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Lecture I. Practice Question Answers.
1. (4 pts) Questions on energy.
a. Why is it necessary for organisms to obtain energy?
b. How do green plants obtain energy?
c. How do animals obtain energy?
d. What is the ultimate source of energy for all organisms?
2. (2 pts) The figure below shows some of the levels
in the biological hierarchy discussed in introductory texts. List four additional levels that fit between genes and populations.
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3. (1½ pts) Disorder in the Department of Entropy.
List three things you could do to reduce entropy
in the office. What would each reduction require?
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4. (8 pts) Consider gas molecules in a box divided into
two equal sized compartments by a permeable membrane. Let 𝑝1 be the fraction
of molecules in compartment
1, and 𝑝2 , the fraction in
compartment 2. The entropy, 𝐸, of the system is
𝐸=
𝑝1 log 𝑝1 +𝑝2 log 𝑝2
−
log 2
(1)
where log 𝑝1 is the common (base 10) logarithm of 𝑝1,
etc. Note that by definition,
𝑝1 + 𝑝2 = 1.
(2)
a. What are the values of p1 and p2 in the figure?
b. Using Equation (1), compute E for p1 = .01,
.10, .25, .5, .75, .9, and .99.
c. For what value(s) of p1 on [0, 1] is E minimal?
d. For what value(s) of p1 on [0, 1] is E maximal?
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5. (4 pts) Hoyle argued that the spontaneous origin
of life, essentially because the time required to
create biological complexity by random mutation
vastly exceeds the time that was available. How
might an evolutionary biologist respond?
6. (4 pts) Crudely, one can think of cells as “bags”
of biological molecules that permit controlled molecular exchange with their environment. From
the perspective of the Second Law, why should
biological molecules be so
packaged?
7. (4 pts) Why did Schrödinger
imagine
the
informationbearing crystal to be aperiodic, i.e., why wouldn’t a “periodic” crystal such as NaCl Table salt (NaCl) is
a “periodic” crystal.
(right) have sufficed?
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8. (4 pts) Regarding cells and viruses: a. If cells
from cells, whence cometh the first cell? Give two
possibilities. b. Viruses lack most of the structure
of even the simplest cells. Whence cometh viruses? Give two possibilities.
9. (4 pts) Regarding the evolution of multicellular
organisms: a. In unicellular organisms, the cell is
the organism; in multicellular organisms, cells are
building blocks. How might the first multicellular
organisms have evolved? b. If complete genomes
are replicated when cells divide, how can one account for different cell types in multi-cellular organisms?
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10. (8 pts) Darwin and Alfred
Wallace, the often neglected co-discoverer of
natural selection, both
imagined phyletic descent as a branching
tree. By this, it is meant
that any two living species have a unique common ancestor, and that,
by extension, there is a
universal common ancestor of all living species.
Famous
a.
'branching tree”
sketch from Notebook B
Does decent with (1837) was Darwin’s first attempt at illustrating his theomodification necessi- ry. From Shu, 2005. Guidtate a tree-like pat- ance to Reading 'On the
tern of relatedness? Origin of Species'. Peking
University Press.
b. Why or why not?
11. (8 pts) Redraw Figure 20 under the assumption that
the environment is never limiting, i.e., that reproduc-
tion and survival rates do not change with increasing
population size. Do superior descendant varieties still
exterminate their ancestors?
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12. (8 pts) Regarding altruistic behavior, i.e., acting
in a way that benefits another individual’s fitness
at cost to your own: a. Why is this a problem for
the theory of evolution by natural selection? b.
Give three reasons why altruistic behavior might
nevertheless evolve.
13. (8 pts) As an example of unexpected relationships consequent to ecological complexity, Darwin (1859, pp. 73-74) argued that village cats
can promote the abundance of red clover as
shown below.
Can you think of another example of complex
ecological interactions that produce unexpected
and/or important effects?
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14. (2 pts) What do you think Darwin and Wallace
might each have had to say about the “little yappers” (below) that infest retirement communities?
“Real” dogs (left) and “rodent” dogs (right), both shown in their
native habitats, share a common wolf-like ancestor.
15. (4 pts) Regarding William Paley. a. Who was he? b.
What was his iconic example? c. In what way does
the existence of vestigial structures such as the
human coccyx, undercut Paley’s argument?
16. Male bighorn sheep contest with each other for mating
privileges. Discuss the factors selecting for and against
large horn size in this species.
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