Evolution Evolution is the change in genetic material of a population of organisms through successive generations emergence of new species Population is a group of inter breeding organisms of a particular species consist of all members of the same species that live in one location Gene pool is the various alleles of all the genes in all the individuals described in terms of allele frequencies Allele frequencies are the gene pool of a population Hardy and Weinberg equation is used to calculate gene frequencies Happens when the conditions under which no evolution occurs and it is a null model for evolution o p2 2pq q2 1 o p the dominant allele A o q the recessive allele a o p q 1 o p2 frequency of the homozygous dominant individuals AA o 2pq frequency of the heterozygous individuals Aa o q2 frequency of the homozygous recessive individuals aa Natural selection acts on phenotype NOT genotype Population Genetics Example 50 plants with red flowers AA 20 plants with red flowers Aa 30 plants with white flowers aa o Number of A alleles 50 AA x 2 20 Aa x 1 120 o Number of a alleles 80 o Total number of alleles 100 plants 2 alleles each 200 o Allele frequency of A A total alleles 0 6 o Allele frequency of a 0 4 Past Pre Post Lab Quiz Questions 1 If a population has 5 homozygous dominant individuals 16 heterozygous individuals and 10 homozygous recessive individuals with regard to a certain gene then how many dominant alleles are in the population 5 homozygous dominant 10 16 heterozygous 16 Answer 26 2 In the population described in question 1 what is the frequency of the dominant allele Report the answer to 2 decimal places 0 00 26 dominant 62 total 0 42 Answer 0 42 3 A biologist studying a population of birds comprised of some individuals with long tailed and some short tailed individuals She is interested in whether a population of birds is randomly mating or if the birds are preferentially mating with their own tail type In this species tail length is controlled by a single gene with two alleles T long t short where the long tail is dominant To examine this aspect the scientist will use controlled populations of birds and assess the results of the mating that occurs Write an appropriate null and alternative hypothesis for this experiment A null hypothesis for this statement can be that the birds are just naturally mating and that the length of the tails has nothing to do with who they prefer to mate with An alternative hypothesis can be that the birds maybe prefer to mate with other birds that have the same tail type 4 In the scenario outlined in question 2 the biologist will use the Hardy Weinberg equation to predict the frequency of heterozygotes based on random mating The Hardy Weinberg equation allows biologists to predict the frequency of heterozygotes based on random mating The biologist knows the fraction of long tailed allele P T is 0 1 The fraction of short tailed allele P t is 0 9 Using the Hardy Weinberg equation calculate the frequency of heterozygous T t individuals in the population based on random mating Report the answer to 2 decimal places 0 00 p TT 2pq Tt q tt 1 and p q 1 where p the freq of dominant homozygous TT 2pq the freq of heterozygous Tt q the freq of recessive homozygous tt So the freq of heterozygous 2pq Tt 2 x 0 1 x 0 9 0 18 5 Which of the following is are discrete data Choose any that are discrete data A The number of freshmen at LSU this semester B The height of the students in your section of biology lab C The number of lab meetings this semester D The time it will take to do this week s lab Answer A C 6 The dependent variable is plotted on the Y axis of a graph 7 How graph shown above before inserting it into a lab report select all that apply would you improve the Add a caption below the graph A Add more information to the axis labels B Add a title above the graph C D Remove the lines connecting the points E Use a best fit trendline F Use absorbance ODU for the y axis instead of E coli number Answer C D E 8 Select whether you would use a table or a graph for the following data sets questions 8 9 and 10 You have measured the number of an invasive fish species caught in a sampling net every month for the past 3 years You want the number caught in January of last year Table 9 You have measured the number of an invasive fish species caught in a sampling net every month for the past 3 years You want to know if that fish population is growing exponentially rapidly doubling or if the number has plateaued Graph 10 You have data from an experiment that shows the amount of fermentation that occurs in a reaction at 10 20 40 80 and 160 minutes You need to estimate how much fermentation occurred at the 2 hour point of the experiment Graph 11 If the homozygous dominant genotype makes up 12 of the population what is the percentage of the population is heterozygous Answer 45 You are using the Hardy Weinberg equilibrium theory So p dominant genotype 2pq heterozygous q recessive genotype 1 Another formula p q 1 So if p is 12 then p the frequency of the dominant is 346 If p is 346 then q the frequency of the recessive allele is 654 according to the p q 1 If the frequency of the recessive allele is 654 then the frequency of the dominant phenotype p is 43 2pq is the frequency of the heterozygous phenotype So 2 346 654 is 45 Aa 12 If the homozygous dominant genotype makes up 36 of the population what is the frequency of the dominant allele in that population Answer 0 6 p 36 0 6 13 If the homozygous recessive genotype makes of 9 of the population and the heterozygous genotype makes up 42 of the population what is the frequency of the dominant allele in that population Answer 0 7 q 9 0 3 so that means that the dominant allele must be 0 7 because the recessive allele is 0 3 and it must add up to 1 0 14 Consider the following 2 PopG graph examples Which of the following requirements genetic equilibrium is the most likely not to be followed for the two results shown Large Population Size 15 The Morph exercise can result in an almost infinite variety of offspring If you attempt it more than once you will not get the same result as the prior runs In one possible scenario a rare gene J was lost from the population due to negative selection pressure Select any from the following variations from genetic equilibrium that could make it possible for that population to have offspring with the J allele …