This exam is closed book, closed notes. You have 2 hours. Good luck! Part I. (48 pts.): Answer 12 of the following 15 short questions. Please cross out the 3 that you do not do. Each of these questions is worth 4 pts.
1) When and why does a star become a "red giant?" When and why does a star become a "white dwarf?"
2) Put the following three "milestones" of the Big Bang in chronological order: nucleosynthesis, decoupling, electron-positron annihilation. For each milestone, tell what happened and give a brief explanation of why it happened.
3) What is "gravitational lensing?" Explain why Einstein's General Relativity predicts gravitational lensing.
4) Like the sun, Jupiter is composed mainly of hydrogen and helium. Explain why Jupiter, unlike the sun, doesn't shine.
5) According to current theory, most of the observable universe is not made up of ordinary matter, but of "dark matter" and "dark energy." Choose either dark matter or dark energy and give one reason we think it exists AND one property that we believe it has.
6) Why are there volcanoes above subduction zones? (i.e., why does rock melt within subduction zones?)
7) Why is the lithosphere (plate) very "stiff", and why is the asthenosphere very "soft"? (Use the words geotherm and solidus in your answer.)
8) Explain the differences/similarities between granite, rhyolite, basalt, and gabbro.
9) What is meant by the greenhouse effect, and how does human activity play a role in it?
10) Why might we be the only "intelligent" life form in the galaxy?
11) Describe how channels participate in achieving intracellular homeostasis and hormones participate in achieving organismal homeostasis.
12) Explain how protein gradients in the egg influence the course of embryology.
13) Using your understandings based on Chapter 9 of Sacred Depths of Nature (or other sources), explain what is meant by saying that sexual organisms shuffle their genomic decks at each generation.
14) Explain what a fitness indicator is and why it is important that it be costly.
15) Explain why neuronal communication in the brain is influenced by both depolarization and hyperpolarization.
Part II: (60 pts.) Answer 6 of the following 9 long questions. Each is worth 10 points. At least one of your 6 answers needs to be from each of the three different sections (A,B, and C). Please cross out the three questions that you do not do. Use the other page side if necessary.
SECTION A:
A1) List the four fundamental forces in order from strongest to weakest. (As
we did in class, use the strengths of the forces between 2 almost touching
protons as the basis for your comparison.) Tell whether each force is short
or long range. Drawing your examples from the Big Bang, stellar processes,
the formation and history of the Earth, or processes within living organisms,
describe two important roles each force plays.
A2) Describe, in as much detail as you can, a supernova explosion. For full credit, your answer should include: (a) a statement about how massive [much less than a solar mass? about a solar mass? much more than a solar mass?] a star needs to be to undergo a supernova explosion , (b) when in the star's life cycle the explosion will take place, (c) what causes the explosion, (d) an explanation of each of the 2 parts of the explosion, (e) a statement about the possible final states of the star's core after the explosion, and (f) a statement about why past supernova explosions are important for the Earth and life on it.
A3a) Imagine you are a two-dimensional creature in a two dimensional world.
You are unable to see or move into the third dimension. Describe two ways you
could tell if your world was curved (like the surface of a ball) or flat (like
a plane).
b) The world we live in has three spatial dimensions --- objects can move in
any of three independent directions: right-left, forward-back, or up-down.
How can you reconcile that obvious fact with the statement that our universe
might be "flat?" Wouldn't "flat" mean objects could only move in two
directions?
c) According to recent observation, what is the shape of our observable
universe? Which observation tells us that?
SECTION B:
B1) What are the conditions required for the bonds between atoms in a stable
mineral? Most minerals are held together with ionic and covalent bonds: what
are the differences between these? Why can changing the temperature or
pressure destabilize a mineral and lead to the formation of a new stable
mineral?
B2) Water plays an important role in the "top" part of the rock cycle, involving the erosion of existing rock and creation of new sedimentary rock. Explain in detail this part of the rock cycle, involving erosion, transportation, deposition, and lithification.
B3) The distribution of economically-important natural resources is often a function of plate tectonic history. Explain why large concentrations of both metals and ores and petroleum are often found at plate boundaries (or former plate boundaries). Is this also true for the distribution of coal or groundwater (i.e., where did these come from?)?
SECTION C:
C1) Explain what is meant by the following: Brain evolution can occur either
by changing the number of input nerves competing for a given "brain space" or
by changing the amount of "brain space."
C2) Describe how genomes have evolved, including in your answer the role of mutation (including duplication and bricolage), natural selection, sexual selection, and speciation.
C3) Give an overall account of human evolution from 80 million years ago to 10 thousand years ago (can be presented in non-prose).