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SC 139 - First Exam 2000
ANSWER KEY
MULTIPLE CHOICE. On the line to the left, place the letter of the choice that best answers the question.
Four Points Each. NOTE: "e" answers are never the correct answer.
1. The fact that many fossils lay in what was obviously layer after layer of
ancient ocean sediments led directly to the idea that
___C __
a. Living things had evolved over time
b. Some whole groups of living things had become extinct
c. The Earth was much older than people thought
d. The Earth's surface once was covered entirely in water
e. Maybe some guys were spending too much time playing with rocks
...the other things were eventually decided, but the layer after layer
only indicated that lots of time had to have passed to produce such
formations...
2. On the Origins of Species was written by
___B___
a. Darwin & Wallace
b. Darwin alone
c. Lamarck
d. Hardy & Weinberg
e. Regis Philbin
...Darwin and Wallace published the first paper together, but
this book
was just by Darwin, and one of the main reasons why he gets most
of the credit for the ideas...
3. Mutations are most likely to produce
___C___
a. Major changes in traits
b. Entirely new traits
c. No change or a change for the worse
d. All of the variation in a population
e. Game show hosts
...because of the way that DNA works, most changes either
don't
change the proteins made from the code in any significant way or
they change it in a way that screws up what a protein is supposed
to do...
4. Changes may accumulate in two separated groups of the same species
which are more due to chance than selection - this process
is called
___A___
a. Genetic drift
b. Mutation
c. Recombination
d. Las Vegas effect
e. What happens when you never call, you never write...
...right out of the notes, as 2 separated groups just drift
apart
genetically...
5. The early discovery of fossils first presented which "blasphemous" idea?
___C___
a. Evolution
b. Giant serpents
c. Extinction
d. Man as just type of animal
e. Ancient fanged Pope
...some of the other stuff would follow, but at that time fundamentalist
reading of Scripture absolutely meant that none of God's creatures
could have been so imperfect as to have gone extinct - it just could
not happen...
6. A hermaphrodite is
___C___
a. An asexual reproducer
b. A population that is both male and female
c. An individual that is both male and female
d. A genetically-identical offspring
e. Probably a bad thing to call an in-law
...right out of the notes. Just don't fall into the trap of
thinking that
something that can reproduce by itself must be asexual...
7. The fitness of a trait is
___D___
a. Always positive
b. Always negative
c. Determined by alleles
d. Determined by circumstances
e. Related to how much it exercises
...from the notes and covered in the lab, too. A trait is only as
good as
how well it fits your current circumstances...
8. If two species are considered ecospecies, then they should be
___B___
a. Similar in appearance
b. Doing the same job
c. Genetically related
d. Living in the same place
e. Very politically correct
...definition from the notes - two species in the same niche but
different
places...
9. Which group would most likely have the most complete fossil record?
___B___
a. Humans
b. Clams
c. Whales
d. Dinosaurs
e. Have the Fossils made any cd's?
...the question is which of these is most likely to have left the
most
continuous set? Most fossils are from hard parts, from hardened
body-of-water sediments - that gives you clams (shells) and whales
(bones); then, what's more widespread and likely to leave lots
of dead guys on the bottom? Clams.
10. Thomas Malthus produced some very influential ideas about how
___D___
a. Living things evolve
b. Fossils are produced
c. Genes work
d. Populations are limited
e. To be a millionaire
...this was one of the people whose ideas Darwin used to shape his
Natural Selection theory...
SHORT ANSWER.
Answer any six of the following questions for 6 Points Each.
Note: if you answer more than six, only the first six will be corrected.
You can get partial credit on these answers.
1. What is an allele?
...it's a variation of
coding for one gene type (like eye color - the gene is eye color,
but blue, brown, green are different alleles for eye color)
2. Why would the sequence of fossil-bearing rock "skip" large blocks of time in a particular
place?
...some
places, like New York, have been underwater for only part of their
history - when out of the water, fossil-bearing rocks not only don't
form, they erode away...
3. a. What types of environments turned out to be most important to Darwin in forming his
Theory of Evolution by Natural Selection?
...islands
at different distances (and with different features) from a mainland -
it was by comparing the animals and plants that he began to see the
relationships that led to his theory...
b. Why were those types of environments so useful?
...they
allowed him to see how environments shape the life in them.
4. Briefly explain how the founder effect can have a huge impact on a descendant group.
...a
descendant group has to work with whatever limited gene choices
were in its founder - a small founder group can only evolve based on
the small gene pool it starts with.
5. What is taxonomy?
...it's how
living things are classified, or the system of classification for living
things.
6. What are two examples of human diseases that display hybrid vigor.
...these
are genetic diseases where having one "disease" allele and one
"normal" allele is better than two of either - examples are cystic
fibrosis, sickle-cell anemia, Tay-Sachs disease, possibly
schizophrenia
7. What, exactly, is a gene?
...it's a DNA
code for a single type of protein.
8. a. What is artificial selection?
...selective
breeding to develop new types of domesticated
organisms.
b. Why was the concept of artificial selection important to growing ideas of evolution?
...it
showed how "picking and choosing" which individuals breed
could change the nature of the "type."
9. What impact does genetic redundancy have on evolution?
... when extra
copies of a gene arise from mutation, it allows genes to develop
new features without losing the old ones
10. Briefly explain how sexual selection works, in evolutionary terms.
...features
that have nothing to do with survival, but get passed on if they
increase the breeding success of the individual - make them more likely
to be chosen as a mate.
11. In modern-day ideas of Natural Selection, what actually is being selected by the
environment?
...traits
that increase an individual's chance to survive and breed in that
particular environment.
12. What prediction of evolutionary species is supported by observations in the field of
biogeography?
...how
different two similar populations are is connected to how close together
their homes are and how different the environments are.
13. Briefly explain (don't just give the name) of the idea Lamarck had about how evolution
works.
...he
thought that features developed during something's life could be
passed on to their offspring.
LONG ANSWER.
Answer any three of the following questions for Eight Points Each.
Note: if you answer more than three, only the first three will be corrected.
You can get partial credit on these answers.
1. What are three "givens," statements easily acceptable that lead into Darwin's Theory
of Evolution by Natural Selection?
Individuals in a population are different
from each other.
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More offspring are produced than will
survive to reproduce.
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Some traits will give individuals survival
advantages in certain environments
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2. Based on the accepted "givens," explain how, according to Darwin, organisms evolve in
a particular environment. There are at least three steps, more depending upon how you
explain them. Note: The KEY answer is more detailed than
what you'd need to give.
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A particular environment will determine which traits in
individuals are advantages, and so which organisms will be more likely
to survive, reproduce, and pass the traits on. |
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Each generation will show, more and more,
traits suited to the current environment, and pass on even more
advantageous combinations or variations of traits. |
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Over time, the basic "type"
for each living thing may be so different from its ancestor that it
becomes a new species. |
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3. Answer the following for the process of sexual reproduction:
| Definition: Offspring
are a mix of genes from 2 sources
(Remember, it isn't male and female or 2 parents - many
sexual reproducers don't do it that way)
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| Evolutionary
Produces lots of variation in offspring.
Advantage: (Evolution
works on variation, remember - the more, the quicker)
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| Evolutionary
Cannot produce exact duplicates of advantageous forms.
Disadvantage: (Offspring
are always a mix of traits - good combinations can be lost)
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4. What are four conditions that the Hardy-Weinberg Law insists are necessary to keep
allele proportions in a population constant over time? (There
are more than 4)
No mutation.
Genes
don't enter or leave the population. |
Mating is random.
Population must be quite large. |
There is no selection of traits.
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5. Describe (don't just give a simple label) four different ways that groups can become
isolated from each other.
Physically exist in different places (geographic).
May exist in same place but move into
different niche (habitat). |
May exist in same place and do similar job
but use different time schedule for feeding
and/or breeding (temporal). |
May develop different patterns for choosing
mates (behavioral).
May develop differences in
structure of breeding devices (mechanical). |
May develop incompatibility between egg cell
and sperm (gamete).
May reject zygote or embryo
before it's fully developed (zygote). |
BONUS QUESTIONS are not
answered - they depend upon class attendance. Some older bonuses
have become part of basic lecture material now, though.
BONUS QUESTIONS. Answer as many as you are able. Wrong answers will not result
in points being lost from the main exam. You can get partial credit on these answers.
What were the first fossil bones and shells explained away as? Two Points.
What discoveries made this last explanation hard to support? Two Points.
What reasons motivated Charles Darwin to sign onto the crew of the HMS Beagle? Two
Points each.
What reasons other than scientific study may have led Charles Darwin to spend as much
time ashore during his voyage on the HMS Beagle? Three Points each.
Where did Alfred Russel Wallace do his work (2 Points), and why was that a good place
to develop his theories (Three Points)?
Why is the really good evidence that exists for evolution in the real world largely ignored?
Three Points.
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