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BIOL 1503 Exam 1 questions
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Evolution - CORRECT ANSWER>>>>change over time of the genetic composition of a population; descent of modern organisms with modification from preexisting organisms evolutionary adaptation Evolution states that organisms descended from ____________ organisms. - CORRECT ANSWER>>>>ancestral Adaptation - CORRECT ANSWER>>>>accumulation of inherited characteristics that enhance organisms ability to survive in specific environment Favorable Adaptation - CORRECT ANSWER>>>>adaptations that help the organism survive and reproduce Catastrophism - CORRECT ANSWER>>>>the principle that events in the past occurred suddenly and were caused by different mechanisms than those operating today Describe the evidence that supports catastrophism. - CORRECT ANSWER>>>>Each strata (layer of rock) represents some sort of catastrophe that destroyed many of the species living at the time. Catastrophism is confined to local regions which were later repopulated by new species. Uniformtarianism - CORRECT ANSWER>>>>the principle that mechanisms of change are constant over time What do scientists who support uniformtarianism believe? - CORRECT ANSWER>>>>The scientists believe that the same geological processes are operating today as in the past and at the same rate. Explain the mechanism for evolutionary change proposed by Jean Baptiste de Lamarck.
- CORRECT ANSWER>>>>1. Use and Disuse: bodies of living organisms are modified through the use or disuse of parts i.e. Giraffes: Back in the day, scientists figured out that giraffes had shorter necks and legs. The giraffes would stretch their legs and necks. The giraffes became longer and taller, and passed the trait to the next generation Inheritance of acquired characteristics: these modifications are inherited by offspring; organisms have the innate desire to become more complex
Natural Selection - CORRECT ANSWER>>>>the unequal survival and reproduction of organism due to environmental forces, resulting in the preservation of favorable adaptations What are the requirements for natural selection to occur? - CORRECT ANSWER>>>>1. Variability: variation in traits in a population
- Heritability: traits have to be inheritable - passed from one generation to the next
- Differential reproductive success: traits must allow the population to survive and reproduce better - favorable traits True or False: Natural selection "selects" from what is available in the gene pool. - CORRECT ANSWER>>>>True Explain why new characteristics are not created on demand. - CORRECT ANSWER>>>>Natural selection only works on the variability already in the population. The favorable traits are the ones that survive more and reproduce more and have a disproportionate effect on the next generation. Explain the mechanisms behind natural selection. - CORRECT ANSWER>>>>Individuals with heritable characteristics experience competition among each other for finite resources. These facts result in those individuals who are more suited for their environment produce more offspring than those who are not well-suited, and, over time, these favorable traits increase in frequency within the population. How does natural selection explain the unity of life? - CORRECT ANSWER>>>>Organisms share many characteristics, indicating that a common ancestor lived in the remote past. How does natural selection explain the diversity of life? - CORRECT ANSWER>>>>It is hypothesized that the ancestral organisms lived in various habitats, so they accumulated adaptations that fit them to certain ways of life. Describe the two inferences Darwin made from his observations that led him to propose natural selection as a mechanism for evolutionary change. - CORRECT ANSWER>>>>1. Individuals whose inherited traits give them a higher probability of surviving and reproducing in a given environment tend to leave more offspring than other individuals.
- This unequal ability of individuals to survive and reproduce will lead to the accumulation of favorable traits in the population over generations. The widespread use of DDT in the mid-1900's put pressure on insect populations to evolve resistance to the insecticide. As a result, large populations of insects today are resistant to DDT. A. Darwinian B. Lamarckian - CORRECT ANSWER>>>>B. Lamarckian
Within a few weeks of treatment with the drug 3TC, a patient's HIV population almost entirely consists of 3TC-resistant viruses. How can this best be explained? A. HIV has the ability to change its surface proteins to resist drugs. B. A few drug resistant viruses were present at the start of treatment and natural selection increased their frequency. - CORRECT ANSWER>>>>B. A few drug resistant viruses were present at the start of treatment and natural selection increased their frequency. Homologous Structures - CORRECT ANSWER>>>>structures or other attributes in different species that resemble each other because of common ancestry How are homologous structures evidence of the theory of evolution? - CORRECT ANSWER>>>>An organism has that feature because a common ancestor had that feature and was passed along. Explain the homologous structures found in mammalian forelimbs. - CORRECT ANSWER>>>>Although our forelimbs are used for different functions, the skeletal structure has the same structure of bones. Why? Vertebrates share a common ancestor with the same or similar plan or format. Explain the similarities found in vertebrate embryos. - CORRECT ANSWER>>>>All vertebrates share similar developmental genes. Differences arise by some genes switched on or off at varying times during development. i.e. pharyngeal pouches and post-anal tails Explain the similarities in biochemistry and molecular biology between organisms. - CORRECT ANSWER>>>>DNA is universal genetic material. All life forms use approximately the same 20 amino acids to make proteins. All use ATP as the primary form of cellular energy. All use RNA and ribosomes to make proteins. Analogous Structures - CORRECT ANSWER>>>>structures that are similar in function but not in structure and developmental and evolutionary origin; superficially similar - serve similar function, but do not have the same origin or common ancestor throughout the lifespan of the organism Convergent Evolution - CORRECT ANSWER>>>>similarity between two organisms, structures or molecules due to independent evolution along similar lines rather than descent from a common ancestor Vestigial Structures - CORRECT ANSWER>>>>a feature of the organism that is a historical remnant of a structure that served a function in the organism's ancestor's past What observations have been made regarding the fossil record? What predictions can be made using evolution to account for the distribution of fossils in sediments? -
CORRECT ANSWER>>>>The fossil record shows that past organisms differed from present day organisms and that many species have become extinct. It also shows evolutionary changes that have occurred in various groups of organisms. Biogeography - CORRECT ANSWER>>>>the study of the past and present geographic distribution of organisms Explain how biogeography is used to infer the evolution of organisms. - CORRECT ANSWER>>>>Biogeography is used to predict where fossils of different groups of organisms might be found. i.e. island species Island species are closely related to mainland species, inferring that mainland species colonized and adapted to the conditions of the island, giving rise to a new species. Discrete Characters - CORRECT ANSWER>>>>classified on an either-or basis Give an example of a discrete character. - CORRECT ANSWER>>>>flower color in pea plants -- can either be purple or white Discrete characters are coded by ____________ gene that has _____ allele(s). - CORRECT ANSWER>>>>a single; two Quantitative Characters - CORRECT ANSWER>>>>vary along a continuum within a population Give an example of a quantitative character. - CORRECT ANSWER>>>>height, weight, etc. Quantitative characters create a ________________ curve. - CORRECT ANSWER>>>>bell-shaped Quantitative characters are determined by not a single gene, but ___________ genes interacting with each other with ____________ alleles. - CORRECT ANSWER>>>>multiple; multiple Mutation - CORRECT ANSWER>>>>changes in nucleotide sequence of DNA _______________ is the source of new alleles and genes and genetic variation. - CORRECT ANSWER>>>>Mutation Point Mutation - CORRECT ANSWER>>>>change in one nucleotide base in a gene When do point mutations occur? - CORRECT ANSWER>>>>during the DNA replication process
A. 0.
B. 0.
C. 0.
D. 0.9 604 - CORRECT ANSWER>>>>B. 0.
About one child in 2,500 is born with phenylketonuria (an inability to metabolize the amino acid phenylalanine). This is known to be a recessive autosomal trait. What proportion of the population are carriers of the phenylketonuria allele (that is, what proportion are heterozygous)? A. 0. B. 0. C. 0. D. 0.98 - CORRECT ANSWER>>>>C. 0. About one child in 2,500 is born with phenylketonuria (an inability to metabolize the amino acid phenylalanine). This is known to be a recessive autosomal trait. If a population has the following genotype frequencies (AA = 0.42, Aa = 0.46, & aa = 0.012), then what are the allele frequencies? A. A = 0.42, a = 0. B. A = 0.6, a = 0. C. A = 0.65, a = 0. D. A = 0.76, a = 0. E. A = 0.88, a = 0.12 - CORRECT ANSWER>>>>C. A = 0.65, a = 0. Genetic Drift - CORRECT ANSWER>>>>a process in which chance events cause unpredictable fluctuations in allele frequencies from one generation to another Statistically, the _______ a sample, the greater the chance of deviation from a predicted result. - CORRECT ANSWER>>>>smaller Genetic drift tends to ___________ genetic variation. - CORRECT ANSWER>>>>reduce Why does genetic drift reduce genetic variation? - CORRECT ANSWER>>>>Alleles are often lost or fixated depending on which organisms reproduce and pass on their alleles. Alleles that are fixed or lost depend on random factors. Founder Effect - CORRECT ANSWER>>>>genetic drift that occurs when a few individuals become isolated from a larger population and form a new population on whose gene pool composition is not reflective of that original population Bottleneck Effect - CORRECT ANSWER>>>>genetic drift that occurs when the size of a population is reduced, as by natural disaster of human actions
True or False: In genetic drift, the best alleles may not be passed on to the next generation. - CORRECT ANSWER>>>>True Gene Flow - CORRECT ANSWER>>>>the transfer of alleles from one population to another, resulting from the movement of fertile individuals or their gametes How does gene flow act to reduce genetic differences between adjacent populations? - CORRECT ANSWER>>>>Since individuals are moving among populations, then variation is reduced - variation/gene frequency among the populations becomes similar. Migration High - CORRECT ANSWER>>>>little genetic variation between populations Migration Low - CORRECT ANSWER>>>>more genetic variation between populations What is the difference between gene flow and genetic drift? - CORRECT ANSWER>>>>gene flow: the transfer of alleles from one population to another, resulting from the movement of fertile individuals or their gametes genetic drift: a process in which chance events cause unpredictable fluctuations in allele frequencies from one generation to another Relative Fitness - CORRECT ANSWER>>>>the contribution an individual makes to the gene pool of the next generation, relative to the contributions of other individuals The __________ amount of offspring equals the best fitness. - CORRECT ANSWER>>>>highest Explain why relative fitness could be high for a short-lived organism. - CORRECT ANSWER>>>>Short-lived organisms can have a high fitness if they significantly contributed to the gene pool over their lifespan. Explain why relative fitness is zero for a healthy, long-lived sterile organism. - CORRECT ANSWER>>>>This organism could not contribute to the gene pool; therefore, the relative fitness of this organism is zero. Which statement describes the swallow with the greatest evolutionary fitness? A. A swallow that lives to be 3 years old and has four offspring, two of which survive to reproduce themselves. B. A swallow that lives to be 5 years old and have five offspring, one of which survives to reproduce. C. A swallow that live to be 2 years old and has four offspring, all of which survive to reproduce themselves. D. A swallow that lives to be 7 years old and has three offspring, all of which survive to reproduce.
of blood types B in eastern European countries and a gradual decrease going east to west in Europe. A. No mutation B. Gene Flow C. Random Mating D. Natural Selection E. Large Population Size - CORRECT ANSWER>>>>B. Gene Flow Diploidy - CORRECT ANSWER>>>>two copies of each chromosome Balancing Selection - CORRECT ANSWER>>>>occurs when natural selection maintains stable frequencies of two or more phenotypic forms in a population What are two examples of balancing selection? - CORRECT ANSWER>>>>1. heterozygote advantage
- frequency dependent selection Frequency-Dependent Selection - CORRECT ANSWER>>>>the selective process is dependent on the frequency of a phenotype in a population Give an example of frequency-dependent selection. - CORRECT ANSWER>>>>i.e. scale-eating fish The fish are left-mouthed and right-mouthed; the prey protects itself on the side that is attacked the most. Selection favors whichever mouth phenotype is less common, and those reproduce and make the phenotype more frequent in the gene pool. Heterozygote Advantage - CORRECT ANSWER>>>>some individuals who are heterozygous for a particular locus have a greater fitness than homozygotes Give an example of heterozygote advantage. - CORRECT ANSWER>>>>Heterozygotes for the sickle-cell gene not only see limited effects from sickle-cell, but also have immunity from the most severe symptoms of malaria. These heterozygotes have a higher fitness and reproduce more. Define Ernst Mayr's biological species concept. - CORRECT ANSWER>>>>defines a species as a population or group of populations whose members have the potential to interbreed in nature and produce viable, fertile offspring Prezygotic Isolation - CORRECT ANSWER>>>>impedes mating between species of hinder the fertilization of ova if members of different species attempt to mate Describe five prezygotic barriers and give examples of each. - CORRECT ANSWER>>>>habitat isolation: two species that occupy different habitats within the same area may encounter each other rarely
i.e. garter snakes Garter snakes live in the same geographic area, but one species live in water and one is terrestrial. temporal isolation: species that breed during different times of the day or year cannot mix their gametes i.e. skunks Each species of skunk live in the same geographic area, but mate at different times of the year. behavioral isolation: courtship rituals that attract mates and other behaviors unique to a species are effective reproductive barriers i.e. boobies Boobies only mate after a courtship display unique to their species. mechanical isolation: mating is attempted, but morphological differences prevent its successful completion i.e. snails The shells of two species of snails have spirals that are in opposite directions that do not allow them to mate. gametic isolation: sperm of one species may not be able to fertilize the eggs of another species i.e. sea urchins This species releases eggs release sperm and egg into the water to fuse, but each species gametes have different protein receptors that prevent reproduction. Postzygotic Isolation - CORRECT ANSWER>>>>often prevents the hybrid zygote from developing into a viable, fertile adult Describe three postzygotic isolating mechanisms and give examples of each. - CORRECT ANSWER>>>>reduced hybrid viability: the genes of different parent species may interact in ways that impair the hybrid's level of development or survival in its environment i.e. salamanders Those who hybridize often produce frail offspring. reduced hybrid fertility: even it the hybrids are vigorous, they may be sterile i.e. mules When male donkeys and female horses mate, they produce mules, which are a sterile species. hybrid breakdown: some first generation hybrids are viable and fertile, but when they mate with one another and the parent species, the next generation are either feeble or sterile i.e. plants
Sympatric Speciation - CORRECT ANSWER>>>>speciation takes place in geographically overlapping populations Explain how polyploidy can cause reproductive isolation. - CORRECT ANSWER>>>>Due to the presence of extra chromosomes, the offspring cannot reproduce with the parents. If the offspring reproduces with a similar offspring, then a new species has formed. Polyploidy - CORRECT ANSWER>>>>presence of extra sets of chromosomes in cells due to accidents during meiosis Allopolyploid - CORRECT ANSWER>>>>species with multiple sets of chromosomes derive from different species Autopolyploid - CORRECT ANSWER>>>>individual has more than two chromosome sets, all derived from a single species Distinguish between an autopolyploid and an allopolyploid species. - CORRECT ANSWER>>>>autopolyploid: individual has more than two chromosome sets, all derived from a single species allopolyploid: species with multiple sets of chromosomes derive from different species Plant species A has a diploid number of 12. Plant species B has a diploid number of 16. A new species, C, arises as an allopolyploid from A and B. The likely diploid number for species C would be A. 12 B. 14 C. 16 D. 28 E. 56 - CORRECT ANSWER>>>>D. 28 The origin of a new plant species by hybridization, coupled with accidents during nuclear division, is an example of A. allopatric speciation B. allopolyploidy C. autopolyploidy D. hybrid inviability - CORRECT ANSWER>>>>B. allopolyploidy Which of the following is the first step in the process of allopatric speciation? A. genetic drift B. interspecies contact C. geographic isolation
D. reproductive isolation - CORRECT ANSWER>>>>C. geographic isolation All but which of the following are likely to promote sympatric speciation? A. gene flow B. ecological isolation C. temporal isolation D. polyploidy - CORRECT ANSWER>>>>A. gene flow Explain how habitat differentiation has led to sympatric speciation in North American maggot flies. - CORRECT ANSWER>>>>The fly's original habitat was the hawthorn tree, but apple trees were introduced and the flies began to exploit the apple trees. The flies who exploited the apples trees matured more quickly, so natural selection favored the apple flies with rapid development. Now, the flies demonstrate temporal isolation. Explain how sexual selection has led to sympatric speciation in the cichlids in Lake Victoria. - CORRECT ANSWER>>>>In this species, the males have different coloring. Mate choice based on male breeding coloration is the main reproductive barrier that normally keeps the gene pools of these two species separated. Describe a hybrid zone and explain that they can be viewed as a "natural laboratory" in which to study speciation. - CORRECT ANSWER>>>>A hybrid zone is a region in which members of different species meet and mate, producing at least some offspring of mixed ancestry. They can be viewed as a "natural laboratory" because hybrid zones occur naturally in nature -- species for not have to be forced to mate and the outcomes can be observed. List and describe the possible outcomes for hybrids. - CORRECT ANSWER>>>>reinforcement: strengthening of reproductive barriers; occurs when the hybrids are less fit and prezygotic barriers are strengthened to cease hybrids from being formed fusion: weakening of reproductive barriers -- two species fuse together; occurs when the reproductive barriers aren't strong and so much gene flow occurs that the two species are becoming more similar and fuse into the same species stability: continued production of hybrid individuals Explain how the process of speciation may be reversing in the cichlid species due to pollution in Lake Victoria. - CORRECT ANSWER>>>>The females of this species chooses to mate with a male of a specific coloration to her species. It is hypothesized that, due to pollution, the cichlid females cannot determine the male's specific coloring. This, first, leads to the frequency of of mating between members of species that had been reproductively isolated. Secondly, this also leads to many hybrids being produced, fusing the parent gene pools and a loss of a species.
organic molecules. Miller and Urey tested this hypothesis, and they wanted to see if they could create organic material from inorganic materials. How their experiment worked:
- Electric spark simulated lightning
- Gases of primeval atmosphere were condensed (representational of the ocean)
- Organic molecules appeared after only a few days Which of the following statements does not support the hypothesis of the RNA world? A. Single-stranded RNA can assume many 3D shapes specified by their nucleotide sequence. B. Some RNAs are important catalysts in modern cells. C. The oldest known fossils contain traces of RNA. D. RNA can store genetic information. - CORRECT ANSWER>>>>C. The oldest known fossils contain traces of RNA. What type of rock strata is home to fossils? - CORRECT ANSWER>>>>sedimentary rocks How do rock strata reveal the age of fossils? Does this provide relative ages or absolute ages? - CORRECT ANSWER>>>>Order of fossils in rock strata tells us the sequence in which they were laid down. Fossils near the surface are more recent. Deeper fossils are more ancient. Rock strata are only able to provide a relative age. Explain why the fossil record provides an incomplete chronicle of evolutionary change. - CORRECT ANSWER>>>>1. Many organisms did not die in the right place and time to become preserved.
- Many were destroyed by geologic processes. <As a result, the fossil record is biased to fossils that existed a long time, were widespread, and abundant and to those who had hard shells, bones, or other features.> Explain how radiometric dating can be used to determine the absolute age of rock strata. - CORRECT ANSWER>>>>Radiometric dating can determine absolute ages of fossils. Radioactive isotopes decay into a daughter isotope at a fixed rate, so scientists use the half-life to determine the age of fossils. A half-life is the amount of time that it takes for 50% of an isotope to decay. When a certain rock was formed, it contained 12 mg of K40. The rock now contains 3 mg K40. The half-life of K40 is 1.3 billion years. How old is the rock? A. 0.4 BY B. 0.3 BY C. 1.3 BY D. 2.6 BY - CORRECT ANSWER>>>>D. 2.6 BY
What were the first organisms? - CORRECT ANSWER>>>>The first organisms were prokaryotes such as bacteria and archaea. These organisms fed on accumulated organic molecules that were in the environment (heterotrophic), and some were likely autotrophic (able to take an energy source and produce their own organic material). Describe the major events in Earth's history from its origin until 2 billion years ago. i.e. Describe the clock analogy. - CORRECT ANSWER>>>> Which is the correct sequence of events? A. anaerobic cells > O2 > photosynthesis > aerobic cells B. photosynthesis > O2 > anaerobic cells > aerobic metabolism C. anaerobic cells > photosynthesis > O2 > aerobic metabolism D. anaerobic cells > aerobic metabolism > photosynthesis > O2 - CORRECT ANSWER>>>>C. anaerobic cells > photosynthesis > O2 > aerobic metabolism Explain the endosymbiotic theory for the evolution of the eukaryotic cell. Describe the evidence that supports this theory. - CORRECT ANSWER>>>>The endosymbiotic theory is a relationship between an anaerobic cell and an aerobic cell. It is the theory that mitochondrion and plastids, including chloroplasts, originated as prokaryotic cells engulfed by an ancestral eukaryotic cell. Eventually, the host cell and the engulfed cells evolved into a single eukaryotic cell. The engulfed cells were possible undigested prey or internal parasites or mutualists. Scientists hypothesize that a heterotrophs engulfed the prokaryotic mitochondria and plastids, able to use the nutrients from photosynthesis from these prokaryotes. However, the world was becoming increasingly aerobic, so the host cell most likely used the oxygen to its advantage -- aerobic respiration. These cells would become one organism over time. The evidence that supports this theory is found with the structure and function of the chloroplasts and mitochondrion. Each structure has its own DNA (circular DNA), which is very similar to the structure of today's prokaryotes. The double membrane structure of each organelle is also very similar to the structure of prokaryotes. In addition, mitochondria and chloroplasts also have their own ribosomes to make their own proteins, which are very similar in structure to those found in prokaryotes. What evidence suggests that eukaryotic cells formed symbiotic relationships with bacteria? A. Both chloroplasts and mitochondria contain DNA that is distinct from that found in the nucleus of the eukaryotic cell. B. Similarities in inner membrane structure and function. C. Both chloroplasts and mitochondria have their own ribosomes and make proteins independent from the cell. D. All of the above - CORRECT ANSWER>>>>D. All of the above When were the first multicellular organisms developed? What type of organisms were plants and animals? - CORRECT ANSWER>>>>1.5 - 1.2 billion years ago
