BSC 2011 UNIT III STUDY GUIDE PART A UNIT III Evolution and Population Genetics The purpose of this study guide is to encourage you to review your notes and text material and to integrate numerous facts and terms into broad but meaningful concepts Please try and work on your own at first but don t hesitate to ask for assistance from your TAs or me Dr Spears 2 a What is the biological meaning of the term evolution b Contrast microevolution with macroevolution Evolution species change over time and new species arise by the modification of their ancestral species Microevolution the gradual evolution of traits within a population of species over time population evolved not individuals Macroevolution the evolution of an entirely new species 3 Describe explain how each of the following serves as evidence that evolution could be a means by which life s diversity arose a artificial selection b comparative anatomy c paleontology and d comparative embryology Artificial Selection Serves as evidence that evolution could be a means by which life s diversity arose because it shows that you human can modify other species over many generations by selecting and breeding individual that posses desired traits Comparative Anatomy Serves as evidence that evolution could be a means by which life s diversity arose because it shows that the anatomy of different organisms could be similar because they descent from a common ancestor Paleontology Serves as evidence that evolution could be a means by which life s diversity arose because within the different layers of fossils there are correlation to where the layers are and the similarity present Also in the oldest layers there are species that no longer exist and there are more similar ones in the closer layers Comparative Embryology Serves as evidence that evolution could be a means by which life s diversity arose because when embryos are at the earlier stages they share many general features 4 a How can molecular biology provide evidence for evolution b Provide two examples Evidence for evolution comes from molecular biology because you can compare the protein and DNA sequence of a human with that of a monkey or mouse and see the similarities The more recently two species shared a common ancestor the more similar their proteins and DNA 5 Distinguish between a homologous b analogous and c vestigial structures providing at least ONE EXAMPLE of each Homologous share similarities because of common ancestry example is the forelimbs of mammals Analogous appear similar due to having a similar function not because of shared ancestry example is bird wings and insect wings Vestigial Structures remnants of once functional ancestral structures an example is the human appendix or the hind legs of a whale 6 a What did Darwin find intriguing about the finches on the Galapagos Islands b Explain why how the Galapagos finches might have helped Darwin formulate his hypothesis of evolution by natural selection Darwin found the finches to be intriguing because these he realized that correlation between location and similarity suggested common ancestry He came to decide that 14 endemic species evolved from a common mainland ancestor each adapted to different lifestyles and conditions This might have helped him formulate his hypothesis of evolution by natural selection because those who adapted best to the conditions survive and reproduced more offspring who have the same traits as the parents This is how Darwin explained how and why species change over time 7 a Describe the process by which populations evolve via natural selection b Why is it said that genetic variation is a prerequisite is required for evolution by natural selection Populations evolve via natural selection by first competing for limited resources in nature the fittest or best adapted survive These survivors reproduce and leave more offspring that share parent s traits Genetic variation is required for evolution by natural selection because it affects an individual s ability to survive and reproduce 8 Lamarck thought that evolution was the best explanation for life s diversity as did Darwin How did Darwin s view differ from Lamarck s Lamarck said that species evolve by gradually changing to adapt to environment microevolution through inheritance of acquired characteristics Although he had the right idea he had the wrong mechanism Darwin s mechanism to explain how why species change over time is natural selection the idea of survival of the fittest Lamarck also said that traits than an individual acquires in its lifetime by responding to their environment could be passed to their offspring which is not true 9 Explain what is meant by the phrase populations evolve not individuals Populations evolve because we see the frequencies of genes change from one generation to the next Individual organisms don t evolve because individuals in a population vary some in the population are better able to survive and reproduce given a particular set of environmental conditions These individuals generally survive and produce more offspring thus passing their traits on to the next generation Over time the population changes 10 Define describe a gene pool b allele frequency c genotype frequency d phenotype frequency e gene fixation Using actual letters and descriptive terms Give an example for b c d and e Gene pool all the alleles in a population The total number of alleles in a gene pool 2 x number individuals Allele frequency How often form of gene appears in gene pool Total alleles 30 so frequency of A 20 30 67 a 10 30 33 Genotype frequency The proportion of genotypes among individuals in a population AA 8 15 Aa 4 15 aa 3 15 Phenotype frequency Proportion of phenotype within a population 3 15 red 12 15 green Gene fixation There is only 1 kind of allele for a trait in the population so all individuals are homozygous 11 a Explain the Hardy Weinberg theorem b provide all of the conditions that are required for a population to remain in HW equilibrium and c how is the HW theorem useful in the study of evolution The Hardy Weinberg Equilibrium states that the genotype frequencies and gene frequencies of a large randomly mating population remain constant provided immigration mutation and selection do not take place The five conditions are 1 Population is large 2 There is no mutation 3 No immigration or emigration 4 Mating is random 5 No natural selection The HW theorem is useful in the study of evolution because under these 5
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