SC 139 - First Exam 1997
ANSWER KEY
Three Points Each. NOTE: "e" answers are never the correct answer.
1. Early attempts at classifying living things led to which logical connections?
___B___
a. Living things must have been around a very long time
b. Related but different groups might have ancestors in common
c. Scientists could decide where dinosaurs came from
d. Fossils could be natural rock formations
e. Giving yourself a fancy Latin name still won't get you a date
...if you know anything about this at all, only one answer makes sense.
...the earlier you set a new course, the farther from the first finish
point
you wind up...
3. Which is true about classification levels?
___A___
a. Families are in orders which are in classes
b. Phyla are in orders which are in a genus
c. Species are in classes which are in families
d. Orders are in classes which are in families
e. It's unusual for a tree to pull rank on a flower
...you need to know the order of groups and which are bigger,
would contain the others.
4. Technically, a gene codes for
___D___
a. A trait
b. An offspring
c. DNA
d. A protein
e. Your long-distance carrier
...basic current definition
5. All the finches on the Galapagos Islands are
___B___
a. Completely unrelated
b. Descended from a common ancestor
c. Now in competition with each other because they all feed on seeds
d. Both a and c
e. a, e, i, o, u and sometimes y
...several different species, but branched off from the same starting
species.
6. Darwin's famous book was called
___A___
a. On the Origin of Species
b. A Theory of Evolution by Natural Selection
c. Survival of the Fittest
d. The Voyage of the Beagle
e. I'm a Chimp, You're a Chimp
...just information you're supposed to know...
7. A small starting group has only those alleles present to pass on to their
descendants. This is
___B___
a. Genetic drift
b. Founder effect
c. Mutation
d. Habitat isolation
e. Tough luck
...the small starting group is the founder group - big clue!
8. A group of organisms called the Ediacarans existed long ago, then
disappeared from the fossil record. They may have died out, or
they may have not fossilized anymore. If the last idea is true,
how might that have happened?
___B___
a. They lived only at the bottom of the ocean
b. They were soft-bodied organisms
c. There were very many of them
d. None of these would explain it
e. They stopped accumulating frequent-fossilizer mileage
...it's hard for soft-bodied things to fossilize, and the other two
would
increase their chances of showing up.
9. An evolutionary pace of short, dramatic bursts with long stable periods
between:
___D___
a. Geologic
b. Catastrophic
c. Staccato stasis
d. Punctuated equilibrium
e. Hurry up and wait
...basic definition.
10. Darwin developed a theory of evolution by natural selection, but a process
that he grew up knowing about was
___B___
a. Artificial selection
b. Genetics
c. Mutations
d. Sexual selection
e. Inheritance of parental expectations
...artificial selection - he knew that things could be bred to be
different over time by people.
11. The science of classifying organisms is known as
___C___
a. Organization
b. Speciation
c. Taxonomy
d. Hierarchy
e. An evolutionary dead-end job
...basic definition
12. The white-tailed deer occupies a niche here almost identical to the niche
filled by kangaroos in Australia; these two groups are
___B___
a. Subspecies
b. Ecospecies
c. Niche relatives
d. Habitat sharers
e. Too nichin' cool
...an example that fits the definition in the notes...
13. The current basic definition of a species is based upon
___C___
a. Physical resemblance
b. Genetic resemblance
c. Reproductive behavior
d. Offspring fertility
e. Whichever of the twelve possibilities the dart hit today
...this is tricky because the other three could be used, but
aren't
currently (although "b" could replace "c" in
the future)...
14. When a population is small, there's a greater chance of
___B___
a. Gene flow
b. Genetic drift
c. Natural selection
d. Mutations occurring
e. Boredom
...the operative part is "greater chance," which allows new
mutations
to have a bigger impact (they start out as a decent fraction in a
small population).
15. One way of figuring out the age of a layer of fossil-containing rock is
to
___B___
a. "Zap" it with radiation
b. Match up layers from different places
c. Determine its sand content
d. Count how many fossils it has
e. Wait for its birthday and count the candles on the cake
...matching layers on an overall chart tells you how "far
down" you
are. Radioactive dating means looking for breakdown materials,
not "zapping."
SHORT ANSWER.
Answer any eight of the following questions for 4 Points Each.
Note: if you answer more than eight, only the first eight will be corrected.
You can get partial credit on these answers.
...the "diploid
organisms" is just kind of a disclaimer - it's the "sexually
reproducing" part that's relevant, that gives us recombination,
that gene "mix and match" of sex, and mutation, which
also provides variation in asexual reproducers.
2. What is hybrid vigor?
...Definition - having two different alleles for a gene is better
than having a pair of either allele. (Remember the sickle-cell
/ malaria example)
3. Briefly describe two different ways that organisms might get fossilized.
...more
than two: covered in sediment at the bottom of a water body
(giving different types of water bodies doesn't give the different ways
asked for); covered in sand; engulfed in mud;
encased in sap (makes amber); covered in volcanic ash (lava
doesn't really work - it incinerates things and then sets too hard).
4. What do homeogenes do?
...They're involved
in basic layout processes during very early development.
(For example, in people they determine where the eyes will
be, which will be left-side-right-side, where limbs grow, etc.)
5. What widely-accepted view of the world's past was put in trouble by the discovery of
remains of extinct animals?
...long
before someone suggested evolution, just finding extinct animals went up
against the view that all creatures made for Eden were perfect and
not capable of dying out.
6. Name two different types of chemicals that can be used in comparative biochemistry.
...there are
more than 2: DNA (and/or RNA), Proteins, Metabolic chemicals.
7. Many human genetic diseases may not be bad in every circumstance. Name two
examples of diseases that may sometimes produce good effects.
...this is
meant to be a hybrid vigor question: sickle-cell anemia
can protect against malaria, cystic fibrosis can produce
resistance to various diarrhetic diseases, Tay-Sachs may resist
tuberculosis, schizophrenia may produce artists and risk-takers.
8. What would be the "ticks" of a DNA molecular "clock?"
...mutations
changing the building blocks, supposedly done at a regular rate over
time.
9. What are the two not-so-great ideas about evolution that Lamarck is remembered for?
...that traits
acquired over a lifetime could be passed on...and that evolution is a
process moving toward a goal of perfection.
10. What is the basic statement made by the Hardy-Weinberg Law?
...the
ratio of an allele in a population can only change if certain things are
true - otherwise, even a rare allele will "hang around"
11. Mass extinctions may have several different causes. Name two different
possibilities.
...a mass
extinction would involve a lot of species over a fairly short time, and
there are more than two: asteroid/comet impacts; volcanic
eruptions; ice ages; continent movement (can produce
major climate changes or connect areas not connected before)
12. What are two ways that Malthus saw populations could be controlled?
...more
than 2: disease, starvation, war
13. What is a niche?
...it is
the purpose (job) that a species could serve in an ecosystem (it can
be there even if it isn't occupied)
14. Gene redundancy can be a very important facet of evolution. Briefly explain how.
...because
it involved mutating an extra copy of a gene, the new copy can evolve a
new purpose without disturbing the function of the original.
15. Briefly explain: what is one way that biogeography can provide evidence for the
process of evolution?
...it can
show the similarities / differences of ecosystems in different places -
how the places differ usually connects to how the organisms differ.
16. There are generally three possible results from a mutation in the DNA molecule.
What are two of them?
...it may have no effect on anything, or it may be an insignificant effect; if there is an effect, it most likely will be a bad effect; rarely, it may produce an improved effect
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. Analogous Structures: Definition... |
Do the same function. |
| Common type of evolution: | Convergent - develop to address similar needs |
| Homologous Structures: Definition... |
Have the same basic structure. |
| Common type of evolution: | Divergent - developing structures to do different things. |
2. There were three "given" statements to set up Darwin's theory on evolution by natural selection. What were they?
|
Individuals in a population are different
from each other. |
|
More offspring are produced than will
survive to reproduce. |
|
Some traits will give individuals survival
advantages in certain environments |
3. After the three givens, Darwin's theory on evolution by natural selection was stated as three follow-up results. What were they?
| 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. |
| Each generation will show, more and more, traits suited to the current environment, and pass on even more advantageous combinations or variations of traits. |
| Over time, the basic "type" for each living thing may be so different from its ancestor that it becomes a new species. |
|
|
4. Charles Darwin's life went through several major steps between his schooling and his becoming famous for his theory of evolution. Briefly describe four of those major steps, placing them in chronological order. Skipping steps is okay, as long as you get four down and they're in the order they happened.
| He signed on the ship Beagle.
He sailed around the world, taking lots of notes and samples. |
| He returned to England and became a fairly obscure
scientist.
He developed his theories and told his fellow scientists. |
| Alfred Russel Wallace came up with similar ideas
and wanted to publish them. It was arranged that Darwin and Wallace "premiere" their ideas together. |
| Darwin wrote On the Origin of Species.
|
5. Name and describe four different types of isolation that can lead to production of a new species.
| Geologic | Physical separation of groups |
| Habitat | Groups in same area use different physical niches. |
|
Temporal
|
Groups do similar things in same place but have different times |
| Behavioral | Groups become separate because they develop different mating patterns |
| Mechanical | Reproductive structures become different enough that they are incompatible between groups. |
| Zygote | Embryos are rejected. |
| Gamete | Sperm or egg cells are not effective in certain combinations. |
| 6. Asexual Reproduction Definition: |
Offspring are genetic copies of the original. |
| Advantage: |
Produces exact copies of successful forms. |
| Disadvantage: |
All of the copies can be equally at risk when risks arise. |
| Sexual Reproduction Definition: |
Offspring are mix of genes from 2 sources. |
| Advantage: |
Great variation (and adaptation potential) in offspring. |
| Disadvantage: |
Exact copies of successful forms cannot be produced. |
|
No mutation. Genes don't enter or leave the population. |
|
Mating is random. Population must be quite large. |
|
There is no selection of traits. |
|
|
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 was the actual task that Darwin was hired on to the Beagle to perform? Describe it, rather than just giving it a name. Three Points.
What major continental-drift development occurred, changed ocean currents, then climate, to
possibly set up the evolution of humans from jungle-living ancestors? Four Points.
Explain what is meant by "Ontogeny recapitulates phylogeny." Three Points.
Explain how the schizophrenia allele might have a positive affect. Four Points.
What particular feature about the history of the world itself would support both theories about
the pace of evolution? Four Points.
What discovery from the bottom of the Gulf of Mexico was announced last weekend? Three
Points.