Biology II Midterm #1
Biology II Midterm #1 Biology 1082
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This 16 page Study Guide was uploaded by Abtin Notetaker on Sunday January 31, 2016. The Study Guide belongs to Biology 1082 at University of Cincinnati Blue Ash College taught by Mark Otten in Spring 2016. Since its upload, it has received 58 views. For similar materials see Biology II in Biology at University of Cincinnati Blue Ash College.
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Date Created: 01/31/16
Biology II Study Guide for Midterm 1 *I will not be posting the answers to the Reading Guides and Prompts* The things you need to know for Chapter 19: - Describe the contribution and ideas of the scientists discussed relative to History of Evolutionary Thought - Explain natural selection - Explain the importance of differential reproductive success to evolution - Explain the Importance of phenotypic/genotypic variation to natural selection (I will highlight these points as well) 1)Predominant view before 1500 a.Young, unchanging Earth b.Fixed (immutable) species- they didn’t change over time c. Species could not change ecological “position” or relationship. 2)Hutton (Geologist) a.Geological features are due to 2 primary processes: Erosion- Reduce the strata (strata- layers of consistent rock formation) Deposition- Produces the strata b.Processes are imperceptible over normal human life span, slow. “Gradualism”: Processes occur very slowly over long periods of time. c. Requires an old Earth. 3)Charles Lyell (Geologist) a.Geologic process occurs at a constant rate over time “Uniformitarianism” or at a uniform constant rate. b.Geologic Processes occurred due to everyday, normal events. Everyday process are sufficient to account for known geologic formation. 4)Cuvier (Geologist, Zoologist) a.Proposed “Catastrophism” to explain geologic location of fossil forms b.Theory: Species are produced during a “creation event.” Once created, species don’t change. Existing species are then eliminated by a catastrophic event. Followed by a new creation event followed with new species then the process repeats. 5)Jean- Baptist Lamark a.First to propose a theory of evolution using only natural processes b.Argued that species evolve over time and become better adapted to their environment c. 2 Parts (Theory): use and disuse account for variation or change in physical structure. Use= larger, more developed Disuse= smaller, less developed d.Acquired characters (features an individual acquires during its lifetime) can be passed from parent to offspring. 6)Darwin and Wallace a.1858 both propose that: Species evolve; current species are then modified descendants of previous species. b.Argued that natural selection is the major process of evolution. 7)Natural selection- a process in which individuals that have certain inherited traits tend to survive and reproduce at higher rates than other individuals because of those traits. a.Individuals in a population relative to morphology and physiology b.Genetic variation can be inherited from parent to offspring c. Some individuals produce proportionally more offspring than other individuals (more fit, differentiable reproductive success) Why? Higher survival rate. more opportunity to reproduce Acquisition of food and other resources which increase gamete production. Mate selection d.Individuals with variation (traits) that increase differential reproductive success will, on average, produce more offspring and transmit their traits more successfully into the next generation. e.Over time adapted traits, those traits that increase reproductive success will spread through the population. Chapter 20: Phylogeny Things you need to know: - Naming the major levels of taxonomic classification in order - Naming the taxonomic levels that comprise the species binomial - Properly formatting the species Binomial - Clades (Defining) - Interpreting a cladogram, a phylogram, or a time- frame phylogram - Identifying and naming derived characters, apomorphy, and pleisomorphy - Principle of Parsimony and how it relates to competing cladograms - Developing a parsimonious cladogram - Explaining and identifying monophyletic, paraphyletic, and poly phyletic clades. 1)When writing out a species binomial, you have to write out its genus (where the species belongs), and its epithet which is unique for each species within the genus. You capitalize the first word of (genus) but not the epithet. You then italicize the whole binomial. Example: Panthera pardus Cladogram: represents patterns of evolutionary relatedness but no measure of divergence. Phylogram: shows patterns of evolutionary relatedness and a measure of divergence. The basic unit of a cladistics is a clade, or a common ancestor and all of its descendants. In other words, a clade represents a branch on a cladogram. A clade does not have a defined taxonomic equivalent and may encompass several taxonomic levels. A Traditional Cladogram: Purpose- show evolutionary relationship among groups of interest Groups may or may not be actually taxonomic categories Not attempting to show time or magnitude of evolution since it disappears. Lemurs-Humans are your terminal branches. Your lemurs (out-group): is the group that is known to have diverged earlier than other groups and is used for comparative reasons Nodes (branch points) represent a common ancestor to the groups above and to the right of it. For example your node on the terminal branch of Tarsiers represents the common ancestor for Tarsiers and above. Clade (New world monkeys, old world monkeys, Apes, and Humans): this clade represents the the the common ancestor for New world monkeys and up, and all of the descendants ranging from New world monkeys-Humans. Plylogram- Uneven branch lengths and uneven clade positions Purpose- show patterns of evolutionary relationship and some measure of evolutionary change since divergence from common ancestor All groups are contemptuous Variable Length of Terminal Branches: shows the different evolutionary change since divergence from common ancestor. Short= smaller change , Long= greater change Despite this, how do we measure or indicate magnitude of evolutionary change? Genetic divergence- several ways to measures Measures in morphologic feature (number of bristles, wing length, etc) Phylogram- Uneven Branch Lengths and even clade position (not important for quiz but for your general knowledge and midterm) Show hypothesized evolutionary relationship Indicates common ancestry Time factor of divergence is included Does not indicate magnitude of change/ divergence. ( I will not include picture because we know what is looks like) Every Clad Positon of all the groups are still alive, and to represent an extinct species we draw a line shorter than the rest. *The lines are not used to represent magnitude of change but the time frame in which the being is alive* *** What Cladograms and Phylograms can tell us*** 1.Evolutionary relationships: both cladograms and phylograms 2.Common Ancestry: both cladograms and phylograms 3.Magnitude of genetic divergence: Phylograms only and it must include uneven branch lengths/value of genetic divergence and or both 4.Timing of Divergence: Phylograms only, must include some time frame Depicting Derived Characters: This is a classic cladogram showing evolutionary relationships Based on the presence, absence, or state of certain key characters. Key Characters- reveal the evolutionary relationships among groups 1.Vertebral column represents a key character and every group to the right of that character expresses that character 2.The Hole in the pocket represents a unique character that exists only on the terminal branch (in this case T-rex and Bird) 3.Plesimophy (Ancestral character)- A character or character that occurs in the common ancestor of a defined clade or taxonomic group. In this case, the clad of Lamprey-Gorilla has a Plesimophy of Vertebral column. 4.Apomorphy (Derived character)- A character or character that state that occurs in a clade or taxonomic group but does not occur in the ancestral species (For example the Prehensile hand in the clad of Cow-Gorilla because only Humans and Gorillas posses that trait, not the cows and the common ancestor of the clade. 5.Homoplasy- a character or character state shared among species that was not inherited from common ancestor. This is traits that species develop in order to adapt to their environment. 6.Parsimony- When developing a cladogram, you may not be able to get all the information. So scientists developed parsimony as a way of determining the best cladogram for a specific clade. “The least change is the most parsimonious” that means that the least changes that occurred during the evolution of a clade is the most likely to happen. Now is that the correct way? We don’t know.. Monophyletic grouping- it is only if it includes the most recent common ancestor of the group and all its descendants. By definition, a clade is a monophyletic group. Paraphyletic grouping- if it includes the most recent ancestor but not all of its descendants. Polyphyletic grouping- If it does not include the most recent common ancestor of all members of the group. Chapter 21: Microevolution (I will not be including the things you need to know for the chapter. Refer to the yellow page. Despite this, I will be going by that same yellow page) I. Microevolution and Macroevolution: Microevolution- The change in allele frequency in a population. A population= group of individuals of the same species in a define that interbreed freely with each other. Why are we interested in Allele Frequency? Alleles determine genotype Genotype influences phenotype most but not all evolutionary agents work on the phenotype. Environment also influences phenotype* II. Genetic Variation “Genetic variation” is a measure of the variation in allele formation and distribution in a population. Most common way to think about this… variation in nucleotide (nitrogenous base) sequence among individuals in population. Why is genetic variation important in a population? a.Maintains future evolutionary potential. A population can persist even selection pressures change like environmental conditions because some in the population have adaptive traits due to genetic variation. b.Low genetic variation suggests inbreeding which can lead to fitness in many members of a population (inbreeding depression). c. Low genetic diversity reduces overall ecosystem diversity. Ecosystem with little diversity can collapse. Measures of Genetic Diversity a.Genetic polymorphism proportion (P)= The percentage of genes in the population genome than have more than 1 allele. b.Average heterozygosity(H: Average number of genes in a population that are heterozygous. Proportion of individuals in a population who are heterozygous for a particular gene. c. Allelic Diversity (A): Average number of alleles/gene in a population genome. d.Example population with 4 genes. Gene “A” has 1 allele: A. Gene “B” has 2 alleles: B b. Gene “C” has 3 alleles: C C* c. Gene “D” has 1 allele : D. Genetic Polymorphism (P)= 2 # (of genes that have more than 1 allele) divided by 4 (# of genes)= .5/50%. Average heterozygosity (H)= (5 individuals) 1. AABb 2. AAbb 3. AABB 4. AAbb 5. AABb [ Gene “A”= 0/5 = 0.0] [Gene “B” 2/5= 0.4/40%]. Allelic Diversity (A): 7 alleles / 4 genes= 1.75. What conditions, processes, or events increase genetic diversity in a population? a.Mutation- creates new alleles. Change in DNA nitrogenous base sequence. b.Chromosomal rearrangements- part of a chromosome duplicates and then mutates. Crossing over during meiosis/Translocations. c. Sexual Reproduction- Random union of gametes, all individual reproduce more than once d.Gene Flow/ migration brings in new allelss form outside the population. What decreases genetic diversity a.Low and variable fertility b.Catastrophic events- reduce population size and unevenly remove some alleles c. Isolation (no gene flow) d.Natural selection Hardy-Weinberg Theorem- states that allele and genotype frequencies will not change from one generation to the next as long as certain conditions are true (p^2+2pq+q^2=1) Conditions for Hardy Weinberg: 1)Very large population size (large enough for genetic drifts to be negligible). 2)Random Mating 3)No gene flow (migration). Population are genetically isolated. 4)No mutations 5)No selections If all of these conditions are met then the population is in equilibrium. Mutations: (Know everything on this list) - 1 mutation/100,00 genes - A mutation is a change in nucleotide sequence in an organism’s DNA - Mutations in somatic cells have no effect on allele frequencies in future generations. Mutations in gametes immediately change the gene pool by substituting one allele for another. - Effects of mutations are that they increase overall heterozygosis in a population by introducing new alleles. They also may produce adaptive traits, but does not facilitate the spread of these traits. - One mutation has little quantitative effect on large populations in a single generation. The cumulative effect of mutations at many locations, however, can be significant. - Types are advantageous (increase fitness), Deleterious (decrease fitness) and Neutral (have no effect on fitness. Genetic Drift: (Know everything on this list) - Genetic drift is the random change in allele/genotype frequency as a result of change. Chance events cause allele to be over or under represented in future generations. - Genetic drifts is unlikely to facilitate the spread of adaptive traits. Adaptive traits have no better chance of staying and spreading in the population than are any other trait. - Effects of Genetic Drift: a.Genetic drift may result in the high occurrence of harmful recessive trait. b.Over time genetic drift may lead to an allele becoming fixed in the population. c. Genetic drift may result in some alleles being eliminated form the population d.Reduced genetic variability may make populations more susceptible to extinction. Gene Flow: (know everything on this list) - Gene flow is the movement of alleles or genes between on e or more populations of the same species. Populations are linked by migration exchange alleles. The amount of gene flow can be variable and is not necessarily equal in all directions. - Effects of Gene Flow: a.Gene flow tends to increase overall heterozygosity (genetic diversity) in a population. The actual effect can be variable. b.Facilitates the spread of adaptive traits. Adaptive traits will tend to accumulate in one population and then spread to other populations during gene flow. Natural Selection: (Know everything on this list) - Natural selection is not random. The direction and strength of selection in a population may change over time due to: Change in environmental conditions, introduction of a new predator, competitor, or pathogen, and changing mate selection pressures. - Over time, certain, “adaptive”, alleles become more frequent in the population, while other, “non- adaptive,”, alleles become less frequent in the population. - Natural selection results in differential reproductive success among individuals. This results in an overrepresentation of “favored” traits in future generation. Relative Fitness and Selection Coefficients - The selection coefficient (s) is the percentage reduction in reproductive output in comparison to the favored (most fit genotype) - Relative fitness (w) is defined as the decimal percentage contribution of a genotype to the next generation compared to he contribution of relative genotypes for the same gene. - Sy= (Rx-Ry)/Rx Mutations: Increase because we have a new allele. No. Adaptive traits/alleles have no greater probability of being preserved and spreading. It only creates new alleles and potentially adaptive traits. Genetic Drift: Effect on Genetic Diversity (Unpredictable, can fluctuate usually decreases) Helps spread adaptive traits? Gene flow: its on effect on genetic diversity is variable, usually increase. Yes because a an adaptive traits are likely to be preserved and spread when individuals move. Natural Selection: Decrease. Less fit alleles are removed or become less frequent. It actually increases the adaptive traits because they become more common in the population as less fit alleles/traits are removed. Modes of Selection 1.Describe the effect of selection on the frequency of phenotypes or genotypes over time-particularly in comparison the frequencies at time 0 (original population). 2.Why are we interested in this? a.Indicates environmental effects on phenotypes and genotypes b.Allows us to predict future frequencies 3.A population may experience variable modes of selection during its evolutionary history. Preserving Genetic Diversity 1.Problem- Several agents of microevolution reduce genetic diversity - Natural selection - Genetic Drift, primarily in small population - Non-Random mating: Mate selection (Females select “fit” males to exclusion of others. Proximity means that neighbors are more likely to interbreed and be more genetically similar. 2.Diploidy Preserves Genetic Diversity - Less fit alleles are “hidden” from selection in heterozygotes AA Aa Protected in heterozygotes Aa phenotype is less fit (Removal of phenotype also removes recessive alleles) 3.Heterozygote advantage Preserves Genetic Diversity - Heterozygotes are more fit than either homozygous dominant or homozygous recessive. AA Aa aa Least fit Most fit Lest fit 4.Frequency-dependent selection - “fitness varies depending on frequency with which a phenotype genotype occurs - The more common, the lower the fitness
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