Download www.njctl.org PSI Biology Evolution

Evolution
Adaptations
Classwork
1. Explain how the LUCA principle helps to explain the universal nature of the
genetic code.
2. What is an adaptation?
3. Explain how competition can help drive the process of evolution.
4. Suppose you are studying a population of bacteria in a lab. Some of the bacteria
are born with a mutation that provides them resistance to antibiotics. Explain
how competition in this population can lead to evolution and make a prediction of
how this evolution will occur.
Homework
5. Pick an animal and provide an example of an adaptation that makes it more fit for
its environment.
6. Explain why competition exists between individuals in a population, or between
individuals of different species.
7. Explain the relationship between the genetic code and the origin of evolutionary
adaptations.
Theories of Evolution
Classwork
8. Explain the error in Lamarck’s theory of Inheritance of Acquired Characteristics.
9. What is epigenetics?
10. Explain why the Galapagos Islands proved to be an integral part of Darwin’s
voyage.
11. What distinguishing feature exists between finches of the Galapagos Islands?
What environmental factor creates these differences?
12. Suppose you are studying big cats around the world. How can you use their
physical structures to study evolutionary relationships? What is the term for this
process?
13. Using Darwinian terminology, explain why a bird would possess wings that are
too small to allow it to fly.
14. Explain why, at one point in our embryonic development, human beings have gill
slits.
15. According to Darwin’s theory of natural selection, what will happen to the
frequency of an allele that allows an organism to successfully compete for
resources in a population?
16. Why is rRNA an especially useful tool when analyzing evolutionary relationships
between organisms?
17. ‘Modern Synthesis’ combines the original work of what two revolutionary
scientists?
Homework
18. Explain how epigenetics proves that at least some of Lamarck’s theory was
accurate.
19. Pick one of the organisms Darwin studied in the Galapagos and explain how it
helped him to develop his theory of evolution.
20. How is comparative anatomy useful in determining evolutionary relationships?
www.njctl.org
PSI Biology
Evolution
21. What is the evolutionary term used to describe the similarity between the
structure of a bat wing and a human arm? How is this used to explain evolution?
22. Provide an example of a vestigial structure in the human body. Explain,
evolutionarily, why this structure exists.
23. Explain, in evolutionary terms, why a fish, pig, chicken and human are virtually
indistinguishable during their early developmental stages? What is the study of
this process called?
24. Scientists during Darwin’s era discovered that the Earth was many millions of
years old (not a few thousand, as previously though) and that the Earth is
constantly changing. How did this influence the development of Darwin’s theory?
25. Briefly summarize the theory of natural selection.
26. What role might fossils have played in the development of Darwin’s theory?
27. Suppose humans share roughly 98% of our DNA with chimpanzees, 92% with
mice and 44% with fruit flies. How would you use this information to help
determine evolutionary relationships?
Natural Selection and Speciation
Classwork
28. What is speciation?
29. Which traits in an environment would tend to be favored in stabilizing selection?
30. Would more diversity exist in an environment that favors directional selection or
disruptive selection?
31. Suppose two species of plants are physically capable of interbreeding and their
gametes are compatible, yet interbreeding cannot occur. Suggest a hypothesis
for how this situation could arise.
Homework
32. What is the difference between directional selection and stabilizing selection?
33. Explain how the process of behavioral isolation can lead to speciation.
34. What is temporal isolation?
35. Suppose you are working as a caretaker at a zoo that has successfully bred a
zebra with a giraffe, but the offspring itself is unable to reproduce. Provide an
explanation to zookeepers to potentially explain this scenario.
36. Suppose you are studying two populations of foxes that are of the same species,
but have become geographically isolated due to deforestation. Over a decade,
you suspect that the two populations may have evolved into separate species.
Explain how you could determine whether this is true.
Population Genetics
Classwork
37. Is a group of sparrows and blue jays living in the same forest an example of a
population? Why or why not?
38. Scientists often refer to a population that exhibits a high level of genetic variability
as being ‘elastic’ or ‘flexible.’ Explain why these terms are used in this context.
39. Can the Hardy-Weinberg Equation be used to analyze multiple populations at
one time? Why or why not?
40. Identify three things that using the Hardy-Weinberg Equilibrium Equation can be
used to determine about a population.
41. Suppose you are studying a population in which 16% of the individuals are
homozygous recessive (bb). Using the Hardy-Weinberg equation, what is the
frequency of the recessive allele in the population?
www.njctl.org
PSI Biology
Evolution
42. Referring to the question above, what is the frequency of heterozygous
individuals in the population?
43. Suppose you are studying a population of sunfish in which long dorsal fins (L) are
completely dominant over short dorsal fins. You find that the population consists
of exactly 30% short finned fish. Calculate the frequency of homozygous
dominant individuals in the population.
44. Referring to question above, what is the frequency of the recessive allele in this
population?
45. Why is the Hardy-Weinberg Equilibrium model more of a theoretical process than
a truly concrete procedure?
46. According to the requirements for Hardy-Weinberg Equilibrium, are humans
evolving? Why or why not?
Homework
47. What is the relationship that exists between genetic variability in a population and
ability to respond to environmental changes?
48. For what purpose do scientists utilize the Hardy-Weinberg Equation?
49. What is the Hardy-Weinberg Equation?
50. Suppose you are studying a population of squirrels in which gray hair is
completely dominant over black hair. The frequency of homozygous dominant
individuals in the population is 41%. What is the frequency of the dominant allele
in the population?
51. Referring to question #51, what is the frequency of heterozygous individuals in
the population?
52. Suppose a population contains 10% homozygous recessive individuals. Using
the Hardy-Weinberg equation, what is the frequency of the dominant allele in this
population?
53. Identify three of the factors that need to be met in order for the Hardy-Weinberg
Equilibrium Equation to be effectively utilized.
54. Utilizing the Hardy-Weinberg equation, how can scientists determine whether or
not a population is evolving?
Genetic Drift and Patterns of Macroevolution
Classwork
55. What is genetic drift?
56. Explain how genetic drift can reduce, or even eliminate variation from a
population.
57. Can genetic drift eliminate variation from a population where there was a
consistently changing set of environmental conditions? Explain your answer.
58. Suppose you are studying an isolated population of elk in Canada that is under
intense hunting pressure. Provide an explanation from a genetic standpoint why
strict hunting regulations should be enacted for this area. Be sure to use
appropriate vocabulary.
59. What is the ‘Founder Effect?’
60. Explain why it is important that populations maintain a certain degree of genetic
diversity.
61. Explain how is it possible that 99% of all species that have ever existed are now
extinct.
62. Using the finches of the Galapagos Islands, explain the process of adaptive
radiation.
www.njctl.org
PSI Biology
Evolution
63. Both cacti (North America) and a group of plants called euphorbs (Africa) have
developed adaptations for surviving drought-like conditions, but they are not
believed to be closely related. Explain how this could possibly occur and the
name for the process.
64. In western North America, there is a species of flowering plant that has an
exceptionally long, deep flower, as well as a species of moth that has an
exceptionally long tongue. Explain how evolutionary theory could likely explain
the seemingly coincidental occurrence of these two species.
65. Explain how a rapid environmental change could lead to punctuated equilibrium.
Homework
66. Does genetic drift tend to have a more drastic impact on large or small
populations? Explain your answer.
67. What effect does a population bottleneck have on the genetic diversity of a
population?
68. Explain why a group that has endured a population bottleneck may be more
vulnerable to disease in the future.
69. Suppose you are a marine biologist working to repopulate the Atlantic bluefin
tuna in the Gulf of Mexico after years of overfishing. Explain why it is important
that you choose a genetically diverse group of tuna for your repopulation. If you
failed to do this, what situation could possible occur?
70. Using what you know about genetic diversity, explain why consanguineous
marriages are frowned upon in most cultures.
71. Explain how population bottleneck and founder effect may contribute to the
extinction of a species.
72. Is extinction a natural process? Explain your answer.
73. What role does the environment play in the process of adaptive radiation?
74. Why do you think it is important to study evolution?
75. Suppose you are studying anteaters in Africa. You find that the anteaters have
developed uniquely long noses and the ants in the area have developed larger
jaws for digging deeper in the hard soil. Explain how the two adaptations could
be related.
76. What is the name of the process described in the above question?
Free Response
1. Darwin gathered evidence to posit his theory of evolution. One category of
evidence was comparative anatomy. Within this category he described
homologous structures. Respond to the prompts below based upon the evidence
of homologous structures.
a. Explain what is meant by homologous structures.
b. The image below shows the forearm of a crocodile as well as the forearm
of a mouse. What do we learn about organisms from comparing
homologous structures such as these?
http://evolution.berkeley.edu/evolibr
ary/article/similarity_hs_10
www.njctl.org
PSI Biology
Evolution
2. Recall the central dogma of biology: “The central dogma of molecular
biology states that biological information flows in only one direction, from DNA to
RNA to proteins.” Using this as our foundation, explain what we can learn, about
evolution, from the fact that organisms from bananas to primates to humans,
produce and utilize common polypeptides. (utilize the terms proteins,
transcription, translation)
3. Natural selection causes changes in populations. Below is a graph representing
one type of selection pressure. Respond to the prompts with this graph, and
what it represents, in mind.
a. What is the term used for this type of selection?
b. When does this type of selection occur?
http://www.sparknotes.com/biolog
y/evolution/naturalselection/sectio
n1.rhtml
c. Use the peppered moth information provided and the image below to
describe how the population changed over time (use the following
information: dark colored moths, light colored moths, coal and black soot)
http://www.kuranvebilim.com/html
2/evrim_teorisi/turlerin_evrimi_yala
ni/turlerin_evrimi_yalani9.htm
4. The Hardy-Weinberg equilibrium using population and genetic information to
determine the possible evolution of a population. Respond to the following
prompts on the basis of the Hardy-Weinberg equilibrium (as shown below): p2 +
2pq + q2 = 1
a. Blondes occur in 36% of a particular self- contained human population.
Calculate the frequency of the recessive allele.
b. Calculate the frequency of the dominant allele.
c. Calculate the frequency of the heterozygous genotype.
d. List two of the five conditions that must be met in order for a population to
meet the Hardy-Weinberg equilibrium.
www.njctl.org
PSI Biology
Evolution
Evolution Answer Key
1. Since all living things share a common ancestry, it makes sense that the general
form of DNA is shared amongst all life
2. An adaptation is an anatomical modification or form of behavior, provided by
genes that allows an organism to be more successful in a specific environment
3. Competition causes some organisms to live longer and reproduce more
successfully than others, thus changing the genetic makeup of a
population/species
4. The bacteria that have the mutation will survive longer and reproduce more
frequently, whereas those that do not have the mutation will not live as long and
pass on their genes. Eventually, all bacteria in the population will be resistant to
antibiotics.
5. Many possible answers here- stripes on a zebra, regenerating teeth of a shark,
non-retractable claws of a cheetah, opposable thumbs of primates etc.
6. Competition exists because the resources needed for survival are finite by
nature, therefore causing organisms to compete to secure them.
7. Mutations in the genetic code provide the raw material for adaptations. An
organism cannot bear an adaptation unless it is provided in the genetic code.
8. Lamarck postulated that the characteristics that an organism acquires over its
lifetime are passed to its offspring. This cannot be true because those
characteristics do not exist in the DNA.
9. Epigenetics is the study of hoe environmental factors influence gene expression
10. The Galapagos provided an ideal setting for Darwin to develop his theory,
because they were a series of islands that provided similar, but unique
environments that contained similar, but unique species
11. Beak size and shape. Availability of food related to climate.
12. The anatomical similarities that exist between different species may suggest a
recent common ancestry. Comparative Anatomy.
13. At one time in the history of the species, the wings were used to fly. However,
over time the species experience different environmental pressures, which no
longer favored flight. The wings exist as a vestigial structure, hinting at the
evolutionary descent of the species.
14. This suggests, as with all vertebrates, that all vertebrates share a common
ancestry from a primitive vertebrate that used gills.
15. The allele will increase in a population
16. rRNA changes very little through the evolutionary time scale, much less than the
rate of change seen in DNA
17. Darwin and Mendel
18. Epigenetics supports the idea that the environment can have an effect on DNA,
though not truly in the way that Lamarck suggested
19. Tortoises on different islands had different shell shapes to allow access to
available food sources, finch beaks different from island to island depending on
food availability, marine iguanas possessed unique characteristics different from
terrestrial iguanas on the mainland, he also studied armadillos, mockingbirds and
a variety of other species
20. Similar anatomical features may suggest common ancestry in some cases
21. Homologous structures. While the arm and the wing are used for different
purposes in different environments, the structure of both is extremely similar,
www.njctl.org
PSI Biology
Evolution
when regarding the bone structure and arrangement. These similarities suggest
common ancestry.
22. Appendix, tailbone. An ancestor of the human race had a tail and used the
appendix, but as our species changed based on the environmental requirements,
these anatomical features decreased in size and function, becoming vestigial
23. All of these vertebrates share a common ancestry, which is evidenced in the
striking similarities of the embryos in each of these species. Comparative
embryology.
24. This expanded time frame allowed for the existence of many extinct species that
existed over the course of the development of the Earth. It made Darwin realize
that as the Earth has changed slowly over time, the species that lived in the
changing environments have had to change with it.
25. Individuals in a population that can secure the best resources will survive the
longest and produce the most offspring, thus increasing the occurrence of the
genes in the population that made the individuals successful.
26. Darwin looked at fossils that closely resembled living species and realized that as
the environment changed, the fossilized species had to change as well, leading
to the extant species. He also studied the development of the fossils in
subsequent layers of the Earth, allowing him to document the change in species
over time
27. This would indicate that humans and chimpanzees share a more recent common
ancestor than either of these species do with fruit flies. The more similar the
DNA is between two organisms, the more likely they are more closely
evolutionarily related.
28. Speciation is the process by which new species are created
29. The average traits
30. Disruptive
31. This could arise through a variety of circumstances. Perhaps the plants bloom at
different times of the year (temporal isolation) or the plants are located in
different parts of the world (geographic isolation). Other possibilities exist as
well.
32. Directional selection favors an extreme allele in a population, pushing natural
selection in a specific direction. Stabilizing selection favors the average allele of
a trait, reducing the occurrence of the more extreme traits in a population.
33. Behavioral isolation can prevent previously interbreeding groups from
interbreeding, which will eventually lead to the creation of a new species
34. Temporal isolation is when two species breed at different times of the year,
preventing interbreeding
35. Even though the species can interbreed, their offspring cannot. This is called
hybrid infertility, and exists in the crossing of many different species. As a result,
the resulting hybrid is not truly considered a species.
36. The easiest way would probably be to cross members from the two populations
to see if they could produce viable offspring.
37. No. A population consists only of a single species
38. This means that the population can withstand drastic changes in the environment
or diseases because the high level of diversity allows the population to fluctuate
genetically without putting it at risk of extinction
39. No. The equation is only effective for a single population.
40. phenotypic frequencies, genotypic frequencies, allelic frequencies, number of
individuals demonstrating each genotype or phenotype, whether or not
population is evolving
www.njctl.org
PSI Biology
Evolution
41. b = 40%
if q2 = 0.16, then q=0.4
42. 48% if q= 0.4, then p= 0.6 and 2pq is 2*0.4*0.6 = 0.48
43. LL = 20% if q2 = 0.3 then q = 0.55 and p = 0.45 and p2 = 0.2
44. l = 55%
45. It cannot truly be applied to real populations because of the stipulations that must
exist, no immigration or emigration, no mutation, random mating, no natural
selection, large population
46. Yes, humans as a whole experience mutations and non-random mating.
47. The more genetic variability, the better the ability to respond to environmental
change
48. To determine whether or not evolution is occurring in a population
49. p2 + 2pq + q2 = 1
50. 64% if p2 = 0.41, then p = 0.64
51. 46% if p = 0.64 and q = 0.36 then 2pq = 0.46
52. 70% if q2 = 0.1 then q = 0.3 and p = 0.7
53. no immigration or emigration, no mutation, random mating, no natural selection,
large population
54. If the ratios of p and q change from one generation to another, then evolution is
occurring
55. Genetic drift is the changing of the frequency of alleles in a population due to
chance
56. Genetic drift encourages a specific allele to increase in a population, which will
eliminate variation over time
57. Not likely. As environmental conditions fluctuate, it decreases the chances that
one particular allele will dominate in a population, and instead would select for
variation through the gene pool as conditions change
58. The more the population is reduced, the more the gene pool is reduced. As you
reduce the gene pool of a population, you decrease variability, thus decreasing
the ability of the population to withstand environmental pressures in the future
and increasing the likelihood of total population loss
59. When a small group of individuals relocates and begins a new population, this
can create unique genetic scenarios, as some times rare alleles may proliferate
in the new population if they were carried by the original founders but were not as
common in the larger population
60. Genetic diversity allows populations to respond to changes in the environment,
whereas a population that lacks diversity may experience severe population
decline due to sometimes even slight environmental changes
61. Life originated about 3.5 billion years ago. Since the Earth has been through
many different large scale environmental changes over this time, species have
been created and eliminated continuously for billions of years
62. Adaptive radiation involves the creation of numerous species from one common
ancestor as a result of many environmental changes. Since the finches of the
Galapagos initially migrated from one location, the differing environments on
each of the islands cause the creation of many new species from one initial
ancestor
63. This is convergent evolution. Similar environmental conditions favor similar
adaptations, but it is the environment, not common ancestry, that initiates these
features.
64. This is coevolution. The species evolve in continuity with each other. Often times
this represents a symbiotic relationship, where both species directly interact with
each other and therefore directly influence the evolutionary trends seen in each
www.njctl.org
PSI Biology
Evolution
species. The moth feeds on the nectar of the flower, and the plant is pollinated
by the moth.
65. Punctuated equilibrium is rapid change followed by long periods of little/no
change. A rapid environmental change would stimulate rapid evolutionary
change, which, if the environment stabilizes, could be followed by a long period
of no change.
66. Small populations. Large populations are less likely to be affected by random
selection trends, whereas a small population could simply because of the lack of
abundance.
67. It greatly reduces the genetic diversity
68. The population bottleneck results in a very small remnant of a once much larger
population. This remnant is less likely to possess the same genetic diversity, and
is thus more likely to negatively affected by disease.
69. If you do not use a genetically diverse group to repopulate, the new population
will have a lack of diversity and could suffer from a Founder’s Effect type
scenario.
70. Consanguineous marriages are more likely to concentrate rare genes in the
offspring they produce, and these rare genes may result in rare disorders.
Opening marriages to a broader group of individuals will reduce the chances of
two rare recessive alleles being inherited by offspring.
71. Population bottleneck and founder effect both reduce genetic variability, which
make species less resistant to change and more likely to go extinct as a result of
rapid environmental change
72. Yes. As the Earth changes and environments change, the traits that once made
a species successful in a particular environment will no longer be favorable. As
these now unfavorable genes accumulate, a species is more likely to go extinct.
Extinction can be viewed as unnatural when human related changes to the
environment cause a species to become unfit and go extinct.
73. The environment causes adaptive radiation, as different environments cause
individuals of a species to develop unique traits to fit their new environmental
conditions.
74. Answers may vary here. To study the history of life on Earth, to discover the
origin of the human race, to gain clues as to how we affect the world around us,
to determine how the Earth has changed over time and predict how it may
change in the future
75. This may be coevolution. The ants and anteaters share a habitat, the anteaters
continue to develop longer noses to reach the bottom of the anthills and the ants
develop the ability to dig deeper to avoid predation from the anteater. Each
species drives the evolution of the other.
76. Coevolution
1. Evidence for Evolution
a. Homologous structures are structures in different organisms that are
similar because they were inherited from a common ancestor that also
had that character.
b. This is one indication that, because they share the same bone structures
that are derived similarly, they have evolved over time, through
adaptations, from the same common ancestor.
2. If diverse organisms share common polypeptides (proteins) this signifies great
similarities in RNA and DNA. This dependent upon the fact that proteins are
produced based upon the information translated and transcribed from DNA. If
the DNA between diverse organisms is similar, (some greatly similar and some
www.njctl.org
PSI Biology
Evolution
less so), then at some point in the past, these organisms shared DNA. If the
organisms shared DNA, then they must arise from a common ancestor.
3. Selection
a. directional selection
b. When one of the “extreme” traits results in the “best fit” for an organism in
its environment.
c. dark colored moths and light colored moths were both traits found within
the original population; environmental conditions changed due to
increased burning of coal; tree trunks became darker due to the build up
of black soot; light colored moths became more visible to predators and
therefore, did not survive to reproduce as well as the dark colored moths.
d. Population graph shifted with a much higher number of black moths in the
population than white moths.
4. Hardy-Weinberg
a. 0.6
b. 0.4
c. 0.48
d. All five conditions are: Extremely large populations; No gene flow;
No mutations; Random mating; No natural selection
www.njctl.org
PSI Biology
Evolution