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SC 139 - First Exam 1998
ANSWER KEY
MULTIPLE CHOICE. On the line to the left, place the letter of the choice that best answers the question.
Three Points Each. NOTE: "e" answers are never the correct answer.
1. Which example fits Lamarck's theory on evolution?
___B___
a. In giraffe ancestors, the taller individuals had more success
b. 2-legged movement in kangaroos can be traced back to the offspring
of an ancestor that injured a front leg
c. Antibiotics select certain bacteria that can withstand them
d. Better-coordinated individuals would be better hunters
e. It's not what you know, it's who you pay off
...you need to know that this involves passing on traits picked up
during
the "parent's" lifetime - only the leg injury fits that
2. Of the energy sources available on the very early Earth, which was least
likely to have been used in forming the first living molecules?
___C___
a. Visible sunlight
b. Heat
c. UltraViolet
d. Radioactivity
e. Hershey's primordial chocolate
...because it can destroy molecules as easily as create them, it
probably
wasn't the energy source...
3. Sickle-cell anemia can, in a hybrid situation, make someone resistant to
___C___
a. Diarrhea
b. Cystic fibrosis
c. Malaria
d. Mutations
e. Telemarketers
...just something out of the notes...
4. Fossil bones seem "rocky" because
___A___
a. Minerals have replaced the bone
b. Radiation changes bone
c. Drying makes them that way
d. The bones were like that
e. It'd be silly for them to seem "bullwinkle"
...also from the notes...
5. Which classification system specifically focuses on the appearance of
traits?
___D___
a. Systematics
b. Taxonomy
c. Speciation
d. Cladistics
e. Traitor system
...each new "branching" comes when a unique feature arises.
6. Charles Lyell's ideas of geologic uniformitarianism and the history of the
Earth has affected most theories on evolution. Which aspect of
those theories reflects this?
___C___
a. Real changes have come about through mutations
b. Traits acquired through a parent's lifetime are sent on to offspring
c. Changes have been very slow and gradual
d. All of these come from geologic uniformitarianism
e. Terms over 15 letters long should be outlawed
...this is almost a definition of the term.
7. The fitness of an adaptation is determined by
___C___
a. Evolutionary biologists
b. Genetic strength
c. The current environment
d. Its mutations
e. Wild athletic trainers
...fitness always relates to current conditions - what's fit today may
not
be tomorrow.
8. The small populations that came across from Asia to North America were
missing some alleles, which remain missing in the current, large
population of Native Americans. This is an example of
___D___
a. Artificial selection
b. Recombination
c. Random mutation
d. Founder effect
e. Why I don't understand any of this
...if you remember what founders are, you'll see it in the question.
9. Homeogenes are involved with
___A___
a. Basic layout of features
b. Mutation control
c. Reproduction
d. Disease resistance
e. Stuff you'd need in the 'hood
...just a definition from the notes...
10. When major fossil discoveries were first made, what immediate implication
challenged the accepted ideas of the time?
___B___
a. Man evolved from apes
b. Living things had become extinct
c. Natural selection was at work
d. Genes had mutated
e. We'll all wind up mounted in museums
...the very first "standing" idea that was called into
question - others were
much later...
11. The process that gave us dachshunds and Siberian huskies is
___C___
a. Natural selection
b. Sexual selection
c. Artificial selection
d. Adaptive radiation
e. Some pretty whacked-out dog breeders
...dog breeding relates directly to the definition from the notes.
12. Darwin's finches, several different species that probably branched out from
a single starting group of mainland finches, are an example of
___A___
a. Adaptive radiation
b. Hybrid vigor
c. Type species or ecospecies
d. Sexual selection
e. The sort of strange little creatures scientists get all gooey about
...the question contains a definition of the term.
13. The organic molecules in Primordial Soup came from
___A___
a. Interstellar dust b. Plants
c. Animals d. Bacteria
e. One of those weird Flintstones' companies
...the P.S. was before living things, so b, c, and d are out
anyway...
14. When a population gets near extinction but recovers, its evolution may show
___C___
a. A higher mutation rate
b. Niche speciation
c. A bottleneck effect
d. Hybrid vigor
e. Extreme nervousness
...matching the term with the definition...
15. What allows the development of new traits without the loss of the old ones?
___C___
a. Reproduction b. Genetic drift
c. Redundancy
d. Hybrid vigor
e. Very well drawn-up contracts
...right out of the notes...
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.
1. What are two different ways that the age of a layer of fossils can be estimated?
...could be matched against a master chart using the fossils present, or
determined by radioactive dating
2. It seems most likely that evolution works at both a gradual and punctuated pace. Why?
...evolution is driven by environmental change, which follows both
patterns at different times.
3. What are type species, also known as ecospecies?
...species serving the same role (in the same niche) in two different
ecosystems
4. What is an allele?
...it's a variation in code for a particular gene (like a particular
recipe for a certain dish).
5. What is the currently-accepted definition of a species?
...a group that breeds exclusively within the group under natural
conditions
6. Explain why both parts should be true: large populations have more evolutionary
potential, but smaller populations probably evolve faster.
...there'd be more variation in the big group, but changes in single
individuals or families have more (and quicker) impact in a small group
7. What are two types of large organic molecules that could have been the first living
things?
...proteins or RNA.
8. Why does evolution tend to "leave alone" processes like embryo development?
...because the earlier a change is started (as in an embryo), the more
dramatic - and less likely to be good - the change will be.
9. Briefly explain what is meant by the biological term recombination.
...it's the mixing of genes from 2 sources that produces most of the
variation in sexual reproducers.
10. Darwin was aware, before he left on the Beagle, of many ideas and processes that
helped shape his theory of natural selection while he traveled the world. What are two
different such ideas?
...he knew about how domestic species are bred, he was aware of the
uniformitarian idea of long, slow changes over the world's history, he
knew of Malthus' ideas on population limits, he'd heard of various ideas
about evolution, including LaMarck's...
11. Most mutations are either neutral or harmful. Why?
...most often, the DNA change either misses genes or changes them in
some insignificant way; if there is a change, it's more likely to
change the coded protein for the worse - a random change to a
complicated molecule probably reduces its effectiveness rather than
raises it.
12.
Put these in order, smallest to largest: Class, Family, Genus, Kingdom, Order, Phylum, Species.
| 1.
Species |
2. Genus |
3. Family |
4. Order |
| 5. Class |
6. Phylum |
7. Kingdom |
XXXXXXXXXXX |
13. To have the best chance of becoming a fossil, what must happen to an organism just
after it dies? (Or, how are most fossils formed?)
...it needs to sink to the bottom of a body of water
14. What are two different types of molecules compared in comparative biochemistry?
...could be DNA / RNA (that's one type), or proteins, or metabolic
molecules
15. What did the fossil-holding mineral amber start out as?
...tree sap
16. Translate to more modern, understandable language: "Ontogeny recapitulates
phylogeny."
...the stages an embryo goes through repeat the stages its ancestors
evolved through
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. According to the Hardy-Weinberg Law, a rare allele stays at its starting proportion in
a population if what four items are true? (There's 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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2. Describe - don't just name! - four basically different types of isolation that can lead to the
development of new species.
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). |
3. For each type of reproduction, give the requested information.
| ASEXUAL |
SEXUAL |
| Definition: Offspring
are genetic copies of original. |
Definition: Offspring are genetic
mix from 2 sources |
| Advantage over sexual:
Can produce exact copies of advantageous forms
|
Advantage over asexual: Produces
great variation.
|
| Disadvantage vs sexual:
Lack of variation makes offspring all equally vulnerable to many
risks
|
Disadvantage vs asexual:
Cannot produce exact copies of advantageous forms. |
4. Given that traits vary in a population, some variations can give advantages, and more
offspring are produced than can survive to reproduce, what points did Darwin propose for
his Theory of Evolution by Natural Selection? Make sure you cover selection, inheritance,
and speciation.
The environment (Nature) will "select" which variations are
advantages and which individuals are more likely to survive and
reproduce.
As the "good" traits are passed on in greater and greater
proportion, more and more of these advantageous traits will show up in
the population over time.
Eventually, the new type of organism will be different enough from the
ancestor to be considered a new species.
| 5.Type of
structure |
Definition |
Type of evolution
usually involved |
| HOMOLOGOUS |
Built from the same underlying structure
|
Divergent
(new features from same basic starting material) |
| ANALOGOUS |
Performs the same basic function
|
Convergent
(similar roles for features, but structurally different) |
6. For four of the five Kingdoms given in the textbook, name the Kingdom and give the trait or
combination of traits that make species in that Kingdom absolutely different from species in the other
four Kingdoms.
|
MONERA |
Single celled but without nuclei. |
|
PROTISTA |
Single-celled, have nuclei |
FUNGI
|
Multicelled, heterotrophs, absorb nutrients through outer layers |
|
PLANTAE |
Multicelled, photosynthetic |
|
ANIMALIA |
Multicelled, heterotrophs, consume and digest nutrients |
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.
For One Point Each, give, in order, the sequence of places visited on Darwin's voyage on the
HMS Beagle.
Darwin formulated his theories on evolution long before he published them. Why did he
finally publish them? Four Points.
What geographic event in our hemisphere is now thought to have produced an environmental
change leading to the evolution of humans in Africa or Asia? Four Points.
What did the Danish study of relatives of schizophrenics discover? Four Points.
A recent fossil discovery was of a dinosaur predator and prey, locked in combat. How did
they die? Three Points.
What is more and more often becoming true of "vestigial organs?" Three Points.
What role might silicate clays have played in the beginnings of Life on Earth? Four Points.
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