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SC 139 - Second Exam 2009
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. Convergent evolution has its best
examples when features are
___B___ a. Analogous and homologous
b. Analogous but not homologous
c. Homologous but not analogous
d. Neither analogous nor homologous
e. Very, very convergey
...species "solve" similar problems in similar ways (analogous) but use
different structures (not homologous).
2. In a typical molecular clock, the
"ticks" of the clock are
___D___ a. Radioactive decay
b. Anatomical changes
c. Minerals in fossil layers
d. Mutations
e. Probably not carrying Lyme disease
...small changes in DNA that accumulate in the separated groups over time.
3. A near-extinction can produce
___A___
a. A bottleneck effect
b. An alternation of generations
c. A primordial effect
d. A founder effect
e. A really bad weekend
...it's part of the basic definition.
4. The beginnings of mitochondria
and chloroplasts are found in the
___B___ a. Colonialism hypothesis
b. Endosymbiont theory
c. RNA world hypothesis
d. Gaia hypothesis
e. Unpronounceable names handbook
...those organelles began as ingested "buddy" cells.
5. Linkage between genes refers to their
___D___ a. Making proteins used in the same processes
b. Similarities when compared between related organisms
c. Codes and the proteins made from the codes
d. Being together on the same chromosomes
e. Scandalous stories being revealed on the blogs
...basic definition.
6. During the Cambrian explosion,
___D___ a. All modern eukaryote groups appeared
b. All modern animal and plant groups appeared
c. All modern multicellular groups appeared
d. All modern animal groups appeared
e. Well, obviously something showed up...
...not much had happened up until that time, and plants didn't "explode" until
they moved onto the land...
7. The "plant problem" made the assumption that
___C___ a. Only plants could absorb greenhouse gases
b. Animals and plants were closely related
c. The very first global ecosystem had to be like today's
d. All organisms use oxygen
e. The green guys were out to get us
...it was hard to come up with a way that photosynthesis could be the first
metabolic chemistry - it's too complex.
8. In adaptive radiation, connections are made
among
___A___
a. Related species in the same ecosystem
b. Related species in very different ecosystems
c. Unrelated but similar species in the same ecosystem
d. Unrelated but similar species in different ecosystems
e. Adapty things that glow in the dark
...from one ancestral group, different subgroups have moved into different
niches and become new species.
9. In alternations of generations, what exactly
alternates?
___D___ a. Male and female
b. Single-celled and multicellular
c. Animal and plant
d. Sexual and asexual
e. Ummmm.... generations?
...part of the definition.
10. 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. American Idol contestants
...the way DNA works, most changes don't affect the system, and changes that do
happen are more likely to mess a system
up than improve it (although rare improvements do happen).
11. Evolution means change over time, but some animals
appear to have evolved a resistance to change, probably because they are
___A___
a. In very stable niches
b. The last of their species
c. Very advanced forms
d. Purely homeostatic
e. The animal equivalents of Rush Limbaugh
...if they are very well-suited to a part of the environment that doesn't
change, they are unlikely to change much.
12. 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
...it's the same job / niche, but in different ecosystems.
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.
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1. What two
factors most strongly influence how quickly or slowly a group might
evolve? |
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The rate that the environment changes |
How fast the group's reproductive rate is / generation time. |
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2. What are
two different things that can be compared in order to find
evolutionary connections between types of organisms? |
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Homologous structures / anatomy.
Homologous molecules. |
Embryos. Basic
chemistry. |
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3. What are
two different types of energy that might have been used by the
first competing molecules in the early Earth oceans? |
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Heat.
Lightning. |
Ultraviolet light.
Unstable chemicals. |
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4. What is
panspermia? |
...it's the
idea that the first Life began somewhere else and was carried to Earth
shortly after the planet formed.
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5. For a high chromosome number - |
| ADVANTAGE
Lots of variability in offspring. |
DISADVANTAGE
More mistakes during cell division
(harder to distribute chromosomes reliably) |
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6. What is
the function of a HOX gene, also called a homeogene? |
...it sets up
basic layout structure of the organism.
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7. Briefly
explain how sexual selection works, in evolutionary terms.
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...traits that
give reproductive advantages are more likely to "spread,"
generation after generation, through a population.
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8. Show the
chemical process of photosynthesis, including the relevant
energy. You can spell out molecule names. |
CO2 + H2O
light > C6H12O6
+ O2
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9. Show the
chemical process of aerobic respiration, including the movement
of relevant energy. You can spell out molecule names. |
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C6H12O6
+ O2 energy to ATP >
CO2 + H2O
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10. Give one reason why embryos
are more likely to show relationships between groups than
adult forms might. |
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Early changes can
have more profound (and worse effects), so they aren't as common.
The environment for
embryos (eggs, seeds, etc.) can be much more similar than the adults'
environment, so fewer changes evolve. |
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11. Translate
into modern English: "Ontogeny recapitulates phylogeny." |
...embryo
development replays the evolutionary history of the species.
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12. Why is
it reasonable for evolution to be both gradual
and punctuated? |
...because
environments change both quickly and slowly, and environmental change is
the main driver of evolution.
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13. If a
currently-living animal appears almost identical to
ancient fossils, what is probably true about that animal's
microenvironment? |
...it is
probably very stable - hasn't changed much since that fossil organisms
occupied it.
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14. What is
hybrid vigor? |
...having two
different alleles can be better than having a matched pair of either
of them.
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LONG ANSWER.
Answer any four of the following questions for
Eight Points Each.
Note: if you answer more than four, only the first four will be corrected.
You can get partial credit on these answers.
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1. What are
four different conditions that a "Hardy-Weinberg population"
must have? |
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No natural selection. |
No sexual selection / random mating. |
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No mutation. |
No migration in or out. |
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Really large numbers of individuals. |
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2. For each step in the theoretical
development of Life on Earth, put them in chronological order,
from earliest to latest, 1 - 8 in the boxes to the left. |
Photosynthesis
____4______ |
Molecular
Evolution ___2_______ |
Cellular
Colonialism ____6______ |
Aerobic
Respiration ____5______ |
Prokaryote
Cells
____3______ |
"Snowball"
Period
___8_______ |
Primordial
Soup
____1______ |
Multicelled
Systems
____7______ |
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The Earth forms with the soup on it,
the molecules in the soup compete, evolve, pick up protective chambers,
protocells, move from RNA to chemistry with proteins and DNA, and you
have prokaryotes. Prokaryotes at hydrothermal vents evolve
chemosynthesis and then photosynthesis, move away from the vents, and
fill the oceans with oxygen, and aerobic respiration evolves.
Prokaryotes diversify, some develop internal chambers to become
eukaryotes, some of which which assemble into colonies and then
multi-celled systems, then the Snowball Period drives intense
competition that leads to advanced animal life. Much later,
plants, fungi, and animals move onto the land by way of tidal zones and
freshwater systems. |
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3. What are
four different circumstances a dead organism can be in
that can likely lead to their becoming fossils? |
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Sink to bottom of body of water, get
covered in sediments. |
Get covered by blowing sand. |
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Get covered in sap (that eventually
hardens into amber fossils). |
Get covered in volcanic ash (good for footprints - lava is NOT good,
though, it incinerates the remains). |
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Get covered in mud. |
Trapped and covered by tar. |
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Covered / encased in ice. |
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4. For
asexual reproduction, in general - |
Definition -
Offspring are genetically identical to "parent." |
Advantage over
sexual
reproduction -
Is actual reproduction of individual -
copies the genes that makes them unique. |
One way it overcomes its
disadvantage -
(The disadvantage is lack of variety in offspring)
Produce large numbers of
offspring, spreading them beyond
environmental changes and producing variety from
mutation. |
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5. Define or explain the exact nature of a - |
| GENE
DNA code for a particular protein. |
ALLELE
Variation of code for a particular gene. |
DOMINANT
ALLELE
Produces protein whose effects can completely hide
those from recessive allele's coded protein. |
MEME
Non-DNA trait that can be passed on to others. |
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6. Describe
(don't just give a simple label!) four different isolating situations
that can lead to the evolution of new species from the same starting
group. |
Barriers arise in environment that
separate groups
(Geographic isolation) |
Different subgroups move into different niches in environment
(Niche isolation) |
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Different subgroups become active
and/or reproductive at different times (Temporal isolation) |
A subgroup uses different reproductive behaviors
(Behavioral isolation) |
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Physical changes makes a subgroup
unable to physically mate with other subgroups (Mechanical isolation) |
A subgroup become incompatible with sperm or offspring of another
subgroup (Gamete / zygote-based isolation) |
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7A. Two
critical features that early molecular systems had to have to be
considered the first steps of "Life" on Earth - |
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Had to be self-organizing.
Had to be able to reproduce. |
Needed basic metabolism / energy-processing ability.
Had to be able to evolve. |
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7B. Two
critical features that didn't have to be there right at the beginning,
but had to develop early because all modern Life has them - |
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Protein-based chemistry.
DNA-based coding system. |
Cells. |
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.
Why would fossils from the bottoms of lakes be hard to find? Three Points.
Give one example of a type of organism that has evolved a resistance to
evolutionary change. Three Points.
Why did Mendel use pea plants? Three Points.
Give an example of a genetic disease and the problem it can give an advantage
over. Three Points.
How does gender determination work in birds? Three Points.
What was Hardy - what was his job? Three Points.
Give an example of a non-human meme. Three Points.
What appears in the fossil record that shows the evolutionary appearance of
photosynthesis? Three Points.
For three points each, what modern discoveries have shown that photosynthesis
probably evolved at hydrothermal vents?
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