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| 9492443065 | 1. (a) Discuss TWO mechanisms of speciation that lead to the development of separate species from a common ancestor. | 1. Geographic isolation (or allopatric speciation) takes place when a population of one species becomes physically separated by some geographic barrier such as a river, mountain range, etc. Long-term isolation of two populations eventually leads to reproductive isolation. 2. Reproductive isolation by prezygotic barriers, such as habitat, temporal, behavioral, mechanical, or gametic incompatibility. | 0 | |
| 9492443066 | 1. (b) Explain THREE methods that have been used to investigate the phylogeny of organisms. Describe a strength or weakness of each method. | 1. Fossils (paleontology). Strength: determine time; reveal extinct species. Weakness: not all species leave fossils. Fossil record is incomplete. 2. Anatomy/morphology. Strength: Homologous structures indicate evolutionary relationships. Weakness: Analogous structures are a result of convergent evolution. 3. Molecular traits (amino acid sequence in proteins or base sequence in DNA). Strength: Most accurate. Allow study of evolution between closely related species. Weakness: No data for extinct species. | 1 | |
| 9492443067 | 1. (c) The two phylogenetic trees represent the relationship of whales to six other mammals. All of the organisms shown have a pulley-shaped astragalus bone in the ankle except for the whale. • For each tree, (1) describe a monophyletic group, (2) the closest relative to the whale, and (3) the point at which the pulley astragalus was lost or gained. • (4) Based on the principle of parsimony (the simplest explanation is the best) and the genomic information in the table shown on the next page, identify which tree is the best representation of the evolutionary relationship of these animals, and justify your answer. | 1. Monophyletic group in Tree I: peccary and pig. Monophyletic group in Tree II: deer and cow. 2. Closest relative of whale in Tree I: camel. Closest relative of what in Tree II: hippo. 3. Loss of pulley astragalus bone in Tree I occurs between the whale and the camel. Loss of the pulley atragalus bone in Tree II occurs between common ancestor of hippo and whale. 4. Tree II because if you take the genomic information into account, the deer and cow, whale and hippo, pig and peccary had many sequences in common. The camel however had no sequences in common with any of the animals. This supports the phylogeny in tree number II. | 2 | |
| 9492443068 | 2. (a) Using a specific example, describe how organisms can reproduce asexually. Discuss two evolutionary advantages of asexual reproduction. | 1. Bacteria, archaea, and protists use binary fission to reproduce. This is a form of asexual reproduction. Process of binary fission: Replication of circular DNA molecule inside cell, replicated DNA move to either poles of cell, cell lengthens, equatorial plate of cell constricts and separates plasma membrane so each new cell has exactly same genetic material. 2. No need to find a mate. It is rapid and efficient. | 3 | |
| 9492443069 | 2. (b) Identify THREE ways that sexual reproduction increases genetic variability. For each, explain how it increases genetic diversity among the offspring. | 1. Crossing over or recombination in prophase I of meiosis generates new combinations of alleles, which contributes to variability. 2. Random mating: nonspecific mate selection creates variability 3. Independent assortment: chromosomes line up randomly during metaphase I and II of meisos, so each offspring will be similar to their parents but a little different as well. | 4 | |
| 9492443070 | 2. (c) Discuss TWO prezygotic isolating mechanisms that prevent hybridization between two species. Include in your discussion an example of each mechanism. | 1. Behavioral isolation: different mating rituals between species. Example: noises of crickets will not be understood by a stinkbug. 2. Habitat isolation: living in different habitats prevents mating. Example: snakes that live in the water will not mate with snakes that live on land. | 5 | |
| 9492443071 | 3. (a) What is the frequency of each genotype (AA, Aa, aa) in this population? What is the frequency of the dominant phenotype? | 1. AA = 36%. Aa = 48%. aa = 16%. Dominant phenotype = .84. | 6 | |
| 9492443072 | 3. (b) How can the Hardy-Weinberg principle of genetic equilibrium be used to determine whether this population is evolving? | 1. Changes in allelic frequencies over time would indicate an evolving population. 2. Means of measurement/detection: it helps us establish the numbers that we can use to determine evolution. | 7 | |
| 9492443073 | 3. (c) Identify a particular environmental change and describe how it might alter allelic frequencies in this population. Explain which condition of the Hardy-Weinberg principle would not be met. | 1. Land where populations of cows lived experiencing severe drought. Population may migrate to find more fertile land, therefore more food. This migration could result in the loss or sudden decrease of a specific allele, altering the allelic frequencies in the remaining population. The "no migration" principle would not be met. | 8 | |
| 9492443074 | --The nonconstancy of species --Branching evolution, which implies the common descent of all species --Occurrence of gradual changes in species --Natural selection as the mechanism for evolution 4. (a) For EACH of the four contributions listed above, discuss one example of supporting evidence. | 1. There is demonstrated variation in species such as horses. This shows individual variation within a species or population that is phenotypic. 2. There must be demonstrated common ancestry. Molecular homologies between organisms indicate common ancestors and how recent that common ancestor was. 3. Change over time. Antibiotic or pesticide resistance is developed over time when a few organisms already have resistance to the drug or pesticide, they survive and reproduce, and gradually, become more prominent in the population. 4. Naturals selection states animals with the strongest traits will survive. In nature, lions feed on the old, young, and weakened gazelles. As a result, the gazelles with superior physical traits survive to pass down those stronger traits to offspring, which in turn are more likely to survive and reproduce themselves. | 9 | |
| 9492443075 | 4. (b) Darwin's ideas have been enhanced and modified as new knowledge and technologies have become available. Discuss how TWO of the following have modified biologists' interpretation of Darwin's original contributions. --Hardy-Weinberg equilibrium; Punctuated equilibrium; Genetic engineering | 1. Hardy-Weinberg Equilibrium: allele frequency remains constant over time and no evolution occurs under certain conditions with large population size, no migration, no mutations, random mating, and no natural selection. Darwin stated that gradual change occurs, and Hardy-Weinberg states that there is a constant allele ratio. 2. Genetic Engineering: manipulation and/or alteration of genes/DNA. Darwin stated a natural gene transfer, but GE can be human-directed gene transfer. For example, GMOs. | 10 | |
| 9492443076 | 5. (a) Provide three examples of adaptations found in various prokaryotes. Explain how these three adaptations have ensured the success of prokaryotes. | 1. Fast reproduction allows organisms to out-compete other organisms by sheer numbers. 2. Asexual reproduction allows the organism to take no risk in change if the environment is constant. 3. Cell walls help prokaryotes resist harsh conditions. | 11 | |
| 9492443077 | 5. (b) Discuss how prokaryotes early in Earth's history altered environments on Earth. | 1. Provided oxygen, cyanobacteria produced oxygen that was previously not present, the ozone (O3) layer formed. Some molecules of existing organisms denature causing some species to go extinct. 2. Nitrogen fixation, converted N2 to usable form, which would allow for the Nitrogen Cycle to occur, which includes assimilation, ammonification, nitrification, and denitrification. | 12 | |
| 9492443078 | 6. (a) Select two kingdoms and briefly describe three characteristics used to distinguish between members on one kingdom and members of the other. | 1. Kingdom Plantae and Kingdom Animalia. -Plantae photosynthetic (autotrophs); Animalia heterotrophs -Plantae cell walls; Animalia just have cell membrane -Plantae have chloroplats; Animalia do not | 13 | |
| 9492443079 | 6. (b) Describe three characteristics (at least one molecular and one cellular) that members of these two kingdoms share. | 1. DNA (molecular) 2. cell membrane (cellular) 3. protein synthesis (talk about protein synthesis) | 14 | |
| 9492443080 | 6. (c) Propose an explanation for the existence of similarities and differences between the two kingdoms. | 1. Similarities are a result of common ancestry. Differences are a result of natural selection. They faced different conditions, and so evolved differently. | 15 | |
| 9492443081 | 7. (a) Explain THREE of the following processes or phenomena, using an appropriate example for each. --mutation --adaptive radiation --polyploidy --population bottlenecks --growth of the human population | 1. Mutation: change in DNA. Ex: deletion/insertion. 2. Growth of human population: near carrying capacity. Rapid increase in developing countries specifically. 3. Population bottlenecks: sudden/drastic decrease in population size. Cheetahs have drastically reduced in size due to human interference. | 16 | |
| 9492443082 | 7. (b) For each process or phenomenon you selected in (a), discuss its impact on the diversity of life on Earth. | 1. Causes increase of diversity of life on earth because proteins can be altered resulting in new geno/phenotypes. 2. Causes a decrease of diversity of life on Earth because use of resources leads to extinction of other species. 3. Decreases diversity of life on earth because a smaller population is not representative of original. | 17 | |
| 9492443083 | 8. 2013 #3. Fossils of lobe-finned fishes, which are ancestors of amphibians, are found in rocks that are at least 380 million years old. Fossils of the oldest amphibian-like vertebrate animals with true legs and lungs are found in rocks that are approximately 363 million years old. Three samples of rocks are available that might contain fossils of a transitional species between lobe-finned fishes and amphibians: one rock sample that is 350 million years old, one that is 370 million years old, and one that is 390 million years old. (a) Select the most appropriate sample of rocks in which to search for a transitional species between lobe-finned fishes and amphibians. Justify your selection. | Selection: rocks from 370 MYA sample. Justification: Transitional fossils are found between 380 MYA (when lobe-finned fishes lived and 363 MYA (when amphibians appeared). | 18 | |
| 9492443084 | 8. (b) Describe TWO pieces of evidence provided by fossils of a transitional species that would support a hypothesis that amphibians evolved from lobe-finned fishes. | 1. Bones such as legs/limbs/digits/vertebrae. 2. Molecular (DNA evidence). | 19 | |
| 9492443085 | Link: http://mrhalverson.com/apessays_evolution.html The table below shows the amino acid sequence of the carboxyl-terminal segment of a conserved polypeptide from four different, but related, species. Each amino acid is represented by a three-letter abbreviation, and the amino acid residues in the polypeptide chains are numbered from the amino end to the carboxyl end. Empty cells indicate no amino acid is present. 9. (a) Assuming that species I is the ancestral species of the group, explain the most likely genetic change that produced the polypeptide in species II and the most likely genetic change that produced the polypeptide in species III. | 1. II was a result of a mutation, potentially a point mutation, and it resulted in an amino acid change only at position 4. III mutation that introduced a stop codon after the codon for Val, which resulted in the termination of the polypeptide after the Val at position 8. | 20 | |
| 9492443086 | 9. (b) Predict the effects of the mutation on the structure and function of the resulting protein in species IV. Justify your prediction. | Protein may have a different structure and a change in function. Justification: change in amino acid sequence of the protein starting at position 5 could alter the overall structure or local structural regions, interfering with function of the protein. | 21 |
