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BIOL 1001 Chapter : T4 Chapter 15 How Populations Evolve

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azuremammoth471
15 Mar 2019
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LSU
Department
Biological Sciences
Course
BIOL 1001
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All

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Evolutionary changes occur from generation to generation, causing descendants to differ from their ancestors. Evolution is a property of population (not individuals) A gene is a segment of dna found at a specific place on a chromosome. Here, there can be different sequences of nucleotides called _______________ The specific alleles of an organism"s chromosomes (its genotype) interact with the environment to influence the development of its physical and behavioral traits (its phenotype) Interaction between genotype and phenotype illustrated by coat color in hamsters. The dominant allele (b)- encodes for an enzyme that catalyzes black pigment formation. The recessive allele (b)- encodes for an enzyme that catalyzes brown pigment. Alleles, genotype, and phenotype in individuals fig. A gene pool consists of all the alleles of all genes in all individuals of a population. Population genetics deals with the frequency, distribution, and inheritance of alleles in populations.

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BIOL 1001 Chapter : Chapter 15
azuremammoth471
BIOL 1001 Chapter : Chapter 15
azuremammoth471
BIOL 1001 Chapter : Chapter 15
azuremammoth471

Related Questions

1. Characters that show a continuous range of variation, such as height and eye color, usually are controlled:

a. by a single gene with two alleles that are codominant.
b. by many genes with an additive effect.
c. by epistatic interactions between two genes.
d. mainly by the environment, with only a small genetic component.

2. In humans, red-green colorblindness is inherited as a sex-linked recessive trait. In order for a woman to be red-green colorblind, which of the following statements must be true.

a. Her mother must be red-green colorblind.
b. All of her brothers must be red-green colorblind.
c. Her father must be red-green colorblind.
d. All of the above statements must be true if a woman is red-green colorblind.

3. The x-ray crystallography data collected by Rosalind Franklin suggested to Watson and Crick that the:

a. structure of DNA is a double helix.
b. two strands of the DNA molecule are joined by hydrogen bonds between the bases.
c. four bases within DNA pair in a specific way.
d. two strands of the DNA molecule are joined by covalent bonds between the bases.

4. In the genetic code, _________ one amino acid.

a. one nucleotide specifies
b. two nucleotides specify
c. three nucleotides specify
d. four nucleotides specify

5. During Meiosis I, a homologous pair of chromosomes may not separate, resulting in daughter cells that have extra chromosomes or are missing chromosomes. This can lead to genetic disorders, including Down Syndrome. This phenomenon is called:

a. independent assortment.
b. nondisjunction.
c. segregation.
d. crossing over.

6. You are a human geneticist studying the incidence of retinitis pigmentosa in the residents of Tristan de Cunha, a group of small islands in the middle of the southern Atlantic Ocean. The allele for retinitis pigmentosa, which causes a form of blindness, is inherited as an autosomal recessive. You have determined that the frequency of this allele (r) in the population is 0.4 (40%). Using the principles of the Hardy-Weinberg rule, you would estimate the frequency of individuals who are heterozygous for this allele (Rr) in the population to be:

a. 0.16 (16%)
b. 0.24 (24%)
c. 0.36 (36%)
d. 0.48 (48%)

7. Natural selection acts at the level of the:

a. phenotype.
b. gene.
c. population.
d. nucleotide.

8. You are working with pea plants, trying to recreate the experiments that Mendel performed. You are doing a dihybrid cross with a plant that is heterozygous for both seed shape and seed color, with the genotype RrYy. Which allelic combinations would you expect to find in the gametes produced by this plant?

a. This plant would produce only RY and ry gametes.
b. This plant would produce only RrYy gametes.
c. This plant would produce RY, Ry, rY, and ry gametes.
d. You cannot determine which gametes this plant can produce without knowing the genotypes of its parents.

9. Biochemist Erwin Chargaff found that in DNA there is a special relationship between the four bases that we now call Chargaff's rule. His observation was that, in an organism's genome the:

a. percentage of A nucleotides = the percentage of T nucleotides, and the percentage of C nucleotides = the percentage of G nucleotides.
b. four bases all occur in an equal frequency (25%) within each organism.
c. percentage of A nucleotides = the percentage of G nucleotides, and the percentage of C nucleotides = the percentage of T nucleotides.
d. genetic material is composed of proteins, not DNA.

10. During DNA replication:

a. each strand of the double helix acts as a template for the synthesis of a new strand.
b. the enzyme DNA polymerase adds nucleotides to the strand being synthesized.
c. the bases A,C,G and T are required.
d. All of the above are true of DNA replication.

11. During translation, amino acids are joined by peptide bonds to make polypeptides. The formation of these peptide bonds is catalyzed by:

a. DNA.
b. mRNA.
c. tRNA.
d. rRNA.

12. If an allele (R) at a gene with two alleles shows complete dominance, individuals with the genotypes ______ will have the same phenotype.

a. RR and rr.
b. RR and Rr
c. Rr and rr
d. Each of the three possible genotypes will have a different phenotype.

Expression vectors inprokaryotes do not make functional eukaryotic gene products inbacteria very well because

Answer Not sure which one ?!

· the codon sequence for prokaryotes is differentthan the codon sequence in eukaryotes

· there are no disulfide bridges formed in proteinsnormally made in prokaryotes

· prokaryotic expression vectors cannot translateeukarytic sequences

· eukaryotic genes have introns, and prokaryotesdon't

· eukaryotic genes have exons and prokaryotesdon't


I create a knockout mouseusing the agouti/black fur system \. When I cross the agoutioffspring of the originally engineered mouse, I find a ratio of 2agouti mice to 1 black furred mouse. What is the bestexplanation?

Answer not sure which one?!

· The gene knocked out was recessive.

· The gene knocked out was dominant.

· The gene knocked out was a lethalgene.

· The knockput was integrated into a random spot,and did not knockput the original gene.

A restriction enzyme cuts DNAand leaves the following end

xxCTGCA
xxG

Which of the following could be the sequence of the correspondingend of the other end of the cut DNA?

Answer

· xxG
xxCTGCA

· xxC
xxGTGCA

· xxCCGAT
xxG

· xxGGCTA
xxC


An SNP always occurs dueto

Answer

· a one base-pair change.

· a three base-pair change.

· a single restriction site change.

· a single amino acid change.

· None of these.


I PCR out a mutated gene in apatient with Lisenbee chorea (the inability to dance in acoordinated fashion) and I compare it to another patient with thatsame disease phenotype. One subject had a mutation on chromosome 4,and the other subject couldn't rock it because of a mutation onchromosome 5. This is an exampe of

Answer

· pleitropy

· locus heterogeneity

· allelic heterogeneity

· dominant negative mutation

· penetrance

In his experiments, Mendelnoted that when two traits are involved in a genetic cross, theyare inherited independently of each other. Though Mendel didn'tknow about chromosomes, this still holds true (mostly)because

Answer

· genes on the same chromosome are often mixedthrough meiotic crossover during the formation ofgametes.

· variant alleles of the same gene do not interferewith the phenotypic expression of the gentoype in different geneticloci.

· most higher organisms are diploid, making only twoalleles available for every genetic locus, and there is a 50/50chance of geting either allele from a single parent.

· expression of phenotypes can vary from thegenotypes because of encironmantal influences.

· chromosomes often recombine

Anticipation is caused by amutation that increases in expressivity over subsequentgenerations.

Answer

· True

· False

Question 44

I have a genotype that shouldproduce a specific phenotype, but some of the individuals with thegenotype do not demonstrate any evidence of the phenotype. I wouldconsider this an example of

Answer

· allelic heterogeneity.

· locus heterogeneity.

· penetrance.

· expressitivity.

· sheer luck.

Question

Which of the following doesnot occur during the PCR reactions?

Answer

· Changes in the reaction temperature by athermocycler

· Denaturation at high temperatures

· Synthesis of oligonucleotide primers

· Extension of primers by DNA polymerase

· Annealing of oligonucleotide primers

Question

DNA markers, or variantnon-coding regions of DNA, are DNA polymorphisms that are usefulfor genetic mapping.

Answer

· True

· False

A mosaic is an organismwith

Answer

· multiple genotypes within one organism

· multiple alleles within one genotype

· more than one color of fur

· transgenes added to the zygote beforedevelopement

· a wt phenotype but a mutated genotype

Question

Genotype causesphenotype.

Answer

· No, gentoype just influences phenotype.

· Yes, genotype is the DNA sequence that createsphenotype.

Question

A true genetic chimera can becreated by

Answer

· mutating a gene early on in the development of anorganism resulting in different alleles being present in theadult

· multiple fertilized eggs or zygotes fusing to formone embryo

· adding a transgene to the genome of an organismduring fetal development only

· adding cells of a different species to an adultorganism

· adding a transgene to the genome of an animal atany stage in development

Question

The ABO blood group can bestbe explained by the concept of _______.

Answer

· dominant traits

· recessive traits

· allelic heterogeneity

· locus heterogeneity

· vampirism

If a loss of functionmutation creates a dominant phenotype, it may be becauseof

Answer

· haploinsufficiency

· penetrance

· expressivity

· allelic heterogeneity

· locus heterogeneity

Please select the best matchfor each.

Answer

· PCR: Technique used to generatecopies of a DNA fragment

· Southern blot : Screeningprocedure used to assay DNA fragments

· RFLPs : DNA fragments generatedby restriction enzymes that vary in length betweenindividuals

· Northern blot : Screeningprocedure used to assay mRNA fragments

· Electrophoresis Movement ofmacromolecules in an electrical field

Answer

A.

Screening procedure used toassay DNA fragments

B.

Movement ofmacromolecules in an electrical field

C.

Screening procedure used toassay mRNA fragments

D.

DNA fragments generated byrestriction enzymes that vary in length betweenindividuals

E.

Technique used to generatecopies of a DNA fragment

A gene mutates, and theprotein produced has a novel way of interacting with the cell, andcreates a new phenotype because of this new functionality. This iscalled

Answer

· pleitropy

· locus heterogeneity

· allelic heterogeneity

· dominant negative mutation

· gain of function dominant mutation

Question 62

Mutations in the somaticchromosomes may be inherited by the next generation.

Answer

· True

· False


A degenerate PCR primer withmany variant sequences must be used to make multiple copies of agene

Answer

· if only the protein sequence of the gene productis known to construct the primers

· if the DNA you are using is cDNA to constructthe primers

· if the DNA you are using is genomic DNA to becopied

· if the DNA you are trying to copy iscDNA

· if the vector is prokaryotic and the transformedcell is eukarytotic

Question

Please select the best matchfor each term.

Answer

· Restriction enzyme


· PCR C

· Plasmid

· YAC A

· Dideoxynucleotide

Answer

A.

Endonuclease isolated frombacteria

B.

Eukaryotic cloningvector

C.

Method for amplification ofDNA sequences

D.

Small circular fragment ofDNA

E.

Molecule used in DNAsequencing

Question

A couple goes on MauryPovitch, and the results are in: you are not the father. But noother man impregnated the female (granted, unlikely for a MauryPovitch guest, but work with me here) and he must be the father.DNA analysis claims otherwise, though the child definitely wasmom's (poor thing). What may be going on here?

Answer

· the child is parthenogenic because the motheractually impregnated herself like a shark, and the child's DNA isall mom's

· the child had a mutation that changed the genethat is used to trace paternity

· the child is a mosaic because he is actually a setof twins fused early during fetal development, and therefore camefrom 2 eggs and 2 sperm

· the dad may have germ-line mosaicism, meaning thatthe genotype of his sperm is different from his somaticgenotype

· mitochondrial DNA only comes from mom, so there isno way to tell whobthe baby's father is




1.. Polymorphisms for a given trait are relatively common in most species. Discuss the possible advantages or polymorphisms in terms of evolutionary fitness. Be sure to relate your discussion to a specific example. It is also possible that organisms showing more heterozygosity may actually be less fit. Describe one such possible scenario.

2. In the peppered moth (Biston betularia), black individuals may be either homozygous (A1A1) or heterozygous(A1A2), whereas the pale gray moths are homozygous (A2A2). Suppose that in a sample of 250 moths from one locality, 108 are black, and 142 are gray.

3. Retrace the history of primate evolution from early primates to monkeys, apes and hominins. When did some ofthe significant divergences occur (such as between the prosimians and the monkeys or between the chimps and hominins)? What was happening with the continents and the major climatic conditions during these times?What are the major species (including the extinct species) along the human lineage after the split with the chimps and bonobos? Where did many of these events occur on the globe and when?

4. Spencer Wells described his study how the genetic markers in humans are being used to infer the historical geographical distribution of humans and the dispersal of our ancestors. Explain how the genetic markers on our DNA (from blood samples) helps us understand that history. What are the techniques he is using? What is the nature of the evidence? What are the major conclusions about the journey of our ancestors out of Africa?What were the major migrations of humans to all the other continents? Approximately when did each migration occur and what were the major paths? How does the evidence support these conclusions? What Supporting evidence besides the DNA evidence is being used to support these conclusions?

5. Provide an adaptive and a non adaptive hypothesis for the evolutionary loss of useless organs, such as eyes in many cave-dwelling animals. How might these hypotheses be tested?

6. Directional selection is one of the models of natural selection. Describe this type of selection in terms of the frequencies of advantageous alleles over time. What is the trend over time? What is the eventual outcome for this allele as long as no other evolutionary factors intervene? Describe at least one good example of directional selection.

7. Consider the first copy of an allele for insecticide resistance that arises by mutation in a population of insects exposed to an insecticide. Is this mutation an adaptation? If, after some generations, we find that most of the population is resistant, is the resistance an adaptation? If we discover genetic variation for insecticide resistance in a population that has had no experience of insecticides, is that variation an adaptation? If an insect population is polymorphic for two alleles, each of which confers resistance against one of two pesticides that are alternately applied, is that variation an adaptation? Or is each of the two resistance traits an adaptation?Explain your reasoning thoroughly.

8. Suppose that a mutation in a species of annual plant increases allocation to chemical defenses against herbivores, but decreases production of flowers and seeds (i.e., there is an allocation trade-off). What would you have to measure in a field study in order to predict whether or not the frequency of the mutation will increase?

9. In many socially monogamous species of parrots and other birds, both sexes are brilliantly colored or highly ornamented. Is sexual selection likely to be responsible for the coloration and ornaments of both sexes? How can there be sexual selection in pair-bonding species with a 1:1 sex ratio, since every individual presumably obtains a mate? Which of the models of sexual selection described in the book might account for these species characteristics?

10. Kin selection explains why organisms may provide benefits to relatives. Is there a conflict between the principle of kin selection and the evolution of siblicide and abortion?

11.Many species of albatrosses and other seabirds nest in colonies on islands. The adult search for food at sea,sometimes over great distances. Some ecologists who study seabirds turn to their favorite topic of discussion in a bar one evening, and one says, “I can imagine an albatross genotype that destroys the eggs of nestlings of its colony mates when the parents are away foraging, and leaves them dead without eating them. Do you think such a behavior would evolve?” One of his companions says, “Yes, because it would make more food available for the albatross and its offspring.” Another says, “No, because it would threaten the survival of the population.” The fourth says, “You’re both wrong. I have a different explanation for why albatrosses don’t kill others’ chicks.” What is the fourth ecologist’s explanation, and why does she think her companions are wrong?

12. The concept of a species is fundamental to understanding biology, yet there may not be one definition that fits all “types” of organisms (e.g. animals, plants, fungi, bacteria, slime mold, lichens, etc.). Discuss several of the definitions of a species as presented in class and present your own definition for a species. Compare the strengths and weaknesses of each definition. Ernst Mayr is strong proponent of the biological species concept.How does he justify his position? Do you agree or disagree? If we employ the biological species concept, when did species first exist? What were organisms before then, if not species? What might the consequences of the emergence of species be for processes of adaptation and diversification? Be sure to explain your reasoning thoroughly.

13. The process of speciation ultimately involves the development of reproductive isolation between two related populations of organisms. Describe the various types of both prezygotic and postzygotic reproductive isolation and give an example of each.

14. Respond to the following quote from the character named Mr. Spock in “Star Trek”:“A truly successful parasite is commensal, living in amity with its host, or even giving it positive advantages, as for instance, the protozoans who live in the digestive system of your termites and digest for them the wood they eat. A parasite that regularly and inevitably kills its host cannot survive long, in the evolutionary sense, unless it multiplies with tremendous rapidity ... it is not pro-survival.”From what you have learned in this course, do you agree or disagree with Spock? How can you apply your reasoning to the relative “fitness” of HIV which causes AIDS, the Ebola virus which causes hemorrhagic fever,fleas which suck blood from dogs, or the prokaryotic ancestors of mitochondria and chloroplasts?

15. In many species of birds and mammals, clutch size is larger in populations at high latitudes than in population sat low latitudes. Species of lizards and snakes at high latitudes often have smaller clutches, however, and are more frequently viviparous (bear live young rather than laying eggs), than low-latitude species. What selective factors might be responsible for these patterns? Explain your reasoning.

16. The popular media often presents evolution as being a predictable process with a definite goal. For instance, in one “Star Trek: Voyager” episode, the captain instructs the ship’s computer to extrapolate the “probable course” of evolution of hadrosaurs (a bipedal dinosaur), if hadrosaurs had been removed from Earth before the Cretaceous-Tertiary (K-T) Extinction and allowed to evolve on another planet. What information about the hadrosaurs’ new environment would have been useful in developing the best possible prediction? Given what you know on genetic drift and selective agents, is it possible to accurately predict the long-term course of evolution?

17. Young children often develop strong food preferences that sometimes seem bizarre to their parents --- such as wanting to eat only a certain food prepared in a familiar way, or being reluctant to each new foods or foods with strong or bitter tastes (like coffee and some vegetables). Develop an evolutionary explanation for such preferences. What evidence would you gather to investigate your hypothesis and rule out alternative explanations?

18. Many organisms, such as mammals, only reproduce by sexual means. Other organisms are exclusively asexual,such as many of the bacteria and fungi. And still others have ways of propagating by both sexual and asexualmeans. Discuss the relative advantages and disadvantages of each mode of reproduction. Why aren’t all organisms sexual critters? Why are many asexual organisms still very successful as evidenced by the pure abundance and diversity? What is the adaptive significance of having different genders (e.g. male and female)?In other words, why sex?

19. How might differential expression and regulation by Hox genes contribute to mosaic evolution in which different segments of an animal body plan evolve different morphology?

20. Development of a morphological structure involves many different types of gene products, including transcription factors, signaling proteins, and “effector” genes such as enzymes. When a morphological change occurs in a single mutational step, which of these types might be more or less likely to be involved? Within a gene, would such single-step events be more likely to involve coding or non-coding sequences, and what characteristics of the gene’s function might affect this likelihood?

21. Since 2001, the complete DNA sequences of the genomes of many people have been determined. If humans,along with other forms of life, have evolved from a common ancestor, what evidence of this would be expected in the human genome? In what ways might the history and processes of evolution help us interpret and make sense of the human genome sequence data?

22. Paleontologists and some biologists commonly infer function, and even behavior, from anatomical details.Skeletal features, for example, are often used to infer that an extinct mammal (such as an early hominid) was highly, somewhat, or not at all arboreal. This inference assumes a good fit of form to function (i.e., optimal form). Can this assumption be justified?

23. Stephen Jay Gould (1989) and others have argued that the evolution of self-conscious, intelligent species (i.e.humans) was historically contingent: it would not have occurred had any of a great many historical events been different. The philosopher Daniel Dennett (1995) and others have disagreed, arguing that convergent evolution is so common that if humans had not evolved, some other lineage would probably have given rise to a species with similar mental abilities. What do you think, and why? If Gould’s position is right, what are its philosophical implications, if any?

24. Explain how Intelligent Design was determined as a religious view rather than a scientific view in the court casein Dover, PA. Should a scientific explanation of evolution be included in a science curriculum in K-12 schools?How is science and religion different in how they seek answers to questions? How is term "theory" used differently in science than in everyday English use? What is biological evolution? What evidence is used to support the scientific explanation of evolution? Is it possible to accept scientific explanations without rejecting religious faith?

25. Discuss how a creationist versus an evolutionary biologist might explain some human characteristics and the implications of their differences. Sample characteristics: eyes; wisdom teeth; individually unique friction ridges(fingerprints); five digits rather than some other number; susceptibility to infections; fever when infected;variation in sexual orientation; limited life span.