BIOL 114/BIO114 Exam 2 Review | Complete Questions and Answers | Updated Fall 2025/26.

BIOL 114 Exam 2 Review Section: Circle the letter of the correct answer for each question. 1) If a population is in Hardy-Weinberg equilibrium and has 64% of its members exhibiting the dominant phenotype, what is the frequency of the dominant allele in this population? A) 0.8 B) 0.64 C) 0.6 D) 0.4 E) 0.36 2) Which of the following statements best explains the purpose of the Hardy-Weinberg model in population genetics? A) It describes the process of natural selection in a population. B) It predicts the rate of mutation in a gene pool over time. C) It measures the impact of environmental changes on gene flow. D) It explains how genetic drift influences allele frequencies. E) It provides the conditions under which allele frequencies remain constant in a population. 3) A research team observes that over several generations, the allele frequencies in a fish population are changing, even though no new mutations have occurred and there is no migration. Based on this information, which of the following would be the most reasonable explanation for why the population is not in Hardy-Weinberg equilibrium? A) Genetic drift is occurring due to the small population size. B) The population is experiencing natural selection favoring one allele. C) Random mating is occurring, but the population size is large. D) A non-random pattern of mutation is increasing genetic diversity. E) Environmental changes are causing mutations that favor survival. 4) Which of the following statements about inbreeding is most accurate? A) Inbreeding increases the number of homozygous dominant individuals in the population, but not the number of homozygous recessive individuals. B) Inbreeding depression is when the number of homozygous genotypes decreases in a population. C) Inbreeding causes a decrease in heterozygosity because heterozygotes lose half of their offspring to homozygosity. D) Inbreeding occurs when homozygous dominant individuals mate with homozygous recessive individuals. E) Inbreeding increases fitness, since the genotype of the offspring is similar to both parents. 5) You are tasked with designing a conservation plan for a critically endangered animal species. Based on the Hardy- Weinberg model, which of the following strategies would best help you ensure that the genetic diversity of the population is maintained over time? A) Selectively breed individuals with the most desirable traits to increase their frequencies in the population. B) Introduce a small number of individuals from a genetically similar population to increase allele variation. C) Allow natural selection to eliminate weaker individuals, ensuring that only the strongest genes persist. D) Isolate the population from all other populations to prevent gene flow. (Maybe) E) Allow random mating and protect the population from selective pressures, even if the population size is small. 6) A population of plants living in one field flowers from May to July. Each individual plant, however, only flowers once during this time. Those that are in flower are pollinated by only those that are also flowering at the same time. Therefore, although we consider all of the individuals to be part of the same population, they are not all interbreeding. Which of the following statements about this scenario is most accurate? A) The reproduction of flowers in this example is considered a form of assortative mating. B) If the population is small enough we can consider this to be an example of a population in Hardy-Weinberg equilibrium. C) The flowers are exhibiting sexual selection. D) This is an example of inbreeding depression. E) Sexual dimorphism must exist in this population in order for it to persist over generations. 7) Two groups of birds are active at different times of day: one in daylight and one in darkness. When one group is performing courtship displays and mating, the other is resting. Assuming there is no overlap in active times for the two groups, which of the following is true? A) This is an example of a temporal prezygotic isolation mechanism. B) This is an example of an abiotic postzygotic isolation mechanism. C) This is an example of a hybrid viability isolation mechanism. D) This is an example of a mechanical postzygotic isolation mechanism. E) This is an example of a behavioral postzygotic isolation mechanism. 8) Which of the following is the correct way to write the scientific name of the white-tailed deer in English text? A) White-tailed deer. B) Odocoileus virginianus. C) Odocoileus Virginianus. D) odocoileus virginianus. E) odocoileus virginianus. #1 #2 #3 #4 9) Regarding the tree above, if traits d and e are the same, which of the following must be true? A) Species #2 and #4 are more closely related to each other than either is to #3. B) Species #2 and #4 have the trait d/e as a homology. C) The common ancestor to species #2 and #4 must also have the trait d/e. D) Species #2 and #4 do not have trait b in common. E) Species #2 and #4 have the trait d/e as a homoplasy. 10) Imagine a fossil record showing a species of marine mollusks with little morphological change over millions of years, followed by the sudden appearance of several distinct but related species. How would this fossil evidence best be explained by proponents of punctuated equilibrium, and how does this explanation contrast with that of phyletic gradualism? A) Punctuated equilibrium would explain the gaps as evidence of mass extinction events, while phyletic gradualism would argue that these species diverged slowly but left no fossils during transitional periods. B) Punctuated equilibrium argues that species evolved gradually, but fossilization occurred more frequently during periods of stasis, whereas phyletic gradualism claims that gaps in the record result from species evolving during catastrophic events. C) Punctuated equilibrium suggests that the fossil gaps represent a period of rapid evolution, while phyletic gradualism would interpret the gaps as incomplete fossil records that obscure slow, continuous change. D) Punctuated equilibrium would attribute the sudden appearance of new species to a long-term accumulation of mutations, while phyletic gradualism would claim that species evolved in response to slow changes in environmental pressures over time. E) Punctuated equilibrium would suggest that evolution occurred continuously but was only recorded during rapid speciation events, while phyletic gradualism would explain the fossil gaps as the result of rapid environmental changes. 11) Which of the following is evidence that competition was a driving force in the evolution of plants moving onto land? A) Some plants evolved to have smaller and smaller cells to take advantage the limited spaces available. B) Some plants evolved a loss of their cellulose, which is not needed on land. C) Some plants evolved to grow extensions above the water to gather CO2 from the air above. D) Some plants evolved lignin to better move fluids around inside their body. E) Two of the above are correct. 12) According to the endosymbiosis theory, chloroplasts in modern plant cells originated from ancient free-living photosynthetic bacteria. Which of the following experimental observations would best support this theory? A) Chloroplasts are surrounded by a double membrane, similar to the membranes found in other eukaryotic organelles. B) Chloroplasts are able to produce energy through photosynthesis, just like modern-day plants. C) Chloroplasts contain their own DNA, which is similar in structure to bacterial DNA. D) Chloroplasts divide and replicate through binary fission, a process commonly found in all eukaryotic cells. E) Chloroplasts have enzymes that function under similar environmental conditions as those in plant cells. 13) Which phylum includes non-vascular plants? A) Bryophyta. B) Pteridophyta. C) Coniferophyta. D) Ginkgophyta. E) Anthophyta. 14) What kind of shoot design describes the tree above? A) Dendritic. B) Bifurcated. C) Axial. D) Adventitious. E) Buttressed. 15) F D E A Which of the following is most accurate about the picture above? A) If an axial bud appears at A the whole structure D is a simple leaf. B) Each structure like C and G are leaves if B and F are axillary buds. C) In order for D to be a leaflet there must be an axillary bud at A. D) This is an example of a doubly compound leaf. E) In order for C and G to be leaves there must be an axillary bud at A. 16) Imagine you are a plant cell living in the leaves of your plant, doing your job. You decide to attend your 10-year reunion, and you get back together with all of the other cells you were created with and share the stories of your life in the plant. You tell them that you are part of the cells where photosynthesis takes place. One of the other cells, that you have never been fond of, says, “Oh, you’re ground tissue." Obviously you’re offended because he spoke to you. Assuming you told the truth about your job, which of the following is the most appropriate response? A) “No, sir. I am vascular tissue, and you smell of root hair!” B) “Well, yes, but I prefer sclerenchyma. And where is your wife? With the trichomes again?” C) “Heavens, no! I am cambium tissue, and your Casparian strip is showing!” D) “Perhaps, yes, but I find parenchyma much more appealing. I hear your children are tubers.” E) “Oh, no no no. You’re thinking of my neighbors. I’m a plasmodesma. Are you using mucigel in your hair?” 17) A B C D E Given the picture of a leaf cross section above, which of the following is most accurate? A) The process of phloem loading takes place from B to E. B) Most of the process of photosynthesis takes place in A. C) Cells in C are mostly sclerenchyma. D) Evapotranspiration takes place from A to B to C. E) The cells at A are spongy mesophyll. I H A B C J K The following 3 questions refer to this diagram of phloem loading. 18) What is the structure labeled E? A) Spongy mesophyll. B) Phloem tube cell. C) Cortex. D) Companion cell. E) Xylem. 19) Which of the following letter combinations represents the flow of carbohydrate in the diagram? A) I to A to J. B) H to C to D to E. C) G to F to E to D. D) E to D to C to H. E) A to B to C. 20) At which letter is diffusion taking place? A) D B) K C) C D) F E) J 21) Which of the following is an example of a macronutrient for most plants? A) Nitrogen. B) Hydrogen. C) Phosphorus. D) Two of the above are correct. E) A, B, and C are correct. 22) Which of the following is correct regarding the phylum Porifera? A) They are the direct ancestors of the Radiates. B) They are asymmetrical. C) They are protostomes. D) Two of the above are correct. E) A, B, and C are correct. 23) Which of the following is a benefit of being a pseudocoelomate over a eucoelomate? A) Less friction between your organs and body wall as you move. B) Protection from pathogens from entering the coelom from a wound. C) Direct diffusion of nutrients from fluids to organs. D) A more advanced development in cephalization. E) Organs are covered with a thin, protective membrane. 24) Which of the following statements about the evolution of animals is accurate? A) Animals showing asymmetry have a significant amount of cephalization. B) Echinodermata develop such that their blastopore becomes the anus of the individual. C) Diplobasts are pseudocoelomates and triploblasts are eucoelomates. D) Lophotrochozoans show growth via repeated shedding of the exoskeleton. E) The coelom referred to in a pseudocoelomate is the digestive tract. 25) The Cnidaria include which of the following? A) Anemones. B) Nematodes. C) Squids. D) Butterflies. E) Sea stars. 26) Who are the closest living relatives of the Animalia? A) Porifera. B) Archaea. C) Bacteria. D) Cyanobacteria. E) Choanoflagellates.