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18bio5785
CU intro to bio: lecture 18
| Question | Answer |
|---|---|
| Populations ________, individuals _______ | evolve, do not |
| A population is | A population is a group of individuals belonging to the same species, occupying the same given area. |
| What types of traits do populations exhibit even though there is variation among the individual members. | but they also hold certain morphological, physiological, and behavioral traits in common... |
| Individuals of the same population have the same ______ and ______ of genes. | Number and kindes of genes |
| the Gene pool. | All of the genes in the entire population constitute the gene pool |
| Alleles.. | Each gene exists in two or more slightly different molecular forms called alleles, |
| Phenotype | Each gene exists in two or more slightly different molecular forms called alleles, which offspring inherit and express as phenotype |
| Dimorphism | is when there are two variations of a trait in a population |
| Polymorphism | Polymorphism is when there are three or more variations in a trait |
| ToF: Offspring inherit genotypes and phenotypes. | False: Offspring inherit genotypes, not phenotypes. |
| ToF: Certain phenotypes are caused by enviornmental conditions. These enviornmentally changed phenotypes cannot be bassed on to offspring. | True. |
| What are the five factors that each particular mix of allels depends on? | Crossing over & genetic recombination Independent assortment of chromosomes occurs Fertilization between genetically varied gametes produces new combinations of genes. Gene mutations create new alleles changes in chromosome structure or number occur |
| Mutations | are heritable changes in DNA that can alter gene expression |
| Mutations are random and the phenotypic outcome may be..... | neutral, beneficial (theoretically at least), harmful, or even lethal to the individual depending on other interactions |
| Lethal mutation | is an expression of a gene that results in death |
| Neutral mutation | whether or no they are expressed in phenotype , have no effect on survival and reproduction |
| Mutations are the only source of what? | New alleles- the genetic foundation for biological diversity |
| Allele frequencies are | a measure of the abundance of each kind of allele in the entire population |
| Evolution can be detected by a change in.. | allele frequencies from the genetic equilibrium of a population. |
| These five conditions are necessary for a stable population (ie. NO evolution of the population) to continue........ | a. No mutations are occurring. b. The population is very, very large. c. The population is isolated from other populations of the same species. d. All members survive, mate, and reproduce (no selection). e. Mating is random. |
| Microevolution is | the change in allele frequencies brought about by mutation, genetic drift, gene flow, and natural selection. |
| Allele frequencies for any gene will.... | remain stable unless the population is evolving. |
| What are the two formulas used to track any deviation from the stable state? | 1: p + q = 1 2: p2 + 2pq + q2 = 1 |
| What does each variable mean? (p,q, p2,q2, 2pq) | p = frequency of the A allele q = frequency of the a allele p2 = frequency of the AA genotype 2pq = frequency of the Aa genotype q2 = frequency of the aa genotype |
| What is known as the Hardy-Weindberg Equilibrium Equation? | p2 + 2pq + q2 = 1 . |
| What happens if traits show up in different proportions to the expected frequencies given the HW assumptions? | It indicates that one or more of the five assumptions is not being met and some evolutionary force is affecting the population. |
| How do researchers us the HW equation? | they use it to estimate the frequency of carriers of alleles that cause genetic disorders and traits. |
| Natural Selection is? | the differential survival and reproduction among individuals of a population based on the details of their sharred traits. |
| What is the most influencial microevolutionary process? | Natural selection may be the most influential microevolutionary process |
| ToF: An allele that ensures better survival or reproduction will influence the frequency of that allele | True... |
| What are the three major catagories of selection? | Directional, stabalizing, and disruptive |
| What is directional selection? | Directional selection shifts allele frequencies ina consistent direction (Selection in the direction of a particular range of phenotypes) which may be in response to enviornmental pressures or may occur as a new mutationappears and is adaptive. |
| Explain the example of the Peppered moth. which selection does it represent. | Populations of peppered moth show classic directional selection where the moth coloration is in direct response to their environment; light moths are camouflaged on lichen-covered tree trunks, and dark moths are camouflaged on soot-covered tree trunks |
| Explain the example of the Pocket Mice. which selection does it represent | Largest population of rock pocket mice is in direct relation to its fur color. It blends in with its surroundings better than its realatives.... Directional selection |
| Stabalizing selection.... | favors the most common phenotype in the population. (steeper slope) |
| Explain the example of the Weaver birds which selection does it represent. | Weaver birds... Leaner birds do not store enough fat..... Larger birds are more desirable for predators and less likely to escape.... therefore birds of intermediate weight have the "selective" advantage. |
| Disruptive selection... | Favors forms at the extremes of the phenotypic range of variation and seects against the intermediate forms. |
| Explain the example of African Finches. Which selection does it represent? | African finches have a bill size that is either large or small, not inbetween. Smaller billed birds feed on softer seeds larger billed birds feed on harder seeds Intermediate size billed brds are therefore selected against. |
| Sexual selection | is based on any trait that gives the individual a competitive edge in mating and producing offspring. |
| Which sex is usually the agent of selection when they pick their mates? | Females... |
| Explain the exampel of Sickle-cell anemia. how does this exhibit polymorphism? | Humans homozygus for sickle-cell anemia develop the disease and may die at an early age obviously homozygus for hemoglobin are fine but humans that are heterozygus for hemoglobin and sickle cell animia are more prone to survive malaria |
| Genetic Drift is? | the random fluctuation in allel frequencies over time, due to chance occurrences alone. |
| where is genetic drift most significant? WHere can genetic drift lead to in that type of population?` | In smaller populations because of the small numbers in the population. genetic drift may lead to a homozygous contition in most populations.... |
| Fixation means? | that one kind of allele remains at a specified locus ina population. |
| What happens in bottlenecks? | some stressful situation greatly reduces the size of a population leaving a few indicviduals to reestablish the population. |
| The founder effect... | a few individuals (carrying genes that may or may not be typical of the whole populationleave the original population to establish a new 4 one. Because only the founders provide for the gene pool of the population, the diversity is limited.rpoint |
| Inbred populations... | it tends to increase the homozygous condition, thus leading to lower potential fitness and survival rates because of the lack of genetic diversity. |
| Gene flow | Genes move with individuals when they move out of (emigration) or into (immigration), a population. |
| Species is? | a “kind” of organism. Ernyst Mayr defined species as “one or more groups of individuals that potentially can interbreed, produce fertile offspring, and do not interbreed with other groups |
| What are the 7 isolating mechanisms? | Gamete inconbatability, temporal isolation, mechanical isolation, behavioral isolation, ecological isolation, Hybrid inviability, hybrid sterility |
| What is temporal isolation | Isolation due to the timing f an organism's reproductive cycle |
| What is mechanical isolation? | isolation due to physical incompatibility between mates or pollinators |
| What is Behavioral isolation | isolation due to individuals of different species ignoring or not getting the required cues for sex. |
| What is Eclogical isolation | isolation due to living in diffent places and therefore never metting up |
| what is Gamete Incompatibility? | reproductive cells meet up, but no fertilization occurs. |
| What is hybrid inviability? | Fertilization occurs but zygote fails to develope. |
| What is hybrid sterility? | Fertilization produces a viabl eoffspring that cannot produce |
| Allopatric speciation... | occurs when a species becomes separated by a physical barrier, thus halting gene flow between two populations, and eventually leading to reproductive isolation |
| Sympatric speciation is? | divergence within the same home range of a species. |
| Polyploidy is? | is a result of nondisjunction during cell division that can lead to a change in chromosome number. In plants, polyploidy can be compatible with life. Therefore if self-fertilization occurs in these plants, this can lead to instant speciation |
| Parapatric speciation occurs? | when one population extends across a large diverse habitat. Distince habitats exert selection pressurs on parts of the population. |
| Macroevolution v microevolution: which view is consistent with the Christian World view? | Micro evolution is consistent because it can be observed and can be mathematically demonstrated. Macroevolution is inconsistent because it is based on theories the Biblical world view cannot support. |
| coevolution | the reasoning that close ecological interactions between two species cause them to evolve jointly. |
| Stasis | The idea that a species can have a long-term lineage with relatively little evolutionary change |
| Pre-adaptation - | This describes a dramatic increase in new species due to the presence of many new niches to fill in a habitat. This rapid adaptation may be in response to teh development of a singel novel trait (flight in birds) or as a result of extinction |
| Extinction | THe fossel record indicates more than 20 mass extinctions, which are losses of many lineages. each mass extinction is followed by a period of adaptive radiation. |
Created by:
jseekins
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