MCQ Question for Class 12 Biology Chapter 13 Organisms and Populations

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Organisms and Populations Class 12 Biology MCQs Questions with Answers

Refer below for MCQ Class 12 Biology Chapter 13 Organisms and Populations with solutions. Solve questions and compare with the answers provided below

Question. Pneumatophores occur in
(a) halophytes
(b) free-floating hydrophytes
(c) carnivorous plants
(d) submerged hydrophytes.

Question. An association of individuals of different species living in the same habitat and having functional interactions is
(a) ecosystem
(b) population
(c) ecological niche
(d) biotic community.

Question. Niche overlap indicates
(a) mutualism between two species
(b) active cooperation between two species
(c) two different parasites on the same host
(d) sharing of one or more resources between the two species.

Question. Which one of the following is not a parasitic adaptation?
(a) Development of adhesive organs
(b) Loss of digestive organs
(c) Loss of reproductive capacity
(d) Loss of unnecessary sense organs

Question. Large woody vines are more commonly found in
(a) temperate forests
(b) mangroves
(c) tropical rainforests
(d) alpine forests.

Question. Reduction in vascular tissue, mechanical tissue and cuticle is characteristic of
(a) mesophytes
(b) epiphytes
(c) hydrophytes
(d) xerophytes.

Question. Niche overlap indicates
(a) mutualism between two species
(b) active cooperation between two species
(c) two different parasites on the same host
(d) sharing of one or more resources between the two species.

Question. Praying mantis is a good example of
(a) camouflage
(b) mullerian mimicry
(c) warning colouration
(d) social insects.

Question. Animals have the innate ability to escape from predation. Examples for the same are given below. Select the incorrect example.
(a) Colour change in Chamaeleon
(b) Enlargement of body size by swallowing air in puffer fish
(c) Poison fangs in snakes
(d) Melanism in moths

Question. In which one of the following habitats does the diurnal temperature of soil surface vary most?
(a) Shrub land
(b) Forest
(c) Desert
(d) Grassland

Question. In Urn shaped age pyramid of the population the trend of growth is
(a) Rapid
(b) Stable
(c) Declining
(d) Stationary

Question. Plants such as Prosopis, Acacia and Capparis represent examples of tropical
(a) deciduous forests
(b) evergreen forests
(c) grasslands
(d) thorn forests.

Question. Which of the following communities is more vulnerable to invasion by outside animals and plants?
(a) Temperate forests
(b) Oceanic island communities
(c) Mangroves
(d) Tropical evergreen forests

Question. The sum total of the populations of the same kind of organisms constitute
(a) colony
(b) genus
(c) community
(d) species.

Question. Homeostasis is
(a) tendency of biological systems to change with change in environment
(b) tendency of biological systems to resist change
(c) disturbance of self regulatory system and natural controls
(d) biotic materials used in homeopathic medicines

Question. A population of 500 that experiences 55 births and 5 deaths during a one-year period. What is the reproductive rate for the population during the one-year period ?
(a) 0.01/year
(b) 0.05/year
(c) 0.1/year
(d) 50/year

Question. Carnivorous animals lions and leopards, occupy the same niche but lions predate mostly larger animals and leopards take smaller ones. This mechanism of competition is referred to as
(a) character displacement
(b) altruism
(c) resource partitioning
(d) competitive exclusion.

Question. Which one of the following plants shows a very close relationship with a species of moth, where none of the two can complete its life cycle without the other?
(a) Hydrilla
(b) Yucca
(c) Banana
(d) Viola

Question. Mycorrhizae are the example of
(a) amensalism
(b) antibiosis
(c) mutualism
(d) fungistasis.

Question. Obligate parasites live on
(a) living host only
(b) living host and dead organic matter
(c) dead organic matter only
(d) artificial liquid medium

Question. 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)
(a) when N/K equals zero
(b) when death rate is greater than birth rate
(c) when N/K is exactly one
(d) when N nears the carrying capacity of the habitat.

Question. In which of the following interactions both partnersare adversely affected?
(a) Parasitism
(b) Mutualism
(c) Competition
(d) Predation

Question. Besides paddy fields, cyanobacteria are also found inside vegetative part of
(a) Equisetum
(b) Psilotum
(c) Pinus
(d) Cycas.

Question. The maintenance of internal favourable conditions, by a self regulated mechanisms inspite of the fact that there are changes in environment, is known as
(a) entropy
(b) enthalpy
(c) homoeostasis
(d) steady state

Question. The age pyramid with broad base indicates
(a) high percentage of old individuals
(b) low percentage of young individuals
(c) a stable population
(d) high percentage of young individuals.

Question. Which one of the following is categorised as a parasite in true sense?
(a) The female Anopheles bites and sucks blood from humans.
(b) Human fetus developing inside the uterus draws nourishment from the mother.
(c) Head louse living on the human scalp as well as laying eggs on human hair.
(d) The cuckoo (koel) lays its eggs in crow’s nest.

Question. The rate of formation of new organic matter by rabbit in a grassland, is called
(a) Net productivity
(b) Secondary productivity
(c) Net primary productivity
(d) Gross primary productivity

Question. Geometric representation of age structure is a characteristic of
(a) population
(b) landscape
(c) ecosystem
(d) biotic community.

Question. Certain characteristic demographic features of developing countries are
(a) high fertility, low or rapidly falling mortality rate, rapid population growth and a very young age distribution
(b) high fertility, high density, rapidly rising mortality rate and a very young age distribution
(c) high infant mortality, low fertility, uneven population growth and a very young age distribution
(d) high mortality, high density, uneven population growth and a very old age distribution.

Question. Which one of the following is a matching pair of certain organism(s) and the kind of association?
(a) Shark and sucker fish – Commensalism
(b) Algae and fungi in lichens – Mutualism
(c) Orchids growing on trees – Parasitism
(d) Cuscuta (dodder) growing on other -flowering plants – Epiphytism

Question. Mycorrhiza is an example of
(a) symbiotic relationship
(b) ectoparasitism
(c) endoparasitism
(d) decomposers.

Question. Which type of association is found in between entomophilous flower and pollinating agent?
(a) Mutualism
(b) Commensalism
(c) Co-operation
(d) Co-evolution

Question. In which of the following plant sunken stomata are found?
(a) Nerium
(b) Hydrilla
(c) Mango
(d) Guava

Question. Keystone species deserve protection because these
(a) are capable of surviving in harsh environmental conditions.
(b) indicate presence of certain minerals in thesoil.
(c) have become rare due to overexploitation.
(d) play an important role in supporting other species.

Question. Mycorrhiza exhibits the phenomenon of
(a) parasitism
(b) symbiosis
(c) antagonism
(d) endemism.

Question. Which one is true?
(a) Commensalism when none of the interacting populations affect each other.
(b) Symbiosis when the interaction is useful to both the populations.
(c) Symbiosis when neither populations affects each other.
(d) Commensalism when the interaction is useful to both the populations.

Question. Competition for light, nutrients and space is most severe between
(a) closely related organism growing in different niche
(b) closely related organisms growing in the same area/niche
(c) distantly related organisms growing in the same habitat
(d) distantly related organisms growing in different niches.

Question. Within biological communities, some species are important in determining the ability of a large number of other species to persist in the community. Such species are called
(a) keystone species
(b) allopatric species
(c) sympatric species
(d) threatened species

Directions : In the following questions a statement of Assertion (A) is followed by a statement of reason (R). Mark the correct choice as :
(A) Both Assertion (A) and reason (R) are true and reason (R) is the correct explanation of Assertion (A).
(B) Both Assertion (A) and reason (R) are true but reason (R) is not the correct explanation of Assertion (A).
(C) Assertion (A) is true but reason (R) is false.
(D) Assertion (A) is false but reason (R) is true.

Question. Assertion (A) : Some organisms like Salmon are known as Euryhaline.
Reason (R) : Euryhalines can tolerate a wide range of salinities.
Answer : (A)

Read the following text and answer the following questions on the basis of the same :
Population is a group of individuals of a single species living in a given area. It includes spatial arrangement, genetic variation and the dynamics including natality, mortality, biotic potential, carrying capacity, etc. Population structure includes features such as density, abundance, spacing,genetic variations. The genetic structure reveals genetic variations and population size.

Question. ______ is the study of the ecology of population.
(A) Autecology
(B) Demecology
(C) Endaphology
(D) None of the above
Answer : (B)

Question. ______ species inhabit different geographical areas. 1
(A) Sympatic
(B) Allopatric
(C) Both (A) and (B)
(D) None of these
Answer : (B)

Question. Increase in population does not increase in :
(A) Health facilities
(B) Employment
(C) Food resources
(D) All of the above
Answer : (D)

Question. Which Indian state has the least population growth?
(A) Kerala
(B) U.P.
(C) A.P.
(D) Assam.
Answer : (A)

Question. There is more competition for survival between :
(A) Different animals of same niche.
(B) Same animals of same niche.
(C) Different animals of different niche.
(D) Same animals of different niche.
Answer : (B)

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