1) Wild Soay sheep live in a cold environment on a small Scottish island. The sheep used to be large because they gained extra weight during the summers in order to survive the harsh winters. A recent change in the island’s climate has caused grass to be available for a longer period each year, so survival conditions for the sheep have become less challenging. Researchers who study these sheep have most likely observed a decrease in the wild Soay’s - a) size b) life expectancy c) reproduction rates d) body temperature 2) When Charles Darwin visited the Galápagos Islands in the 1800s, he observed many types of organisms that were similar but lived on different islands. The four species of mockingbirds found on the Galápagos Islands are shown below. Each species lives on a different island. These species are very similar, but the Hood mockingbird has a longer beak than the other three species. Which of the following best explains this difference? a) The Hood mockingbird needs a longer beak for defense against predators. b) The Hood mockingbird’s longer beak is an adaptation to the food available in the bird’s habitat. c) The Hood mockingbird originated from a different type of bird than the other species. d) The Hood mockingbird’s beak stretched to reach its food, and the longer beak was passed down to its offspring. 3) Before the Industrial Revolution in England, the peppered moth was commonly found on tree trunks that had light-colored lichen on the bark. Most of the peppered moths were a light gray-brown color similar to that of the lichen. A few of the moths had a mutation that made them a dark gray-brown color. During the Industrial Revolution, coal-burning factories produced black soot that covered the trees and killed the lichen in and near cities. In these areas the number of dark peppered moths increased, while the number of light peppered moths decreased. What contributed to this change? a) The soot-covered trees camouflaged the dark moths b) Bird populations increased in the areas near the factories. c) The dark moths preyed on the light moths. d) The dark moths laid fewer eggs than the light moths. 4) DDT is a pesticide that was once widely used to control agricultural pests and mosquitoes. However, this pesticide caused the eggshells of certain birds, including the brown pelican, to become fragile and thin. The adults would then accidentally crush the eggs while trying to incubate them. What happened to the brown pelican populations as a result of DDT use by humans? a) The populations increased much more slowly. b) The populations remained stable over time. c) The populations decreased as fewer eggs survived long enough to hatch. d) The populations increased as pelicans laid more eggs so that more offspring would survive. 5) Which of the following is most likely to cause a change in the genetic traits in an isolated population of a ground-dwelling lizard species? a) The exposure of an individual lizard in the population to radiation that causes a mutation that is not passed on to its offspring b) The introduction of an invasive species that preys on the brightest colored individuals in the lizard population c) An unusually dry summer in the lizard population’s ecosystem d) A fast-moving wildfire that burns the canopy of the trees in the lizard population’s ecosystem

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