EXAM I 2015
EVOLUTIONARY BIOLOGY – PART II
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Name
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TA Name
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Lab Day & Time
Negative Points
Positive Points
Page 1
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11 pts
Page 2
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16 pts
Page 3
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15 pts
Page 4
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8 pts
TOTAL
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50 pts
B. Matching Question. Write the letter identifying a cell function with the appropriate cell structure.
A cell function may be used for more than one structure. And a cell structure may have more than
one function. Further, a cell function may not apply to any structure, if so, write an “X” next to
the cell structure.
(1 pt. each)
Eukaryotic Cell Stucture
Function or Characteristic
__E_____Mitochondria
A. synthesizes protein
__X____ Golgi Body
B. 9+2 array of microtubules
__I____ Chloroplast
C. contains peptidoglycan
__G____ Nucleolus
D. organelle containing digestive enzymes
__A____ Ribosome
E. uses oxygen and produces ATP
__F_____Chromosome
F. circular hereditary material of prokaryotes
__X_____Cytosol
G. synthesizes ribosomes
__J_____Cell Wall
H. fluid storage reservoir
__X_____Plasma membrane
I. carries chlorophyll
__H,K___ Vacuole
J. composed of cellulose in plants
_X______ Smooth ER
K. storage organelle for carbohydrate
L. Network of internal membranes with
ribosomes attached
X. No appropriate function
1.
C. Definition Questions. Define the following terms or phrase giving an example and answer
the follow up question. Do not be superficial in your responses; give details. Use the back of this paper
if you need more space (4 pts. each)
1. Hardy-Weinberg principle (explain this in words, not the equation)
This is the principle that states that the allele frequencies in a sexually reproducing population tend to
remain the same as long as there is no mutation, no immigration or emigration, no selection among
genotypes, random mating, and the population is very large; i.e there will be no evolution.
Example: Any population of organisms which has the above conditions will not evolve
In this equation p2 + 2pq + q2, what does the q2 stand for?
It stands for the frequency of recessive genotypes in the population.
2. Vestigial Structure
These are structures of a organism without any apparent function or reduced function compared to the
same organ found in its ancestor.
Example: Tail bone (coccyx) in humans, goose bump muscles, muscles to move the ears and scalp,
appendix, eyes of blind cave animals, lung of snakes, etc.
How do Creationists explain such structures?
They say, who can explain God’s ways. Also, they say the structure has a function and scientists will
find it if they keep looking.
3. Molecular clock
This is the approach used by biologists to determine how closely one species or individual is related to
another one. It is accomplished by counting how many nucleotides are different between the DNA (or
RNA) between two species; the greater the number the longer the time they have been separated. This is
based on the assumption that mutation rates are constant.
Example: Many examples are possible. E.g. This allows us to determine that humans and apes diverged
about 7 million years ago.
What method is used to calibrate the clock; i.e. to know the real time when two species have
separated?
You have to use the fossil record as a reference. If you have a good fossil record that shows when the
first human appeared and you have a method for determining the age of the fossil, then by noting the
number of differences in nucleotides say between humans and chimps, you have a way of determining
the rate of mutation. This information can be used to estimate how long the different human ethnic
groups have been separated.
4. Translation (as used in molecular biology)
This term refers to the process of converting messenger RNA code (composed of a sequence of
nucleotides) into a sequence of amino acids in a protein. This occurs at the ribosome
Example: Suppose the mRNA code reads ….AAAUUUCCCGGG….
This would be read by the ribosome to mean place these amino acids in a chain=
….lysine-phenylalinine-proline-glycine….
What role do codons play in this process?
Every 3 RNA nucleotides (a codon) specifies a particular amino acid which should be linked next.
2.
D. Short Answer Questions (3 pts each) State whether the statement is true or false and then give the evidence
supporting your claim
1. Mutations in genes which lead to a stop codon typically lead to a non-functional gene.
True. If a DNA triplet which normally would code for an amino acid mutates to a STOP, then the
formation of the protein which is being synthesized by the ribosome, would cease and the protein would
not be complete and thus be non-functional.
2. A silent mutation is one that does not lead to a protein.
False. Some silent mutations can lead to proteins. A Silent Mutation is one that does not have an effect
upon the fitness of the organism. This can occur in several ways: one way is that a modified protein is
produced but it doesn’t alter the fitness of the organism (i.e. it is a neutral mutation).
3. It is possible to test if the radiometric dates of the earth are correct.
True. We can do so by comparing different radiometric dating methods to see if they lead to the same
result. We can compare the dates determined via radioactive dating to historical records or to tree reing
date to see if they are accurate. If these dates are accurate and all efforts to change the rate of radioactive
decay have failed, then we can be confident that our methods are sound.
4. The critical feature of the scientific method that separates it from everyday reasoning is that it
makes hypotheses.
False. We make hypotheses (guesses) all of the time in our everyday life. The critical difference is that
we test our hypotheses and do so repeatedly. And on the basis of these tests we often alter our
thinking—Thus Science is said to be a self-correcting enterprise.
5. Both the genotype of an individual and phenotype of an individual cannot change over the lifetime
of an organism.
False. The genotype (the DNA) will not change over the lifetime of an organism, but the phenotype (the
physical appearance of the organism) can certainly change depending upon the diet or environment. For
example, flamingoes are basically white birds unless they eat foods with carotene in them and then they
become pink. (Many other examples)
3.
D. Long Question (Do not be superficial in your answer; this is worth 8 points. Notice you have a lot of
space to answer the question; this means it is important to give detail.) Use complete sentences in your
answer.
The concept of consilience plays a big role in our acceptance of the theory of evolution. First, define
consilience. Second, tell the main steps in Darwin’s version of the theory. Third, give three examples of
where consilience is seen in the acceptance of theory of evolution. And when you give your examples be
sure to explain exactly how this discovery advanced our acceptance of the idea.
Consilience or convergence of evidence refers to the principle that evidence from independent, unrelated
sources can "converge" to strong conclusions. That is, when multiple sources of evidence are in agreement,
our confidence in the conclusion can be very strong. So, for the theory of evolution we have evidence that
comes from anatomy and embryology, geology, chemistry, and physics all supporting the correctness of the
theory.
The steps in Darwin’s theory are these:
1) Individuals vary in populations of organisms—they have different traits.
2) Populations tend to overbreed—they produce many more offspring than there are resources to support
them.
3) Because of this there is a struggle for existence—competition exists among the individuals of a species.
4) Ones that survive are said to be the fittest—Survival of the Fittest.
5) If the variations that exist among individuals have added their survival are hereditary, they will be
passed on to their offspring—Variations are inherited.
6) The population will change over time because the environment will tend to vary and different types of
individuals will survive in different environments—the species will change and new species will
develop.
Three examples (among many possibilities from biology, geology, chemistry, physics.)
e.g. From anatomy we find many examples of homology including skeletal structure such as the basic limbs of
vertebrates all being structured on the same plan: humerus, ulna, and radius, wrist bones, and finger bones. The
dimensions of them vary, but the plan is the same. And vestigial structures such as the blind eyes of cave
animals exist which have no function and are present only because the ancestors evolved and used them. We
can only reasonably explain these structural similarities and vestiges by assuming that all of the organisms
have had a common ancestor and that change has occurred over time. ETC.
e.g. From geology, we have evidence from the fossil record that change in the earth has happened and the
animals that were once present no longer exist and new ones appear. And there is a sequence on change such as
we see in the vertebrates: fishamphibiansreptilesmammals. ETC. Also from geology and physics we get
radioactive dating methods that confirms the age of rocks and gives us real dates when organisms originated in
the fossil record. And it provides evidence of the great age of the earth showing there is plenty of time for
evolution to occur.
e.g. From chemistry and genetics we can determine the structure of the genetic material and understand how
variation occurs in organisms and note how the cell structure of animals is similar and the DNA and RNA is
built with the same nucleotides and coded the same way. This strongly suggests that we all have a common
ancestor back in time. Just how far back can be calculated by counting the number of nucleotide differences we
have with other organisms (the more differences, the farther back in time the divergence occurred). THs
biochemical data in fact correlate very well with the fossil record—something that Darwin could not have
known. ETC.
4.