Chapter 20 Lecture and Reading Note taking Template Fill in this outline in lecture then use your textbook to add to it Notes from just the lecture are not enough to do well in this class 1 Genetic Variation and Evolution Population species in a specific place at once a Complete the definition of genetic variation i Genetic variation is the differences in alleles of genes found within individuals in a population It is the raw material for natural selection ii b Complete the definition of evolution i Evolution is how an entity changes things over time ii Darwin proposed natural selection as a means or mechanism for evolution to iii Jean Baptiste Lamarck proposed evolution by inheritance of acquired occur characteristics 1 Natural selection produces evolutionary change when some individuals in a population possess certain inheritable traits and 2 Use Fig 20 1 to compare Lamarck s idea of inheritance of acquired characteristics to Darwin s natural selection c What is population genetics How is it related to evolution and genetic variation i Population genetics study if properties of genes in a population d What is polymorphic variation Why is it important and give an example or two i Evolution results in a change in the genetic composition of a population ii Genetic variation is the raw material for selection 2 Changes in Allele Frequency a Explain the Hardy Weinberg Principle i Allows predictions of a genotype frequencies If a population is in H W equilibrium is evolution occurring b c List the 5 characteristics of a population in H W equilibrium i ii iii iv v No mutation takes place No genes are transferred to or from other sources 1 Written as an equation 2 Used to calculate allele frequencies 3 For 2 alleles p and q p B for black coat q b for white coat p 2 2pq q 2 1 BB Bb bb 1 1 2 1 ratio frequency of genotype 4 p q 1 frequency of allele d Using the H W equation to predict allele and genotype frequencies Be able to calculate allele frequencies and genotype frequencies in a population in H W equilibrium See Fig 20 3 lab manual lab tutorial worksheet and homework e H W predictions can be applied to data to find evidence of evolutionary processes Chapter 20 Lecture and Reading Note taking Template i ii iii In reality most populations will not meet all 5 assumptions But is used to measure changes in frequency and to Suggest hypotheses about what process or processes at work 3 Five Agents of Evolutionary Change a List define and provide an example i Mutation 1 Rates generally low 2 Other evolutionary processes usually more important in changing allele frequency 3 Ultimate source of genetic variation 4 Makes evolution possible ii Gene flow iii Nonrandom Mating 1 Movement of alleles from one population to another 1 Inbreeding is the most common form It doesn t alter allele frequency but reduces the proportion of heterozygotes iv Genetic Drift 1 2 Magnitude is related to population size 3 Examples Founder effect Bottleneck effect In small populations allele frequency may change by chance alone v Selection 1 Favors some genotypes over others 2 Some individuals have more progeny a Based on by phenotype and behavior 3 Artificial selection 4 Natural selection b Differentiate between the founder effect and bottleneck effect by defining and providing an example i Founder effect new population ii Bottleneck effect can lead to the loss of alleles in isolated populations 1 Alleles that initially are uncommon are particularly vulnerable iii Which agent of change are these both an example of c Selections favors some genotypes over others i Three conditions of selection must be met for natural selection to occur and to result in evolutionary change Variation in a population Differences in the number of offspring surviving 1 2 3 Variation must be genetically inherited ii Selection is the only agent that produces change d Natural selection and evolution are not the same thing i Natural selection process ii Evolution is historical record outcome of change through time iii Result of evolution driven by natural selection is populations become better adapted to their current environment Chapter 20 Lecture and Reading Note taking Template 4 Quantifying Natural Selection a Define evolutionary fitness i Individuals with one phenotype leave more surviving offspring in the next generation than individuals with an alternative phenotype ii Relative concept the most fit phenotype is simply the one that produces on average the greatest number of offspring b Fitness has many components i Survival ii Sexual selection some individuals more successful at attracting mates iii Number of offspring per mating iv Traits favored for one component may be a disadvantage for others c Selection favors phenotypes with the greatest fitness d Phenotype with greater fitness usually 5 Natural Selection s Role in Maintaining Variation a Explain what is meant by frequency dependent selection i Fitness of a phenotype depends on its frequency within the population b Add examples of each of these types of freq dependent selection i Negative frequency dependent selection 1 Rare phenotypes favored by selection 2 Rare forms may not be in search image ii Positive frequency dependent selection 1 Favors common form 2 Tends to eliminate variation 3 Oddballs stand out iii Oscillating selection flip flops back and forth due to environmental conditions another time 1 Selection favors one phenotype at one time and another phenotype at 2 Effect will be to maintain genetic variation in the population iv What is heterozygote advantage 1 Define Heterozygotes area favored over homozygotes 2 Works to maintain both alleles in the population 3 Example Sickle Cell Anemia 6 Selection Acting on Traits affected by Multiple Genes This section is presented through an online lecture posted on D2L We will not have lecture Nov 13th you can plan on watching this then a Define and contrast disruptive stabilizing and directional selection Also explain the evolutionary outcome of each of these types of selection Be able to provide or identify an example of each b Know Figure 20 13 and the caption i Disruptive selection ii Directional selection iii Stabilizing selection Chapter 20 Lecture and Reading Note taking Template 7 Experimental Studies of Natural Selection This section is presented through an online lecture posted on D2L We will not have lecture Nov 13th you can plan on watching this then a Understand the experiment with guppy color variation and Figure 20