Q3. If mutations arise that affect shell thickness within a sn… Show more Some of these are hard to understand. Q3. If mutations arise that affect shell thickness within a snail population, then with crabs present, those mutations: Will result in offspring having thicker shells than their parents. Will result in offspring having thicker or thinner shells than their parents. Will happen because the parents choose to give them to their offspring. Will help protect the snails with mutations against crab predation. Q4. The 14 species of finches on the Galapagos Islands evolved from a single species that migrated to the islands several million years ago. Different finch species live on different islands. A major difference among finch species is in their beaks: both size and shape vary greatly. Within a population of one of these finch species, what are the primary changes that occur gradually over time? The traits of each finch within a population gradually change. The proportions of finches having different traits within a population change. Useful traits acquired by finches during their lifetimes are passed on to offspring. Mutations occur to meet the needs of the finches as the environment changes. Q5. Could individuals of a species look different today than individuals of the same species did many generations ago? Why or why not? Yes, all individuals can change a little and pass those changes on to their offspring. Yes, some individuals can change a little and pass those changes on to their offspring. Yes, some individuals with certain traits are more likely to survive and pass those traits on to their offspring. No, species do not change even after many generations, so individuals of the same species would not look different. Q6. Which of the following is REQUIRED for the process of evolution by natural selection to occur? Numerous species in the same region must have recently become extinct. A food source must disappear. There must be a sudden environmental change. Traits must be inherited from one generation to the next. Q7. A number of mosquito populations are today resistant to DDT, even though those species were not resistant to DDT when it was first introduced. Biologists would explain that DDT resistance evolved in mosquitos because: A few mosquitos were probably resistant to DDT before it was ever used. Mosquitos learned to adapt to their environment. Mosquitos needed to be resistant to DDT in order to survive. Individual mosquitos built up an immunity to DDT after being exposed to it. Use the following passage to answer the next two questions. Read the passage and then the statements that follow. For each question, select the best answer. Ducks are aquatic birds. Their feet are webbed and this trait makes them fast swimmers. Biologists believe that ducks evolved from land birds, which did not have webbed feet. Q8. The trait of webbed feet in ducks: (a) Appeared in ancestral ducks because they lived in water and needed webbed feet to swim. (b) Appeared in ducks because of a chance mutation. Only the top statement is correct. Only the bottom statement is correct. Both statements are correct. Neither statement is correct. Q9. While webbed feet were evolving in ancestral ducks: (a) With each generation, most ducks had about the same amount of webbing on their feet as their parents. (b) With each generation, most ducks had a tiny bit more webbing on their feet than their parents. Only the top statement is correct. Only the bottom statement is correct. Both statements are correct. Neither statement is correct. Use the following passage and graphs to answer the last question. Horned lizards use their horns to defend against predatory birds. A researcher observed that lizards living in areas with predatory birds have longer horns than those in areas with no predatory birds. This observation led her to hypothesize that longer horns offer more protection against predation than do shorter horns. To test this hypothesis, the researcher tagged 20 lizards with long horns and 20 lizards with short horns in each of two locations: Desert Valley, where there are no predatory birds, and Cactus Corner, where there are predatory birds. She returned every week for 12 weeks to measure survival of tagged lizards. The graphs below represent her findings. Lizard graphs Q10. What can you conclude from the researcher’s results? The hypothesis that longer horns offer greater protection against predation is supported. The hypothesis that longer horns offer greater protection against predation is NOT supported. The experiment is well designed, but the data is inconclusive about the hypothesis. The experiment is not well designed to test the hypothesis. • Show less