CLEP Biology - Problem Drill 23: Evolutionary Processes No. 1 of 10 The biological-species concept is based on. (A) Form. (B) Similar size. (C) Similar appearance to all other individuals in the population. (D) Ability to breed with other individuals in the population. (E) Genetics. Form is a characteristic used in the morphological species concept. Size is a characteristic that would be used in the morphological species concept. Similar appearance is something that could be used to classify individuals according to the morphological species concept. D. Correct! With the biological species concept individuals within the same species are able to interbreed with each other, but not with other species. With the biological species concept individuals within the same species are able to interbreed with each other, but not with other species. Reproductive isolation is the key to the biological species concept (BSC). That is, members of one population are unable to mate with members of another. Individuals that are able to interbreed, or potentially interbreed are considered a single species. The offspring produced by these individuals are all viable and fertile. The correct answer is (D).
No. 2 of 10 In allopatric speciation, what event occurs first? (A) Reproductive isolation. (B) Geographic isolation. (C) Reinforcement. (D) Genetic isolation. (E) Separation. Reproductive isolation occurs once the populations have been geographically isolated. B. Correct! Geographic isolation is the first step that occurs in allopatric speciation and leads to reproductive isolation. Reinforcement occurs once the two populations come back into contact after separation. Genetic isolation is a consequence of geographic isolation. It is not the first event to occur in allopatric speciation. Geographic isolation is the first step that occurs in allopatric speciation and leads to reproductive isolation. With allopatric speciation, a population is first divided into two by a geographical or physical barrier. Once the populations are separated reproductive isolation occurs over time because each population is undergoing different selective pressures. When the populations come back into contact reinforcement occurs. With enough divergence between the two populations, new species will form because they will not be able to interbreed. The correct answer is (B).
No. 3 of 10 Natural selection is an evolutionary process that results in changes in gene frequencies over time. Natural selection acts on which of the following? (A) Genotype of individual. (B) Phenotype of individual. (C) Genotype of the population. (D) Phenotype of the population. (E) Genotype and phenotype of the population. Genotype is the genetic makeup of an organism and natural selection cannot act directly on the genotype. B. Correct! Phenotype is the expressed trait resulting from a combination of gene by environment interaction. Because the this is the observable trait, it is what natural selection acts upon. Natural selection acts on individual phenotypes, not on populations. Natural selection does not act on genotypes or populations. Natural selection does not act on populations. E. Correct! Phenotype is the expressed trait resulting from a combination of gene by environment interaction. Because the this is the observable trait, it is what natural selection acts upon. Natural selection acts on individual phenotypes, not on populations. Phenotype is the result of the genotype by environmental interaction and is what natural selection acts upon. Selection does not act on populations, but on individuals. However, note that populations evolve. The correct answer is (B).
No. 4 of 10 Which of the following statements about fitness is not true? (A) A measurement of physiological capacity. (B) The ability to survive and reproduce in a particular environment. (C) A measurement of the reproductive success of a particular genotype. (D) The average contribution of an allele or genotype to the next generation compared to alternative alleles or genotypes. (E) The ability to survive to reproductive age and produce viable offspring. A. Correct! This statement is not true. Fitness is not a measurement of physiological capacity. This statement is true. Fitness is a measurement of genetic contribution to the next generation. This statement is true. Fitness is a measurement of genetic contribution to the next generation. This statement is true. Fitness is a measurement of genetic contribution to the next generation. This statement is true. Fitness is a measurement of genetic contribution to the next generation. Individuals within a population with the highest fitness are those that are most suited for that particular environment. These individuals with have more offspring and will contribute more genes to the next generation compared to the less fit individuals. In order to contribute the most genetically to the next generation, the individual must survive and reproduce. The correct answer is (A).
No. 5 of 10 Which of the following statements is correct regarding the origin of life on Earth? (A) Life on Earth originated approximately 4.5 billion years ago from abiotic matter. (B) Laboratory experiments have shown that life likely originated from abiotic matter under reducing atmospheric conditions. (C) Laboratory experiments have shown that life was brought to Earth from another planet. (D) Life on Earth originated approximately 3.5 billion years ago from organic compounds. (E) Life on Earth originated approximately 4.5 billion years ago from a single cell prokaryotes. Life did not originate 4.5 billion years ago, the Earth originated 4.5 billion years ago. B. Correct! Organic compounds are produced in the absence of oxygen when hydrogen, methane, water, and ammonia are combined in the presence of an electric shock. There is no laboratory evidence suggesting that life was brought to Earth from another planet. Life is thought to have originated approximately 3.5 billion years ago, but not from organic compounds. Life did not originate 4.5 billion years ago, the Earth originated 4.5 billion years ago. Earth originated about 4.5 billion years ago and life originated about 1 billion years after the origin of Earth, most likely from abiotic matter. This all occurred in the absence of oxygen. Laboratory experiments support this theory. The correct answer is (B).
No. 6 of 10 RNA was likely the most ancient form of life that we know today. What characteristics of RNA make it suitable for being the first life form on Earth? (A) It only has a phenotype. (B) It only has a genotype. (C) It can be self replicating. (D) It reproduces sexually. (E) It does not replicate itself. RNA has a phenotype and a genotype. RNA has a genotype and a phenotype. C. Correct! The fact that RNA can replicate itself means that it could reproduce and contribute to a new generation of RNA. RNA does not reproduce via sex. The fact that RNA can replicate itself means that it could reproduce and contribute to a new generation of RNA. RNA may have been one of the first life forms that was encapsulated by organic molecules. RNA can evolve because it self-replicates, it is autocatalytic and it can act as rudimentary templates for protein synthesis. RNA can compete for scarce resources such as RNA monomers and this competition leads to natural selection of the fittest RNA molecule followed by replication of that RNA molecule this is evolution. The correct answer is (C).
No. 7 of 10 The bottleneck effect refers to which of the following? (A) Increase in the genetic variation within a population due to migration. (B) Increase in the genetic variation within a population due to chance. (C) Decrease in the genetic variation within a population due to dispersal. (D) Decrease in the genetic variation within a population due to migration. (E) Increase in the genetic variation within a population due to dispersal. The bottleneck effect results in a decrease in genetic variation. The bottleneck effect results in a decrease in genetic variation. C. Correct! The bottleneck effect results in a decrease in genetic variation due to a dispersal event. With the bottleneck effect the decrease in genetic variation is not due to migration. The bottleneck effect results in a decrease in genetic variation due to a dispersal event. Genetic drift is one way that populations can rapidly diverge after separation Dispersal may lead to the founder effect, which is also called a population bottleneck because of the way the founder effect can be illustrated. Assume there is an original population of individuals having an average amount of genetic diversity. If only two individuals migrate and found the new population, not all genetic diversity from the original population will be represented in the new population. This is dispersal and the founder effect. Consequently, dispersal can lead to rapid divergence between the original population and the founder population in this example only yellow and green individuals are represented in the new population. The correct answer is (C).
No. 8 of 10 A symbiotic relationship between two organisms in which one organism benefits and the other is not harmed is which of the following? (A) Parasitism. (B) Mutualism. (C) Sexism. (D) Commensalism. (E) Non-Commensalism. With parasitism, one organism benefits and the other is harmed. With mutualism, both organisms benefit. Sexism is not a symbiotic relationship. D. Correct! With commensalism, on organism benefits and the other is unharmed. With commensalism, on organism benefits and the other is unharmed. Commensalism is a symbiotic relationship between two organisms where one benefits and the other is not harmed or helped. Examples of commensalism occur when the benefiting organism uses another for transportation (mites on a fly), the benefiting organism using another for housing (orchids living on a tree), and the benefiting organism using something that a previous organism abandoned (hermit crabs using gastropod shells). The correct answer is (D).
No. 9 of 10 The concept of ontogeny recapitulates phylogeny refers to which of the following ideas? (A) The development of a vertebrate embryo resembles the path of vertebrate evolution. (B) An aspect of molecular evolution. (C) The taxonomy of seeds. (D) All of the above. (E) Both A and B. A. Correct! The concept of ontogeny recapitulates phylogeny refers to the idea that embryonic development corresponds to the phylogenetic history of that organism. This concept is not referring to molecular evolution. This concept is not referring to the classification of plants. There is only one correct answer above. There is only one correct answer above. The theory of recapitulation was developed by Ernst Haeckel in 1866. It is a theory that a species development corresponds to its phylogenetic history and is otherwise known as ontongeny recapitulates phylogeny. An Example is the gill slits in human embryo development that are due to human s evolutionary phylogenetic relationship with fish however, Note: this assumption is incorrect; human embryos have pharyngeal arches that look similar to gills, but serve a different function. This theory is Discredited in its absolute form. The correct answer is (A).
No. 10 of 10 The morphological species concept can be most appropriately applied to which of the following? (A) Higher plants. (B) Fossils. (C) Small businesses. (D) None of the above. (E) All of the above. Plants can vary in form and still interbreed with related species. Hence, the morphological species definition has only limited value for this group. B. Correct! Since fossils are the remains of extinct organisms, we have no way of knowing if they could interbreed with related species or not. Hence, the morphological species definition is the most useful in this case. Small businesses are not organisms so this definition does not apply. There is one correct answer above. There is one correct answer above. A species is the fundamental unit of evolution. Individuals within a species vary and the splitting of one species into two species is a macroevolutionary process. Individuals that are able to interbreed are considered a single species. The morphological species concept classifies a species based on morphological appearance. For example, a duck and a chicken are considered separate species because they look different. It is one of the most ancient forms of classification, and although this species concept is widely used, it is often criticized today because of recent evidence from molecular/genetic data. That is, some genetically similar organisms look very different, and some organisms that look very similar are genetically different. No one Species Concept is entirely objective. There are problems/exceptions with all of them, but the biological species concept is most often applied. However, in the instance of fossil evidence, only the morphological species concept can be used because there is no way to know whether ancient species were able to interbreed. The correct answer is (B).