Problem 1: Which of the following is REQUIRED for the process of evolution by natural selection to occur?
Problem 2: DDT is an insecticide that was used extensively in the mid-1900s to kill mosquitoes. It was very effective at first, but after a few decades DDT became less effective at killing mosquitoes because many populations had evolved resistance to DDT.
Problem 3: Which of the following conditions would biologists say was required for the evolution of DDT resistance in a population?
Problem 4: While webbed feet were evolving in ancestral ducks, with each generation:
Problem 5: Consider the following hypothetical scenario: An ancestral species of duck had a varied diet that included aquatic plants and terrestrial plants and insects. These ducks spent time on both land and water. Individuals of this species varied in the amount of webbing in their feet, with some individuals having more webbing and some having less. As many years went by, the environment changed such that the aquatic food sources were much more plentiful than those on land. Many generations later, almost all ducks had more webbing on their feet. How is this best explained?
Problem 6: 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.