BIO 148 Unit 6 Exam Solved Correctly

BIO 148 Unit 6 Exam Solved Correctly Biological Species concept - Answer- The definition of a species as a population or group of populations that are reproductively isolated from other groups. Members of a species have the potential to interbreed in nature to produce viable, fertile offspring but cannot produce viable, fertile hybrid offspring other species. Clade (monophyletic group) - Answer- An evolutionary unit that includes an ancestral population and all of its descendants but no others. Allopatric speciation - Answer- The divergence of populations into different species by physical isolation of populations in different geographic areas Beneficial - Answer- In genetics, referring to any mutation, allele, or trait that increases an individual's fitness. Cladistics approach - Answer- A method for constructing a phylogenetic tree that is based on identifying the unique traits of each monophyletic group. Convergent evolution - Answer- The independent evolution of analogous traits in distantly related organisms due to adaptation to similar environments and a similar way of life. Deleterious - Answer- In genetics, referring to any mutation or allele that reduces an individual's fitness Derived trait - Answer- A trait that is clearly homologous with a trait found in an ancestor, but which has a new form. Directional Selection - Answer- A pattern of natural selection that favors one extreme phenotype with the result that the average phenotype of a population changes in one direction. Generally reduces overall genetic variation in a population. Disruptive Selection - Answer- A pattern of natural selection that favors extreme phenotypes at both ends of the range of phenotypic variation. Generally increases overall genetic variation in a population. Founder effect - Answer- A change in allele frequencies that often occurs when a new population is established from a small group of individuals (founder event) due to sampling error (i.e., the small group is not a representative sample of the source population). Gene flow - Answer- The movement of alleles between populations; occurs when individuals leave one population, join another, and breed. Gene pool - Answer- All of the alleles of all of the genes in a certain population Genetic bottleneck - Answer- A reduction in the size of a large population (population bottleneck) due to a random event. Can lead to a change in allele frequencies and increases the effect of genetic drift. Genetic Drift - Answer- Any change in allele frequencies due to random events. Causes allele frequencies to drift up and down randomly over time, and eventually can lead to the fixation or loss of alleles. Is more severe in smaller populations. Genetic variation - Answer- The number and relative frequency of alleles present in a particular population. Homoplasy - Answer- Similarity among organisms of different species due to convergent evolution. Monophyletic group - Answer- An evolutionary unit that includes an ancestral population and all of its descendants but no others. Also called a clade or lineage. Morphology - Answer- The shape and appearance of an organism's body and its component parts. Morphospecies concept - Answer- The definition of a species as a population or group of populations that have measurably different anatomical features from other groups Mutation - Answer- Any permanent change in the hereditary material of an organism Outgroup - Answer- A taxon that is closely related to a particular monophyletic group but is not part of it. Paraphyletic group - Answer- An evolutionary unit that includes an ancestral population and some but not all of its descendants. Parsimony - Answer- The logical principle that the most likely explanation of a phenomenon is the most economical or simplest. When applied to comparison of alternative phylogenetic trees, it suggests that the one requiring the fewest evolutionary changes is most likely to be correct Phenetic approach - Answer- A method for constructing a phylogenetic tree by computing a statistic that summarizes the overall similarity among populations, based on the available data Phylogenetic Species concept - Answer- The definition of a species as the smallest monophyletic group in a phylogenetic tree. Phylogeny (phylogenetic tree; cladogram) - Answer- The evolutionary history of a group of organisms. Quantitative Traits - Answer- a trait produced by the interaction and additive effects of numerous genes (each of which contribute a small amount to phenotype) Radiometric Dating - Answer- technique used to date materials such as rocks, usually based on a comparison between the observed abundance of a naturally occurring radioactive isotope and its decay products, using known decay rates Sexual dimorphism - Answer- Any trait that differs between males and females. Sexual selection - Answer- A pattern of natural selection that favors individuals with traits that increase their ability to obtain mates. Acts more strongly on males than females. Stabilizing Selection - Answer- A pattern of natural selection that favors phenotypes near the middle of the range of phenotypic variation. Reduces overall genetic variation in a population. Sympatric speciation - Answer- The divergence of populations living within the same geographic area into different species as the result of their genetic (not physical) isolation. Synapomorphy - Answer- A shared, derived trait found in two or more taxa that is present in their most recent common ancestor but is missing in more distant ancestors. Useful for inferring evolutionary relationships Transposable element - Answer- a DNA sequence that can change its relative position in the genome Mutations can be categorized as beneficial, deleterious, or neutral, based on... A. the number of bases that are changed B. the effect on the protein produced C. their effect on individual fitness D. the ease of locating them in a genome - Answer- C. In a population of frogs, tge green colored frogs have higher fitness than the brown colored frogs. Each generation there are more green colored frogs than brown colored frogs because the green frogs have higher fitness than the brown frogs. In this scenario, average relative fitness of the population... A. keeps increasing B. keeps decreasing C. increases in some generations and decreases in some generations - Answer- A. In the population of frogs with green and brown coloration, green coloration was advantageous in the environment. One generation, the environment changes and brown colored frogs have higher fitness than green colored frogs. In this scenario, average relative fitness of the population... A. keeps increasing B. keeps decreasing C. increases in some generations and decreases in some generations - Answer- A. more brown frogs, leads to evolution, leads to natural selection. Natural selection always increases the average relative fitness of a population. Gene Pool - Answer- all alleles in the population evolution - Answer- Change in average trait value in the population. Change in allele frequency in the population. How do allele frequencies change? - Answer- genetic variation underlies phenotypic variation. genetic variation: the number and relative frequency of alleles present in a particular population. Mechanisms of evolution- what causes shifts in allele frequencies within populations? - Answer- Mutation Selection: natural and sexual Genetic drift Gene flow Mutations in (somatic/germline) cells only spread through the population. - Answer- germline a mutation is a permanent change in DNA. - Answer- True A mutation would lead to an (increase/decrease) in genetic variation in the population. - Answer- increase Are mutations caused by evolution? - Answer- No; mutations LEAD to (or cause) evolution. Do mutations lead to evolution? - Answer- yes Do mutations cause selection? - Answer- No; selection acts on variation produced due to mutation.