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KEY
Name
Date
Period
HBiology
Sections 16.1-16.2
Darwin’s Epic Journey
1. Darwin spent most of his time exploring the continent of SOUTH AMERICA; he did not visit NORTH
AMERICA, ASIA, and ANTARCTICA.
2. During Darwin’s time, geologists were suggesting that Earth was ANCIENT, CHANGED OVER TIME.
3. Darwin’s work offers insight into the living world by showing organisms are constantly
CHANGING/EVOLVING.
Observations Aboard the Beagle
Isabela Island tortoise
Hood Island tortoise
4. What important information about the Galápagos Islands tortoises did Darwin learn?
THE SHELL SHAPE OF A TORTOISE COULD BE USED TO IDENTIFY THE ISLAND IT
INHABITED.
5. Given its body structure, which tortoise above would require a habitat where food is easy to reach?
BECAUSE THE ISABELA ISLAND TORTOISE HAS A SHORT NECK THAT RESTRCTS MOVEMENT
OF ITS HEAD, IT WOULD REQUIRE A HABITAT WHERE FOOD IS EASY TO REACH.
6. On what continents are the Rheas, Emus, and Ostriches typically found? Why were the similarities among
rheas, ostriches, and emus surprising to Darwin?
RHEA – S. AMERICA, EMU – AUSTRALIA, OSTRICH – AFRICA; THE THREE DIFFERENT BIRDS
LIVED SO FAR AWAY, YET LOOKED SIMILAR
7. Why might Darwin come to think that the finches of the Galápagos Islands might be related to the finches of
South America, despite how different the birds were in appearance?
THE ISLANDS WERE VERY CLOSE TO THE COAST OF S. AMERICA AND THE BIRDS MAY HAVE
MIGRATED FROM THERE.
8. Darwin observed that the birds he would eventually discover were finches had differently shaped beaks.
What might this suggest about the eating habits of the birds? Explain.
BIRDS USE THEIR BEAKS TO EAT OR CAPTURE FOOD, DIFFERENTLY SHAPED BEAKS MIGHT
MEAN THAT THE BIRDS LIVED ON DIFFERENT DIETS.
9. What did the similarities between fossil animals and modern animals, like the glyptodont and armadillo,
suggest to Darwin?
THE SIMILARITIES SUGGESTED TO DARWIN THAT THE MODERN SPECIES MAY BE RELATED
TO THE EXTINCT FOSSIL SPECIES
An Ancient, Changing Earth
1. In what two ways did an understanding of geology influence Darwin?
KNOWING THAT THE EARTH COULD CHANGE OVER TIME ALLOWED DARWIN TO BELIEVE
THAT LIFE COULD CHANGE AS WELL; KNOWING THE EARTH WAS MUCH OLDER THAN
PREVIOUSLY THOUGHT ALLOWED ENOUGH TIME FOR THESE CHANGES
For Questions 2–5, write True if the statement is true. If the statement is false, change the underlined
word or words to make the statement true.
OLDER
2. Hutton realized that Earth was much younger than previously believed.
SLOWLY
3. Lyell thought most geological processes operated extremely quickly.
THE SAME AS
4. The processes that changed Earth in the past are different from the processes that operate
in the present.
TRUE
5. Lyell’s work explained how large geological features could be built up or torn down over
long periods of time.
Lamarck’s Evolutionary Hypotheses
6. How did Lamarck propose that species change over time?
SELECTIVE USE/DISUSE LED TO TRAITS BEING ACQUIRED OR LOST DURING A LIFETIME;
THESE ACQUIRED TRAITS COULD BE PASSED DOWN TO OFFSPRING; OVER TIME THIS LED TO
A CHANGE IN A SPECIES
7. How did Lamarck pave the way for the work of later biologists?
FIRST TO DEVELOP HYPOTHESES ABOUT EVOLUTION IN RESPONSE TO THE REALIZATION
THAT SPECIES CHANGE OVER TIME
Population Growth
For Questions 8-9, write the letter of the correct answer on the line at the left.
D
C
8. Which of the following is an idea attributed to Malthus?
A. As a population decreases in size, warfare and famine become more common.
B. As a population increases in size, the percentage of offspring that survive also increases.
C. If the human population grew unchecked, its rate of evolution would increase geometrically.
D. If the human population grew unchecked, there wouldn’t be enough living space and food for
everyone.
9. Malthus’s ideas led Darwin to conclude that
A. Earth is much older than previously thought.
B. the size of the human population can grow indefinitely.
C. many more organisms are born than will survive and reproduce.
D. organisms are able to evolve through a process known as artificial selection.
Artificial Selection
10. How do humans affect artificial selection? What role does nature play?
NATURE PROVIDES THE VARIATION AMONG ORGANISMS, HUMANS SELECT AND BREED FOR THE
VARIATIONS THEY FIND USEFUL OR APPEALING
Name
HBiology
Sections 16.3-16.4
KEY
Date
Period
Evolution by Natural Selection
1. What does the phrase struggle for existence mean?
MEMBERS OF A POPULATION COMPETE REGULARLY TO OBTAIN FOOD, LIVING
SPACE, AND OTHER NECESSITIES OF LIFE
2. How does an animal’s level of fitness relate to its chances of survival and reproduction?
THE HIGHER THE LEVEL OF FITNESS, THE BETTER THE CHANCE OF SURVIVAL
AND REPRODUCTION
For Questions 3-5, write True if the statement is true. If the statement is false, change the underlined word
or words to make the statement true.
INHERITED 3. Natural selection acts on acquired traits.
TRUE
4. Any inherited characteristic that increases an organism’s chance of survival is considered an
adaptation.
FITNESS
5. Natural selection is the ability of an individual to survive and reproduce in its specific
environment.
6. Below is a partially completed flowchart that models how natural selection drives evolution. The missing
steps are listed below, out of order. Write the missing step in a blank box in the flowchart.
A. Adaptations are passed on to the next generation.
Individuals in a population have many
variations.
B. The accumulation of adaptations may lead to the
evolution of a new species.
Some offspring inherit traits that
D
C. These offspring have few or no
decrease fitness.
offspring of their own.
D. Some offspring inherit traits that
increase fitness (adaptations).
C
A
Over time, adaptations accumulate in a
population.
Common Descent
B
For Questions 7–12, complete each statement by writing the correct word or words.
7. Natural selection depends on the ability of organisms to REPRODUCE, which means to leave descendants.
8. Every organism alive today DESCENDED from ancestors who survived and reproduced.
9. Over many generations, adaptation could cause successful species to EVOLVE into new species.
10. Common descent suggests that all species, living and extinct, are RELATED.
11. The principle that living species descend, with changes, from other species over time is referred to as
DESCENT WITH MODIFICATION .
12. The FOSSIL RECORD provides physical evidence of descent with modification over long periods of
time.
Biogeography
For Questions 1–3, complete each statement by writing the correct word or words.
1. Biogeographers study where organisms live now and where they and their ANCESTORS lived in the past.
2. When individuals from a mainland bird population immigrate to various islands, natural selection may result
in CLOSELY RELATED, but different, island species.
3. Distantly related organisms may be similar if they live in SIMILAR ENVIRONMENTS.
4. What explains the distribution of finch species on the Galápagos Islands?
THE FINCHES DESCENTED WITH MODIFICATION FROM A COMMON
MAINLAND ANCESTOR
5. What explains the existence of similar but unrelated species?
SPECIES EVOLVED FEATURES IN COMMON BECAUSE THEY WERE EXPOSED TO
SIMILAR PRESSURES OF NATURAL SELECTION
Comparing Anatomy and Embryology
For Questions 6-10, match the structure with the correct type. A structure type may be used
Anatomical Structure
A
6. bat wing and mouse arm
A
7. reptile foot and bird foot
B
8. dolphin fin and fish tail
C
9. eyes on a blind cave fish
B_______ 10. snake tongue and dog nose
11. How are homologous structures such as forelimbs evidence for common descent?
THE BONES ARE NOTICIBLY SIMILAR IN STRUCTURE AND ARRANGEMENT SO
IT CAN BE ASSUMED THEY ARE DESCENDED FROM A COMMON ANCESTRAL
FORM
12. How does the pattern of embryological development provide further evidence that organisms have descended
from a common ancestor?
THE EARLY DEVELOPMENTAL STAGES OF MANY VERTEBRATES LOOK VERY
SIMILAR; IT IS REASONABLE TO ASSUME VERTEBRATES ARE DESCENDED
FROM A COMMON ANCESTOR
Genetics and Molecular Biology
For Questions 13-18, complete each statement by writing the correct word or words.
13. The science of GENETICS provides molecular evidence that supports evolutionary theory.
14. All living cells use DNA and RNA to code heritable information.
15. The universal genetic code is used by almost all organisms to MAKE PROTEINS.
16. Proteins that are HOMOLOGOUS share extensive structural and chemical similarities.
17. Cytochrome c is a protein used for CELLULAR RESPIRATION in almost every living cell.
18. Homologous genes called Hox genes control timing and growth in EMBRYOS.
Name
HBiology
Sections 17.1-17.2 WS
KEY
Date
Period
Genetics Joins Evolutionary Theory
1. Natural selection works on an organism’s PHENOTYPYE rather than its GENOTYPE.
2. A(n) GENE POOL consists of all the genes, including the alleles for
each gene, that are present in a population.
3. In the diagram to the right, use circles to represent the alleles within
each segment of the population. Draw the B alleles as solid circles and
the b alleles as outline circles. The total number of individuals in this
population is 25; the total number of alleles is 50 .
4. How many alleles for black fur are in the sample population and what
percentage of allele frequency does that represent?
12 `
12
8
18
20 B ALLELES; 20/50 = 40%
5. How many alleles for brown fur are in the sample population and what percentage of allele frequency does that represent?
30 b ALLELES; 30/50 = 60%
6. Describe how a geneticist might be able to tell that this population is evolving.
IF IT’S EVOLVING, THE ALLELE FREQUENCY WILL CHANGE
7. Can you determine whether an allele is dominant or recessive on the basis of the ratio of phenotypes in the population?
Explain your answer.
NO, THE FREQUENCY OF ALLELES HAS NO RELATIONSHIP TO DOM/REC (A DOM ALLELE CAN
BE LESS PREVALENT IN A POPULATION)
Sources of Genetic Variation
8. What are mutations? When do they affect evolution?
CHANGE IN THE GENETIC MATERIAL OF A CELL; CAN ONLY AFFECT EVOLUTION IF (A) THEY
ARE IN A GERM CELL AND (B) IF THEY AFFECT FITNESS OF AN ORGANISM
9. How does sexual reproduction affect a population’s genetic variation?
GENETIC RECOMBINATION RESULTS IN NEW GENETIC COMBINATIONS WHICH CAN RESULT
IN NEW PHENOTYPES
10. Identify two ways in which genes can be recombined during meiosis.
INDEPENDENT ASSORTMENT, GENE SWAPPING (CROSSING OVER) DURING MEIOSIS
11. What is lateral gene transfer? How does it affect variation?
OCCURS WHEN GENES ARE PASSED FROM ONE ORGANISM TO ANOTHER WHO IS NOT ITS
OFFSPRING
Single Gene and Polygenic Traits True or False?
If false, change underlined to make true!
TRUE
12. The number of phenotypes produced for a given trait depends on how many genes control the trait.
POLYGENIC
ALLELES
13. Height in humans is an example of a single-gene trait.
14. Each gene of a polygenic trait often has two or more phenotypes.
TRUE
15. A single polygenic trait often has many possible genotypes.
TRUE
16. A symmetrical bell-shaped graph is typical of polygenic traits.
17. Why is genetic variation important to the process of evolution?
IT’S THE RAW MATERIAL FOR EVOLUTION, PROVIDES VARIATIONS WHICH MAY PRODUCE
VARIOUS LEVELS OF FITNESS
How Natural Selection Works
1. If a trait made an organism less likely to survive and reproduce, what would happen to the allele for that
trait? FEWER COPIES OF THE ALLELE WOULD BE PASSED ONTO FUTURE GENERATIONS
2. If a trait had no effect on an organism’s fitness, what would likely happen to the allele for that trait? IT
WOULD BE UNDER NO PRESSURE FROM NATURAL SELECTION SO IT MOST LIKELY WOULD
NOT CHANGE ITS ALLELIC FREQUENCY
Use the table showing the evolution of a population of mice to answer Questions 3–4.
3. Is the trait for fur color a single-gene trait or a polygenic
trait? Explain your answer.
SINGLE; THERE ARE ONLY TWO PHENOTYPES
(GREY AND BLACK)
4. Describe how the relative frequency of fur color alleles is
changing in this population and propose one explanation
for this change.
BLACK ALLELE IS INCREASING IN FREQUENCY;
PERHAPS DARKER IS HARDER FOR PREDATORS TO
SEE AND THEREFORE THEY ARE MORE LIKELY TO
SURVIVE/REPRODUCE
Type of Selection
B
5. Directional
C
6. Stabilizing
A
7. Disruptive
Situation
A. Individuals at the upper and lower ends of the curve have
higher fitness than individuals near the middle.
B. Individuals at one end of the curve have higher fitness than
individuals in the middle or at the other end.
C. Individuals near the center of the curve have higher fitness
than individuals at either end.
Genetic Drift
8. In small populations, random changes in ALLELIC FREQUENCIES is called genetic drift.
9. A situation in which allele frequencies change as a result of the migration of a small subgroup of a population
is known as the FOUNDER EFFECT.
10. The BOTTLENECK EFFECT is a change in allele frequency following a dramatic reduction in the size of a
population.
Evolution Versus Genetic Equilibrium
11. What does the Hardy-Weinberg principle state? ALLELIC FREQUENCIES SHOULD REMAIN CONSTANT
UNLESS EVOLUTION IS ACTING ON A POPULATION
12. What is genetic equilibrium? A SITUATION WHERE ALLELIC FREQUENCIES REMAIN CONSTANT
13. Explain how sexual selection results in non-random mating.
WHEN SPECIES PRACTICE SEXUAL SELECTION (CHOOSING A MATE BASED ON HERITABLE
CHARACTERISTICS SUCH AS SIZE AND STRENGTH), THE INDIVUDUALS MATE OF CHOICE
14. Suppose a population of insects live in a sandy habitat. Some of the insects have tan bodies and some have
green bodies. Over time, the habitat changes to a grass-filled meadow. Use the ideas of natural selection to
explain how and why the insect population might change.
IN THE ORIGINAL POPULATION, TAN WOULD HAVE BEEN CAMOUGLAGED FROM PREDATORS,
MAKING THEM MORE SUCCESSFUL. AFTER THE CHANGE TO A GREEN MEADOW, THE GREEN
WOULD HAVE BEEN MORE SUCCESSFUL AND PRODUCE MORE OFFSPRING. OVER TIME, THE
FREQUENCY OF THE GREEN ALLELE WOULD INCREASE.
Name
HBiology
Sections 17.3-17.4 WS
KEY
Date
Period
Isolating Mechanisms
1. What is speciation?
THE FORMATION OF NEW SPECIES
2. What does it mean for two species to be reproductively isolated from each other?
MEMBERS OF TWO SPECIES DO NOT INTERBREED AND PRODUCE FERTILE OFFSPRING
3. What must happen in order for a new species to evolve?
MUST BE REPRODUCTIVEY ISOLATED FROM ONE ANOTHER
4. List three ways that reproductive isolation occurs.
BEHAVIORAL, GEOGRAPHIC, TEMPORAL
5. When does behavioral isolation occur?
WHEN POPULATIONS HAVE DIFFERENCES IN COURTSHIP RITUALS
6. When does geographic isolation occur?
WHEN POPULATIONS ARE SEPARATED BY GEOGRAPHIC BARRIERS SUCH AS RIVERS,
MOUNTAINS, BODIES OF WATER, ETC
7. What is an example of temporal isolation?
EACH OF THREE SIMILAR SPECIES OF ORCHIDS IN THE SAME RAIN FOREST RELEASE POLLEN
ON DIFFERENT DAYS
8. Suppose a seamount forms from an underwater volcano. Birds on the mainland colonize the island. How
might this lead to speciation?
THE BIRDS ON THE ISLAND MAY BECOME REPRODUCTIVELY ISOLATED FROM MAINLAND BY
GEOGRAPHIC ISOLATION; THE GENE POOLS THAT COLONIZED THE ISLAND WOULD REMAIN
ISOLATED AND THE BIRDS MAY EVOLVE INTO A NEW SPECIES (VERY SIMILAR TO THE
FINCHES ON THE GALAPAGOS ISLANDS)
Speciation in Darwin’s Finches
For Questions 9–13, complete each statement by writing the correct word or words.
9. Peter and Rosemary Grant spent years on the Galápagos Islands studying changes in FINCH
populations.
10. Many finch characteristics appear in bell-shaped distributions typical of POLYGENIC traits.
11. The ancestors of the Galápagos Island finches originally came from the continent of S. AMERICA.
12. The populations of finches on separate islands are GEOGRAPHICALLY isolated from one another by large
stretches of open water.
13. Big-beaked finches that prefer to mate with other big-beaked finches are BEHAVIORALLY isolated from
small-beaked finches living on the same island.
14. Explain why reproductive isolation must occur for separate populations of the same species to evolve into
different species.
REPRODUCTIVE ISOLATION MUST OCCUR SO THAT THE GENE POOLS ARE ISOLATED. WHEN
THE GENE POOLS ARE ISOLATED, CHANGES THAT OCCUR IN ONE GENE POOL WILL NOT BE
CARRIED OVER TO THE OTHER GENE POOL. THUS, OVER TIME, ACCUMULATED GENE POOL
CHANGES CAN PRODUCE A NEW SPECIES.
Timing Lineage Splits: Molecular Clocks
1. What is a molecular clock?
MODEL THAT USES DNA COMPARISONS TO ESTIMATE THE LENGTH OF TIME THAT TWO
SPECIES HAVE BEEN EVOLVING INDEPENDENTLY
2. Why are only neutral mutations useful for molecular clocks?
THEY OCCUR IN THE DNA OF DIFFERENT SPECIES AT ABOUT THE SAME RATE BECAUSE THEY
ARE UNAFFECTED BY NATURAL SELECTION
Use the diagram of an ancestral species to answer Questions 3-4. Each picture in the diagram
represents a gene. Each shaded portion of a gene represents a mutation.
3. Which species is most closely related to Species B? Explain your
answer.
SPECIES C; SPECIES B AND C HAVE TWO MUTATIONS IN
COMMON WHERE B AND A HAVE NO MUTATIONS IN COMMON
4. How can you tell that Species C is probably not a descendant of the
organism with Gene 2?
SPECIES B AND THE SPECIES WITH GENE 2 DO NOT SHARE
ANY MUTATIONS
Gene Duplication
D
A
5. Multiple copies of a duplicated gene can turn into a group of related genes called
A. globins.
C. a Hox gene.
B. duplicates.
D. a gene family.
6. A chromosome may get several copies of the same gene during the process of
A. crossing-over.
C. gene expression.
B. gene mutation.
D. artificial selection.
7. How can Hox genes help reveal how evolution occurred?
HOMOLOGOUS HOX GENES ESTABLISH BODY PLANS IN SPECIES THAT HAVE NOT SHARED A
COMMON ANCESTOR IN HUNDREDS OF MILLIONS OF YEARS. IN ADDITION, MAJOR
EVOLUTIONARY CHANGES MAY BE BASED ON HOX GENES. A CHANGE IN ONE HOX GENE CAN
RESULT IN MAJOR BODY CHANGES IN AN ANIMAL. SCIENTISTS MAY BE ABLE TO TRACE HOX
GENE CHANGES TO DETERMINE WHEN AND WHY CERTAIN SPECIES OF ORGANISMS DEVELOPED.