Prairie dogs once covered the expanses of the Great Plains. Their grazing made the grass more nutritious for the huge herds of bison, and a variety of snakes, raptors, and mammals   preyed on the rodents. In fact, the black- footed ferret (now endangered) specialized in prairie dog predation. Today, growing housing and agricultural developments have covered many prairie dog towns. Which of the following statements about prairie dogs is true?

TLS Online TPP Program

#Question id: 12252

#Unit 10. Ecological Principles

In a study of interactions between plants, ants and caterpillars, the following experimental treatments were imposed: i) Control (both ants and caterpillars are present); ii) Ant removal; iii) Caterpillar removal; iv) Ant and caterpillar removal. Plus (+) indicates presence and minus (-) indicates absence on plants. The results for plant performance (growth) from this experiment  are shown in the figure below. Plant performance in all treatments were significantly different from each other. Based on these results, which of the following inferences is correct?

TLS Online TPP Program

#Question id: 12251

#Unit 10. Ecological Principles

A plant produces flowers that are open through the day and the night. An experimenter places pollen on the stigmas of freshly opened flowers and covers them after pollination to prevent natural pollinators from having access to the flowers. When experimental pollination was carried out during the day, 40% of the flowers yielded fruit. When experimental pollination was carried out during the night, 80% of the flowers yielded fruit. However, when flowers were  kept  open  to  natural  pollination  during  the  day  (covered  at  night),  35%  of  flowers  produced  fruit.  20%  of flowers exposed to natural pollination during the night (covered during the day) produced fruit. Which of the following statements is NOT a plausible explanation of these results ?

TLS Online TPP Program

#Question id: 12250

#Unit 10. Ecological Principles

Two islands, P and Q, are similar in habitat and other features. They are 100 and 200 km2 in size respectively, but have the same number of species. Which of the following statements can independently explain this observation?

(i)    P is closer to the mainland than Q

(ii)   P is further away from the mainland than Q

(iii)  P has higher speciation rates than Q

(iv) P has lower speciation rates than Q

TLS Online TPP Program

#Question id: 12249

#Unit 10. Ecological Principles

In Batesian mimicry, a harmless species mimics a harmful or toxic model species. Increasing the relative abundance of the mimic will:

TLS Online TPP Program

#Question id: 12247

#Unit 10. Ecological Principles

Which of the following is NOT a hypothesis explaining the advantage of group living? 

TLS Online TPP Program

#Question id: 12246

#Unit 10. Ecological Principles

The graphs below show that the relationship between atmospheric CO2 and mean global temperature is