How is the Information Encoded in DNA Actually Used by Organisms

CHAPTER 1 How is the information encoded in DNA actually used by organisms? The information in DNA is transcribed to RNA and then translated into protein. A scientific theory is a well-supported concept that has broad explanatory power What is the molecule that can account for both the unity and the diversity of life? DNA The energy used by most organisms for metabolism and growth ultimately comes from the sun The fundamental organizing principle of biology and core theme is evolution Which of the following statements is most clearly inductively derived? If the animals observed required organic molecules as nutrients, then it can be concluded that all animals require organic molecules as nutrients. Which of the following is an attribute of living things? They must be able to evolve and adapt Regulation of molecules within an organism in response to a changing level of chemicals and the ability to self-regulate is called feedback regulation. A hypothesis must be testable and falsifiable to be scientifically valid. Being testable and falsifiable means that some conceivable observation or experiment could reveal whether a given hypothesis is incorrect Natural selection tends to act at which of the following levels? Population With evolution as the core theme of biology, we can explain traits shared by organisms as evidence of descent from a common ancestor and traits that differ among organisms as evidence of adaption through natural selection The units of inheritance are called genes Some properties and processes that are associated with life include all of the following except reductionism The information in a gene that directs the production of a cellular product is gene expression. The correct sequence for the transfer of information from a gene to a function protein is transcription, translation, protein folding The use of energy by living organisms – involves chemical cycling from light energy from the sun for the production of chemical energy in food to the decomposition and the returning of chemicals to the cycle The concept of “descent with modification” was proposed by Charles Darwin The process that directs the manufacture of a cell product from a gene is called gene expression 1/13 The genetic material within cells is called DNA and is organized into structures called chromosomes Which series of terms is in the correct sequence of biological organization, from the simplest to the most complex? Cell, tissue, organ, population, community Using models that represented camouflaged and non-camouflaged mice, Hoekstra and her students tested the hypothesis that coloration of beach and inland mice provides camouflage that protects them from predation. Regardless of whether the models were placed in the beach or the inland habitat, the camouflaged model always acted as the control group. Which of the following is the smallest unit of organization that can perform all activities required for life? Cell CHAPTER 22 Homologies that appear to have marginal, if any, importance to an organism are called Vestigial structures Carolus Linnaeus is considered to be the founder of the binomial classification system, and he thought that resemblances among different species reflected the pattern of their creation. Darwin’s explanation of how adaptations arise centered on natural selection Which of the following is not an observation or inference that Darwin made while developing his theory of evolution? Interactions between individuals and their environments cause individuals to evolve. During periods of rapid environmental change, what may happen to a species that was well-suited to the former environment? – the population may change so much in adapting to the new environment it is considered a new species. – traits that were favorable in the original environment may be detrimental in the new environment. – the species may go extinct. – individuals with particular traits that provide an advantage in the new environment will have higher reproductive success. A(n) population is the smallest unit that can evolve. What does it mean to describe evolution as a scientific theory? Evolution is a broad model that is supported by many observations and much experimental evidence. 2/13 Which of the following is not an observation or inference on which natural selection is based? Poorly adapted individuals never produce offspring Animals that possess homologous structures probably evolved from the same ancestor An important challenge to traditional (pre-1860) ideas about species was the observation that seemingly dissimilar organisms such as hummingbirds, humans, and whales have similar skeletal structures. This most directly suggested to biologists that __ dissimilar organisms might have evolved from a distant, common ancestor Which of the following people developed the idea known as the scala naturae, or scale of nature? Aristotle How does our understanding of genetics today refute Lamarck’s principle of the inheritance of acquired characteristics? -----At the time Darwin voyaged on the HMS Beagle, the popularly accepted theory in Western culture that explained the origin of Earth's plants and animals held that the various species ____ had been created by divine intervention a few thousand years before Adaptations are defined as _ inherited characteristic of organisms that enhance their survival and reproduction in specific environments Even though rodents known as sugar gliders and flying squirrels are members of distinctly different groups of organisms and live on different continents, they possess similar characteristics. This is an example of _ convergent evolution (effects independently evolving species in similar environments in similar ways. Organisms found only in specific places in the world are referred to as __ endemic The bacteria Staphylococcus aureus has developed resistance to some antibiotic drugs. How did this resistance come about? Some members of the bacteria populations possessed some sort of genetic variation for antibiotic resistance that was selected for when the bacteria was exposed to the drugs. The modern idea of extinction as a common occurrence in Earth's history was first proposed in the early 19th century writings of _ curvier Darwin's view of descent with modification, _ natural selection can improve the match between an organism and its environment The upper forelimbs of humans and bats have fairly similar skeletal structures, whereas the corresponding bones in whales have very different shapes and proportions. 3/13 However, genetic data suggest that all three kinds of organisms diverged from a common ancestor at about the same time. Which of the following is the most likely explanation for these data? Natural selection in an aquatic environment resulted in significant changes to whale forelimb anatomy. On an evolutionary tree, _ homologous characteristic form a nested pattern What does each branch point on an evolutionary tree represent? The common ancestor of the lineages beginning there and to the right of it How did Hutton and Lyell’s ideas influence Charles Darwin’s thinking? Darwin reasoned that the earth must be very old and that slow, subtle processes could produce substantial biological changes All known organisms transcribe genetic information to protein molecules via the same genetic code. This finding strongly supports the hypothesis that _____ all organisms are descended from a single common ancestor The breeding of plants and animals for particular traits by humans is called ___ Artificial selection Paleontology, the study of fossils, was developed by _Georges Cuvier A population of zooplankton is exposed to a small number of predatory fish that feed on the larger-sized (adult) zooplankton. Which of the following predictions would most likely occur based on the principles of natural selection? Adult zooplankton will start to reach sexual maturity when they are still relatively small. Darwin originally defined evolution as _ descent with modification Which of the following is correct regarding natural selection? – natural selection is a process in which individuals that have certain inherited traits tend to survive and reproduce at higher rates than do individuals without those traits. – individuals do not evolve; populations do. – if an environment changes, or id individuals move to a new environment, natural selection may result in adaption to these new conditions, sometimes giving rise to new species. – overtime, natural selection can increase the correspondence between organisms and their environments. CHAPTER 23 Which type of selection maintains stable frequencies of two or more phenotypic forms in a population? Balancing selection 4/13 In a certain group of people, 4% are born with sickle-cell disease (homozygous recessive). If this group is in Hardy-Weinberg equilibrium, what percentage of the group is heterozygous for the sickle hemoglobin allele? 32% The gene pool of a population consists of all copies of every type of allele at every locus in all members of the population. In the context of populations, how do we define evolution? Evolution is a change in a populations allele frequencies over generations. In a population that is in Hardy-Weinberg equilibrium, 64% of the individuals express the recessive phenotype for a particular gene locus. What is the expected frequency of the dominant allele in this population? 0.2 In the Hardy-Weinberg equation, 2 pq represents the expected frequency of the heterozygous genotype. In a population that is in Hardy-Weinberg equilibrium, 64% of the individuals express the recessive phenotype for a particular gene locus. What is the expected frequency of the recessive allele in this population? 0.8 Stabilizing selection favor intermediate variants in a population. Natural selection leads to adaptation, but there are many organisms on Earth that exhibit characteristics that are less than ideal for their environment. Which of the following statements correctly explain(s) this? - adaptations are often compromises. - selection can act only on existing variations. - chance, natural selection, environment interact. - evolution is limited by historical constraints Which of the following can form entirely new alleles? Mutation The sickle-cell allele, which is recessive, causes anemia but confers resistance to malaria in individuals who possess it. However, homozygous recessive individuals often die from anemia but not from malaria, and homozygous dominant individuals do not have anemia but could die from malaria. Heterozygous individuals have the highest relative fitness. This is an example of the heterozygote advantage. 5/13 Which of the following sets of conditions is required for Hardy-Weinberg equilibrium? Random mating, no natural selection, a large population, no mutations, no gene flow. In a large population of randomly breeding organisms, the frequency of a recessive allele is initially 0.3. There is no migration and no selection. Humans enter this ecosystem and selectively hunt individuals showing the dominant trait. When the gene frequency is reexamined at the end of the year, the frequency of the homozygous dominants will go down, the frequency of the heterozygous genotype will go down, and the frequency of the homozygous recessives will go up. A hurricane hits a small island, killing all but a few members of a bird population. This is an example of the bottleneck effect (a severe drop in population size). which statement below is true about sexual selection? Sexual selection can result in sexual dimorphism- marked differences between the sexes in secondary sexual characteristics that are not associated directly with reproduction. No two people are genetically identical, except for identical twins. The main source of genetic variation among human individuals is the reshuffling of alleles in sexual reproduction. Which type of mutation plays the most important role in increasing the number of genes in the gene pool? Duplication A population of squirrels is preyed on by small hawks. The smaller squirrels can escape into burrows. The larger squirrels can fight off the hawks. After several generations, the squirrels in the area tend to be very small or very large. What process is responsible for this outcome? Disruptive selection Which of the following statements correctly describe(s) characteristics of genetic drift? - it can lead to a toss of genetic variation in a population - it can cause allele frequencies to change at random - it is significant in small populations - it can cause harmful alleles to become fixed in a population 6/13 Which of the following is the best example of gene flow? Wind blows pollen from one population of plants to another and cross-fertilization occurs (the transfer of alleles between populations, tends to reduce genetic differences between populations over time). Which of the following statements correctly describes a population in HardyWeinberg equilibrium? Allele and genotype frequencies in the population will remain constant from generation to generation. At what level does gene variability quantify genetic variation? Whole gene Which of the following would seem to be an example of neutral variation? Human fingerprints Sexual recombination includes the shuffling of chromosomes in meiosis and fertilization. Point mutations in noncoding regions of DNA result in neutral variation. Antibiotic resistance in bacteria is an example of which of the following? Directional selection Which of the following statements explains why male peacocks with brightly colored feathers are more prevalent than those with plain colors? Female peacocks choose the showiest males as mates, causing this trait to be more prevalent in the population. A storm separates a small number of birds in a migrating population. These birds end up at a destination different from where they usually migrate and establish a new population in this new area. This is an example of the founder effect. In the Hardy-Weinberg equation, q2 represents the expected frequency of the homozygous recessive genotype. CHAPTER 23 QUIZ The original source of all genetic variation is – mutation (Mutation is, in itself, very important to evolution because it is the original source of the genetic variation that serves as the raw material for evolution.) 7/13 According to the Hardy-Weinberg theorem, the frequencies of alleles in a population will remain constant if _____ is the only process that affects the gene pool. Sexual reproduction (Sexual reproduction does not change the frequency of alleles in the gene pool.) What is true of microevolution? It is the kind of evolution that can change the relative abundance of a particular allele in a gene pool over the course of generations. (Microevolution is a generation-to-generation change in allele frequency.) How does diploidy help to preserve genetic variation? It allows recessive alleles that may not be favored in the current environment to be preserved in the gene pool by propagation in heterozygotes. (Natural selection tends to decrease genetic variation. Recessive alleles are shielded from natural selection in heterozygotes.) The evolutionary effects of genetic drift are greatest when _____. The population size is small (changes in the gene pool of a small population are frequently due to genetic drift.) What situation most likely explains the occasional high frequency of certain inherited disorders among human populations established by a small population? Founder effect (The founder effect is genetic drift attributable to colonization by a limited number of individuals from a parent population.) In evolutionary terms, an organism's fitness is measured by its _____. Contribution to the gene pool of the next generation (Those organisms with adaptations best suited to the current environment will make the most significant contribution to the next generation.) Blue poppies native to China were grown at a plant-breeding center in California. The plants with the thickest leaves were most likely to survive and reproduce in the drier climate. After several generations, the percentage of thick-leaved plants had increased by 42%. This adaptation of the poppies to their new environment is due to _____. Directional selection What is the only evolutionary mechanism that consistently leads to adaptive evolution? Natural selection (Because natural selection has a "sorting" effect, it consistently increases the frequency of alleles that improve the match between an organism and its environment.) CHAPTER 24 NOTES Which of the following organisms is most likely to be subject to allopatric speciation? Pine trees in Alaska snd pine trees on the island of Madagascar. In which of the following groups has sympatric speciation been most important? Plants 8/13 A hybrid zone is defined as a region in which members of different species meet and mate, producing at least some offspring of mixed ancestry. Three species of sea stars all mate near the same reef by secreting their gametes into the water, but none of the gametes from the different species fertilize each other. This is an example of a prezygotic barrier called gametic isolation. When gene flow between two populations ceases, the potential for speciation exists. In the case of the Lake Victoria cichlids, sympatric speciation has been shown to be driven by sexual selection. Prezygotic barriers prevent fertilization of gametes from members of closely related species. Sympatric speciation typically occurs by all of the following mechanisms except a geographic barrier splitting a population. Two different species of frogs mate successfully and produce fertile hybrid offspring. However, the offspring of the hybrids do not develop completely to adulthood. This is an example of which type of reproductive barrier? Hybrid breakdown. The time interval between speciation events vary widely and depend on generation times, causes of speciation, environmental factors, and chance. A new species of plant evolved by allopolyploidy from two species of plant that are 2n = 6 and 2n = 12. What would the diploid number of chromosomes be in this new species? 18 How many genes must change in order to form a new species? There is no set number of genes or loci that produces a new species. Genetic and environmental factors interact. 9/13 There are two groups of pine trees that appear to be very similar phenotypically and genotypically. However, one releases pollen in January, when the female structures of that group are receptive, and one in March. What kind of reproductive barrier is this? Temporal isolation. According to the punctuated equilibrium model of evolution, According to the punctuated equilibrium model of evolution, the tempo of evolution consists of abrupt episodes of speciation among long periods of equilibrium. At which point in the adaptation of a population is it clear that speciation has occurred? Gene pool changes establish reproductive barriers between two populations. According to the biological species concept, a species is a group of populations whose members have the potential to interbreed in nature and produce viable, fertile offspring—but do not produce viable, fertile offspring with members of other such groups. Imagine that part of a population of South American finches is blown by a storm onto an island far offshore and manages to survive and reproduce there for a period of 10,000 years. After that period, a climate change results in lower sea levels and the reconnection of the island with the mainland. Members of the formerly isolated island finch population can now interact freely with members of the original mainland population. Which of the following observations would, by itself, lead you to conclude unequivocally that the island finch population had evolved into a distinct species, according to the biological species concept? Individuals from the different populations sometimes mate with each other, but all of the resulting eggs are sterile. A new species of plant is discovered that closely resembles a known species. Upon further examination, it is discovered that the new species has a tetraploid number of 4n = 12, while the known species has a diploid number of 2n = 6. Which of the following statements provides a reasonable explanation for the evolution of this new species of plant? An error in cell division occurred in the 10/13 known species, leading to the development of an autopolyploid tetraploid offspring that evolved into the new species. Postzygotic barriers contribute to reproductive isolation after a hybrid zygote has been formed. The morphological species concept distinguishes species by body shape and other structural features. Which of the following evolutionary mechanisms does not contribute to the process of allopatric speciation? Gene flow The evolution of multiple species of snapping shrimp following the formation of the Isthmus of Panama is an example of allopatric speciation Reproductive isolation is necessary for speciation to occur. A horse and a donkey can reproduce successfully, producing a mule. However, the mule is sterile. This is an example of a postzygotic barrier called reduced hybrid fertility. Which of the following is an example of a postzygotic reproductive barrier? Two fruit flies of different species produce sterile offspring. What is the first thing that must happen in order for speciation to occur? Gene flow between populations must be interrupted. The behavior of a male blue-footed boobie during the courtship ritual elicits no response from the masked boobie. The reproductive barrier between them is an example of behavioral isolation. A new species of plant arises as an allopolyploid from two other plants, one with a diploid number of 14 and one with a diploid number of 18. What would the diploid number of the new species most likely be? 32 Which of the following reproductive barriers actually prevents individuals of closely related species from copulating successfully? Mechanical isolation 11/13 Which of the following statements correctly describes one aspect of the punctuated model of evolution? Species tend to change rapidly in a short period of time. CHAPTER 24 QUIZ What is the most important factor that holds a gene pool of a species together and prevents speciation? Gene flow Two animals are considered members of different species if they __ cannot mate and produce viable, fertile offspring According to the phylogenetic species concept, what is a species? A set of organisms with a set of unique genetic history Which of these is an example of temporal isolation? One species is nocturnal, and the other species is not Which of the following is the first step in allopatric speciation? Geographic isolation Sympatric speciation is _ the appearance of a new species in the same area as the parent population (due to a radical change in the genome) Which of the following has been shown to cause speciation most rapidly? (in plants)autopolyploid Hybrid zones provide an opportunity to investigate __ the evolution of reproductive isolation (A hybrid zone allows researchers to see what happens when closely related species come together. Reproductive barriers may be strengthened or weakened, depending on environmental and genetic factors) A certain species of salamander was split into two populations by a wide, dry valley, and the populations began to diverge from each other. After a period of time, some members of the two populations began to interbreed in a hybrid zone at the southern end of the valley. Only weak reproductive barriers existed by this time, so the two populations could freely interbreed and re-establish gene flow. This outcome in a hybrid zone is known as __ FUSION (Fusion refers to the weakening of reproductive barriers, allowing the two populations to fuse and remain (or become) one species) According to the _____ model, evolution occurs in spurts; species evolve relatively rapidly then remain unchanged for long periods. Punctuated equilibrium CHAPTER 25 QUIZ 12/13 Miller and Urey's experiments that attempted to recreate conditions on early Earth were significant because they showed that organic molecules such as amino acids could be produced from inorganic molecules (Miller and Urey showed that under conditions postulated to have existed on early Earth, it was possible to spontaneously form essential organic molecules.) Why do some scientists believe that RNA, rather than DNA, was the first genetic material? RNA has both information storage and catalytic properties (RNA has been shown to catalyze certain reactions (as part of ribosomes, rRNA participates in the catalysis of the peptide bonds that form proteins). It can also store information and perform some self-replication.) Earth probably formed 4.5 billion years ago, and the first life evolved as early as 3.9 billion years ago. (Because fossils of bacterial communities have been discovered that are 3.5 billion years old, it is reasonable to assume life originated around 3.9 billion years ago.) The oldest fossils usually found in the deepest strata (Younger sediments are deposited over older sediments; thus, relatively older fossils are found in deeper strata than relatively younger fossils.) Radiometric dating allows us to indirectly date fossils up to billions of years old based on minerals in surrounding volcanic strata (By dating minerals in volcanic strata above and below the fossils, we can determine a reasonable age range for the fossils.) The earliest organisms were most likely prokaryotic (Prokaryotes originated a few hundred million years after Earth's crust cooled and solidified.) The atmosphere of early Earth probably contained no O2 until the emergence of organisms that used water as an electron source for photosynthesis (Oxygen began to accumulate in the atmosphere due to the action of photosynthetic cyanobacteria.) How does continental drift affect living organisms? It causes climate change which puts selective pressure on organisms, it causes changes in habitats, such as when large amounts of shallow marine habitat were lost in the formation of Pangaea, it may cause an increase or decrease in competition among different species, it happens so slowly that it does not affect living organisms (Continental drift affects organisms by changing the current environment in all of these ways. Organisms may have to adapt, move, or go extinct.) Hox genes are thought to play an important role in the development of different morphologies because they provide positional information in the embryo (Changes in Hox genes can have large effects on body plans in different organisms.) Evolution works by “tinkering” with existing structures (Evolution, and in particular natural selection, can only select for the best available traits. Modifications to those traits are usually made in small, incremental steps, and new inventions are rare.) 13/13