Organisms and Populations

Secondary metabolites such as nicotine, strychnine and caffeine are produced by plants for their

1. Nutritive value
2. Growth response
3. Effect on reproduction
4. Defence action

Which of the following is not an attribute of a population?

1. Natality
2. Sex ratio
3. Mortality
4. Species interaction

Niche is

1. all the biological factors in the organism’s environment
2. the physical space where an organism lives
3. the range of temperature that the organism needs to live
4. the functional role played by the organism where it lives

Which one of the following population interactions is widely used in medical science for the production of antibiotics?

1. Commensalism
2. Mutualism
3. Parasitism
4. Amensalism

Natality refers to

1. death rate
2. birth rate
3. number of individuals leaving the habitat
4. number of individuals entering a habitat

In a growing population of a country,

1. pre-reproductive individuals are more than the reproductive individuals
2. reproductive individuals are less than the post-reproductive individuals
3. reproductive and pre-reproductive individuals are equal in number
4. pre-reproductive individuals are less than the reproductive individuals.

Asymptote in a logistic growth curve is obtained when :

1. K > N
2. The value of 'r' approaches zero
3. K < N
4. K = N

Plants which produce characteristic pneumatophores and show vivipary belong to :

1. Halophytes
2. Psammophytes
3. Hydrophytes
4. Mesophytes

Mycorrhizae are the example of :

1. Fungistasis
2. Antibiosis
3. Mutualism
4. Amensalism

It is much easier for a small animal to run uphill than for a large animal, because -

1. The efficiency of muscles in large animals is less than in the small animals
2. Smaller animals have a higher metabolic rate
3. It is easier to carry a small body weight
4. Small animals have a lower O2 requirement

When does the growth rate of a population following the logistic model equal zero? The logistic model is given as dN/dt = rN(1-N/K)

1. When death rate is greater than birth rate.
2. When N/K equals zero.
3. When N/K is exactly one.
4. When N nears the carrying capacity of the habitat.

Gause's principle of competitive exclusion states that -

1. Larger organisms exclude smaller ones through competition
2. More abundant species will exclude the less abundant species through competition
3. Competition for the same resources excludes species having different food preferences
4. No two species can occupy the same niche indefinitely for the same limiting resources

Which of the following is correct for r-selected species ?

1. Small number of progeny with small size
2. Small number of progeny with large size
3. Large number of progeny with small size
4. Large number of progeny with large size

If '+' sign is assigned to beneficial interaction, '–' sign to detrimental and '0' sign to neutral interaction, then the population interaction represented by '+' '–' refers to

1. parasitism
2. commensalism
3. mutualism
4. amensalism

The principle of competitive exclusion was stated by

1. MacArthur
2. G. F. Gause
3. Verhulst & Pearl
4. C. Darwin

In which of the following interactions both partners are adversely affected?

1. Competition
2. Predation
3. Mutualism
4. Parasitism

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.

The logistic population growth is expressed by the equation:

1. dt/dN = Nr ( K-NK )
2. dN/dt = rN ( K-NK )
3. dN/dt = rN ( N-KN )
4. dN/dt = rN

Consider the following statements (A)-(D) each with one or two blanks : (A) Bears go into (1) during winter to (2) cold weather. (B) A conical age pyramid with a broad base represents (3) human population. (C) A wasp pollinating a fig flower is an example of (4) . (D) An area with high levels of species richness is known as (5) . Which of the following options gives the correct fill ups for the respective blank numbers from (1) to (5) in the statements ?

1. (1) - aestivation, (2) - escape, (3) - stable, (4) - mutualism
2. (3) - expanding, (4) - commensalism, (5) - biodiversity park
3. (1) - hibernation, (2) - escape, (3) - expanding, (5) - hot spot
4. (3) - stable, (4) - commensalism, (5) - marsh

What type of human population is represented by the following age pyramid? [figure]

1. Declining population
2. Vanishing population
3. Expanding population
4. Stable population

Large woody vines are more commonly found in

1. Mangroves
2. Tropical rainforests
3. Alpine forests
4. Temperate forests