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BIOL 2061 1st Edition Lecture 5 Outline of Last Lecture I. Views on evolutionII. Charles Darwin and Alfred Russell WallaceIII. EvolutionIV. Natural selectionOutline of Current Lecture I. What Darwin didn’t knowII. Evidence of evolutionIII. Phenotype, genotype, homozygous, heterozygousIV. Genetic diversityV. Hardy-Weinburg EquilibriumLecture-I. What Darwin didn’t know-a. Darwin didn’t know how traits got passed from parent to off spring.i. This happens through genes and Gregor Mendel figured that out.b. Darwin didn’t know how new variation arises in a population.i. How does it arise?1. Random mutation- happens with in pre-existing genes of the sex cells not somatic cells.2. Exon shuffling- abnormal cross-over events results in exons from one gene being put on another.3. Gene duplication- genes get copied more than once and then change after that through mutation.4. Horizontal gene transfer- gene from one species is introduced to another species. (very common in bacteria)II. Evidence of evolutionThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.a. Fossil record- i. the fossil record is evidence of evolution because it is a record of preserved artifacts that helps link relationships between species over many generations.1. Example: trace fossils, plant fossils, the “Lucy” fossil (ape-like hominid classified as 3.2 million years old)ii. How do you “age” a fossil? 1. Carbon2. Radio isotopes3. Geological layers (where it’s found)iii. Why is the fossil record incomplete?1. Not everything can be found yet2. Not everything is representedb. Bio Geography-i. See different related life forms in close locations1. Example- Darwin’s Finches of the Galapagos Islands2. Bio geography is evidence of evolution because it shows how some life can be very closely related but different because of where the species live.c. Convergent evolution-i. Two organisms have the same evolution without a common ancestor.ii. This is evidence of evolution because two separate special have the same evolution to survive and reproduce when there is no common link in theirorigin.d. Selective breeding/ Artificial Selection-i. Humans select who gets to survive and breedii. This is evidence of evolution because it shows that only the best of the best survive.1. Example: bananas, apples, dogsiii. SB/AS reduces genetic diversitye. Homology-i. A structure that is similar because of a common ancestorii. Homology is evidence of evolution because when a species is traced back to its origin similar characteristics are shown back in the day as they are now.1. Example: arms, filangesiii. Vestigial structures, have no apparent function but resemble structures ofpresumed ancestorsIII. Pheno/Genotypes and homo/heterozygousa. Phenotype- and outward expression of a trait, coded for in the genotypei. Ex. Color of a pea pod, or color of a Brassica rapa plant.b. Genotype- genetic composition of an individual (which alleles they have; GG, Gg or gg)c. Homozygous-individual who has two matching copies of an allele.i. Ex. (RR) and (rr)d. Heterozygous- an individual who has two different copies of an allele.i. Ex. (Rr)e. Example: there are 56 yellow flowers (RR)i. The (RR) is the GENOtype and the yellow is the PHENOtypeIV. Genetic Diversity-a. Monomorphic gene- Having or existing in only one form, as having only one alleleof a gene in a population that is the sameb. Polymorphic gene- there are at least two or more variations of alleles in a populationc. Single Nucleotide polymorphism (SNPs)i. Smallest type of genetic change in a gene.ii. Most common (90% of variation in human gene sequences)d. Large, healthy populations exhibit high levels of genetic diversity.V. Hardy-Weinburg Equilibrium-a. If a population is in Hardy-Weinburg equilibrium then it means that allele frequencies are staying the same, there is no evolution occurring.b. For a population to be in HW equilibrium then there must be:i. No natural selectionii. No mutationiii. Random matingiv. No migrationc. Change over time on populationsi. Selection- natural/ artificialii. Migration- migration of individuals in or out of a populationiii. Genetic drift- Variation in the relative frequency of different genotypes in a small population, owing to the chance disappearance of particular genes as individuals die or do not reproduce.iv. Non-random matingv. Mutationd. HW equilibrium equationsi. p+q= 1 (alleles)ii.p2+2 pq+q2=1 (genotypes)e. Of the equation p+q=1i. p= frequency of Dominant alleleii. q= frequency of recessive alleleiii. Ex. The frequency of R is .4….. What is the frequency of r?1. p+q=1….. .4+q=1….. q=1-.4….. q=.6f. of the equation p2+2 pq+q2=1i.p2= frequency of homozygous Dominant genotype (RR)ii.2 pq= frequency of heterozygous genotype (Rr)iii.q2= frequency of homozygous recessive genotype (rr)iv. Ex. You know the frequency of the dominant allele is .4 and the recessive allele is .6 what is the frequency of:1. Homozygous genotypea.p2=? ?..... p=.4….. Square .4….. p2=0.16 2. Homozygous genotypea.q2=? ?..... q=.6….. Square .6….. q2=0.363. Heterozygous genotypea. 2pq=??..... p=.4 and q=.6…… 2 x .4 x.6=0.48….. 2pq=0.48g. When a population is not in HW equilibrium then you use the allele and genotype frequency equations first!i. Allele frequency=total¿ of copies of a specific allele∈populati on¿of all alleles for that gene∈population ¿2 x2 x2 x(¿ of RR x freq .of allelelooking for)+(¿of Rr x freq .of allele looking for)+(¿ of rr x freq. of a llele looking for)(¿of RR)+(¿Rr)+(¿ of rr)ii. Genotype frequency=total¿ of individuals witha certain genotype∈population¿of individuals∈population ¿¿of genotype looing for¿ of RR+¿of Rr +¿of


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