Ecology (Test 1) 4. The following is a food web for a meadow habitat that occupies 26.2km2. The primary producers’ biomass is uniformly distributed throughout the habitat and totals 1,500 kg/km2. Developers have approved a project that will permanently reduce the primary producers’ biomass by 50% and remove all rabbits and deer. Which of the following is the most likely result at the completion of the project?

The biomass of the coyotes will be 6kg, and the biomass of the hawks will be 0.5kg. The biomass of coyotes will be dramatically reduced. The coyotes will switch prey preferences and outcompete the hawks. There will be 50% fewer voles and 90% fewer hawks.

Ecology (Test 1) 6. The diagram below shows the progression of ecological events after a fire in a particular ecosystem. Based on the diagram, which of the following best explains why the oak trees are later replaced by other trees?

Eventually the other trees grow taller than the oak trees and form a dense canopy that shades the understory. Oak trees alter the pH of the soil, making the forest better suited for shrubs and other trees. Roots of shrubs proliferate in the soil of the forest ad prevent the oak trees from obtaining water. Oak trees succumb to the environmental pollutants more readily than do either the shrubs or the other trees.

Ecology (Test 1) In a hypothetical population of beetles, there is a wide variety of color, matching the range of coloration of the tree trunks on which the beetles hide from predators. The graphs below illustrate four possible changes to the beetle population as a result of a change in the environment due to pollution that darkened the tree trunks. Which of the following includes the most likely change in the coloration of the beetle population after pollution and a correct rationale for the change?

The coloration range shifted toward more light-colored beetles, as in diagram I. The pollution helped the predators find the darkened tree trunks. The coloration in the population split into 2 extremes, as in diagram II. Both the lighter-colored and the darker-colored beetles were able to hide on the darker tree trunks. The coloration range became narrower, as in diagram III. The predators selected beetles at the color extremes. The coloration in the population shifted toward more darker-colored beetles, as in diagram IV. The lighter-colored beetles were found more easily by the predators than were the darker colored beetles.

Ecology (Test 1) 40.Figure 1 shows the growth of an algal species in a flask of sterilized pond water. If phosphate is added as indicated, the growth curve changes as shown in Figure II. Which of the following is the best prediction of the algal growth if nitrate is added instead of phosphate?

Ecology (Test 2) 11. Innate behaviors are genetically motivated behaviors. Which of these is an innate behavior? Altruism Migration Imprinting Operant conditioning

12. Which statement best describes pheromones? Ecology (Test 2) 12. Which statement best describes pheromones? Pheromones are chemicals emitted by an organism that communicates information to other organisms in the immediate area. Pheromones are proteins that interact with sensory receptors in the nose and mouth to elicit the desired response. Pheromones are proteins emitted by an organism that communicate information to other organisms in the area. Pheromones are fast acting chemicals, often carried by water that can affect the thoughts and responses of another organism.

Ecology (Test 2) 13. Scouting bee behavior is important for the survival of the entire hive and is an example of: cooperative behavior altruistic behavior commensalism mutualism

Fixed action patterns in fish Dominance hierarchies Ecology (Test 2) 16. Organisms respond to changes in their environment through behavioral and physiological mechanisms. Which of the following is an example of this type of response? Fixed action patterns in fish Dominance hierarchies Shivering and sweating in humans Imprinting

Ecology (Test 2) The world’s longest predator/prey study has been ongoing on Isle Royale in Lake Superior. Isle Royale is one of our nation’s beautiful National Parks. The world’s largest freshwater lake has secluded the moose and wolf on this island, and the study of their interactions and interdependence has been ongoing since 1959. as a result of this study of predators and their prey, and enormous amount of data has been gathered and the populations of moose have been studied at depth. With a moose population that has reached a maximum of 2422 animals and a minimum of 385 animals and a wolf population that has reached a maximum of 50 animals and a minimum of 12 animals, there has been much speculation about how the populations react to each other.

20. Some of the most recent data shoes a wolf population of 21 animals (larger than average) and the moose population of 385 animals (smaller than average). Which of the following is an approximate prediction of the immediate future populations of these animals? The wolf and moose populations will neither increase nor decrease because of the effects of climate change on this isolated ecosystem. The wolf population will decrease because of the lack of prey while the moose population will grow because of the increasing lack of predators. The wolf population will decrease because of the availability of prey while the moose population will decrease because of the increase of predators. Both the moose and wolf populations will increase because of the interdependence in this isolated ecosystem.

21. During the mid 1970’s the population of moose on Isle Royale dropped from 1500 to 850, and the population of wolves dropped from 40 to 14. Which of the following might be a factor in this significant depression of populations? Natural deviations in population size caused by factors such as overpredation. Decreased winter temperatures due to climate changes. Human impact such as a forest fire depleting an essential food source from the moose population causing starvation of both species. Genetic mutations in both populations due to these small populations being “trapped” on this island and exhibiting the founder effect.

22. The wolf population on Isle Royale has bloomed from a small group of wolves that crossed an ice bridge during the winter of 1950. Without the addition of more wolves to this ecosystem the population has grown and shrunk several times. What problem may the wolf population face in this very isolated ecosystem? Inbreeding will result in allelic frequencies that encourage potentially harmful diseases. A new species of wolf may develop due to the geographic barriers presented to this population. The lack of gene flow due to isolation may change allelic frequencies compared to the general population. The population may be unable to respond to changes in the environment because of the lack of genetic diversity in the population.