Review sheet for EXAM IV BIOSCI150 Fall 2022 Read chapters 13 and 16 1 Evolution change over time 2 Lamarck Use and disuse theory is incorrect 3 What is the study of biological evolution all about Origin of species 4 Differentiate between antigenic drift antigenic shift and lateral transfer Where do these occur 5 Can variation be created on demand No Selection works only upon preexisting variation 6 Can acquired traits be inherited No The reason why Lamark s explanation for evolution is incorrect 7 Charles Darwin and Alfred Wallace Voyage of the beagle Two books that influenced Darwin when he was developing the concept of Natural selection Charles Lyell Principles of geology 1830 1833 slow changes over time Thomas Malthus Essay on Populations 1798 Alfred Wallace came up with a similar explanation to account for biological evolution as Darwin 8 Darwin published his The Origin of Species in 1859 Much of the evidence for variation came from his observation of domestic animals and plants and species that were common such as beetles How did Darwin draw on artificial selection in advancing his arguments about natural selection Why does artificial selection usually proceed more rapidly than natural selection 9 Darwin s Theory of Natural Selection is based on Populations have a potential to increase exponentially Distinguish between exponential and arithmetic growth Populations are fairly constant in size Logistic growth model K carrying capacity Natural resources are limited There is variation among individuals in a population and variations are inherited Only some organisms survive and there is a struggle for existence among individuals Individuals with favorable variations are more likely to survive and reproduce Accumulation of inheritable variation over many generations is evolution 10 All life on earth share a common lineage Why is it difficult to trace the very first life that gave arise to all species today Swapping of genetic material between bacteria i e horizontal gene transfer has made it difficult to follow linages 11 Is Darwin s finches cited as an example for evolution when Darwin initially wrote his Origin book No In fact he did not even label them by islands and just briefly mentions finches and these are not the finches he was referring to but he does mention mocking birds But these are an excellent model species to study speciation there are isolated populations in closely knit islands and they are relatively easy to catch and track them over several generations 12 How did the Grants follow the role of natural selection in these birds What did they measure 13 How did drought influence the survival of offspring in these finches How did they show that individual that survived during the drought period was not just random but natural selection played a significant role in it 14 How did they correlate survival of offspring with variations due to inherited traits 15 Why was there a rapid shift in bill size in Geospiza fortis medium ground finch following a severe drought After the drought ended why didn t mean bill morphology rapidly shift back to the mean just prior to the drought If bill size were not heritable would there have been a difference in bill size of offspring immediately prior and immediately following the drought 16 What is character displacement What differences would you see when you are studying this phenomena in species sympatrically living together vs those living allopatrically geographically separated 17 If natural selection operates on individuals why does evolutionary change occur at the population level 18 What are 4 evolutionary mechanisms that change allele frequencies within populations Which of these mechanisms involves differential survival and reproductive success Mutation Gene flow Genetic drift natural selection 19 Where would find the highest rate of nt substitutions In Pseudogenes synonymous nonsynonymous substitutions Why 20 Why did the Drosophila experiment involving bristle number so quickly evolve into those with low or high bristles very quickly What was the mean number of bristles in the original population 21 What comparisons did Michael Lynch carry out to study mutation rate Why is this important 22 How is evolutionary change quantified 23 What are the five assumptions of the Hardy Weinberg Theorem model 24 If the Hardy Weinberg assumptions are met then after a generation of random mating what will happen to genotype frequencies Large populations no selection no mutation no gene flow and mating is random 25 What is the Hardy Weinberg formula p2 2pq q2 1 26 If you know the frequency of a recessive trait how do you determine the frequency of recessive alleles If you now know what q is can you calculate what p would be When a trait is inherited as a dominant allele how can the Hardy Weinberg formula be used to determine the proportion of homozygous dominant and heterozygous individuals 27 What would happen to genotypic frequencies if a population is at HW equilibrium and you study and quantify these for 10 generations What if there is selection for a particular genotype Practice some simple problems such as if q2 0 04 then q if you take the square root of 0 04 0 2 and p 1 q 0 8 From here you can easily calculate p2 and 2pq Try out other problems where q 0 09 q 0 16 28 Describe different ways by which Natural Selection can operate with examples for each Directional selection Stabilizing selection Disruptive selection Frequency dependent selection Heterozygote advantage Does directional selection always proceed only in one direction What if the environment changes How does stabilizing selection explain optimal number of eggs a bird lays when fitness implies having as many young as possible Which is the phenotype that is not selected in disruptive selection Explain when and how frequency dependent selection and heterozygote advantage will affect allele frequencies 29 How does the supergene complex explain the evolution in a single species of Heliconius numata seven morphotypes that mimic seven different species of Melinaeae How many gene clusters are present 30 What kind of selection could lead to speciation events in the short video on butterflies we watched in class 31 Based on Stephen Fry s study of snake venom is it the product of just one gene or many genes Where does selection act in these genes How do expression levels vary in these genes What evidence does he provide to show that these genes were present before the evolution of