Quiz 1 Review - Bio 94 Burley PDF

Quiz 1 Review BSPT - Harshada Sharma and Gracey Singh  Lecture 1 - Relationships between organisms are defined through DNA analysis (comparing on a nucleotide level) - Before, they were defined through morphological traits - A Cladogram represents a strong hypoth...

Quiz 1 Review BSPT - Harshada Sharma and Gracey Singh  Lecture 1 - Relationships between organisms are defined through DNA analysis (comparing on a nucleotide level) - Before, they were defined through morphological traits - A Cladogram represents a strong hypothesis regarding the relationship between organisms - Hypothesis: a proposed explanation for a specific phenomenon or set of observations Question 1: Do scientists completely understand the relationship between all organisms? a. Yes b. No Question 1: Do scientists completely understand the relationship between all organisms? a. Yes b. No Evolution relationships between organisms have the potential to change as organisms continue to be studied and discovered. The relationships that have been defined between organisms are strong hypotheses for their relationships.  Lecture 2 - A scientific theory explains a general phenomenon that is supported by a wide body of evidence - Scientific theories suggest hypotheses that can be tested - Theories have a pattern component and a process component: - Pattern component: (1) organisms are produced by other organisms, and (2) species are not static, but rather change over time - Natural Selection: - the process by which individuals with certain heritable traits tend to produce more surviving offspring - Differential reproduction of genotypes - Non-random - Identified by Darwin - Wallace can be credited to be a co-discoverer 4 steps in Darwin’s reasoning process which led to the identification of Natural Selection 1. All organisms have great capacity for reproduction 2. Despite the great capacity for reproduction, most populations maintain stable sizes for long periods of time a. Many offspring or eggs die before reproducing b. The pattern of death is NON-RANDOM 3. Within populations, individuals vary in their traits, including some that affect their ability to survive and reproduce 4. Individuals with traits best suited to the environment will tend to produce more surviving offspring Lines of evidence for species change through time 1. Fossils a. provides evidence of organisms that lived in the past (extinction) b. Often resemble extant species in the same area, suggesting descent with modification c. Transition features are evident in many lineages 2. Homologies a. structural/morphological homologies b. Developmental homologies c. molecular/genetic homologies Homologies: - Allow us to construct cladograms of relationships among organisms through tracking the relative similarities among different types of organisms - These trees are necessary to map much of the tree of life Homoplasy: - Similarity between organisms which is not due to common descent - Convergent evolution: adaptation of members of different lineages to similar environments Question 3: Which type of homology is used to create a tree of life which accounts for all organisms? a. Developmental b. Genetic c. Morphological d. Physiological Question 3: Which type of homology is used to create a tree of life which accounts for all organisms? a. Developmental b. Genetic c. Morphological d. Physiological Genetic homology, the comparison of protein or nucleotide sequences, is the primary type of homology which is needed to construct a comprehensive “Tree of Life,” which takes into consideration all organisms. Using genetic homology can help determine relationships between all three domains of life: Bacteria, Archaea, and Eukarya. Question 4: What is the difference between evolution and natural selection? a. There is no difference, they are synonymous b. organisms need evolution for natural selection to occur c. Evolution is the change in allele frequencies and natural selection is the change in genotype frequencies d. Natural selection is a mechanism of evolution, but is not the only mechanism. Question 4: What is the difference between evolution and natural selection? a. There is no difference, they are synonymous b. organisms need evolution for natural selection to occur c. Evolution is the change in allele frequencies and natural selection is the change in genotype frequencies d. Natural selection is a mechanism of evolution, but is not the only mechanism. Natural selection is one of the mechanisms of evolution. Evolution also includes genetic drift, gene flow, non-random mating, and mutations.  Lecture 3 - The process of evolution: - Change in allele frequency in a population over time - Allele: - A form/version of a gene - Population: - A group of individuals of a species that live in one place - Phenotype: - Physical expression of the two alleles for a gene - Genotype: - The genetic basis of a trait (combination of both alleles for a specific gene) - Trait: - any measurable aspect of an organism A trait is any measurable aspect of an organism (behavior, physiology, morphology, etc.) - Traits are known to be heritable when allelic variation influences expression Allele Frequency: the % of dominant allele and the % of recessive alleles present in a population - Allele frequency is the percentage of a particular allele in a population - For any given gene, (p) is the frequency of allele A, and (q) is the frequency of allele a - Genotype Frequency: the % of a given genotype in a population - Genotype is the alleles of a gene present in a given individual Hardy Weinberg Principle - In a large population, genotype frequencies do not change from generation to generation in the absence of evolution processes - Two equations: - p + q = 1 — allele frequencies - p^2 + 2pq + q^2 = 1 — genotype frequencies - Allele frequencies can be used to predict genotype frequencies. - If genotype frequencies change from one generation to the next, the population is NOT in Hardy Weinberg equilibrium Four Mechanisms of Evolution: - Natural Selection is the only mechanism which leads to adaptation - can result in NON-RANDOM loss of alleles in populations of any size - Mutation is the ultimate source of genetic novelty (introduction of new alleles in a population) - Genetic drift can result in the random loss or the fixation of alleles, which is a tendency that has the potential to be offset by gene flow between populations Four Types of Natural Selection: 1. Disruptive selection - favors both extremes 2. Stabilizing selection - favors the intermediate 3. Directional selection - one extreme is favored 4. Balancing selection - no one phenotype is favored Gene flow: - a change in allele frequency due to migration between established populations, which results in increased genetic similarity between them Genetic Drift: - A change in allele frequency due to chance. - Bottleneck Effect: a natural disaster or other phenomenon reduces the population size - Results in poor sperm quality, disease susceptibility due to homozygosity - Founder effect: a small portion of the population breaks off of the main population - Leads to less genetic diversity than the original population Genetic drift can result in RANDOM loss of alleles in populations, particularly in small populations Question 5: Assuming the population is in Hardy-Weinberg equilibrium, what would be the genotype frequencies of the following first generation? Parental Generation Allele A a Frequencies: (A)= 0.3 and (a) = 0.7 A AA Aa a Aa aa Question 5: Assuming the population is in Hardy-Weinberg equilibrium, what would be the genotype frequencies of the following first generation? Parental Generation Allele A a Frequencies: (A)= 0.3 and (a) = 0.7 A AA Aa a Aa aa AA = 0.09, Aa = 0.42, aa=0.49 Question 6: For a population in Hardy-Weinberg equilibrium (population A), which one of these would not deviate the genotype ratios from equilibrium? a. Homozygous dominant zygotes do not develop in utero, therefore do not survive past fertilization b. females from population A only reproduce with males of the same species of a neighboring population c. Males from population A consistently reproduce with females of another species, leading to infertile offspring d. A tsunami decreases the population size by half e. None of the above Question 6: For a population in Hardy-Weinberg equilibrium (population A), which one of these would not deviate the genotype ratios from equilibrium? a. Homozygous dominant zygotes do not develop in utero, therefore do not survive past fertilization b. females from population A only reproduce with males of the same species of a neighboring population c. Males from population A consistently reproduce with females of another species, leading to infertile offspring d. A tsunami decreases the population size by half e. None of the above (a) = prezygotic isolation, (b) = gene flow, (c) = non-random mating, (d) genetic drift. All of these phenomena violate at least one of the five essential components that are needed to have a population in Hardy-Weinberg equilibrium: no genetic drift, no gene-flow, random mating, no mutations, and no natural selection.  Lecture 4 - Adaptation: - a specific trait that has evolved because it increased the fitness of individuals with that trait in a particular environment - Fitness: - the ability of an individual to produce viable offspring relative to others of the same population - Cladogenesis: the splitting of two lineages Biological Species Concept Prezygotic isolation: 1. Mating does not occur - Temporal: populations are isolated because they breed at different times - Habitat: populations are isolated because they breed in different habitats - Behavioral: populations do not interbreed because they have different courtship displays 2. Mating does occur, but no zygotes are produced - Mechanical: mating fails because male and female reproductive structures are incompatible - Gametic barrier: mating fails because eggs and sperm are incompatible Postzygotic Isolation 1. Zygotes are produced but offspring do not survive or are sterile a. Hybrid inviability: hybrid offspring do not develop normally and die at some point during their early development b. Hybrid sterility: hybrid offspring mature but are sterile as adults Morphological species concept: - Do organisms from two populations look different? - Pros: - mating success, gene flow is not necessary - Can be used for extinct and asexual species - Cons: - Very subjective - It cannot identify polymorphic or cryptic species Phylogenetic species concept: - Do members of two populations have unique genetic histories? - Defines species as being the smallest monophyletic group on the tree of life  05 Lecture 5  Phylogeny & History of Life Phylogeny Study of evolutionary relationships among organisms. Represented using phylogenetic trees ("Tree of Life"). Key Terms: Branches: Evolutionary pathways. Nodes: Common ancestors where branches split. Tips: Represent species or taxa. Root: The base of the tree, representing the most distant common ancestor.  Macroevolution Macroevolution Pattern of evolution over large time scales (above the species level). Governed by the same four mechanisms: ○ Natural selection ○ Genetic drift ○ Mutation ○ Gene flow  Cladograms and Cladistics Cladograms Type of evolutionary tree built on cladistic principles. Key Concepts: Synapomorphy: Trait shared by two or more taxa from their most recent common ancestor. Parsimony: Prefers the simplest tree with the fewest evolutionary steps. Coherence: Different traits should support the same tree.  Taxa and Nodes Taxon (Plural: Taxa) A named group of organisms at any level Node Point of branch splitting. Represents the most recent common ancestor of descendant groups.  Generalizations about Relatedness Taxa sharing a more recent common ancestor are more closely related. Key Note: The number of nodes between taxa does not indicate relatedness. Branch lengths are often arbitrary unless a scale bar is provided. Precambrian Era What is the Precambrian Era? Time before the Cambrian Period (~4.5 billion to 542 million years ago). Major Events: Origin of Earth (~4.5 BYA). Origin of Life (~3.5 BYA). Rise of Eukaryotes. Evolutionary Misconceptions Common Misconceptions: 1. Evolution is goal-oriented. ○ Example: "Plants produce oxygen for animals." 2. Evolution always occurs slowly. 3. Natural selection provides organisms what they need. 4. Evolution is not testable.  Important Terms Phylogeny: The evolutionary history and relationships among organisms. Cladistics: A classification method grouping organisms by common ancestry. Monophyletic Group: A group including a common ancestor and all its descendants. Synapomorphy: A shared derived characteristic unique to a group. Parsimony: The simplest explanation with the fewest evolutionary changes. Precambrian: The time before the Cambrian period, spanning Earth’s early history. Cambrian Explosion: A rapid diversification of life ~541 million years ago. Fossil Record: Preserved remains or traces of past organisms in rock layers.  Review Activity: Recap 1. Compare two cladograms. Do they Phylogenetic trees illustrate represent the same relationships? evolutionary relationships. 2. True or False: "The number of nodes Precambrian Era was a critical between taxa indicates how closely period for the origin of life. related they are." Understanding cladistics helps Correct Answer: FALSE. in constructing and interpreting evolutionary trees. Explanation: Relationships depend Always question and correct on the most recent common evolutionary misconceptions. ancestor, not node count.  Questions Natural selection directly drives which type of evolutionary change? A. Adaptation to the environment B. All speciation events C. Reduction in genetic diversity D. Formation of hybrid species  Questions Natural selection directly drives which type of evolutionary change? A. Adaptation to the environment B. All speciation events C. Reduction in genetic diversity D. Formation of hybrid species Natural selection favors traits that improve survival and reproduction in a specific environment, leading to adaptation.  Questions Two species of frogs have distinct mating calls that females use to identify mates of their species. What type of reproductive isolation does this represent? A. Prezygotic/temporal B. Prezygotic/behavioral C. Postzygotic/hybrid inviability D. Prezygotic/mechanical  Questions Two species of frogs have distinct mating calls that females use to identify mates of their species. What type of reproductive isolation does this represent? A. Prezygotic/temporal B. Prezygotic/behavioral C. Postzygotic/hybrid inviability D. Prezygotic/mechanical The distinct mating calls prevent mating between species, which is behavioral isolation, occurring before fertilization.  Questions Why have pitcher plants evolved to trap insects in nutrient-poor soils? A. To absorb additional carbon sources B. To obtain nitrogen and other nutrients C. To reduce competition with other plants D. To enhance photosynthesis efficiency  Questions Why have pitcher plants evolved to trap insects in nutrient-poor soils? A. To absorb additional carbon sources B. To obtain nitrogen and other nutrients C. To reduce competition with other plants D. To enhance photosynthesis efficiency Pitcher plants trap insects to obtain essential nutrients, particularly nitrogen, from their prey in nutrient-poor environments.  Questions In the absence of vascular tissue, how do mosses transport water to their cells? A. Through stomata B. By diffusion C. Using specialized tubes D. By gravity  Questions In the absence of vascular tissue, how do mosses transport water to their cells? A. Through stomata B. By diffusion C. Using specialized tubes D. By gravity Mosses lack vascular tissue, so water moves through the plant by diffusion, from cell to cell.  Questions Which evidence best supports the endosymbiotic origin of chloroplasts? A. Chloroplasts contain ribosomes similar to bacteria. B. Chloroplasts have fewer membranes than mitochondria. C. Chloroplasts lack DNA but produce proteins. D. Chloroplasts resemble fungi in structure. Chloroplasts have their own ribosomes, similar to those of bacteria, supporting the hypothesis that they originated from symbiotic bacteria.  Questions What explains the geographical distribution of marsupials in Australia and South America? A. Genetic drift B. Continental drift C. Coevolution D. Stabilizing selection  Questions What explains the geographical distribution of marsupials in Australia and South America? A. Genetic drift B. Continental drift C. Coevolution D. Stabilizing selection Continental drift explains the distribution of marsupials, as Australia and South America were once part of the supercontinent Gondwana.  Questions Which of the following is a scientific pattern? A. Plants conserve water through waxy coatings. B. Amphibians are more diverse in tropical climates. C. Extinct species often share traits with living ones. D. All of the above  Questions Which of the following is a scientific pattern? A. Plants conserve water through waxy coatings. B. Amphibians are more diverse in tropical climates. C. Extinct species often share traits with living ones. D. All of the above  Questions Which statement accurately describes a scientific theory? A. It is based on repeated experimental evidence. B. It is a hypothesis recently proposed by a leading scientist. C. It is an untested assumption about natural phenomena. D. All of the above  Questions Which statement accurately describes a scientific theory? A. It is based on repeated experimental evidence. B. It is a hypothesis recently proposed by a leading scientist. C. It is an untested assumption about natural phenomena. D. All of the above A scientific theory is a well-substantiated explanation of some aspect of the natural world, supported by a body of evidence.  Questions How can horizontal gene transfer influence bacterial evolution? A. By increasing mutation rates B. Through the transfer of antibiotic resistance genes C. By eliminating genetic variation within populations D. Through the inheritance of traits from parent to offspring  Questions How can horizontal gene transfer influence bacterial evolution? A. By increasing mutation rates B. Through the transfer of antibiotic resistance genes C. By eliminating genetic variation within populations D. Through the inheritance of traits from parent to offspring Horizontal gene transfer allows bacteria to acquire genes, such as those for antibiotic resistance, from other bacteria, which can accelerate evolution. Thank you ! Here is our evaluation form: Good Luck