Bioscience II Exam 1

The fact that birds have the same bones in their wings as whales have in their flippers suggests that modern birds and whales share a common ancestor. This is because the similarity in bone structure indicates a common evolutionary origin, where the ancestor possessed these bones that were later modified in different lineages to serve different functions. This explanation is supported by the principles of comparative anatomy and evolutionary biology.

The walking stick species is currently composed of two genetically distinct morphs, each adapted to blend in with a specific plant species. The mating tests have shown that individuals prefer to mate with those that have the same color pattern. Over time, this preference for mating with individuals of the same color pattern will likely lead to reproductive isolation between the two morphs. As a result, the species will eventually divide into two distinct species, each specialized for a specific plant species.

The formation of distinct species of bushmaster snakes in different regions on either side of the Andes Mountains suggests that they have undergone allopatric speciation. Allopatric speciation occurs when populations of a species are geographically separated and evolve independently, leading to the formation of new species. In this case, the geographic barrier of the Andes Mountains has likely prevented gene flow between the populations of bushmaster snakes in Amazonia and Central America, allowing for genetic divergence and the development of distinct species.

Darwin was familiar with and contributed to his theory by studying the modification of populations of animals and plants through selective breeding. This concept of selective breeding, also known as domestication, allowed Darwin to observe how certain traits could be artificially selected and passed on to future generations. This understanding of artificial selection provided a foundation for his theory of natural selection, where he proposed that similar processes occur in nature, leading to the evolution of species over time.

Electrophoresis is a technique used to separate molecules based on their size and charge. It is commonly used in genetics to study genetic variation within populations. By subjecting DNA samples from different individuals to electrophoresis, scientists can observe differences in the banding patterns, which indicate genetic variations. This information is important for understanding the genetic diversity within a population and can provide insights into evolution, adaptation, and disease susceptibility. Therefore, electrophoresis is a suitable method for determining genetic variation within populations.

The explanation for the correct answer, which is True, is that some species of Whiptail lizards are indeed parthenogenetic, meaning they can reproduce without the need for males. This is possible because the females are able to produce unfertilized eggs that develop into offspring. Additionally, it is believed that modern species of these lizards have evolved through the process of hybridization, where closely-related species mate and produce offspring with a combination of traits from both parent species.

During a particularly arid period in the 1970s on an island in the Galapagos, a species of finch experienced a change in the size of their beaks. The explanation for this change is that larger-beaked individuals were more successful at harvesting the limited food resources available. As the environment became drier, the larger beaks allowed these individuals to access and consume the available food more efficiently, increasing their chances of survival and reproduction. Over time, this led to a shift in the average beak size of the population, with larger beaks becoming more prevalent.

The wings of a bird and the arms of an orangutan are likely examples of homologous organs or structures because they have a similar underlying structure and evolutionary origin, despite serving different functions in different organisms. This suggests that they share a common ancestor and have diverged over time to adapt to different environments and lifestyles.

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In the early twentieth century United States, the government promoted policies of Social Darwinism to influence the gene pool. These policies included sterilizing humans judged to be mentally defective, restricting human immigration, and proscribing interracial marriage. However, genetic engineering of humans was not a method utilized by the government to influence the gene pool during this time period.

In the early twentieth century, one form of "social Darwinism" involved discouraging the reproduction of individuals considered genetically inferior. This ideology was influenced by the belief that certain traits and characteristics were inherited and that the human population should be improved through selective breeding. This approach aimed to prevent the passing on of traits deemed undesirable or detrimental to society.

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Linneaeus based his classification system on morphology and anatomy. This means that he categorized organisms based on their physical characteristics and structures. By studying the external appearance and internal structures of different organisms, Linneaeus was able to group them into different taxonomic categories. This approach allowed for the organization and classification of species based on their observable traits, rather than on their evolutionary history or the fossil record.

Darwin is credited with promoting an approach to biology such that theories may be proposed without having first compiled an exhaustive background of observations. This means that Darwin encouraged scientists to develop hypotheses and theories based on limited observations and then gather more evidence to support or refine those theories. This approach allowed for the advancement of scientific understanding and the development of the theory of evolution.

In order for evolution to occur, some individuals must be more successful at leaving offspring than others. This is because the process of evolution involves the passing on of advantageous traits from one generation to the next. If all individuals had an equal chance of leaving offspring, there would be no selection pressure and no opportunity for certain traits to become more common in a population over time. By having some individuals be more successful at reproduction, natural selection can act upon the variation within a population and drive evolutionary change.

The two populations of flies are kept reproductively isolated because they find different fruits acceptable as stages for courtship dances. This means that each population of flies is attracted to and performs their courtship dances on different fruits, preventing them from mating with flies from the other population. This leads to reproductive isolation and eventually speciation, as the two populations are unable to interbreed due to their different preferences for fruits during courtship.

The reason for the change in only one or two genes in the crickets could be attributed to natural selection and genetic drift. Natural selection refers to the process by which certain traits become more or less common in a population based on their impact on survival and reproduction. In this case, the intense fly infestation caused a decrease in the number of male crickets that were able to sing, leading to a decrease in their reproductive success. This would have exerted selective pressure on the population, favoring individuals with mutations in the genes responsible for chirping equipment. Genetic drift, on the other hand, refers to random changes in gene frequencies in a population over time. In this case, the small population size of male crickets with functional chirping equipment may have made them more susceptible to genetic drift, leading to the rapid changes in gene frequencies.

The theory that a meteor impact played a role in the mass extinction of dinosaurs is supported by the discovery of a crater dating to 65 million years ago, shock crystal distributions, a layer of the rare earth element iridium in deposits dating to the time of that mass extinction, and results of computer modeling of volcanic and nuclear incidents. However, the caves near Lascaux in France, with sketches, engravings, and paintings depicting events around the time of the event, do not directly support the theory of a meteor impact causing the mass extinction of dinosaurs.

The biological species concept focuses on the ability of individuals to successfully breed with each other. This means that individuals belonging to the same species are capable of producing fertile offspring when they reproduce. This concept emphasizes reproductive isolation as the key factor in distinguishing species. Morphological differences and geographic distribution may be indicators of different species, but the ability to interbreed and produce viable offspring is the defining characteristic of the biological species concept.

The correct answer is that there is less diversity in the mitochondrial DNA of finches on San Cristobal than among their finch ancestors remaining in the Americas. This is because when a small group of individuals colonize a new area, they carry only a subset of the genetic diversity present in the original population. Over time, genetic drift and natural selection can further reduce the genetic diversity in the colonizing population. Therefore, the finches on San Cristobal, which are descendants of a small group that colonized the island, would have less diversity in their mitochondrial DNA compared to their finch ancestors remaining in the Americas.

The given answer suggests that the populations of bower birds appear to be reproductively isolated. This means that the two populations are not interbreeding and producing viable offspring, which indicates that they may be evolving into separate species. Reproductive isolation is a key factor in speciation, as it prevents gene flow between populations and allows for the accumulation of genetic differences over time.

The distribution of shock crystals suggests that the impact of a meteor occurred in what is now Mexico. This implies that the extinction of dinosaurs 65 million years ago was caused by a meteor impact in Mexico.

India being a separate continent until about 55 million years ago is the most likely factor that caused the animals and plants of India to differ greatly from species in nearby southeast Asia. The separation of India allowed for distinct evolutionary processes to occur, leading to the development of unique species in India.

Eugenics is essentially artificial selection in human populations. Eugenics is a belief system that aims to improve the genetic quality of the human population through controlled breeding. This involves selecting individuals with desired traits and encouraging them to reproduce, while discouraging or preventing those with undesirable traits from reproducing. Artificial selection is the process of intentionally selecting and breeding individuals with specific traits to create offspring with those traits. Therefore, artificial selection is the most appropriate term to describe eugenics in human populations.

The explanation for the given correct answer is that the statement is incorrect. The theory mentioned in the question, which suggests that there were local mass extinctions followed by immigration of novel organisms, is actually considered a scientific theory. While it may not be possible to prove that these immigration events occurred in the past, scientific theories are not necessarily required to be proven beyond doubt. They are based on evidence, observations, and logical reasoning, and can be supported or refuted through further research and investigation. Therefore, the statement that such a theory is not considered scientific is false.

The explanation for the correct answer being False is that the statement in the question about sugar gliders and flying squirrels sharing a common ancestor is incorrect. While sugar gliders and flying squirrels do have similar abilities and physical characteristics, they are not closely related. Sugar gliders are marsupials and are more closely related to kangaroos and koalas, while flying squirrels are rodents and are more closely related to other squirrels. Therefore, their similarities in size and gliding abilities are a result of convergent evolution, not a shared common ancestor.

The given question presents four statements regarding a theory that suggests the presence of intelligence to explain the complexity of biological systems. The correct answer states that none of the four statements are correct. This implies that none of the statements accurately reflect the general acceptance or rejection of the theory, its consistency with Darwin and Wallace's theories, or the demonstration of the existence or non-existence of an intelligence responsible for the organization of modern biological systems. Therefore, the correct answer suggests that all four statements are incorrect in their assessment of the theory.

The explanation for the correct answer is that the statement "They are found in New Zealand because the island was once part of a larger land mass which included what is now Europe" is not correct. Red deer are not found in New Zealand because it was once part of a larger land mass that included Europe. Instead, red deer were introduced to New Zealand by humans for hunting purposes. They are not native to the island.

The Hardy-Weinberg equilibrium predicts that the frequencies of alleles and genotypes in a population will remain constant from generation to generation if certain conditions are met. One of these conditions is that the population is large, which is true in this case. However, the observed frequencies of the MM and NN genotypes do not match the expected frequencies based on the allele frequencies. According to the Hardy-Weinberg equilibrium, the expected frequencies of the MM and NN genotypes would be (0.3)^2 = 0.09 and (0.7)^2 = 0.49 respectively, but the observed frequencies are 0.49 and 0.42. Therefore, the population does not appear to be in Hardy-Weinberg equilibrium.

When two plant species with different diploid numbers undergo hybridization, the resulting polyploid species will have a diploid number that is the sum of the diploid numbers of the two parent species. In this case, species A has a diploid number of 12 and species B has a diploid number of 16. Therefore, when they hybridize to form species C, the diploid number for species C would be 12 + 16 = 28.

The given statement is false. Sympatric speciation refers to the formation of new species within the same geographical area, without any geographic isolation. The example of "true" fruit flies that feed on apples and cherries in Wisconsin does not demonstrate the necessity for geographic isolation before speciation occurs, as it is an example of sympatric speciation.

The figure shows a graph with two populations, A and B, that are geographically isolated from each other. The graph also shows the amount of gene flow between the populations, with a higher degree of geographic isolation resulting in less gene flow. This supports the hypothesis that the greater the degree of geographic isolation between populations, the less gene flow there is.

The reason for the higher incidence of the mutation among the Roma than among Indians or Pakistanis is likely due to both genetic drift in the small populations of the Roma and gene flow from India and Pakistan to the various parts of the world where the Roma live. The small populations of the Roma would experience genetic drift more significantly, leading to the higher frequency of the mutation. Additionally, the gene flow from India and Pakistan would introduce the mutation to different regions where the Roma live, further contributing to its higher incidence among them.

In this scenario, red-green color blindness is inherited as a sex-linked recessive trait. Since it is a sex-linked trait, it is more commonly found in males. The question states that 1% of females are afflicted with this disorder, which means that 99% of females have normal color vision. Since there are 600 females in the population, approximately 99% of them (594 females) would have normal color vision. Since there are an equal number of males in the population, we can expect that approximately the same number of males (594 males) would also have normal color vision. Therefore, the correct answer is 60.

In a population at Hardy-Weinberg equilibrium, the frequency of the recessive allele can be calculated using the equation p^2 + 2pq + q^2 = 1, where p represents the frequency of the dominant allele and q represents the frequency of the recessive allele. Since the trait is autosomal recessive, the frequency of individuals with normal-length eyelashes (dominant phenotype) is 75%, which can be represented as p^2 = 0.75. Solving for p, we find that p = √0.75 ≈ 0.866. Therefore, q = 1 - p ≈ 1 - 0.866 ≈ 0.134. The expected frequency of the recessive allele is q^2 = 0.134^2 ≈ 0.018 ≈ 0.50.

In the ABO blood group system, the B phenotype is determined by the presence of the B allele. The O phenotype is determined by the absence of both the A and B alleles. Since the frequency of the O phenotype is 9%, the frequency of the A phenotype (AA genotype) can be calculated by subtracting the frequency of the O phenotype from 100% (100% - 9% = 91%). Since the A and B alleles are codominant, the frequency of the B phenotype (BB genotype) can be calculated by squaring the frequency of the B allele (sqrt(1%)). Therefore, the frequency of the B phenotype is 0.72 or 72%.

In this population, the frequency of the allele responsible for hair (+) is 0.7. Since normal-haired dogs are homozygous (++), their genotype would be ++. The frequency of the homozygous genotype (++), which represents the normal hair phenotype, can be calculated by squaring the frequency of the allele responsible for hair (+), which is 0.7. Therefore, the fraction of the population of adult dogs with the normal hair phenotype in the next generation should be about 0.7^2 = 0.49, which is approximately 0.54.