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EEB245/Evolutionary Biology: Problem Set 3
Due date: 04/07/2004
Name:________________________________
PLEASE TYPE YOUR ANSWERS ON A COMPUTER AND PRINT THEM OUT. Try to be as
brief and concise as possible (my longest answer is only 4 sentences long, and most are 3 or fewer).
1. In August 2001, a board member for the Hawaiian school system proposed teaching creationism
along with evolution in Hawaiian schools. This measure was defeated by a vote of the school
board on the basis of several strong arguments. List three of the arguments that you feel most
strongly justify the position of not jointly teaching creationism and evolution as alternative
theories. (3 pts)
I was looking for arguments that people used to justify the position of not jointly teaching
creationism and evolution as alternative theories in this particular case. There were quite a few
answers to choose from and I basically took any of them if your argument was compelling. Here are
some of the popular answers:
• The Constitutional amendment that requires the separation of church and state
• Creationism is a religious belief rather than a scientifically testable hypothesis and therefore
should not be taught in science classes
• The Bible contradicts what is known about the age of the earth, fossils, etc.
• Different religions have different views of creationism. Which one should be taught?
2. Why is the theory of evolution by natural selection now considered to be fact? (4 pts)
The theory of evolution by natural selection has been tested repeatedly by huge numbers of studies,
and the sheer volume of compelling evidence in its favor is so overwhelming that we now consider it
to be fact. We have also seen natural selection operate under both natural and experimental
conditions.
3. How might we use evolutionary biology to explain the apparent non-adaptive value of certain
traits? Provide a real-life example of such a trait to support your answer. (4 pts)
For certain traits that seem non-adaptive in the modern organisms that possess them, we can trace
the evolution of that character back through time using a phylogenetic approach. We can see how
that trait arose in the ancestors of the organism we are interested in, which would provide insight as
to how that character was modified in descendant taxa. It is not uncommon to find characters that
were once adaptive in some ancestral taxa but have lost their functional significance through time.
These characters persist in descendant lineages because they are selectively neutral (e.g. vestigial
organs such as the human appendix), or they might be developmentally associated with a character
complex such that they have ‘piggy-backed’ their way through speciation events (i.e. pleiotropy).
4. Creationists often argue that no ‘intermediates’ exist in the fossil record, suggesting that gradual
evolution within organismal lineages could not have occurred as Darwin suggested. List three
well-documented examples that contradict this statement (hint: we discussed a few possible
answers during the first half of the course). (3 pts)
There are many possible answers to this question, but here are a few of the most popular ones:
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There are excellent fossils that demonstrate the transition between certain lineages of
Saurichian dinosaurs and modern birds. Many of you mentioned Archeopteryx (which I
accepted), but don’t forget that Archeopteryx is actually considered to be a true bird. It’s
correct to say that this species had characters that were more dinosaur-like than any modern
bird, but it shares derived features with modern birds that place them in the same clade.
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There are excellent transitional fossils that demonstrate the evolution of whales from extinct
terrestrial and semi-aquatic mammals.
One of the best examples of transitional fossils involves the evolution of horses, beginning
with the extinct equid Hyracotherium. Some authors of the early 20th century believed that
horse evolution was under the control of a weird inner force because the transitional fossils
follow such clear, directional trend toward modern equid taxa.
The evolution of the homid lineages is a good one as well. Remember all of those fossils
demonstrating transitional morphology from the various Australopithecine species to the
extinct Homo species?
5. Biologists typically define subspecies as distinct evolutionary lineages within a species, which
can be recognized on the basis of both morphological and DNA evidence. a.) Why do we not
recognize traditional subspecies in humans? b.) If we considered morphology alone, could we be
led to a different conclusion? Justify your answer. (4 pts)
a.) We do not recognize subspecies in humans because a greater proportion of the genetic variation is
observed within races rather than among races (due to extensive gene flow). b.) Based on the
distinctiveness of racial phenotypes, one could be misled to the conclusion that subspecies do exist
within humans.
6. Following question 5, how might evolutionary biology be used to refute racism? (3 pts)
Here are some of the popular answers:
• Humans all share a common ancestor and are united as a single evolutionary lineage.
• There is almost no genetic variation that distinguishes among human races.
• The greatest proportion of genetic variation in humans is observed within races rather than
among races. This means that you are probably more genetically differentiated from members of
your own race than you are to people of a different race.
There are many possible answers to this question. If you had an idea and supported it well, I gave
you credit.
7. a.) Is rapid, global climate change more likely to lead to extinction or speciation? If it helps, you
can provide an example from nature, fossil or otherwise, to explain your answer (hint: you could
discuss some historical event that led to a climate change and its subsequent effects on plant or
animal life). b.) How might the rate of climate change affect either process? (4 pts)
Generally speaking, rapid global climate change is more likely to cause extinction. Three of the five
mass extinctions we discussed in class were largely caused by fast, extreme changes in climate, with
75% of all species on earth going extinct. Slower and more gradual climate change is more likely to
result in speciation given that organisms will have adequate time to adapt to the changing
environmental conditions.
8. Creationists claim that some species, such as the tuatara, ginko, cockroach, horseshoe crab, and
the coelacanth are “fossil species” that have not evolved for millions of years, and therefore
contradict the theory of evolution. Explain why this statement is false. (4 pts)
If the environment of these species has not changed over time, evolutionary theory would predict that
their morphology would not change, or change very little. Also, these organisms are genetically
evolving in ways that aren’t necessarily observed in the phenotype. Some of you also mentioned
punctuated equilibrium: the idea of punctuated equilibrium is that the major new features of a
higher taxon are established rapidly in the early evolution of a lineage. The overall body plan is then
‘stabilized’ under stabilizing selection and changes little thereafter.
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9. The endangered tailed frog Ascaphus truei is the last species of an ancient evolutionary lineage
that is the sister taxon to all other living frogs, and occupies a restricted geographic area in the
Pacific Northwest. On the other hand, the northern spotted owl Strix occidentailis caurina is an
endangered subspecies that is not genetically distinct from two other currently recognized
subspecies of the spotted owl, and is more geographically widespread than the tailed frog. This
suggests that the spotted owl Strix occidentailis consists of a single unified lineage with little or
no geographic differentiation among the currently recognized subspecies (similar to the human
example above).
If you were forced to prioritize your conservation efforts as a wildlife biologist, how might you
use the phylogenies and the distribution of these organisms to decide whether to focus your
efforts on the tailed frog or the northern spotted owl? (5 pts)
The vast majority of you favored saving the tailed frog Ascaphus truei, which I agreed with. The
general argument that I found most compelling was that this species represents that last of an
ancient evolutionary lineage. It has no close living relatives, and its extinction would result in the
loss of millions of years of evolution. Furthermore, its range is very small and the effects of
inbreeding are likely to be pervasive.
10. Name three factors that affect the speed of evolution in natural populations. (3 pts)
There were 3 factors that Dr. Simon specifically pointed out repeatedly during the semester:
a. the strength of natural selection
b. genetic drift, which is related to population size
c. gene flow, or the rate of immigration of alleles
11. Although ecology and evolutionary biology have traditionally been considered separate
disciplines, the two fields have become united under more recent times as the study of
“evolutionary ecology”. Provide a brief explanation as to how the two fields are interfaced under
evolutionary ecology. (4 pts)
Evolutionary ecology integrates evolution biology and ecology through the study of how organisms
have adapted to both the biotic and abiotic factors of their environment.
Go to the website below to answer questions 12-14:
www.law.umkc.edu/faculty/projects/ftrials/scopes/scopes.htm
12. What Tennessee law was on trial and what did this law state? (2 pts)
13. Scopes Trial matching (each participant in the trial has two descriptors; 5 pts)
_________ George Rappalyea
_________ John Scopes
_________ H. L. Menken
_________ William Jennings Bryan
_________ Clarence Darrow
a) His popular columns were marked by flair for exaggeration, caustic wit, and hostility to
prohibition, censorship, and other attempts to purify America.
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b) His crusade had succeeded in getting legislation proposed in fifteen states banning the
teaching of evolution in public schools; he hoped to establish a US Constitutional antievolution amendment but died before he could accomplish this.
c) Rhea County science teacher and athletic coach arrested while sipping a coke at a local
drug store.
d) Know for defending “murderers, communists, socialists, and anarchists”
e) His distaste for fundamentalism was increased when he overheard a minister say, “This
here boy, cause his pappy and mammy didn’t get him baptized, is now awithin’ the
flames of hell.”
f) Had a life-long interest in science, and his family “had all of Darwin’s books as fast as
they were published.
g) Contacted the ACLU and asked them to finance a trial testing the anti-evolution law.
h) He called the people of Dayton, “yokels”, “primates”, “morons”, “half-wits”, and
“hillbillies”.
i) Was taught evolution as the University of Kentucky.
j) As a young man, “looked into evolution” and found it wanting. He said, “When I want to
read fiction, I don’t turn to the Arabian Nights; I turn to works of biology – I like my
fiction wild!”
14. Which phrase describing “Inherit the Wind” is incorrect? (2 pts)
a) It was first a play and then a movie.
b) The character’s names were changed from their real life models.
c) Its main theme was intolerance.
d) It was meant to be a historically accurate treatment of the trial.
e) The transcript of the cross-examination was very close to that of the real trial.
Bonus: A prominent figure in American politics recently said, “They jury is still out on evolution.” This
same person also added that he “doesn’t take every word of the bible to be literally true.” Who is this
person? (hint: use Google). (2 pts)