The Norway rat (Rattus Norvegicus), a widespread pest, was controlled for about a decade by the anticoagulant warfarin. This chemical substance, placed in food pellets, is absorbed by the intestinal tract and inhibits the clotting of blood. After a population decline for about 10 years, rat populations increased and stabilized. In one European population, as illustrated in the graph below, the percentage of rats resistant to warfarin has remained fairly stable over a number of years

Resistance to warfarin is governed by a dominant autosomal gene, R. More than 15 percent of the resistant animals are heterozygous at this locus (Rr). The table below indicates the response to warfarin and relative reproductive fitness of individuals that are homozygous or heterozygous for the dominant gene (R). The RR individuals have a 20-fold increase in vitamin K requirement over individuals.

Fitness is a measure of the reproductive success of a particular genotype. The highest fitness is 1.00.

The strong dependence of RR individuals on large quantities of vitamin K probably is responsible for

#Question id: 9200

#Unit 9. Diversity of Life Forms

During the inventory of bacterial genes present in the Sargasso Sea, a deep isolated area in the middle of the Atlantic Ocean, a research team concluded that at least 1,800 bacterial species were present. Based on what you might predict about the habitat structure of such an area, what kind of bacterial diversity would you expect to see in tropical coral reef waters?

#Question id: 9198

#Unit 9. Diversity of Life Forms

Tropical forests are being converted to farm or pasture land at an alarming rate, and one major focus is on the biodiversity and the impact to these ecosystems. What is a direct benefit to humans that helps explain why these forests need to be preserved?

#Question id: 9196

#Unit 9. Diversity of Life Forms

If all individuals in the last remaining population of a particular frog species were all highly elated, which type of diversity would be of greatest concern when planning to prevent the species from going extinct?

#Question id: 9195

#Unit 9. Diversity of Life Forms

Philippe Bouchet and colleagues conducted a massive survey of marine molluscs on the west coast of New Caledonia. For 20% of the total species that were located and identified, only a single specimen was found. What does that suggest about the diversity of molluscs in this area?

#Question id: 9185

#Unit 9. Diversity of Life Forms

Plants are affected by an array of pathogens. Which of the following is a plant defense against disease?

#Question id: 9186

#Unit 9. Diversity of Life Forms

A pathogenic fungus invades a plant. What does the infected plant produce in response to the attack?