ENVIR ST 260 1st Edition Lecture 5 Outline of Last Lecture I DesignLab II Practice Problems Outline of Current Lecture I Student Questions II Exam Information Current Lecture Clicker Question There are 111 students registered for this class How many have viewed the Additional PopG Problems PDF 17 which the professor finds worrisome because the exam is on Tuesday Student Questions Question about the non evolving population and population size Null Model No natural selection No mutation No gene flow Random Mating Large Population size Small Populations 50 100 individuals Susceptible to random events and there is less genetic variation If you have a really harsh winter more individuals are likely to die Starting with a small population and making it smaller there will be less diversity in genetics because there won t be as many members to contribute different genes to pass on In PopG you can see more visible change with small population sizes Large Population 1 000 10 000 individuals They ll suffer from disasters but there s still a good number of individuals left so you ll have more genetic variability These 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 Large populations do evolve but they re less likely to change genetically based on random events Question What is Initial Allele Frequency on PopG If the line on the graph is at 5 then 50 of the alleles in the population are dominant The y axis always tells us the frequency of the dominant allele It just gives a single value You re essentially looking at p and q in the population If p 3 and q 7 the generation 0 would be starting at 0 3 Initial frequency is equivalent to frequency of the dominant allele p at generation 0 Question about genetic drift Gene flow versus Genetic drift Genetic Drift Ties into idea of small population When you get these really rapid random changes there s genetic drift It s random and is in small populations Even if fixation does not occur there is genetic drift when the population greatly differs from the theoretical line on PopG Gene Flow When individuals move back and forth immigration and emigration Question about mutation versus natural selection Mutations are generally just random recombination of alleles DNA does a pretty good job of matching itself up but sometimes mistakes are made Mutations occur from mismatches in genes So mutations are random events they don t happen to adapt to environmental conditions When we see changes in populations that better suit individuals to their environment that s where we have natural selection occurring Bacteria mutate faster and a genetic change that occurs in that population may be better suited for the environment and then natural selection acts on it Mutation is something that natural selection can act upon so it can be a good thing Question Null Model and Mutation If there s a population that has all 5 conditions of the null model and a mutation occurs that gives individuals an advantage you now have a population with potential to be evolving About the Exam What to Bring Something to write with Calculator Photo ID Exam Day Rules ALL bags books etc staged at front of lecture hall All we should have is something to write with calculator and photo idea No phones phone does not equal calculator Sit every other seat Exit out door at front Format Short Answer Fill in blank questions Word problems that incorporate popG and the Hardy Weinberg equation Essay questions know all the content Not too much writing limited on space Two to three paragraphs Clear concise arguments and examples