Test 5 (Chapters 7-8)

What is a karyotype?

A display of an individual's complete set of chromosomes

What is evolution?

A genetic change in the population

What is a population?

A group of organisms of the same species living in a particular geographic region; the region can be a small area such as a test tube, or a large area such as a lake.

A vestigial structure?

A structure that has lost most or all of its ancestral function in a given species, but has been retained during the process of evolution

What is a homologous structure?

A structure that is the same because of common ancestry

What is a pedigree?

A type of family tree used to used to explore inheritance patterns for genetic information carried in a group of related individuals (to decipher and predict the inheritance patterns of genes)

What is convergent evolution?

Analogous structures all developed from different original structures.

How did Georges Cuvier influence Darwin?

By documenting fossil discoveries, he showed that extinction had occurred.

Line 1 of evidence demonstrating the occurrence of evolution: Fossil record

Documents the process of natural selection

What causes Down syndrome?

Down syndrome is caused by having an extra copy of chromosome 21 or 3 copies instead of 2 copies (Trisomy 21)

Line 5 of evidence demonstrating the occurrence of evolution: Laboratory and field experiments

Enable us to watch/observe evolution in progress; evidence for the occurrence of evolution is comes from multigenerational experiments and observations

What is a XXX female?

Female with an extra X chromosome (XXX) = may be sterile/infertile, no obvious physical or mental problems, sometimes called "metafemales"

What is Turner syndrome?

Female with only one X chromosome (X) = shorter height, webbed skin between neck and shoulders, underdeveloped ovaries (often sterile/infertile), some learning difficulties

How did the Tour of Galápagos Islands influence Darwin?

Fossils resembled but were not identical to the living organisms in the same area. Finch species on the Galapagos Islands differed in small but significant ways (beaks). These observations helped him to develop his theory of how species might change over time and confirmed his idea of natural selection.

Line 2 of evidence demonstrating the occurrence of evolution: Biogeography

Geographic patterns of species' distributions reflect their evolutionary histories

What was Gregor Mendel's contribution to biology?

He laid the foundation for genetics and determined factors of hereditary info passed on to offspring. In the mid-1800s he proved that there wasn't a whole tiny pre-made human in each sperm cell. Also, contributed the Law of Segregation.

How did Alfred Russel Wallace influence Darwin?

Independently came up with the same idea of natural selection; pushed Darwin to publish his book; published a joint presentation on their ideas

What is a carrier?

Individual that carries one allele for a recessive trait, and so does not exhibit the trait, but can have offspring that do.

What is Klinefelter syndrome?

Male with an extra X chromosome (XXY) = underdeveloped testes, lower testosterone levels (usually sterile/infertile), development of some female features, long limbs and slightly taller than average

What is a XYY male?

Male with an extra Y chromosome (XYY) = taller than average, moderate to severe acne, intelligence may be slightly lower than average, sometimes called "super males"

What is an autosome?

Non-sex chromosomes

How did Charles Lyell and his book Principles of Geology influence Darwin?

Noted the dynamic geological nature of the Earth; believed that geological forces still operate & account for changes that are seen in the in the earth surface; very important for Darwin - (1) the earth is not static & (2) maybe organisms are not static but could undergo change?

How did Jean-Baptiste Lamarck influence Darwin?

Noted the possibility of descent with modification; organisms "acquire" traits during their lives and pass these traits to their offspring; In the case of ducks they may stretch their toes for swimming and in time membranes would grow between their toes

Line 3 of evidence demonstrating the occurrence of evolution: Comparative anatomy and embryology

Reveal common evolutionary origins

Line 4 of evidence demonstrating the occurrence of evolution: Molecular biology/genetic code

Reveals that common genetic sequences link all life forms

How did Thomas Malthus' Essay on the Principle of Population influence Darwin?

Said populations have a way higher potential of growth than the environment can support, meaning there will be death of a portion of the population due to insufficient resources

What does true breeding mean?

Same as homozygous = breeding that always produces offspring with the same variant of the trait as the parents

What does dominant mean?

Strongest trait; masks the effect of a recessive trait when an individual carries both possible versions of the instructions for the trait

What does biogeography mean?

Study of the distribution patterns of living organisms around the world

How did Georges Buffon influence Darwin?

Suggested that the earth was much older than previously believed

What does heterozygous mean?

The genotype for a gene when an individual inherits a different allele from each parent

What is a phenotype?

The outward appearance of an individual

What is heredity?

The passing of characteristics from parent to offspring through their genes

What is nondisjunction?

The unequal distribution of chromosomes during meiosis; error of cell division that creates a gamete with zero or two copies of a chromosome rather than a single cop. It is the failure of homologous chromosomes or sister chromatids to separate during meiosis.

What is amniocentesis?

This procedure can be done approximately three to four months into a pregnancy. A needle is pushed through the abdomen, through the amniotic sac, and into the amniotic fluid. Using ultrasound for guidance, the doctor aims for a small pocket of fluid as far as possible from the fetus and withdraws about 2 tablespoons of fluid. This fluid contains many cells from the fetus, which can then be used for karyotype analysis. Any chromosomal abnormalities in the fetus will be present in these cells—and many of them can be seen in the karyotype.

An analogous structure?

Through convergent evolution, structure that are developed look the same because of their environment instead of ancestry

What is chorionic villus sampling (CVS)?

Tissue is removed from the placenta; Because the fetus and placenta both develop from the same fertilized egg, their cells contain the same genetic composition; Can be done several weeks earlier in the pregnancy, usually between the 10th and 12th weeks.

What are examples of single-gene traits?

Traits that are determined by the instructions a person carries at one gene (one gene causes one trait); not the norm

What is a genotype?

Underlying the phenotype; this is an organism's genetic composition

What does recessive mean?

Weakest trait; masked by the effect of a dominant trait when an individual carries both possible versions of the instructions for the trait

What organism did Gregor Mendel study?

Worked with pea plants to determine how hereditary info passed on to offspring.

Explain Mendel's law of segregation.

You've got two copies of each gene called alleles, but you only put one copy in each gamete (sperm or egg)

Which of the following proposed methods is most likely to give rise to a large population of smaller-than-average dogs after 20 generations? a. 1) Start with a large population of dogs of varying sizes. 2) When selecting the dogs to breed in order to generate a new generation, choose dogs in the lowest 20%, with respect to body size. 3) Repeat this for multiple generations. b. 1) Start with the two smallest dogs that you can obtain. 2) Have them produce as many litters as possible. 3) Repeat this for multiple generations. c. 1) Start with a large population of dogs of varying sizes. 2) When selecting the dogs to breed in order to generate a new generation, choose the smallest two dogs, with respect to body size, and have them produce as many litters as possible. 3) Repeat this for multiple generations. d. 1) Start with a large population of dogs of varying sizes. 2) When selecting the dogs to breed in order to generate a new generation, select random pairs of dogs. 3) Repeat this for multiple generations. e. None of the proposals above will give rise to a large population of smaller-than-average dogs. Natural selection can only occur in the wild.

a. 1) Start with a large population of dogs of varying sizes. 2) When selecting the dogs to breed in order to generate a new generation, choose dogs in the lowest 20%, with respect to body size. 3) Repeat this for multiple generations.

If two giraffes were crossed, where one is heterozygous for albinism (a) and the other has a homozygous dominant genotype, what would be the expected genotypic and phenotypic ratios? a. 2 AA: 2 Aa: 0 aa; all pigmented b. 2 AA: 2 Aa: 0 aa; 4 pigmented: 2 albino c. 2 AA: 0 Aa: 0 aa; all pigmented d. 1 AA: 2Aa: 1aa; 3 pigmented: 2 albino e. 0 AA: 0 Aa: 1 aa; all albino

a. 2 AA: 2 Aa: 0 aa; all pigmented

Which of the following statements about mutations is FALSE? a. Mutations always decrease an organism's fitness. b. Somatic cell mutations do not lead to evolution. c. Mutations occur in all species. d. Mutations are the ultimate source of all genetic variability. e. Mutations can be induced via ultraviolet radiation.

a. Mutations always decrease an organism's fitness.

The phenotypic trait of polydactyly, where an individual has extra fingers or toes, is one symptom of Ellis-van Creveld syndrome. This syndrome is more commonly found in Old Order Amish populations. Which of the following is a possible explanation for why this occurs within this population? a. The Old Order Amish experience the "founder effect" where all the members of a population descend from a small group of founding individuals. b. The Old Order Amish live near biowaste dumping sites that increase their number of genetic mutations and result in strange disorders. c. The Old Order Amish experience the "bottleneck effect" because they are physically isolated from other communities. d. Both a and c are correct. e. None of the above is correct.

a. The Old Order Amish experience the "founder effect" where all the members of a population descend from a small group of founding individuals.

Which of the following did Gregor Mendel never see? a. a chromosome b. a stamen c. an F2 generation d. a pea e. a hybrid

a. a chromosome

Natural selection means most nearly the same as: a. differential reproductive success. b. diploidy. c. gene flow. d. non-random mating. e. genetic drift.

a. differential reproductive success.

A diploid individual with two identical alleles for a particular gene is said to be a. homozygous for that gene. b. homozygous for every gene. c. heterozygous for that gene. d. sex-linked dominant. e. heterozygous for every gene.

a. homozygous for that gene.

The descendants of a single finch-like species that arrived in Hawaii 4-5 million years ago are called: a. honeycreepers. b. marsupials. c. Darwin's finches. d. tinkerers. e. honeydrippers.

a. honeycreepers.

The amount of time that has passed since two species last shared a common ancestor: a. is revealed by the degree of similarity in sections of their DNA. b. cannot be determined, due to gaps in the fossil record. c. cannot be determined, due to the fact that most species pass through the same embryological stages. d. can be determined for prokaryotic species but not eukaryotes. e. can be determined by the relative amounts of uranium-238 found in the bones of individuals from each species.

a. is revealed by the degree of similarity in sections of their DNA.

Peas (Pisum sativum) were well suited for Mendel's breeding experiments for all of the following reasons except: a. peas have a particularly long generation time. b. the pea plant is rather prolific in seed production. c. Mendel and his staff could control the pollination between different pea plants. d. many of the characteristics that vary in pea plants are controlled by single genes. e. peas exhibit variations in a number of observable characteristics, such as flower color and seed shape.

a. peas have a particularly long generation time.

The longer two species have been evolving on their own: a. the greater the genetic differences there are likely to be between them. b. the more different they will look. c. the more likely their hemoglobin will be composed of the same sequence of amino acids. d. the more likely they will be to share a common embryology. e. Both a and b are true.

a. the greater the genetic differences there are likely to be between them.

Which of the following is NOT true about Mendel's genetics experiments? a. Mendel studied only seven traits found in pea plants. b. Mendel believed that a tiny, pre-formed pea plant was passed via pollen to a pea plant egg. c. Mendel use relatively unsophisticated methods and good experimental design to learn about inheritance. d. True-breeding, to Mendel, meant that certain plants always produced the same version of traits as their parents. e. Mendel controlled which plant was "crossed" with another by using "pollen dusting".

b. Mendel believed that a tiny, pre-formed pea plant was passed via pollen to a pea plant egg.

How can two pea plants that have different genotypes for seed color be identical in phenotype? a. One of the two plants could be homozygous for the dominant allele, while the other could be homozygous for the recessive allele. b. One of the two plants could be homozygous for the dominant allele, while the other could be heterozygous. c. Genotype has no relation to phenotype. d. Seed color in pea plants is not genetically determined. e. One of the two plants could be homozygous for the recessive allele, while the other could be heterozygous.

b. One of the two plants could be homozygous for the dominant allele, while the other could be heterozygous.

A fossil is defined most broadly as: a. a piece of an organism that has turned into rock. b. any preserved remnant or trace of an organism from the past. c. the process of preservation of intact animal bodies. d. the preserved bones of vertebrates. e. the preserved pieces of hard parts (e.g., shell or bone) of extinct animals.

b. any preserved remnant or trace of an organism from the past.

A phenotype: a. does not include an organism's behavior. b. consists of the observable properties of an individual. c. depends on the environment rather than the genome. d. cannot change during the course of an organism's life. e. does not reveal the heritability of traits.

b. consists of the observable properties of an individual.

Prior to Mendel: a. humans observed, manipulated, and understood heredity and how it worked. b. humans observed and manipulated heredity; however, they did not understand how it worked. c. humans knew that heredity was controlled by genes; however, they didn't know the DNA structure. d. humans had no ideas about heredity. e. humans observed heredity; however, they could not understand or manipulate it.

b. humans observed and manipulated heredity; however, they did not understand how it worked.

When first used in medicine in the 1940s, penicillin was uniformly effective in killing the bacterium Staphylococcus aureus. Today, ____________________ has led to an increase in antibiotic-resistant alleles, and humans are increasingly at risk from untreatable Staphylococcus aureus infections. a. molecular genetics b. natural selection in Staphylococcus aureus populations c. natural selection in human populations d. uncleanliness in hospitals e. the substitution of methicillin for penicillin

b. natural selection in Staphylococcus aureus populations

Which of the following is a single-gene trait? a. height b. the widow's peak hairline c. brown hair d. blue eyes e. All of the above answer choices are correct.

b. the widow's peak hairline

Which of the following characteristics would NOT increase or decrease the fitness of the organisms that possess it? a. Certain mice in a population carry genes that cause their fur to be darker than the fur of other mice in the population that do not possess those genes. b. Certain fruit flies in a population carry genes that increase their ability to survive longer without food than other fruit flies in the population that do not possess that gene. c. Certain sterile mules in a population carry genes that allow them to carry heavier loads than other sterile mules in the population that do not possess those genes. d. Certain humans in a population carry genes that cause their eyesight to deteriorate at a more rapid rate than other humans in the population that do not possess those genes. e. Certain male birds in a population carry genes that increase the size of their tail relative to the size of the tails of the male birds in the population that do not possess those genes.

c. Certain sterile mules in a population carry genes that allow them to carry heavier loads than other sterile mules in the population that do not possess those genes.

You are studying the allele frequencies of the M and N blood types within a single population. Which of the following choices best describes how you calculate this frequency? a. Count the number of M and N alleles and divide by the total number of individuals in the population. b. Count the number of M and N alleles, divide by the total number of alleles and multiply by the total number of individuals in the population. c. Count the number of M and N alleles and divide by the total number of alleles. d. Count the number of M and N alleles and multiply by the total number of alleles. e. None of the above is correct.

c. Count the number of M and N alleles and divide by the total number of alleles.

Which of the following was NOT true of Gregor Mendel? a. He was an Austrian monk. b. He developed the first theory about how traits are inherited. c. He understood basic concepts about DNA replication. d. He lived in the 19th century. e. His primary research system was the pea plant.

c. He understood basic concepts about DNA replication.

Which of the following statements is NOT consistent with evolution by natural selection? a. Natural selection can lead to speciation. b. Certain individuals in a population have a higher rate of reproductive success than other individuals due to a variety of environmental and developmental factors. c. Individuals change during their lifespans to fit their environment better, and these changes can be inherited by their offspring. d. Individuals that reproduce most successfully are more likely to have offspring that also reproduce successfully if the environment remains stable. e. Individuals in a population exhibit variation, some of which can be inherited by their offspring.

c. Individuals change during their lifespans to fit their environment better, and these changes can be inherited by their offspring.

Which of the following statements is NOT important to Darwin's theory of natural selection? a. Some variation found in natural populations is heritable. b. Variation is found in all natural populations. c. Offspring tend to inherit characteristics acquired by their parents during their lifetimes. d. All species have the ability to produce more offspring than can live and reproduce. e. None of the above; all are important to his theory.

c. Offspring tend to inherit characteristics acquired by their parents during their lifetimes.

What was the MOST important scientific advance gained from Gregor Mendel's experiments with pea plants? a. We learned that chromosomes are composed of DNA. b. We learned that recessive alleles occur more frequently in the F2 generation than do dominant ones. c. We learned that many traits are inherited in discrete units, and are not the result of blending. d. We learned that there is considerable genetic variation in garden peas. e. Darwin's theory of evolution by natural selection was confirmed.

c. We learned that many traits are inherited in discrete units, and are not the result of blending.

Most genes come in alternative forms called a. dominants. b. recessives. c. alleles. d. chromosomes. e. gametes.

c. alleles.

Most mutations: a. are beneficial to the organism in which they occur. b. are in response to natural selection. c. are random, meaning they are unrelated to how useful or harmful they might be to the organism in which they occur. d. are random, meaning that they only occur in small populations. e. migrate from one population to another.

c. are random, meaning they are unrelated to how useful or harmful they might be to the organism in which they occur.

The amino acid chains making up hemoglobin in different species: a. can only be compared among mammalian species because non-mammalians do not possess hemoglobin. b. are identical, otherwise the hemoglobin cannot function properly. c. differ depending on how long it has been since the species last shared a common ancestor. d. reflect differences in how the hemoglobin functions in the species. e. differ depending on whether the species are marine or terrestrial.

c. differ depending on how long it has been since the species last shared a common ancestor.

The law of segregation states that: a. the number of chromosomes in a cell is always divisible by 2. b. eggs and sperm separate before fertilization occurs. c. each of two alleles for a given trait segregate into different gametes. d. gametes cannot be separate and equal. e. an allele on one chromosome will always segregate from an allele on a different chromosome.

c. each of two alleles for a given trait segregate into different gametes.

"Scientists can never observe evolution in action." This statement is: a. true; because evolution is the change in allele frequencies in a population, and scientists cannot view the alleles, they can only infer the activity of evolution from observed phenotypic changes. b. true; because evolution occurs over thousands to millions of years, scientists can only infer its activity after the fact. c. false; multiple replicated, controlled laboratory experiments and long-term studies of natural populations have enabled scientists to observe and measure evolution as it occurs. d. false; all evolutionary changes are observable as they occur. e. true; evolution is a theory and not a fact, and no one can observe a theory.

c. false; multiple replicated, controlled laboratory experiments and long-term studies of natural populations have enabled scientists to observe and measure evolution as it occurs.

Gregor Mendel performed his famous experiments on: a. finches. b. pigeons. c. garden peas. d. humans. e. green beans

c. garden peas.

According to the information in the above graphic: a. when insect wings became aerodynamically beneficial, they lost their thermoregulatory benefits. b. when insect wings became beneficial for thermoregulation, they lost their aerodynamic benefits. c. insect wings originally conferred thermoregulatory benefits on the organisms that possessed them and later, as they enlarged, began to confer aerodynamic benefits on those organisms. d. insect wings originally conferred aerodynamic benefits on the organisms that possessed them and later, as they enlarged, began to confer thermoregulatory benefits on those organisms. e. at all points in insect evolution, the aerodynamic characteristics of wings conferred a greater benefit than the thermodynamic characteristics.

c. insect wings originally conferred thermoregulatory benefits on the organisms that possessed them and later, as they enlarged, began to confer aerodynamic benefits on those organisms.

For a population to evolve through natural selection: a. it must be in a stable environment. b. it must have a small population size. c. its members must possess inheritable variation. d. individuals must be migrating in and out of the population. e. the mutation rate must be high.

c. its members must possess inheritable variation.

Consider a population of 5000 garter snakes. Two hundred of those snakes split off from the population to a new habitat. When the original population dropped from 5000 to 4800, the allele frequencies of various genes changed. The evolutionary process that caused the change in allele frequencies in the original population is: a. genetic drift. b. mutation. c. migration. d. stabilizing selection. e. disruptive selection.

c. migration.

The alternation between dry and wet years in the habitat of these Galápagos finches illustrates that: a. natural selection does not differentiate between the amount of rainfall that occurs in a species' habitat. b. finches with smaller beaks are more likely to mate with finches with larger beaks in dry years. c. natural selection does not march simply toward an optimized endpoint. d. in dry years, smaller beaks were selected for. e. finches with larger beaks went extinct during wet years.

c. natural selection does not march simply toward an optimized endpoint.

How many human traits are controlled by a single gene? a. 2 b. over 100,000 c. over 9000 d. 0 e. about 100

c. over 9000

Which of the following is true about evolutionary success? a. Humans are the crowning achievement of evolution. b. Vertebrates are the most evolutionarily successful. c. Any species that existed on Earth is evolutionarily successful. d. A successful organism can find food, escape predators, and reproduce. e. Darwin said that some species are better than others.

d. A successful organism can find food, escape predators, and reproduce.

Which of the following is NOT an important reason that natural selection does not lead to perfect organisms? a. Variation is needed as the raw material of selection; if a mutation that would have created the "perfect" organism never occurs, those organisms will never evolve to be a perfect fit for their environment. b. Environments change quickly; natural selection may be too slow to adapt an organism in a population to the constantly moving target that is its environment. c. There are often multiple alleles for a trait; each allele may represent an equally fit "solution" to the challenges of the environment. d. All of the above are important reasons that natural selection does not lead to perfect organisms. e. None of the above is an important reason that natural selection does not lead to perfect organisms.

d. All of the above are important reasons that natural selection does not lead to perfect organisms.

A plant with pink flowers is allowed to self-pollinate. Generation after generation, it produces pink flowers. This is an example of a. interbreeding. b. allopolyploidy. c. incomplete dominance. d. a true-breeding plant. e. the law of independent assortment.

d. a true-breeding plant.

If a baby has "his father's nose," it's because the baby has a. inherited the "father's nose" allele from his mother. b. not inherited the "suppress father's nose allele" from his mother. c. inherited the "father's nose" allele from his father. d. inherited many alleles from his father that work together to shape the baby's nose. e. been cobbled together from a bunch of used parts.

d. inherited many alleles from his father that work together to shape the baby's nose.

The larvae of the Gooseneck barnacle and Brine shrimp display similar morphological features despite differences observed in the adult forms. The similarities present in the larval forms suggests that: a. evolution was "descent with modification." b. the genes that regulate development are highly conserved. c. changes in genes regulate the development of organisms. d. similarities among embryos can infer relationships between species. e. the results of evolution could be viewed as a "tree of life."

d. similarities among embryos can infer relationships between species.

In general, in a population in which a trait is exposed to stabilizing selection over time: a. the mean stays approximately the same and the variation increases. b. the mean increases and variation decreases. c. the mean increases and variation increases. d. the mean stays approximately the same and the variation decreases. e. the mean becomes bimodal and the variation increases.

d. the mean stays approximately the same and the variation decreases.

In 1988, a biologist named Richard Lenski introduced 12 genetically identical populations of E. coli to test tubes and subjected them to the same conditions: a period of growth followed by starvation. After several years, all 12 strains had adapted to the conditions in similar ways; however, their genetic sequences were very different. Which of the following conclusions from this experiment is CORRECT? a. Similar phenotypes may result from a variety of underlying genotypes. b. Similar selective pressures on genetically identical organisms can have different effects at the level of the genome. c. Evolution by natural selection can be directly observed in organisms with short generation times. d. The 12 E. coli populations underwent convergent evolution resulting from similar environmental conditions. e. All of the above are correct conclusions drawn from Richard Lenski's experiments.

e. All of the above are correct conclusions drawn from Richard Lenski's experiments.

Why can radioactive carbon be used by scientists to date the ages of ancient fossilized organisms? a. The rate of decay for radioactive carbon always remains the same. b. After an organism dies, its radioactive carbon concentration decreases while the concentration of nonradioactive carbon stays the same. c. Radioactive carbon is produced in the atmosphere at the same rate as the radioactive carbon decays. d. Carbon components are found in all of the earth's creatures. e. All of the above choices are correct.

e. All of the above choices are correct.

Which of the following illustrates disruptive selection? a. Female long-tailed widowbirds prefer males with the longest tails. b. Female starlings that lay four or five eggs per clutch have more surviving young than those with larger or smaller clutches. c. The most common color form of an insect experiences the heaviest predation. d. A cattle breeder selects the largest male calf to be the sire for his next herd. e. Coho salmon eggs tend to be fertilized by the smallest or largest males.

e. Coho salmon eggs tend to be fertilized by the smallest or largest males.

How can an individual whose parents did not have the "fish odor syndrome" trait inherit that trait? a. If each parent were a silent carrier of the "fish odor syndrome," then their offspring would have a 100-percent chance of having the syndrome. b. If each parent were a silent carrier of the "fish odor syndrome," then their offspring would have a 50-percent chance of having the syndrome. c. Under the circumstances outlined above, the "fish odor syndrome" cannot be inherited. d. The "fish odor syndrome" trait is inherited extra-genetically. e. If each parent were a silent carrier of the "fish odor syndrome," then their offspring would have a 25-percent chance of having the syndrome.

e. If each parent were a silent carrier of the "fish odor syndrome," then their offspring would have a 25-percent chance of having the syndrome.

You are a conservation biologist, studying genetic variation in three populations of an endangered species of ladybug beetle. Population 1 has 20 beetles, two of which have brown spots, a recessive trait; the other nine beetles have red spots. Population 2 has 150 beetles and 15 of them have brown spots, while 135 have red spots. Population 3 has 50 beetles, and five of them have brown spots. In which population is the frequency of the allele for brown spots the highest? a. population 1 b. population 2 c. population 3 d. The frequency of the allele for brown spots is the same in all three populations. e. It is not possible to answer this question from the given data.

e. It is not possible to answer this question from the given data.

In pea plants, purple flower color is dominant to white flower color. If two pea plants that are true-breeding for white flowers are crossed, in the offspring a. all of the flowers will be purple. b. three-quarters of the flowers will be purple and one-quarter will be white. c. half of the flowers will be purple and half will be white. d. one-quarter of the flowers will be purple and three-quarters will be white. e. all of the flowers will be white.

e. all of the flowers will be white.

A cross between homozygous red-eyed flies and homozygous white-eyed flies results in progeny that all have red-eyes. This result demonstrates a. a dihybrid cross. b. the norm of reaction. c. the blending model of genetics. d. the law of independent assortment. e. dominance.

e. dominance.

According to Darwin's theories and observations on "the struggle for existence", organisms better suited to an environment have a greater probability of surviving and will also: a. be faster runners. b. lead a long, satisfying life. c. have larger bodies. d. have fewer predators. e. leave more offspring.

e. leave more offspring.

The phenotype of an organism can best be determined by a. sequencing its genes. b. inbreeding. c. outbreeding. d. a reciprocal cross. e. observing the organism.

e. observing the organism.

Two fruit flies are crossed, resulting in offspring with a 3:1 phenotypic ratio for a particular trait. This suggests a. that the parents were both homozygous for the gene associated with that trait. b. incomplete dominance. c. that one parent had complete dominance for the gene associated with that trait, while the other parent had incomplete dominance. d. that the one parent was heterozygous for the gene associated with that trait and the other parent was homozygous. e. that the parents were both heterozygous for the gene associated with that trait.

e. that the parents were both heterozygous for the gene associated with that trait.

Who was Gregor Mendel?

"Father of modern genetics"

What did people believe before Darwin?

- Organisms were all put on the earth by a creator at the same time - Organisms are fixed/unchanging = no additions, no subtractions - Earth is about 6,000 years old - Earth is mostly unchanging

What does homozygous mean?

- The genotype for a gene when an individual inherits the same 2 alleles - Same as true breeding = always produces offspring with the same variant of the trait as the parents