Lecture 2.1: Practice Questions.

Transcription

1 Lecture 2.1: Practice Questions. In an interesting essay on the social / moral implications of Darwinism linked to the Announcements page, philosopher of science Ian Johnston writes as follows: Darwin's theory is totally rejected by approximately half of the population in North America, one of the best educated and most scientifically sophisticated societies the world has ever seen. People have no trouble accepting Newton or Einstein; there is, by contrast, enormous hostility to Darwin. it is far too simple to write that rejection off as the result of ignorance or simple religious prejudice. The fact is that what Darwin did in 1859 was the most revolutionary act in our intellectual history, and millions of people still find the consequences unsettling and unacceptable. 1. (4 pts) Why does Johnston characterize writing The Origin as the most revolutionary act in our intellectual history? 2. (4 pts) What are the consequences that millions find unacceptable? 3. (7 pts) Consider the following observations often cited as supporting the assertion that species change 1

2 through time. Which of these is consistent with TSC? In each case, explain your answer. a. Most species extinct. b. Fossil species frequently resemble living species in the same area. c. Among contemporary species, relatedness more closely correlated with geography than with environment. d. Existence of transitional fossils missing links. e. Earth ancient. f. Vestigial organs. g. Populations and species changing today. 4. (4 pts) Which of Darwin s facts have anything to do with natural selection? 2

3 5. (6 pts) The same genes determine eye development in fruit flies, cephalopods and humans. In flies & vertebrates, the structures are different; in vertebrates & cephalopods, superficially similar, but developmentally distinct. Give two possible scenarios for the evolution of complex eyes in the three groups. 6. (6 pts) The picture at the right illustrates structural homologies in vertebrate forelimbs. a. What conclusion would an evolutionist deduce from the picture? b. What might an intelligent designer have to say about it? 3

4 7. (4 pts) Which of the following scientists would most likely have been comfortable with the Eldredge-Gould model (punctuated equilibrium) of evolution? a. Cuvier. b. Darwin. c. Lamarck d. Lyell. 8. (6 pts) According to the phylogeny at the right, sponges (Porifera) are primitive in the sense that they lack socalled derived characters (gut, cell layers, bilateral symmetry, etc.), that distinguish higher animals. Contrast the different explanations that Darwin and Lamarck would have offered for simplicity in sponges. Phylogeny of animals. Red circles are evolutionary innovations that unite descendent phylogenetic groups. 4

5 9. (8 pts) In the figure at the right, carbonaria stands out against the lichen-encrusted tree trunk; typica, against soot-covered trunk. This is often held to be evidence supporting the bird predation hypothesis. Implicit in this assertion are two assumptions. What are they? Speckled and melanic moths on natural and polluted trees. 10. (8 pts) The emergence of antibiotic resistance has led to renewed interest in phage therapy (use of bacteriophage) as a way of dealing with superbugs. Give at least one advantage and one disadvantage of phage therapy vis-a-vis antibiotics. (Requires outside reading see, for example, Häusler, Viruses vs. Superbugs: A Solution to the Antibiotics Crisis?) 11. (4 pts) What is the purpose of the control plate in the Lederberg experiment? 5

6 12. (8 pts) Changing beak morphology in Darwin s finches illustrates what Steve Gould called the contingent nature of evolution. a. What did Gould mean by this? (You may have to look up the word contingent.) b. What are the implications for constructing a theory of evolution that predicts the broad outlines of the history of life on earth? 13. (8 pts) Many evolutionists maintain that evolution is neither goal directed nor progressive. Yet both cell / molecular biology and the fossil record show an overall increase in maximum size and complexity over the past 4.5 billion years. What do you make of that? Increasing numbers of cell types over the past 4 billion years. From Hedges, S. B. et al A molecular timescale of eukaryote evolution and the rise of complex multicellular life. BMC Evol. Biol. 4. 6

7 14. (6 pts) Natural selection is sometimes described as survival of the fittest, a term due to Herbert Spencer who ironically rejected selection as the principal driver of evolution. Spencer s metaphor suggests competition for resources. Such competition can involve interference (male-male contests for mates, territoriality, etc.) or exploitation. Note the essential difference: In the first case, you outcompete your rival by reducing his efficiency more than your own; in the second, you win the game by being more efficient. a. Consider the case of trees growing in a forest. Give an example of how they compete with each other by interference. Give an example of how they compete exploitatively. b. If selection favors traits that increase the fitness (reproduction and/or survival) of individuals, it would seem to follow that animals should not do things for the good of other animals aside from their offspring. Explain why. c. How then do you account for altruism? 7