Organisms and Populations

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

Consider the following four conditions (a – d) and select the correct pair of them as adaptation to environment in desert lizards. The conditions : (a) burrowing in soil to escape high temperature (b) losing heat rapidly from the body during high temperature (c) bask in sun when temperature is low (d) insulating body due to thick fatty dermis

1. (c), (d)
2. (b), (d)
3. (a), (c)
4. (a), (b)

Which one of the following is categorised as a parasite in true sense?

1. The female Anopheles bites and sucks blood from humans
2. Head louse living on the human scalp as well as laying eggs on human hair
3. The cuckoo (koel) lays its eggs in crow's nest
4. Human foetus developing inside the uterus draws nourishment from the mother

Which one of the following is most appropriately defined?

1. Parasite is an organism which always lives inside the body of other organism and may kill it.
2. Host is an organism which provides food to another organism.
3. Amensalism is a relationship in which one species is benefited whereas the other is unaffected
4. Predator is an organism that catches and kills other organism for food.

The figure given below is a diagrammatic representation of response of organisms to abiotic factors. What do a, b and c represent respectively – [figure]

1. (a) partial regulator, (b) regulator, (c) conformer
2. (a) conformer, (b) regulator, (c) partial regulator
3. (a) regulator, (b) conformer, (c) partial regulator
4. (a) regulator, (b) partial regulator, (c) conformer

Study the four statements (a–d) given below and select the two correct ones out of them – (a) A lion eating a deer and a sparrow feeding on grain are ecologically similar in being consumers (b) Predator starfish Pisaster helps in maintaining species diversity of some invertebrates (c) Predators ultimately lead to the extinction of prey species (d) Production of chemicals such as nicotine, strychnine by the plants are metabolic disorders The two correct statements are –

1. b and c
2. a and d
3. c and d
4. a and b

A country with a high rate of population growth took measures to reduce it. The figure below shows age-sex pyramids of populations A and B twenty years apart. Select the correct interpretation about them : [figure]

1. "A" is more recent and shows slight reduction in the growth rate
2. "B" is more recent showing that population is very young
3. "A" is the earlier pyramid and no change has occurred in the growth rate
4. "B" is the earlier pyramid and shows stabilized growth rate