CBSE Questions for Class 12 Medical Biology Organisms And Population Quiz 10 - MCQExams.com

Consider the following statements.
Biological control through antagonism involves.
a. Amensalism
b. Competition
c. Parasitism
d. Predation
Which of the statements given are correct?
  • $$1$$ and $$2$$ only
  • $$2, 3$$ and $$4$$ only
  • $$1, 3$$ and $$4$$ only
  • $$1, 2, 3$$ and $$4$$
Which one of the following statements correctly defines the term biomass in forestry?
  • The dry weight of the crop when it has attained the maximum growth
  • The dry weight of the crop when it has attained the maximum height
  • The dry weight of the crop when the spread of its canopy is maximum
  • The dry weight of the standing crop at any moment of time
Match List-I with List-II and select the correct answer.
List-IList-II
a. Total root parasite$$1$$. Santalum
b. Total saprophyte$$2$$. Cuscuta
c. Total stem parasite$$3$$. Monotropa
d. Partial root parasite$$4$$. Rafflesia
  • A-$$4$$, B-$$2$$, C-$$3$$, D-$$1$$
  • A-$$4$$, B-$$3$$, C-$$2$$, D-$$1$$
  • A-$$2$$, B-$$3$$, C-$$1$$, D-$$4$$
  • A-$$2$$, B-$$4$$, C-$$3$$, D-$$1$$
Which type of organism, live in the body of termites, and digest wood cellulose converting it to soluble carbohydrates?
  • Algae
  • Fungi
  • Protozoa
  • Nemtoda
Which of the following is not a factor that would limit the growth of a population?
  • Food shortage
  • Immigration
  • Disease
  • Famine
A white footed mouse 'Peromyscus leucopus', a common rodent of South America can maintain core body temperature near $$37^{\circ}C$$ even if the air temperature is below $$0^{\circ}C$$. This capacity gradually increases from birth to adulthood. Which graph correctly depicts ability of isolated individual animals to thermoregulate during their development stages?
Note: Y axis depicts the temperature at which the animal can thermoregulate.
Interaction between, two species in which one feeds on the other is 
  • competition
  • a community
  • an ecosystem
  • predation
In large natural ecosystems, competition between two species over time will usually result in
  • Each species occupying a slightly different niche
  • Equal numbers of each species persisting for a long time
  • Death of all the members of one species within a short time
  • Hybridization between the two species, resulting in a third species
In commensalism interspecific relationship
  • neither species affects the, other
  • favourable to both species
  • favourable to one but no affect on other
  • adverse effect on both species
In a population interaction between the species X and the species Y, which one of the following statements is correct?
  • When X benefits and Y is disadvantaged, it is Competition
  • When both X and Y benefit, it is Mutualism
  • When both X and Y are disadvantaged, it is Predation
  • When both X and Y are disadvantaged, it is Parasitism
Which of the following statements is not true about parasitism ?
  • The host is generally larger than the parasite.
  • An efficient parasite usually kills its host.
  • Smaller parasites often live as endoparasites within the body of the host
  • Ectoparasites are attached to the outside of the host's body by specialized organs
According to the principle of competitive exclusion
  • Two species cannot coexist-in the same habitat
  • Extinction or emigration are the only possible results of competitive interactions
  • Intraspecific competition results in the success of the best-adapted individuals
  • Two species cannot share the same realized niche in a habitat
A two-way flow of benefits in mutualistic interactions between species is an outcome of
  • two-way exploitation
  • resource partitioning
  • close cooperativeness
  • competitive coexistence
Parasitism is an interaction between two species in which
  • Both are harmed
  • Both are benefited
  • One is benefited and the other is neither benefited nor harmed
  • One is benefited and the other is harmed
Which of the following is correct in a predator-prey cycle?
  • A decline in the numbers of predators causes a decline in the number of prey
  • A decline in the numbers of prey causes a decline in the number of predators
  • An increase in the number of predators triggers an increase in the numbers of prey
  • All of the above are correct, causing an up-and-down cycle for each animal
Interaction between two species as both attempt to use the same environmental resources is
  • competition
  • an ecosystem
  • predation
  • symbiosis
Which one of the following is an example of mutualism
  • Lichens
  • Hypertrophy
  • Cuscuta
  • Nepenthes
A probable example of commensalism is
  • mycorrhizal fungal roots on the roots of plants
  • termites with protozoa in their digestive tracts
  • flowering plants and their pollinators
  • barnacles on whales
Which of the following is a commensalistic relationship?
  • Plasmodium-humans
  • Epiphytes-trees
  • Human colon bacteria-humans
  • HIV-humans
Mutualism is an interaction between two species in which
  • Both are benefited
  • Both are harmed
  • One is benefited and the other is harmed
  • One is benefited and the other is neither benefited nor harmed
Intraspecific competition is competition among
  • Populations and their regulatory factors
  • Individuals of a community
  • Individuals of a population
  • Species
Choose the correct from the alternatives given.
A stronger species being benefited at the cost of weak species is an example of:
  • predation
  • commensalism
  • parasitism
  • proto-cooperation
State whether the following statements are true or false.
One of the effects of predation is the stabilization of the predator-prey relationship when 
there is not too much predatory pressure on the prey population
  • True
  • False
State whether the following statements are true or false.
In commensalism one partner derives benefit from the other and adversely affects the benefit of other organism.
  • True
  • False
Choose the correct answers from the alternatives given.
Human population growth curve is a
  • J-shaped curve
  • zig-zag curve
  • parabola curve
  • S-shaped curve
Which two of the given points are known as the twin characteristics of growth?
(i) Increase in mass
(ii) Increase in number of individuals
(iii) Cellular organisation
(iv) Cellular differentiation.
  • (i) and (ii)
  • (i) and (iii)
  • (ii) and (iii)
  • (iii) and (iv)
Among the following organisms which is a completely non-parasitic form?
  • Sea anemone
  • Tapeworm
  • Leech
  • Mosquito
Symbiosis is a relationship in which a member of one species lives in intimate association with a member of another species.
  • True
  • False
The carrying capacity of a population is determined by its ?
  • limiting resources
  • natality
  • mortality
  • population growth rate
Which of the following pairs contributes to an increase in population?
  • Natality and immigration
  • Mortality and emigration
  • Natality and emigration
  • Mortality and immigration
Organisms that can tolerate a wide range of salt concentration are termed as 
  • stenosaline
  • stenohaline
  • euryhaline
  • eurysaline
Study the characteristics of a population represented in the graphs below.
Mark the correct graph that represents the type of selection that this population is likely to undergo.
_____ : Past
.......... : Future
928223_1b750704509f4d5296c6e6935184e75d.jpg
The exponential growth can be mathematically expressed as
  • $$L_t\,=\,L_0\,+\,rt$$
  • $$W_1\,=\,W_0\,+\,e^{rt}$$
  • $$W_1\,=\,W_0e^{rt}$$
  • $$L_t\,=\,L_0\,-\,rt$$
Which of the following representation shows the pyramid of numbers in a forest ecosystem?
Desert, rain forest, tundra, etc, are examples of 
  • Community
  • Biome
  • Ecosystem
  • Population
Certain characteristic demographic features of developing countries are
  • high fertility, high density, rapidly rising mortality rate and a very young age distribution
  • high infant mortality rate, low fertility, uneven population growth and a very young age distribution
  • high mortality, high density, uneven population growth and a very old age distribution
  • high fertility, low or rapidly falling mortality rate, rapid population growth and a very young age distribution.
In the given figure, identity the temperate forest and coniferous forest respectively from the marking A-F and select the correct option. 
928890_e6d953c8d7204159bc4bde9fa630b510.png
  • A and B
  • B and D
  • D and E
  • C and F
Which of these interactions has negative effects?
(i) Predation
(ii) Mutualism
(iii) Commensalism
(iv) Parasitism
  • (i) and (iii)
  • (i) and (iv)
  • (ii) and (iii)
  • (i) only
A parasite that lives within a plant tissue is called as
  • ectoparasite
  • endoparasite
  • epiphyte
  • hydrophyte
Organisms show migration in order to avoid unfavorable conditions of 
  • temperature
  • food availability
  • precipitation
  • All of these
Match the following and select the correct combination from the given options.

  Column I
(Population interaction)
  Column II
(Examples)
 A. Mutualism (i)  Tick on dogs
 B. Commensalism (ii) Balanus and Chathamalus
 C. Parasitism (iii) Sparrow and any seed
 D. Competition (iv) Epiphyte on a mango branch
 E. Predation (v) Mycorrhiza
  • $$A-(i), B-(v), C-(iv), D-(iii), E-(ii)$$
  • $$A-(ii), B-(i), C-(v), D-(iv), E-(iii)$$
  • $$A-(iii), B-(ii), C-(i), D-(v), E-(iv)$$
  • $$A-(v), B-(iv), C-(i), D-(ii), E-(iii)$$
Parameters related to age structure include 
  • fecundity (birth rate)
  • generation time
  • death rate
  • All of these
Assuming that an animal generates heat at a rate proportional to its volume and can radiate heat at a rate proportional to its body surface area, which of the following would be best at maintain its body temperature in a cold climate?
  • Mouse
  • Rabbit
  • Bear
  • Fox
What does the shape of the given age pyramids (A to C) reflect about the growth status of populations? 


            A                                 B                                  C
930591_6cf995e25a934b5abdc055937747e4fa.jpg
  • Declining Stable Expanding
  • Stable Expanding Declining
  • Expanding Stable Declining
  • Declining Expanding stable
Increased IMR and decreased MMR in a population will
  • Cause rapid increase in growth rate
  • Result in decline in growth rate
  • Not cause significant change in growth rate
  • Result in an explosive population
Which of the following statements is false regarding predators?
  • Predators keep prey populations under control.
  • Predators help in maintaining species diversity in a community.
  • If a predator is not efficient, then the prey population would become extinct.
  • Herbivores have a greater advantage over carnivores since the plants cannot run away to avoid predation.
Study the four statements (i - iv) given below and select the two correct ones out of them.
(i) A lion eating a deer and a sparrow feeding on grains are ecologically similar in being consumers.
(ii) Predator star fish helps in maintaining species diversity of some invertebrates.
(iii) Predators ultimately lead to the extinction of prey species.
(iv) Production of chemicals such as nicotine, strychnine by the plants are metabolic disorders.
The two correct statements are
  • (ii) and (iii)
  • (ii) and (iv)
  • (i) and (iv)
  • (i) and (ii)
Percentage of individuals of a given age group in a given population is called as 
  • age distribution
  • age density
  • age graph
  • age curve
Penicilium does not allow the growth of Staphylococcus bacterium and Tridchoderma stops the growth of fungus Aspergillus. This type of biotic interaction is called:
  • parasitism
  • amensalism
  • commensalism
  • competition.
In some cases, polpulation density is measured in terms of biomass rather than in terms of numbers becouse ________________________.
  • it is a more meaningful measure when the considered organisms vary greatly in size.
  • it is more convenient when population is huge and counting is impossible or very time consuming
  • it is a relatively constant measure
  • both a and b
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