Organisms and Populations

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

Reduction in vascular tissue, mechanical tissue and cuticle is characteristic of :

1. Xerophytes
2. Epiphytes
3. Hydrophytes
4. Mesophytes

Consider the following four statements (i)–(iv) about certain desert animals such as kangaroo-rat. (i) They have dark colour and high rate of reproduction and excrete solid urine (ii) They do not drink water, breathe at a slow rate to conserve water and have their body covered with thick hairs (iii) They feed on dry seeds and do not require drinking water (iv) They excrete very concentrated urine and do not use water to regulate body temperature Out of these four, which two are correct?

1. (i) and (ii)
2. (ii) and (iii)
3. (iii) and (i)
4. (iii) and (iv)

Quercus species are the dominant component in:

1. Temperate deciduous forests
2. Alpine forests
3. Scrub forests
4. Tropical rain forests

Geometric representation of age structure is a characteristic of :-

1. Biotic community
2. Landscape
3. Ecosystem
4. Population

The population of an insect species shows an explosive increase in numbers during rainy season followed by its disappearance at the end of the season. What does this show ?

1. The food plants mature and die at the end of the rainy season
2. The population of its predators increases enormously
3. Its population growth curve is of J-type
4. S-shaped or sigmoid growth of this insect

A high density of elephant population in an area can result in :-

1. Mutualism
2. Interspecific competition
3. Predation on one another
4. Intraspecific competition