purple-blue) when deoxygenated. • Humans have a “tailbone” (coccyx). • Many desert plants have leaves shaped like needles. • The presence of sickle-cell hemoglobin allele helps the holder survive malaria.

6. Descent with Modification Which of the following conclusions could you correctly draw after studying the figure on the next slide? a) Barytherium is an ancestor of Platybelodon but not of the manatees and relatives. b) Loxodonta cylotis is more closely related to Loxodonta africana than to Elephas maximus. c) Mammut shares a more recent common ancestor with Stegodon than with Elephas maximus. d)Manatees are more closely related to the living elephant species than hyraxes are. e) Elephas maximus is an ancestor of both Loxodonta species.

8. Action of Natural Selection Imagine a species of bird in which females prefer to mate with brightly colored males. However, males with bright backs are more often preyed upon by hawks. Assuming that a wide variety of genetic variation exists in the species, which do you think is the most likely evolutionary outcome? • Males will be selected to be brightly colored. • Females will be selected to choose drab males. • Males will be selected to have bright chests and dull backs. • Females will not mate. • The species will go extinct because the hawks catch all the males.

9. Evidence for Evolution Which of the following statements could challenge the evolutionary view of the history of life on Earth? Be prepared to explain your answer. • New mammal fossils are discovered in the oldest rocks on Earth. • Coal deposits are found in Antarctica. • The mitochondrial DNA of the medium ground finch in the Galápagos is identical to a bird species in Europe. • Both sugar gliders (Australia) and flying squirrels (North America) use flaps of skin to help them glide from one tree to another. • Horse fossils occur in North America even though there were no wild horses in North America in 1492.

10. Homologies and “Tree Thinking” Imagine that a phylogeny was developed for a group of mammals based on bone structure. Which of the following statements would be a reasonable prediction about a phylogeny for the same group of species based on similarities and differences in the structure of a particular enzyme? • The same phylogeny would be predicted. • The same phylogeny would be unlikely. • No prediction could be made. • The amino acid sequence would be identical in all species. • The new phylogeny would be different.

11. Imagine two species that are thought to have a recent common ancestor. If this idea is correct, these two species most likely have Homologies and “Tree Thinking” • no morphological similarities. • few biochemical similarities. • some genes with identical amino acid sequences. • very different habits. • similar embryological development.

12. Evolution of Adaptations Imagine that you have discovered a new lizard that lives in a foggy desert in southwestern South America. As fog rolls in, this lizard stands on its head and lets water condense on its back and roll in grooves to its mouth. Considering the Namibian beetle in the figure below, this trait is an example of which of the following? • convergent evolution • inheritance of acquired characteristics • homology