Organisms and Populations

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

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

Annual migration does not occur in the case of

1. Arctic tern
2. salmon
3. Siberian crane
4. salamander

The formula for exponential population growth is-

1. dN/dt = rN
2. dt/dN = rN
3. rN/dN = dt
4. dN/rN = dt

Praying mantis is a good example of-

1. Warning colouration
2. Camouflage
3. Mullerian mimicry
4. Social insects

Niche overlap indicates-

1. Sharing of one or more resources between the two species
2. Mutualism between two species
3. Active cooperation between two species
4. Two different parasites on the same host

More than 70% of world's fresh water is contained in –

1. Polar ice
2. Greenland
3. Antarctica
4. Glaciers and Mountains

At which latitude, heat gain through insolation approximately equals heat loss through terrestrial radiation -

1. 40 North and South
2. 42 12 North and South
3. 66 North and South
4. 22 12 North and South

Animals have the innate ability to escape from predation. Examples for the same are given below. Select the incorrect example

1. Poison fangs in snakes
2. Enlargement of body size by swallowing air in puffer fish
3. Colour change in chameleon
4. Melanism in moths

Which one of the following pairs is mismatched ?

1. Tundra - permafrost
2. Savanna - acacia trees
3. Prairie - epiphytes
4. Coniferous forest - evergreen trees

Certain characteristic demographic features of developing countries are -

1. High fertility, low or rapidly falling mortality rate, rapid population growth and a very young age distribution
2. High mortality, high density, uneven population growth and a very old age distribution
3. High fertility, high density, rapidly rising mortality rate and very young age distribution
4. High infant mortality, low fertility, uneven population growth and a very young age distribution

In which of the following pairs is the specific characteristic of a soil not correctly matched ?

1. Chernozems – Richest soil in the world
2. Laterite – Contains aluminium compound
3. Terra rossa – Most suitable for roses
4. Black soil – Rich in calcium carbonate

In which one of the following habitats does the diurnal temperature of soil surface vary most ?

1. Grassland
2. Desert
3. Shrub land
4. Forest

Two opposite forces operate in the growth and development of every population. One of them relates to the ability to reproduce at a given rate. The force opposing it is called:

1. Biotic potential
2. Environmental resistance
3. Morbidity
4. Fecundity

Mycorrhiza is an example of :-

1. Ectoparasitism
2. Decomposers
3. Endoparasitism
4. Symbiotic relationship

The growth curve of bacterial population in lab is plotted against time. What will be the shape of graph?

1. Sigmoid
2. Hyperbolic
3. Ascending straight line
4. Descending straight line

Choose the correct sequence of stages of growth curve for bacteria.

1. Lag, log, stationary, decline phase
2. Lag, log, decline, stationary phase
3. Stationary, lag, log, decline phase
4. Decline, lag, log phase, stationary

In a population, unrestricted reproductive capacity is called as -

1. Biotic potential
2. Birth rate
3. Carrying capacity
4. Fertility

Cause of mimicry is -

1. offence
2. concealment
3. defence
4. both (2) and (3)

Which type of association is found in between entomophilous flower and pollinating agent ?

1. Cooperation
2. Co-evolution
3. Mutualism
4. Commensalism