Transcript MC Question
Review Projects – 2013
Big Idea 1 - answers
ANSWER KEY - LO 1.1
In the table below, which graphs the height of a population of birds over three generations, what type of
selection is occurring?
A. Stabilizing selection
B. Directional selection
C. Disruptive selection
D. No selection is occurring
In the diagram to the left, name and define what happened to the population, and offer three possible
explanations for what could have caused it. Also, explain how and why the new population’s genetic makeup
will be different from the original population in the future.
This population is experiencing the bottleneck effect, in which a natural disaster dramatically reduces the
size of a population, and the new population is genetically unrepresentative of the original one. This could
have been caused by a forest fire, introduction of a new predator, or a change in general climate. The new
population will have a much higher proportion of the red phenotype, to the extent where it will almost be
the population’s exclusive version of this trait. The reason for this is that the red individuals had some sort
of adaptation that allowed them to better survive the disaster that occurred. For example, if the area was
much colder than usual, they might have more fur, or if it was predation, they might be better
LO 1.2 Answers M.C. Question: At a locus with a dominant and recessive allele in Hardy-Weinberg
Equilibrium, 16% of the individuals are homozygous for the recessive allele. What is the frequency of the
Learning Log/FRQ-style Question: Surprisingly chimps and pigeons have been found to be fairly similar.
How could you determine how close of relatives they are? What would this data be able to tell you? Create
a graph of their evolutionary line. What other evidence is needed to determine lineage? How could natural
selection play a role in their two different niches today?
By using their DNA sequence in combination with
BLAST we are able to find the percentage of proteins
that are similar between pigeons and chimps along
with the gene similarity. While the data found using
the gene and protein similarities would be a good
start, homologous structures and traits would be
able to confirm a stronger relationship. A cladogram
could be created to see the evolutionary paths of
these two species. Natural selection would have
selected the birds to be able to fly for safety and
their beaks to crack nuts in order to lower the
competition for the insects and fruit that chimps eat.
LO 1.3 Answers
M.C. Question: You have sampled a population in which you know that the percentage of the
homozygous recessive genotype (aa) is 36%. Calculate the frequency of the homozygous dominant
The answer is E. The frequency of aa is 36%, which means that q^2=0.36.
By definition if q^2=0.36 then q=0.6. Since q=0.6, and p+q=1, then p=0.4.
The frequency of AA is equal to p^2, therefore the frequency of AA would
be (0.4)^2 which is 0.16 or 16%.
Learning Log/ FRQ-style question answer: The Hardy-Weinberg theorem describes a
hypothetical population that is not evolving. The five conditions are that the population has
to have an extremely large population size, no gene flow, no mutations, random mating, and
no natural selection. If one or more of the conditions was not met many things could
happen. But departure from these conditions usually results in evolution. The smaller the
population, the greater the role played by chance fluctuations in allele frequencies from one
generation to the next, known as genetic drift. Gene flow, the transfer of alleles between
populations, can alter allele frequencies. By introducing or removing genes from
chromosomes or by changing one allele into another, mutations modify the gene pool. If
individuals preferentially choose mates with certain genotypes, including close relatives
(inbreeding), random mixing of gametes does not occur. Finally, differential survival and
reproductive success of individuals carrying different genotypes will alter allele frequencies.
Answer Key LO 1.4
Which statement about natural selection is the most accurate?
A. It always requires genetic variation, but only requires differential reproductive success with certain species
B. Adaptations beneficial at one time should generally be beneficial during any other time as well
C. Well adapted individuals leave more offspring, and thus contribute more to the next generation’s
gene pool, than do poorly adapted individuals
D. Different species that inhabit the same area will adapt to that environment by undergoing the same genetic
Choice A is somewhat correct, but not completely. Natural selection requires genetic variation and differential
reproductive success all the time, not just with certain species. Choice B is not correct because environments
can change over time, therefore an adaptation to an environment 20 years ago would not be useful in an
environment that has changed drastically over the future 20 years. Choice D is not correct because all species
are different and the way that they adapt to changes in their environment could be completely different than
the way other species adapt.
Suppose you have been studying a population of species for 10 years and you have noticed a nonconstancy in
the species based on your recorded data. Explain how this could happen and use a real life example to support
Nonconstancy in a species simply demonstrates the variations in a population due to evolution and
natural selection. Different species possess different adaptations based on their environment, what
they do, how they live, etc. For example, when Darwin studied his finches in the Galapagos, he
gathered evidence of different beak sizes for different finches. He concluded from his data that the
finches adapted to their certain environment and food choices through their beaks; if a species
lived where there were large, hard nuts, then the finches would have short and strong beaks. If a
species lived where there were only leaves/berries/insects, then the finches would have long
beaks. The environment of each different species of finch selected for a beak size that best suited
Answer LO 1.5
M.C. Question: Look at the diagram to the right, what most likely was the cause that the
lighter circles were not able to pass on their genes?
B) Natural selection did not favor their traits and they were unable to survive for
reproduction in their environment.
Explanation: The diagram represents natural selection favoring traits that the darker circles
have inherited and that have benefitted them for survival. The lighter circles did live to
reproduce the first generations, but as the diagram moves forward the lighter circles do not
that the inherited trait better suited to survive in their environment. Therefor they die before
they can reproduce and the species gene pool begins to change and they all have the
favorable trait to survive. It is survival of reproduction not survival of the fittest!
Learning Log/ FRQ-style Question: Suppose you are studying giraffes and
you separate one species into two different locations. One into captivity feeding
off of only bushes and one feeding off of only trees. Hypothetically, over many
generations you notice the neck length in the two species are different. Which
giraffe would have the longer neck? What would cause the this to happen if both
have the same common ancestor? Draw a diagram representing what happened in
this situation, and use your diagram to explain your reasoning.
The giraffe with the longer neck would be the one that was only able to eat
off of the trees. Over time natural selection would have selected the giraffes
with the longer necks to survive long enough to reproduce in their
environment of only eating trees. The giraffes with the longer necks would
have been able to reach their food source better and over time only they
would reproduce and their young would have the longer neck length trait in
their genes. Then those young would grow up with a longer neck and they
would survive over others with a short neck to reproduce and pass on the
trait once again until all giraffes in the population would have inherited the
trait and the rest would have died off. Even though the two giraffes have the
same common ancestor the giraffes feeding off of the bushes had no need for
their neck length to change when the giraffes eating off of only trees had to
adapt to their environment in order to survive. The two diagrams are what
would be drawn to explain this. As you can see the giraffes without the
longer neck length trait did not survive and probably died of starvation
before they could reproduce in diagram one. Diagram two supports the need
for the giraffes eating off of only trees to have a longer neck to survive and
not die of starvation.
LO 1.6 Answers
M.C. Question: C
Learning Log Question:
q² = 396/953= 0.416
q = √0.416= 0.645
AA= p²= 0.355²= 0.126
aa= q² = 0.0645²= 0.416
If the population consisted of 1,245 fish the next year, in order to find out the number of fish with dwarfed or
normal fins, the expected phenotype frequencies of the previous generation would have to be determined. The phenotypes
would be as follows:
Normal fins (dominant)= 0.126+0.458= 0.584
Dwarfed fins (recessive)= 0.416
Knowing this information, the number of fish with normal and dwarfed fins can be figured out by multiplying these phenotype
frequencies with the number of fish in the total population.
Normal fins (dominant)= 0.584 x 1,245= 727 fish with normal fins
Dwarfed fins (recessive)= 0.416 x 1,245= 518 fish with dwarfed fins or (1,245-727=518)
ANSWER KEY– LO 1.7
MC Question: In a population that is in Hardy-Weinberg equilibrium, the frequency of the “z.” allele is 0.6.
What percentage of the population is heterozygous at this locus?
A) 2pq = .48 (p = .4 and q = .6)
B) p2= .16
C) 2pq= .36 (p= .6 and q= .6)
D) q2= .1
Evolution is one of the unifying themes of biology. Evolution involves change in the frequencies of alleles in a population.
For a particular genetic locus in a population, the frequency of the recessive allele (a) is 0.4 and the frequency of the
dominant allele (A) is 0.6.
(a)What is the frequency of each genotype (AA, Aa, aa) in this population? What is the frequency of the dominant
(b) How can the Hardy-Weinberg principle of genetic equilibrium be used to determine whether this population is evolving?
(c) Identify a particular environmental change and describe how it might alter allelic frequencies in
this population. Explain which condition of the Hardy-Weinberg principle would not be met.
(a) The frequency of the genotype, AA, or the homozygous dominant genotype, is expressed as p 2 in the Hardy- Weinberg
equation. The frequency of AA is 36 %. The frequency of Aa, or heterozygous, is expressed as 2pq, and is 48%. The
frequency of genotype aa, or homozygous recessive, is expressed as q2, and is 16%. The frequency of the dominant
phenotype is found by adding p2 (homozygous dominant) with 2pq (heterozygous). The frequency of this phenotype is
(b) The frequency results (above) of the phenotypic/ genotypic frequencies are of a certain population under given
conditions. This same population can be tested with the Hardy- Weinberg equilibrium equation at a different time or
under different conditions. The results can then be compared and observed to see if there is a change or indication that
the population is evolving.
(c) If a forest where a specific population of squirrels lives burns down due to a massive forest fire, a large majority of the
squirrels would migrate to a new habitat and begin to mate with a new population of the same species. This mating
could potentially alter the gene pool of this population of squirrels and could result in the loss of, or drastic decrease in, a
certain allele within the population. This violates the Hardy-Weinberg principle of: no gene flow (immigration/
Answer Key LO 1.8
MC Question: Which of the following is true about artificial selection in dogs?
A) Artificial selection aids natural selection by selecting for the most desirable and fit traits for dogs to
B) Artificial selection can only occur in large islands that are close to shore so that dogs can immigrate
C) Artificial selection is performed mostly by humans breeding dogs for desirable traits like size and fur
D) A and C only
E) A, B, and C
Learning Log/FRQ-style Question: Explain the effect on a population’s gene pool based on an island’s
size and distance from shore. How do genetic drift, migration, and artificial selection play into this
The farther from mainland and smaller the island is, the less genetic drift and therefore less
change in the gene pool. The island supports a smaller population so it cannot support many
more immigrants. It is also farther from mainland, being less likely to receive immigrants. Islands
that are larger and closer to shore have a greater genetic drift in the gene pool because it can
support more immigrants and is closer to mainland so more immigrants of the population have a
better chance of entering in. Genetic drift affects gene variance on these islands through
migration and other mechanisms. As more of a population immigrate, alleles become more
frequent in the gene pool, whether they are new alleles or alleles currently in the population. As
more of a population emigrate, alleles become less frequent. Artificial selection can occur on an
island where humans selectively breed. Humans may immigrate new alleles into the gene pool
from far away places or also take away alleles. This causes the variations of a population’s gene
LO 1.9: The student is able to evaluate evidence provided by data from many scientific disciplines that
support biological evolution
SP 5.3:The student can evaluate the evidence provided by data sets in relation to a particular science
Explanation: Evolution has tried to be explained by many scientists of many which were incorrect, Charles Darwin was a pioneer in this field and was
able to lay out the core principles of Evolution. Descent with modification was how Darwin perceived unity, with all organisms related through descent
from an ancestor that lived in the remote past where each organism had accumulated modifications that help them with specific ways of life. Darwin
explained natural selection by saying with each generation there are organisms with traits that are favored by the environment. These organisms tend
to produce more offspring than do organisms that do not have the preferred traits. The offspring of the favored traits then reproduce which increases
that amount of favored traits in the overall population which makes the population stronger. Lamarck had a differing view of evolution than Darwin,
he had two main principles which was use and disuse and inheritance of acquired characteristics. Use and disuse was the idea that parts of the body
that were used extensively would become larger and stronger. Inheritance of acquired characteristics stated that an organism could pass modifications
to its offspring. Georges Cuvier's view of evolution was catastrophism where each boundary between a strata represents a catastrophe such as a flood
or drought. Other scientist's like Darwin supported the theory of gradualism which is the idea that profound change can take place through cumulative
effect of slow continuous processes.
M.C. Question: What were the two main ideas of Darwin's Theory?
A) use and disuse; inheritance of acquired
B) evolution explains life's unity and diversity; natural
selection is the cause of adaptive evolution
C) gradualism; uniformitarianism
D) catastrophism; gradualism
FRQ: Discuss the similarity’s on Darwin's
processes of evolution and those seen by
doctors dealing with antibiotic resistant
bacteria on patients
LO 1.9 Answers
M.C correct answer : B, evolution explains life's unity and diversity; natural selection is
the cause of adaptive evolution
FRQ correct answer : Each bacteria that are left in a patient after a dose on antibiotics
from a doctor contain the favored traits for survival. Bacteria are able to reproduce at an
exponential rate, just as Darwin states the organism with the favored traits will
reproduce passing down the favored trait to its offspring, so the offspring of the bacteria
are now immune to the previous antibiotic. Doctors must now make a stronger antibiotic
that is able to kill all bacteria but weigh the consequences of putting the patient at a
greater health risk due to the stronger chemicals.
LO 1.10: The student is able to refine evidence based on date from many scientific disciplines that support biological
SP 5.2: The student can refine observations and measurements based on data analysis.
D) A and C are both correct
Learning Log/ FRQ-Style Question:
Yes, the student is correct in his assumptions. Although the four organisms inhabit different regions, it is possible
that they share a common ancestor. Thousands of years ago all four species shared a common ancestor, but
eventually they diverged into four different species after each group inhabited four different regions. Because each
group lived in a different environment and could no longer mate with each other, they evolved differently and
adapted to their own particular environment. In reference to biogeography, the geographic distribution of a species,
the student can be considered incorrect. Only closely related species (those sharing a common ancestor) live in the
same geographic region. The fact that they all have the same characteristics and features can be because they all
adapted to their environment similarly, but they still could have come from different ancestors. This would be an
example of convergent evolution not divergent.
The fact that the four species found in the first image had similar bone structure to organisms in the other, it
could be concluded that they all have a common ancestor. Since the bones in their fore limbs have the same
arrangement, although performing different functions, it is logical to say that they all evolved from the same
organism. This would therefore be an example of homologous structures.
All organism have the same genetic machinery of DNA and RNA and the fact that all of these organisms have this
machinery means that they did originate from the same organism. In addition, the organisms share like-genes
because they all make similar proteins such as hemoglobin and histone. Also, they have genes, which are responsible
for creating the right type of bones; this would also support the students assumptions.
LO 1.11 Answers
Question: Which of the following is an evolutionary process not based on random factors?
FRQ: Two new islands, relatively close together, are found in the Pacific ocean. On these different individual islands, two
species of birds are found. One species of bird has a long thin beak and one species has a short fat beak. Upon BLAST
sequencing the DNA, researchers find that the birds share an overwhelming majority of genetic material. What are some
possible explanations for this strange difference in beak structure?
FRQ Response: Due to the fact that the birds share the majority of their DNA, one can assume that both bird
species derived from a common ancestor. A selective pressure would cause mutations that are beneficial for
survival and reproduction to be more common. The different beak sizes could indicate a lack of food in the past and
the birds with beaks that were able to eat a different food were more likely to survive. A bird with a long narrow
beak would be better at getting hard to reach food and could get in between the spines of cacti and other plants
with physical defenses. A bird with a short hard beak on the other hand could crack hard nuts and chew the bark
and flesh of trees and cacti respectively. If a few birds with beak mutations flew to the other island it could cause
genetic drift in the form of the founder effect, where the unrepresentative sample of birds change the gene pool
much faster than if they had stayed on the original island. Non-random mating between the now quickly
differentiating species coupled with different habitats and resource usage would cause the original bird population
to now have two distinctly different species, the short beak and the long beak.
LO 1.12: The student is able to connect scientific evidence from many scientific disciplines to support the modern
concept of evolution.
SP 7.1: The student can connect phenomena and models across spatial and temporal scales.
M.C. Question: What type of method is used when incorporating both
mathematical and geological techniques to support modern evolutionary theory?
The answer is C) Half-Life Calculations because the use of carbon dating with
calculating half-lives of Carbon 14 in organic tissue. Samples such as fossils
are dated and compared by the utilization of half-lives.
FRQ: There are multiple disciplines in biology that are used to support the modern theory of evolution, including
geographical, geological, physical, chemical, and mathematical disciplines.
a) 1 – Geographical location can be considered when determining why a species is like it is. Organisms native to an
environment are going to be adapted to survive in that climate/habitat. Natural selection explains
change/evolution that favors these adaptations.
2 – Geology helps to support the theory of evolution by providing preserved samples of species often long past
in forms such as fossils. These fossils can be analyzed for their structures as well as sometimes genetic material
to see connections to potential evolutionary ancestors.
3 – Mathematical calculations can be done for DNA or RNA sequence matches. Graphing this data gives a clear
picture as to likely relationships between species, and can also be used to help find a common ancestor.
b) 1 – For geographical examples, the finches on the Galapagos Islands all had different beaks that favored their
2 – Preserved prokaryotes have been found in core samples that are billions of years old, and still have
analyzable DNA. These sequences are similar to today's organisms, and are made up of the same nucleotides.
3 – A bar graph can be used to easily see gene code match percentages in relation to an organism of interest.
This allows one to easily see which species is most closely related according to the genome.
c) Caniformia is the closest common ancestor that the dog and the bear share according to the chart. It is possible
that there are nearly identical physical structures that are found in both the dog and the bear, that they received
in part from their ancestor Caniformia. Vestigial structures are also another possible physical connection
between the two species.
LO 1.13 M.C. Question: According to the figure
to the right, which of the following could be the
correct data regarding the similarity in gene and
protein make up when comparing to humans?
Gene Percentage Similarity
Protein Percentage Similarity
Gene Percentage Similarity
Protein Percentage Similarity
Gene Percentage Similarity
Protein Percentage Similarity
Gene Percentage Similarity
Protein Percentage Similarity
Learning Log / FRQ-style Question: What are five indications that have led
scientists to conclude that evolution has occurred? Explain and give an example of
each. What are three examples of scientific evidence that evolution continues to
Learning Log / FRQ- style Answer: One indication that provides evidence for evolution is biogeography, the study of organisms and how they
relate to the environment. Some organisms may be unique to certain geographies; hence, those organisms have adapted to live in that
environment. Fossils help indicate the progression of organisms from simple to complex. For example, transitional fossils are fossils of
animals that display a trait that helped the organism attain a competitive advantage. At one time, whales had limb-like appendages indicating
they may have been land dwellers. Another indication is comparative anatomy, the study of anatomical similarities between organisms. More
specifically are homologous structures, structures in organisms that indicate a common ancestor (example: a human arm, cat leg, whale
flipper, and bat wing all have a similar structure, but different functions) and vestigial organs, remnants of structures that were at one time
important for ancestral functions. Comparative Embryology, or comparing the embryonic structure of one organism to another also provides
evidence. Lastly, molecular biology, used in the study of evolution by looking at homology in DNA and protein sequences and genes, allows
for an even broader level of comparison between organisms as different as prokaryotes, plants, and humans. Three examples of scientific
evidence that evolution is still occurring include emergent diseases, chemical resistances caused by mutations (such as resistance to
antibiotics, pesticides, herbicides, and chemotherapy drugs), phenotypic change in a population (such as Darwin’s finches in the Galapagos),
and eukaryotes eventual development of certain structures (such as limbs, brain, and immune system).
ANSWER KEY– LO 1.14
Which of the following statements concerning core life processes is true?
A) They are the same in animals than in plants.
B) They have only DNA carriers of genetic information through
C) Linear chromosomes are present in life processes.
D) Genetic code varies extremely in living systems.
Illustrate the relationships between
prokaryotes and eukaryotes. Then explain in
terms of molecular and cellular features that
are common to life.
Major features of the genetic code are shared
by all modern living systems; DNA and RNA
are carriers of genetic information through
transcription, translation and replication.
Structural evidence supports the relatedness
of all eukaryotes and prokaryotes, because of
membrane bound organelles and cell walls.
LO 1.15 Answers
M.C. Answer: Which of the following is NOT an example of common ancestry?
A)Similar forelimbs structures in cats and humans
B)Similar metabolic processes in rodents
C)Sharks and dolphins both living in an aquatic environment
D)Post-anal tails in the human and chick embryo
E)Opposable thumbs in humans and chimpanzees
Learning Log/FRQ-style Answer: If I was a biologist observing a cladogram, I would
expect to see evidence of evolution stemming from a common ancestor. Splits in
evolutionary pathways symbolize divergent evolution, if this “split” occurs early in
evolution it can result in drastic differences between species, however, a late “split”
can cause only minute differences in species. Evidence of common ancestry can come
in the form of similar physical structures and/or biological processes. For example, I
would see similar forelimb structure in humans and whales, this would lead me to
believe that whales and humans share a common ancestor.
LO 1.16 Answers
Which one of these statements is incorrect?
(A) All organisms, with the exception of plants, have mitochondria.
(B) All eukaryotes have mitochondria.
(C) All living organisms have similarities in their genetic code.
(D) Answers A, B, and C are incorrect.
(E) Answers A, B, and C are correct.
Free Response Question
Name and thoroughly describe 2 biological features or processes that are found in all living organisms today.
A maximum of 4 points will be rewarded:
1 point for each of the following structures and/or functions being mentioned and described
1 point if student says that the structures and functions are found in most modern organisms
Answer LO 1.17
M.C. Question: Using figure A identify the most recent evolutionary characteristic that causes the
primates and rodents & rabbits to be similar?
a) Four limbs
b) Amniotic egg
d) Bony Skeleton
Learning Log/FRQ-style Question: Explain the purpose of
the phylogenetic tree or cladogram using figure A and how it
allows scientists to see how species have evolved. A new fossil
has been found showing the characteristics of a vertebrae, bony skeleton, and
four limbs. Where on Figure A would this new species be located.
Phylogenetic trees and cladograms allow scientists to compare species and see what
evolutionary characteristics separate certain species from others. Figure A shows many
different characteristics separate different species. For example, the hair on the primates
and rabbits causes them to be similar to each other and the four limbs that they have gives
them a shared characteristic with amphibians, crocodiles, and dinosaurs and birds.
Phylogenetic trees and clsdograms are a simple way to compare species and show the
evolution of characteristics over time. Due to the three characteristics known about this
fossil it would fall after the evolution of the four limbs and before the evolution of the
amniotic egg. So it has many of the same characteristics as amphibians.
LO 1.18 Answers
• MC Answer: B
• FRQ: Each of the organisms on the cladogram has
evolved from a common ancestor. The lancelet is
closely related to the other organisms. The data table
shows the character traits that the organisms share
with a 1 representing a characteristic that is present
and a 0 representing a characteristic that is absent.
Each of the organisms in the figure shares many of the
same traits, and the higher up on the cladogram the
species, the more evolved and developed the species
LO 1.19 Answers
M.C Question: In constructing a cladogram, there are four species you are looking at (three of which are the ingroup and one of which is the
outgroup), along with a chart with their characteristics. Based on the chart provided, which of the species is most likely the outgroup in the
A) The gray wolf, because it has the most characteristics that the other species don’t have so it can be inferred
that it is less related to the other species than they are to each other.
B) The crocodile, because it does not have fur, so it can be inferred that it is less related to the other species
than they are to each other.
C) The Salmon, because it does not have four legs, so it can be inferred that it is less related to the other species
than they are to each other.
D) The lancelet, because it doesn’t show any of the characteristics that the others have on the chart, so it can be
inferred that it is less related to the other species than they are to each other.
Free Response Answer:
a) In my phylogenetic tree, an example of a monophyletic group would be
the group which is highlighted in green. This is the group Carnivora. It is considered
monophyletic because it consists of a group of organisms who are all descended from the
same common ancestor. This group contains all of the descendants that branch off from that
ancestor (as opposed to the paraphyletic, which has common ancestor, but not all of its
descendants). In the taxa with Carnivora, all of its descendants – the Felidae, Mustelidae, and
Canidae branches- are included, and it is the common ancestor for all of the branches.
b) An example of a paraphyletic group is highlighted in yellow. The common
ancestor of all the branches in the Carnivora group is included, but only one branch of
descendants is included. The animals in the Canidae branch in this case are the only
descendants included, even though the Felidae and Mustelidae branches are also descended
from the same ancestor. Paraphyletic groups are those that include the most recent common
ancestor of a group, but not all of the descendants of that ancestor.
c) An example of a polyphyletic group in the phylogenetic tree is highlighted
in blue. Polyphyletic groups do not include the common ancestor of all the animals in the
group. In this instance, the leopard (Panther pardus) and the coyote (Canis latrans) do not
share their most recent common ancestor. Since no common ancestor is included within the
group, it can be considered polyphyletic.
d) The only one of these groups that can be considered a clade is the group
from a – the monophyletic group. A clade is a group of species that includes an ancestral
species and all its descendants. The only type of grouping that fits this requirement is the
monophyletic type of grouping, because it includes a common ancestor and all of its
descendants. On the other hand, paraphyletic groupings lack some of the descendants of the
ancestor, while polyphyletic groupings lack the common ancestor. When building the
phylogenetic trees, we use cladistics – which is the analysis of how species may be grouped
Answer Key- LO 1.20
Why would extracting a single evolutionary progression from the fossil record be deluding?
A) It actually is not deluding because all trends can be seen from that branch.
B) You would not be able to see all the adaptive radiations and the series of speciation episodes, which have
the ability to make the trend disappear.
C) Evolution usually follows a straight trend and progresses to a fated speciation.
D) Changes in that single progression would show muddled trends and lead back to the wrong lineage.
In what way would “differential speciation success” play a role in macroevolution? How would this be considered
to be similar to the relationship of differential reproductive success in microevolution?
The term “macroevolution” refers to evolutionary changes that are reviewed through fossil records, in which the
cumulative effects of speciation over large tracts of time, such as the earth’s history, are displayed. This type of
evolutionary change occurs above species level. “Differential speciation success” being the situation where
the species that endure the longest and generate the most new offspring species determine the direction of
major evolutionary trends. These incidents would affect macroevolution in that the new species originated from
an ancestry that had already survived, subdivided, and experienced divergences of the gene pools would lead to the
new species. That evolutionary change is able to be referred upon and related to higher taxa if that trend was
displayed. Differential speciation success in correlation to macroevolution is similar to differential reproductive
success in microevolution because microevolution is defined by its confinement to a single gene pool and the
adaptaions and the evolution of that population and differential reproductive success because reproduction usually
concerns that one gene pool and the natural selection that occurs there, instead of species selection such as with
differential speciation success.
LO 1.21 Answers
Multiple Choice Answer: B. Deforestation. This would be categorized as the most damaging type
of human activity because it is heavily exercised in tropical rainforests that house more than 50%
of the Earth’s known species. This statement is true in relation to number of species driven to
extinction as noted in the question.
Free Response Answer: To start with the question has to be asked if the current ecosystems will
be able to sustain animals that are brought back from the dead. Even animals that have only
been extinct 10 years would be coming back to a slightly different environment than it left, not
to mention one that has been extinct thousands of years and will be returning to a drastically
different ecosystem. IF an animal is able to adapt and make it past this barrier the next
potential consequence is relating to if the species brought back could soon come to the role of
an invasive species. What good is it to bring back one species and cause the extinction of one or
more others as a result? Efforts put into de-extinction projects could be put forth attempting to
save the animals that are still fighting to get off the endangered and threatened lists. Aside from
excitement produced from bringing an animal back that has ceased to be there are a couple
possible positives. These species could potentially provide insight into how they went extinction
and what can be done to improve conservation efforts to current animal species at risk. They
could also teach us what future environmental changes can cause in organisms and maybe aid us
in avoiding extinction of the human race.
Answer Key: L.O. 1.22
Which of the following possibilities most likely describes the changes represented in the graphs of the seahorse head length?
a) They have overcome reproductive barriers with similar species and thus have undergone convergent evolution to two
b) Stabilizing selection has occurred.
c) As a result of selective mating the species has undergone disruptive selection, and in this case can also be classified as
d) The species has been geographically isolated , as a result, directional selection occurs.
The seahorse population represented in the graphs has naturally undergone disruptive selection. When 50 generations have
passed, scientists have the desire to maintain part of the original population. Through human interference ( via artificial
selection), a new breed of seahorse, which are avoided by typical seahorse predators, is introduced that is meant to maintain
those original characteristics. Despite this introduction, and several successful attempts at reproduction, there is no change
in the graphs. Explain why this was the case.
There are several factors which can be used as an explanation
to why the original population was not maintained. Since the
reproduction, meaning fertilization and birth of a hybrid
organism, was successful it signifies that all the pre-zygotic
barriers had been overcome. However, post-zygotically, the
hybrid may not have been viable, or it might have been
infertile and therefore could not reproduce further. Thus, the
disruptive selection of the species was unable to be altered.
Another factor which could have affected the attempt to
maintain the original species’ characteristics are biological,
meaning that even in a different organism they are ruled out
by natural selection due to survival issues that do not include
predation, such as obtaining nourishment.
ANSWER KEY - LO 1.24
M.C. Question: Which is not an example of how genetic frequency that can cause speciation.
A) recombination during meiosis
B) A mutation in an allele coding for beak size
C) Difference in allometric growth
D) Gamete incompatibility
Describe the two ways speciation can occur and name two factors that can cause
speciation. For each factor be sure to describe how each leads to speciation.
Speciation can occur through gradualism where species gradually diverge from a
common ancestor as they develop their own specific adaptions. Also, species
can diverge drastically from its ancestor and then change very little for the rest of
its existence. Two factors leading to speciation are changes in genetic frequency
and genetic drift. Genetic frequencies can be changed due to mutations and
simple recombination during meiosis. This can lead to speciation when a
mutation or gene combination becomes just as favorable or more favorable than
a previous gene, reproducing and producing a new species. Genetic drift causes
geographical isolation of species. When a species becomes isolated, it adapts to
its environment and may select for specific genes than its ancestors, creating a
LO 1.25 Answers
• Multiple Choice: The correct answer is C (Species evolve according to the
selective pressures of their environments to become more adapted to their
environments. E is incorrect, because natural selection does occur with
evolution. The other answers are incorrect because they use the word
“always” and not all evolution occurs through mutation, natural selection,
etc., all of the time.
• FRQ/Learning Log Style: In the above image, the majority of the lady
bugs are brightly colored, either orange or red and have spots. Based on
the image, the theory of natural selection would favor the brighter bugs
with spots. This deduction is reliable because ladybugs have evolved to
have this color so they look like a species that is not tasty. If any predator
has tried to eat a ladybug before, they will know to stay away because they
can give off a bad taste, and the predators are warned of this, because of
their bright colors.
LO 1.26 Answers:
M.C. Question: C-Leopard On a character table 1s represent an animal having a trait and 0s
represent an absence of a specific trait. The leopard has the greatest number of traits and
is therefore most evolved.
Free Response Question:
b) Koalas would be added to the cladogram on the branch after the evolution of hair but on
a different branch from rabbits and primates because koalas have developed all the traits
from vertebrae to hair (but not eggs with shell) as well as adaptations unique to koalas that
are different from primates and rabbits.
LO 1.27 Answers
M.C. Answer: The Answer is C, because Mitochondria/Chloroplasts and
Bacteria do not use Multiple Fission, they use Binary Fission for
FRQ Answer: RNA is a complex molecule, which carries information in
its linear sequence of base molecules (Genotype) and also has a three
dimensional conformation (Phenotype). In the proper setting, RNA can
replicate itself, and certain base sequences and conformations are
intrinsically more stable and lead to faster replication with less error. This
would lead to a selection advantage for replication of these molecules.
LO 1.28 Answers
M.C. Question: Why is abiotic synthesis unlikely to occur today?
A. Abundance of oxygen in the atmosphere
B. More adapted, evolved enzymes and nucleic acids that replicate at higher rates
C. Insufficiency of light in today’s oceanic systems
D. Climate change is occurring too quickly for abiotic synthesis to be effective
E. All of the above
Learning Log/ FRQ-style Question: Why is it more likely that RNA was the first genetic
material? Suppose it was discovered that DNA was the first genetic material. How would this
effect the current hypothesis of the origin of life? How would it effect the path of evolution?
Answer: It is more likely that RNA is the first genetic material
due to the discovery of ribozymes as a catalyst in the earliest
biochemical reactions. RNA has the ability to catalyze reactions
and carry information, making it a more necessary and effective
material for that time. It is also believed that without the
presence of RNA, a primer to create DNA could not have been
formed therefore RNA must have come first. However, if DNA
was found to be the first genetic material, the current hypothesis
would become highly flawed. DNA’s more stable double helix
and less flawed systematics would call in to question what
organisms were around in that time and what life was really like
back then. DNA is a more complex genetic material and
therefore is able to create more complex organisms. This would
result in a quicker evolution rate as there would be no drastic
change from RNA to DNA and most likely a less drastic
comparison between life today and back then.
LO 1.29 Answers
M.C Question: Which of the following statements
regarding the origins of life on Earth is false?
A) All 20 amino acids needed for life can be formed from
B) Primitive Earth was unable to support the development
of organisms that used the process of cellular respiration
C) The process of abiotic synthesis has proved to produce
all monomers of life with the exception of lipids
D) The monomers necessary for life were able to evolve
into polymers through an abiotic process
Free Response answer: That the molecules necessary for life were still able to be created with the reduced
lightning, though not all, means that the lightning may not have been necessary for the creation of life. It also
means that it is most likely that not all of the molecules necessary for life require the same amount of energy
to be created. Those that weren't able to be made with the reduced amount of electrode stimulation needed
more energy to be made. This affects the hypothesis on the origin of life by changing the necessary
environment for the creation of life. It could also mean that the atmospheric conditions suggested by the
original Miller-Urey experiment could be wrong and cause further experimentation on the atmospheric
conditions in order to become conclusive. Also the fact that the rate at which the molecules were made for
those that were able to be made was reduced signifies that the lightning is still an important factor in the
creation of life on Earth.
ANSWER KEY– LO 1.30
How is it possible that organisms from North America can also be found on Africa?
A)The continents were all one big one known as Pangea
B) The complex known as continental drift
C) The Cambrian Explosion
D) A and B only
E) A, B, and C
The Cambrian complex refers to the phenomenon during the Cambrian period. It is
fossils of animal phyla that seem to from around the same time period. But now
scientists are saying that the phyla, Cnidaria, are from much earlier than the Cambrian
period. They thought all animal phyla were from 20 million years ago, but now because
of the “Cambrian Explosion” they are now varying from 1 million to 700 million years
Explain the similarities and difference between prokaryotes and eukaryotes. Why do organelle like mitochondria have genetic
material in them? Give an example of another organism with the same problem as the mitochondria.
Prokaryotes are bacteria, they do not have a nucleolus nor do they have membrane bound organelles. Eukaryotes on the other
hand have both. Especially membrane bound organelles. The eukaryotic cell would not function at all if they did not have all the
membrane bound organelles that they do. Since prokaryotes are bacteria they are so much smaller than eukaryotes. Prokaryotes
have a cell wall, eukaryotes do as well but it is not as common in them than in prokaryotes.
The organelle mitochondria has genetic material in it because of a hypothesis known as serial endosymbiosis. The process called
endosymbiosis is when a cell lives in another cell and engulfs it. Therefore mitochondria was engulfed by itself and now has
genetic material. Another organelle in the same place as mitochondria is plastids, aka chloroplasts.
Answer Key- LO 1.31
M.C Question: The first genetic material was probably
A) DNA Polymer
B) Protein enzyme
C) RNA Polymer
learning log/ FRQ-style Question: Why is Ph important to the origin of life?
Ph is important to the origin of life because enzymes are only active in a narrow range of Ph.
Organisms need enzymes to metabolize reactions and catalyze reactions. If enzymes are not in
this optimal range then will denature and will not catalyze reactions. Organisms can not survive
in environments that are too acidic or too basic. Therefore, without optimal Ph organisms would
have never been able to survive.
ANSWER KEY- LO 1.32
Which of the following best indicates that prokaryotes evolved before eukaryotes?
A) Abiotic experiments with liposomes proved prokaryotes evolved first
B) Fossilized cells closely resemble prokaryotes
C) The structure of primitive plants
D) Prokaryotes have membrane-bound organelles
An isotope’s half-life is the number of years it takes for 50% of
the original sample to decay. Explain how scientists calculate and
determine the age of a fossil based off it’s half-life. What elements
are used and produced during the aging of fossils?
Fossils contain isotopes of elements that accumulated in the organisms when
They were alive. The carbon in a living organism includes the most common
Carbon isotope, carbon-12, as well as radioactive isotope, carbon-14. When the
Organism dies, it stops accumulating carbon, and the carbon-14 that it contained
At the time of death slowly decays and becomes another element, nitrogen-14.
Thus, by measuring the ratio of carbon-14 to total carbon or to nitrogen-14 in
A fossil, scientists can determine the fossil’s age. With a half-life of 5,730 years,
Carbon-14 is useful for dating fossils up to about 75,000 years old. Fossils older
Than that contain too little carbon-14 to be detected with current techniques.
Radioactive isotopes with longer half-lives are used to date older fossils.