Organisms and Populations

The following graph depicts changes in two populations (A and B) of herbivores in a grassy field. A possible reason for these changes is that: [figure]

1. Population B competed more successfully for food than population A
2. Population A consumed the members of population B
3. Both plant populations in this habitat decreased
4. Population A produced more offspring than population B

Most animals are tree dwellers in a:

1. temperate deciduous forest
2. tropical rain forest
3. coniferous forest
4. thorn woodland

Just as a person moving from Delhi to Shimla to escape the heat for the duration of hot summer, thousands of migratory birds from Siberia and other extremely cold northern regions move to:

1. Keoladeo National Park
2. Meghalaya
3. Corbett National Park
4. Western Ghat

A sedentary sea anemone gets attached to the shell lining of hermit crab. The association is :

1. Commensalism
2. Amensalism
3. Ectoparasitism
4. Symbiosis

A biologist studied the population of rats in a barn. He found that the average natality was 250, average mortality 240, immigration 20 and emigration 30. The net increase in population is :

1. 15
2. 05
3. 10
4. zero

The age pyramid with broad base indicates :

1. high percentage of young individuals
2. high percentage of old individuals
3. a stable population
4. low percentage of young individuals

Which one of the following is not a parasitic adaptation ?

1. Loss of digestive organs
2. Loss of unnecessary sense organs
3. Development of adhesive organs
4. Loss of reproductive capacity

Benthic organisms are affected most by :

1. Surface turbulence of water
2. Water-holding capacity of soil
3. Light reaching the forest floor
4. Sediment characteristics of aquatic ecosystems

Cuscuta is an example of :

1. Ectoparasitism
2. Predation
3. Endoparasitism
4. Brood parasitism

People who have migrated from the plains to an area adjoining Rohtang Pass about six months back

1. have more RBCs and their haemoglobin has a lower binding affinity to O2
2. are not physically fit to play games like football
3. suffer from altitude sickness with symptoms like nausea, fatigue, etc.
4. have the usual RBC count but their haemoglobin has very high binding affinity to O2.