BIO 2400 FINAL EXAM QUESTIONS AND ANSWERS AND NOTES FALL 2024/2025.

BIO 2400 FINAL EXAM NOTES Emphasis on Middy TWO PRACTICE EXAM MC QUESTIONS 1. Which of the following sentences is FALSE about Homo neanderthalensis? o Their brains were either larger or the same proportion size to our own (depending on study) and had larger areas devoted to vision and hearing o They were hunters of large game and their diet was rich in meat o They painted figurative images of animals and made sophisticated sculptures of feminine forms o Is believed that H. neanderthalnesis hybridized with H. sapiens 2. According to fossil and molecular evidence, Homo neanderthalensis and H. sapiens are two independent lineages that descended from a common ancestor. o True o False 3. There is evidence that populations of Homo sapiens from Europe and Asia share about 2% of their alleles with H. neanderthalensis indicating that ____? o They share a common ancestor o They hybridized during their coexistence o They’re not really distinct phylogenetic and morphogenic species o 1 and 2 o 2 and 3 4. Which of the statements is true about the respective species concept? o The morphological species concept can only be used on extinct organisms o The biological species concept is easily applied to all organisms, from bacteria to vertebrates o The phylogenetic species concept defines a species to be a paraphyletic lineage of individuals that all possess a synapomorphy o The biological species concept is defined as the set of populations of individuals that interbreed or could potentially interbreed with one another yet are reproductively isolated from all other sets of populations 5. What is a ring species? o A species whose geographic distribution spans the entire globe at the equator only because it is most well adapted to the tropical conditions o A circular series of population of a species which can interbreed with the closest neighbouring population but populations at extreme ends of the geographic range can no longer interbreed o A species whose migration patterns match the circular currents found in the north Atlantic Ocean o Any species of elongate, worm-like organisms with ring-shaped body segments produced from convergent Hox gene evolution 6. Which of the following best describes allopatric speciation? o Speciation where allometry (change in shape with size) of traits in two subpopulations determines whether or not interbreeding can occur o Speciation whereby divergent ecological pressures in the same environment can cause a population to diverge into two or more populations with some gene flow between them (0 m 0.5) o Speciation whereby allopolyploidy creates reproductive barriers between two populations o Speciation whereby geographical separation of one population into multiple populations (by vicariance or other geological events) prevents interbreeding and results in independent evolution in each. There is NO gene flow (m = 0) between the multiple populations 7. How can barriers to gene flow between two separated populations separated by vicariance or a founder effect (m=0) evolve without natural selection directly acting on traits contributing to reproductive isolation? Of the following statements, which are true: 1 Selection for opposing values of an ecological trait in the two populations, cannot possibly contribute to barriers to reproduction 2 They cannot, only natural selection can create barriers to gene flow strong enough to prevent two populations from merging into one species 3 Genetic drift in the two populations could fix different alleles at a locus or loci that make interbreeding between those two populations impossible later after they come into contact again. 4 A mutation in one of the two populations might have pleiotropic effects that makes interbreeding between the two populations impossible after the they come into contact again. o 3 and 4 o 1 and 2 o 1 and 3 o 1 and 4 8. Why do many phenotypic traits have a continuous distribution rather than fitting into non-overlapping categories? o Because phenotypic traits are a result of dominance interactions among alleles o Because phenotypic traits are influenced only by the environment o Because phenotypic traits are often affected by large numbers of genetic loci and environment o Because phenotypic traits aren’t related to genotypes 9. Which of these statements about narrow sense heritability (h²) is TRUE? o Narrow sense heritability can be estimated by comparing allele frequencies at quantitative trait loci among offspring and their parents using regression o The numerator of narrow sense heritability includes additive, dominant and epistatic gene effects o The numerator of narrow sense heritability includes only the additive effects of alleles o Narrow sense heritability only includes the epistatic effects of alleles o None of the above is a true statement 10. The breeder’s equation incorporates two variables that must be non-zero for evolution by natural selection to take place. Which two? o Variation in phenotypic traits (R) and the narrow sense heritability (h²) o Difference between the mean trait values between individuals that survive long enough to reproduce and the value for the entire population (S) and the narrow sense heritability (h²) o Greater survival (S) and reproduction (R) of phenotypes with specific alleles o Heritability of additive alleles (h²) and the evolutionary response of the population (R) o None of the above demonstrate evolution 11. If age of sexual maturation is a phenotypically plastic trait with a heritability of zero, which of the following relationship(s) would you expect to find? o A genotype differs in the age at first reproduction across different environments o Body size affects the age at which genotypes reproduce which differs in different environment o Environmental conditions (such as nutrition) affect the age at which individuals begin reproducing o All of the above o None of the above 12. Which of the following is an example of the process of evolution? o humans changing their clothing during different seasons throughout the year o A man becoming immune to a strain of virus that caused him to have a cold when he was younger o A female bird laying more eggs one season than the three previous seasons combined o A population of snowshoe hares having different frequencies of alleles at particular loci than were present in the previous generation o Trees dropping their leaves in the fall 13. Which is NOT one of the three conditions that must be met for evolution by natural selection to take place? o Difference in the phenotype affect the probability of survival or successful reproduction o Variation in phenotypic traits must exist in the population o One extreme of phenotypic distribution leads to greater survival o Differences in phenotypic traits must be at least partially heritable 14. What is phenotypic plasticity?: o The range of phenotypes exhibited by a species o The range of physical stresses a phenotype can be exposed to before it ceases to function properly o The changes in the phenotype produced by a single genotype in different environments o How well an organism with a given trait can respond to challenges presented by its environment 15. Genetic drift is never the major evolutionary force in most populations: o True, because most populations are too small for genetic drift to me the major force o False, because in small populations genetic drift can be the major force o True, because selection is always stronger than drift o False, because the Hardy-Weinberg equation states that drift doesn’t cause evolution 16. Which of the following statements about quantitative traits is NOT true? o Quantitative traits aren’t controlled by multiple genes o A single genotype can produce multiple phenotypes o The phenotype of discrete traits (controlled by a single locus) is never affected by the environment o Both the environment and genotype affect quantitative traits o The genetic basis of quantitative traits such as height can be determined by a few loci with moderately large effects and by hundreds of loci with very small effects 17. True or False: Populations must be completely separate from one another before speciation can occur. o True o False 18. True or False, for a population to obey the Hardy-Weinberg Theorem the rates of migration, drift, selection and mutation should remain zero. o True o False 19. A small group of Madagascar hissing cockroaches with a rare allele becomes geographically isolated from their main population. Over time the rare allele, which had no positive or negative effect on any individual cockroach, becomes lost in the new population. This is an example of: o Mutation o Natural selection o Migration o Emigration o Genetic drift 20. Ernst Mayr’s biological species concept while useful is problematic because: o 16% of European butterfly “species” can interbreed and produce viable hybrids but the next generation is sterile o Not all organisms reproduce sexually o European red deer and North American elk, separated for 7 million years, sometimes produce offspring in zoos o Two different “species” of monkey flowers pollinated solely by birds and bees respectively, can produce hybrids when pollinated by hand o All of the above 21. True or False, Bateson-Dobzhansky-Muller incompatibilities describe the underlying genetic mechanisms for impaired hybrid viability, fertility or performance which help to prevent gene flow between species. o True o False 22. Which factors would you consider if you want to estimate the relative fitness of a genotype? o Mating success and fecundity o Survival to reproductive age and offspring survival o Dominant and recessive alleles o 1 and 2 o All of the above 23. When we say that the genotypes at a particular locus do not differ from HardyWeinberg Equilibrium for a particular population we mean that: o That allele frequencies in the population will change from one generation to the next o That allele frequencies at a genetic locus will not change from one generation to the next o That the population is evolving due to migration, mutation and natural selection o That the population is evolving in the absence of migration, mutation and natural selection o The genotypes: A1A1 A1A2 A2A2 have the frequencies that aren’t significantly different from those predicted by HWE 24. Which of the following is NOT TRUE about the effect of genetic drift in small populations? o Allele frequencies can change drastically from one generation to the next o Genetic drift eliminates alleles more rapidly in small populations o An allele can be fixed sooner o Selection is more powerful in small populations than in large populations o Genetic drift in small populations can decrease genetic diversity 25. A new mutation arises in a large population of migratory birds. The birds with the new mutation have higher relative fitness than those without the mutation. This changes the allele frequencies at this genetic locus after a few generations. Which is the main force driving evolution in this population? o Selection o Migration o Genetic drift o Founder effect o All of the above 26. True or False? The direction and strength of natural selection do not change over time. o True o False 27. True or False: Mutations that occur in germline cells (that produce gametes) are relevant to evolution because they can be inherited in the next generation. o True o False 28. Three populations of ants became geographically isolated after the construction of a highway (m=0). Which of the following statements is FALSE? o Populations will diverge genetically because evolutionary forces will act independently in each population (M = 0) o After many generations the three differentiated populations may show premating reproductive isolation o The geographic barrier will interrupt gene flow between populations o The strength of reproductive barriers will NOT be important if populations can make contact again 29. A phenotype is: o A complex trait involving the interaction between the genotype and the environment o The physical appearance of an organism resulting from input of the environment only o A measurable characteristic such as a morphological character, developmental or physiological process or behaviour o A feature of an organism that can never change during its lifetime o 1 and 3 o 3 and 4 30. A researcher publishes a paper saying that pugs are a separate species from other breeds of dog. Using the biological species concept, what evidence would this researcher need to provide? o Their reduced snout and impaired ability to breathe differentiates them sufficiently so that the owners of most other breeds of dogs refuse to use them as studs o Pugs cannot successfully have fertile offspring with other breeds of dogs o Pugs comprise a single gene pool separate from other dog breeds o Pugs are ecologically distinct from other breeds of dog because they can successfully use resources closer to the ground that other breeds may not recognize 31. Which are the two mechanisms driving evolution due to the introduction of new variations into the population? o Migration and genetic drift o Mutation and migration o Natural selection and sexual selection o All of the above o None of the above 32. Which of the following would result in the weakest sexual selection on males? o Each female chooses one male to mate with for life o Males fight each other for access to females o Females choose males with a fancy ornament o Males compete for territories inside which multiple females build nests 33. Anisogamy is: o The reproductive capacity of an individual o Adaptations that evolve in asexual populations o Sexual reproduction involving two dissimilar gametes (differing in size or form) o A trait that often leads to the evolution of differential parental investment in offspring care o 3 and 4 are correct 34. Consider the following 4 statements: 1. Sperm competition is a form of pre-copulatory sexual selection. 2. Sperm Competition is likely to occur in species where females tend to be monogamous. 3. Sperm competition is a form of post-copulatory sexual selection. 4. Sperm Competition is likely to occur in species where females tend to be promiscuous. Which statements are correct: o 1 and 4 o 2 and 3 o 1 and 2 o 3 and 4 35. What are some reasons why an adaptive radiation by a group of organisms might occur? o The evolution of a key innovation, such as wings or seeds, which makes dispersal into new environments easier o The population size of that group of organisms shrinks, mutations accumulate, and new adaptations evolve through genetic drift o The extinction of a dominant group of organisms which opens up niches which a group of organisms can exploit o 1 and 3 o 1 and 2 PRACTICE EXAM SHORT ANSWER QUESTIONS (2 OF 4) Short Answer: Briefly answer the following questions in the space provided. Remember that longer answers are not necessarily better, and we recommend that you make an outline of your answer on the back of the previous page before starting to write. Please show details of all your calculations and label any figures or tables that you draw. Put your name and student number on all pages even the ones that you do not do. All parts of the question are worth the same amount of the total. **Note, however, that there are lots of tables requested below to help you summarize your notes but many of the Final exam short answer questions will NOT involve making a table. [10 marks] SNP data (the third codon position of a nuclear gene) from 1000 individuals on the enzyme Phosphoglucose isomerase (PGI) was collected from two populations of perch in two local rivers and also from Guelph Lake. As is usual for a SNP only two alleles were found: A1=C and A2=G. The genotype data for each population is given in the Table 1 below: Table 1: Perch genotypes: [a] Estimate the frequency of the A1 and A2 alleles (separately) for each population and write it in the last two columns. [b] Are these populations approximately in Hardy-Weinberg equilibrium? If they are not in HWE then which assumptions are likely being violated? For the Eramosa River*: Chi squared, χ2 = 21.267 with 2 degrees of freedom. The two-tailed P value 0.0001. Very highly significant! (This statistical analysis is not required for our class as many students have not yet taken statistics). *Chi square calculator at: Chi squared, χ2 = 40.000 with 2 degrees of freedom. [c] Do you think the perch are swimming between the Eramosa and Speed Rivers and Guelph Lake? Why or why not? 2) [10 marks] You are studying a population of deer mice Peromyscus maniculus in Algonquin Park. You are interested in whether there is a heritable component to body weight and to running speed for a sprint of 30 metres. You trap wild mice for two generations and estimate that for this population: Table 1. Phenotypic statistics and heritability for a deer mouse population. Narrow sense heritability from the slope of a linear regression with the average offspring value as the y value and the average value for their parents as the x value. a) Which trait has the larger phenotypic variance using its original units? b) Calculate which trait has a larger additive genetic variance using its original units. (Assume that the phenotypic variances are similar in the laboratory and in the field and that the trait has the same genetic basis in both environments). c) Your summer’s trapping data shows that there was intense selection for decreased body size (S, the selection differential is -1.271) likely because of changes in predator abundance. Use this estimate of S and the data from the Table 1 above to predict what the mean body size would be after one generation of directional selection. 3) [10 marks] You are responsible for monitoring a non-indigenous species of mollusc-eating fish that has been accidently introduced into the Great Lakes. You have found that each year the average body size of this fish population is becoming larger with a relatively deeper and more heavily muscled head region and more massive teeth. You have also observed that each year the stomachs of the larger fish contain progressively larger and thicker-shelled zebra mussels. a) Suggest a hypothesis based on the breeder’s equation quantitative genetics that explains why and how this fish population might be evolving a larger body size. b) How might the shell thickness of the zebra mussels respond to this increased jaw size by its predator? 4) [10 marks] a) Discuss how sexual selection might result in prezygotic reproductive isolation that leads to speciation. b) List all the steps that might occur. c) Give an example of a species group where sexual selection might have been the cause of speciation. d) Explain why you choose the species group that you did. 5) [10 marks] Make a table of at least four hypotheses that explain why females might choose males with particular elaborate male traits and reject other males when the males are not providing any resources or parental care. Briefly summarize the evidence that supports each hypothesis. 6) [10 marks] Make a table comparing the biological species concept, the phylogenetic species concept, and the morphological species concept. Which species concept is likely to be most useful for your favorite group of: 1) mammals, 2) alpine flowers, and 3) dinosaurs. Please give reasons behind your choice for a particular taxa. 7) [10 marks] a) Make a table describing the amount and duration of gene flow that takes place between two incipient (almost) species during the four modes of gradual speciation (as opposed to instantaneous speciation through polyploidy) that we discussed in detail. b) For each mode of speciation give an example of a species group in which this mode may have taken place. 8) [10 marks] a) Make a table summarizing the fossil, molecular and morphological evidence supporting the hypothesis that humans are just another great ape. b) Which selective pressures on our early ancestors may have resulted in our modern, highly technological society? 9) [10 marks] Which traits and environmental variables did Peter Boag and the rest of Peter and Rosemary Grant’s team need to measure or record in order to demonstrate the effect of natural selection on the beak size of finches in the Galapagos during the drought in 1977? 10) [10 marks] Make a table comparing methods used in studies on microevolution with those on macroevolution. a) List the types of data collected by scientists in each field. b) In your opinion which of the two fields has accumulated more evidence to support that the hypothesis that their definition of "evolution" has occurred? ACTUAL EXAM NOTES ~ Post MIDDY Two Definitions I think I need to know o Ecological speciation: adaptation to different host plants drives reproductive isolation o Stromatolite: layered mats of bacteria (rare) o Lagerstatten: sites with lots of well-preserved fossils o Burgess shale: is a Lagerstatten in Canada o Biomarkers: molecular evidence in fossil record (fragments of DNA, lipids, etc.) o Bacteria and Archaea: prokaryotic domains of life o Ediacaran fauna: multicellular animal species during Ediacaran period (geometrical disks) o Notochords: backbone of early chordates (flexible and rod-shaped) o Chordates: phylum of animals including vertebrates o Trilobites: marine arthropods o Tetrapods: vertebrates with 4 limbs o Synapsids: lineage of tetrapods and gave rise to mammals but are distinct because opening in skull behind eyes (temporal fenestrae) o Hominins: includes humans and closely related species (humans are the only surviving members in this group) Cambrian Camels PERIODS FOR PALEOZOIC AND MESOZOIC Ordovician Often Silurian Sit Devonian Down Carboniferous Carefully Permian Perhaps Triassic Their Jurassic Joints Cretaceous Creak Paleocene Perhaps EPOCHS FOR CENOZOIC Eocene Early Oligocene Oiling Miocene Might Pliocene Prevent Pleistocene Permanent Recent Rheumatism Paleozoic Era o Cambrian to Permian period o Trilobite fossil (has three lobes) discovered during this time o Certain species of crabs o Must shed exoskeleton o Evolution of mammals from synapsid tetrapods begins Mesozoic Era o Triassic to Cretaceous period o Mass extinction at the end of this era  increased divresification o Two pelvis types during this time o Reptile hipped (dominant in Triassic) o Example: Allosaurus Fragilis (T-rex?) o Feathers evolved during this time but before flight was actually possible o Bird hipped (dominant in Cretaceous) Example: Stegosaurus Stenops o Hole in the middle is a synapomorphy Cenozoic Era o Horse evolution (body size became larger) o Teeth evolved to become less sharp and more molar-like o Changes in feet (now more hoof-like and less toes) More definitions I think I need to know: o Gradual evolution: oldest rocks at bottom of the strata, species slowly gets legs o Punctuated evolution: large change in morphology in next strata above but in reality the transitions aren’t preserved as fossils, so the evolution seems drastic o Microevolution: small scale processes operating within populations to change allele frequencies over short timescales o Mutation o Natural selection o Genetic drift o Genetic flow o Macroevolution: large scale evolutionary patterns and processes at or above the species level over long periods of time o Speciation and extinction o Changes in biodiversity o Origin of new traits o Major events in history of life o Extrapolations: believe macroevolution is just microevolution over long periods of time (nothing more than change in allele frequencies) o Macroevolution: (usually paleontologists) argue that it’s more than just microevolution o Speciation by anagenesis: evolutionary change within one lineage (no net change in number of species) o Speciation by cladogenesis: branching of one lineage into two or more, lineages may coexist with each other) Weird facts I think I need to know: o Life present on Earth about 1 billion years after our planet’s formation o Bacteria still constitutes most of Earth’s biodiversity o Transition to multicellular photoautotrophs began at least 1.6 bya o Only a fraction of Ediacaran fauna share traits with existing animal lineages today (most are extinct) o The Cambrian Explosion: o Bilateral symmetry o Segmented body o Hard exoskeleton o Jointed legs o Paired primitively biramous appendages Phyletic Gradualism o Morphological evolution is gradual and relatively constant and involves entire populations Punctuated Equilibria o Speciation is rapid and involves branching o Species remain static (no significant anagenesis) o Morphological change usually occurs during speciation events o Small population becomes separated from the rest and co-exist with parental species o New fossils appear in fossil record because of this Extinction o Background extinction: ongoing extinction of relatively small numbers of species, roughly balanced by speciation (species usually persist 4 million years) o Mass extinction: usually 50% of species diversity is lost o The big five mass extinction events o opens up formerly occupied or otherwise unavailable niches that can be adapted by a new group of species  diversification Pre-evolutionary concepts o Scala naturae o Species immutable (unchanging overtime) o No extinction o Hierarchy with humans ranked the highest (but below god) o Lamarckism o Striving for perfection o Humans represent the most perfect form of life Post-evolutionary concepts o Improvement, perfection, progress o Industrial revolution o Less of a hierarchy, more of a branching tree o Evolutionary scale