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.

Which of the following is most likely correct concerning the gene for resistance to warfarin? 

#Question id: 10631

#Section 2: Evolution

To estimate the number of foxes m an area, a researcher conducted a mark-recapture survey. In the fast survey, he caught and marked 90 foxes. In his second survey a week later, he caught 120 foxes of which 40 were marked (recaptures). If you are told that the actual number of foxes in this area is 400, which of the following is a plausible explanation for the anomaly in the researcher's data? 

#Question id: 10632

#Section 2: Evolution

Three different population growth pattern related to population density are shown in figure

#Question id: 10633

#Section 2: Evolution

Following some characteristic feature of r selected species

A. late maturity

B. Provision of parental care

C. High mortality during early stages of life

D. large clutch size

What is the above combination is correct?

#Question id: 10634

#Section 2: Evolution

Consider a population which is changing from one generation to the next as per the equation N(t) = R*N(t-1), where N(t) represents the size of the population at time t and R is a constant growth parameter. Under what condition is the population likely to go extinct?

#Question id: 10635

#Section 2: Evolution

Three important biological parameters – generation time, per capita growth rate (r) and clutch size are a function of the organism‟s body size. Which of the curves (a) or (b) represents the correct relation of each of the parameters to body size?

#Question id: 10636

#Section 2: Evolution

The demographic transition model depicts demographic changes from high- to low-level births and deaths in five stages

Stage 1 is characterized by total population numbers are low and the high birth rate is balanced by the high death rate.

B) Stage 2 is characterized by high population growth rate is results of high birth rate however, decline death rate

C) Stage 4 is characterized by decline in the proportion of the population in the reproductive age group and these changes stabilizes population size

D) Stage 3 is characterized by falling birth rates and death rates and population growth rate is zero due to the less numbers of people in the reproductive age group