Bihar Board 12th Biology Objective Questions and Answers
Bihar Board 12th Biology Objective Answers Chapter 13 Organisms and Populations
Question 1.
Refer to the given flow chart.
Identify X and select the correct option.
(a) Communities
(b) Biospheres
(c) Biomes
(d) Species
Answer:
(a) Communities
Question 2.
Basic unit of ecological hierarchy is
(a) population
(b) community
(c) ecosystem
(d) individual.
Answer:
(d) individual.
Question 3.
Several plant and animal species present together at a place constitute a
(a) genus
(b) population
(c) biome
(d) community.
Answer:
(d) community.
Question 4.
The branch of science which studies the interactions among organisms and between organisms and physical environment is called as
(a) epidemiology
(b) ecology
(c) ethology
(d) etiology
Answer:
(b) ecology
Question 5.
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.
Answer:
(d) sharing of one or more resources between the two species.
Question 6.
Seasonal variations on Earth occur due to its
(a) tilted axis
(b) rotation around its own axis
(c) revolution around sun
(d) both (a) and (c).
Answer:
(d) both (a) and (c).
Question 7.
Different biomes are formed due to annual variations in _______ over the earth’s surface.
(a) temperature
(b) precipitation
(c) incident solar radiation
(d) all of these
Answer:
(d) all of these
Question 8.
Deserts, rainforest, tundra, etc, are examples of
(a) community
(b) biome
(c) ecosystem
(d) population.
Answer:
(d) population.
Question 9.
Characteristics of a terrestrical biome are strongly influenced by its
(a) flora
(b) climate
(c) fauna
(d) all of these.
Answer:
(b) climate
Question 10.
The key elements that determine differences in environmental conditions of different habitats include
(a) temperature
(b) light
(c) soil
(d) all of these.
Answer:
(d) all of these.
Question 11.
Which of the following is not a part of an organism’s physical environment ?
(a) Temperature
(b) Light
(c) Other organisms
(d) Humidity
Answer:
(c) Other organisms
Question 12.
Mango trees do not and cannot grow in temperate regions. The most important environmental factor responsible for it is
(a) soil
(b) temperature
(c) water
(d) light.
Answer:
(b) temperature
Question 13.
Temperature is considered as the most ecologically relevant environmental factor because it affects of organisms.
(a) physiology
(b) morphology
(c) geographical distribution
(d) all of these
Answer:
(d) all of these
Question 14.
Organisms that can tolerate a wide range of salt concentration are termed as
(a) stenosaline
(b) stenohaline
(c) euryhaline
(d) eurysaline.
Answer:
(c) euryhaline
Question 15.
A freshwater organism cannot survive in a water body that has greater _______ than its original habitat.
(a) oxygen content
(b) depth
(c) salt concentration
(d) water clarity
Answer:
(c) salt concentration
Question 16.
A place has very scanty rainfall, the dominant plants there may be
(a) Opuntia
(b) Nymphaea
(c) Asparagus
(d) both (a) and (c).
Answer:
(d) both (a) and (c).
Question 17.
Many animals use the diurnal and seasonal variations in light intensity and photoperiod to time their
(a) migration
(b) reproductive activities
(c) suspension
(d) all of these.
Answer:
(d) all of these.
Question 18.
Nature and properties of soil depends upon
(a) climate
(b) weathering process
(c) development of soil
(d) all of these.
Answer:
(d) all of these.
Question 19.
Water holding capacity of the soil depends upon
(a) chemical composition of soil
(b) particle size of soil
(c) aggregation of soil particles
(d) all of these.
Answer:
(d) all of these.
Question 20.
An animal that can survive at 10°C and 40°C both, can be placed under the category of
(a) conformers
(b) regulators
(c) migratory organisms
(d) modifiers.
Answer:
(b) regulators
Question 21.
Organisms that can maintain a constant internal temperature are called as
(a) homoiothermic
(b) poikilothermic
(c) oligothermic
(d) heterothermic.
Answer:
(a) homoiothermic
Question 22.
When we are in a hot room, we sweat profusely. It is a _______ means of maintaining homeostasis.
(a) morphological
(b) physiological
(c) behavioural
(d) none of these
Answer:
(b) physiological
Question 23.
Which of the following is an important adaptation of animals to the cold climate ?
(a) Thin layer of body fat
(b) Aestivation
(c) Increased tendency to shiver
(d) Reduced surface area to volume ratio
Answer:
(d) Reduced surface area to volume ratio
Question 24.
When organisms change their location to escape from harsh environment, it is called as
(a) hibernation
(b) vernalisation
(c) migrtion
(d) aestivation.
Answer:
(c) migrtion
Question 25.
Organisms show migration in order to avoid unfavourable conditions of
(a) temperature
(b) food availability
(c) precipitation
(d) all of these.
Answer:
(d) all of these.
Question 26.
Which of the following is an incorrect match ?
(a) Bacteria – Thick walled resting spores
(b) Bear – Hibernation
(c) Zooplanktons – Diapause
(d) Lizard – Aestivation
Answer:
(d) Lizard – Aestivation
Question 27.
Adaptation may be
(a) behavioural
(b) morphological
(c) physiological
(d) all of these.
Answer:
(d) all of these.
Question 28.
_______ is an attribute of the organism (morphological, physiological, behavioural) to survive and reproduce in its habitat.
(a) Migration
(b) Hibernation
(c) Adaptation
(d) Homeostasis
Answer:
(c) Adaptation
Question 29.
Opuntia has spine like leaves which help in
(a) reducing the rate of transpiration
(b) increasing the rate of transpiration
(c) increasing the rate of photosynthesis
(d) reducing the rate of photosynthesis.
Answer:
(a) reducing the rate of transpiration
Question 30.
_______ generally have shorter ears and limbs to minimise heat loss.
(a) Allen’s
(b) Berger’s
(c) Borge’s
(d) Powell’s
Answer:
(a) Allen’s
Question 31.
Which of the following statement is correct with regard to Bergmann’s rule ?
(a) Animals of colder area have large size than of hot areas.
(b) Fish of colder area have large size.
(c) Birds of colder areas have narrow wings.
(d) Animals of colder areas possess thick fur.
Answer:
(a) Animals of colder area have large size than of hot areas.
Question 32.
A behavioural strategy of a daptation called echolocation is found in
(a) bats
(b) butterfly
(c) praying mantis
(d) arctic tern.
Answer:
(a) bats
Question 33.
Parameters related to age structure include
(a) fecundity (birth rate)
(b) generation time
(c) death rate
(d) all of these.
Answer:
(d) all of these.
Question 34.
Percentage of individuals of a given age group in a given population is called as
(a) age distribution
(b) age density
(c) age graph
(d) age curve
Answer:
(a) age distribution
Question 35.
If the age distribution is plotted for a population, the resulting structure is called as
(a) age graph
(b) age curve
(c) age pyramid
(d) age diagram.
Answer:
(c) age pyramid
Question 36.
rule states that mammals from colder climates The age structure of a population represents
(a) relative number of individuals at each age
(b) number of new boms each year
(c) number of individuals reaching puberty each year
(d) relative number of deaths at each age.
Answer:
(a) relative number of individuals at each age
Question 37.
A population with a larger proportion of older individuals than younger ones will likely to
(a) grow larger and then decline
(b) continue to grow-larger indefinitely
(c) decline
(d) not experience a change in population size.
Answer:
(c) decline
Question 38.
An urn shaped population age pyramid represents
(a) growing population
(b) static population
(c) declining population
(d) extinct population.
Answer:
(c) declining population
Question 39.
Total number of individuals of a species per unit area and per unit time is called
(a) population size
(b) population density
(c) demography
(d) population dynamics.
Answer:
(b) population density
Question 40.
Which of the following is not a factor that would limit the growth of a population ?
(a) Food shortage
(b) Immigration
(c) Disease
(d) Famine
Answer:
(b) Immigration
Question 41.
Which of the following factors has a negative effect on the population growth rate ?
(a) Emigration
(b) Immigration
(c) Natality
(d) Fecundity
Answer:
(a) Emigration
Question 42.
Which of the following factors influence population density under normal conditions ?
(a) Deaths
(b) Immigration
(c) Emigration
(d) Both (a) and (c)
Answer:
(a) Deaths
Question 43.
Exponential growth is observed in a population when
(a) resources in the habitat are unlimited
(b) each species has the ability to realise its full innate potential
(c) both (a) and (b)
(d) none of these.
Answer:
(c) both (a) and (b)
Question 44.
Which of the following equations correctly represents the exponential population growth curve ?
(a) dN/dt = rN
(b) dN/dt = rN\(\left(\frac{K-N}{K}\right)\)
(c) Nt = N0eπ
(d) Both (a) and (c)
Answer:
(d) Both (a) and (c)
Question 45.
The maximum possible number of individuals that a habitat can support is called its
(a) fecundity
(b) surviving ability
(c) carrying capacity
(d) biotic potential.
Answer:
(c) carrying capacity
Question 46.
Which of the following equations correctly represents Verhulst-Pearl logistic growth ?
(a) dN/dt = rN\(\left(\frac{K-N}{K}\right)\)
(b) dN/dt =\(\frac{\mathrm{rN}}{\mathrm{K}}\)
(c) dN/dt = \(\frac{\mathrm{N}(\mathrm{K}-\mathrm{N})}{\mathrm{K}}\)
(d) dN/dt = \(\frac{\mathrm{r}(\mathrm{K}-\mathrm{N})}{\mathrm{K}}\)
Answer:
(a) dN/dt = rN\(\left(\frac{K-N}{K}\right)\)
Question 47.
The population growth is generally described by the following equation:
\(\frac{\mathrm{dN}}{\mathrm{dt}}=\mathrm{rN}\left(\frac{\mathrm{K}-\mathrm{N}}{\mathrm{K}}\right)\)
What does V represent in the given equation ?
(a) Population density at time’t’
(b) Intrinsic rate of natural increase
(c) Carrying capacity
(d) The base of natural logarithm
Answer:
(b) Intrinsic rate of natural increase
Question 48.
Species interaction with negative influence on both is referred to as
(a) amensalism
(b) mutalism
(c) commensalism
(d) competition.
Answer:
(d) competition.
Question 49.
Which type of interaction is being shown in the given figure ?
(a) Parastitism
(b) Commensalism
(c) Predation
(d) Amensalism
Answer:
(b) Commensalism
Question 50.
The prickly pear cactus became unusually abundant after its introduction in Australia, because it
(a) had no coevolved herbivores
(b) formed new mycorrhizal association
(c) lost its thorns
(d) all of these.
Answer:
(a) had no coevolved herbivores
Question 51.
Why you never see cattle or goats browsing on weed Calotropis ?
(a) The plant produces highly poisonous tannins.
(b) The plant produces quinine which is bitter in taste.
(c) The plant produces poisonous cardiac glycosides.
(d) The plant bears prickles.
Answer:
(c) The plant produces poisonous cardiac glycosides.
Question 52.
Which of the following is not an example of preypredator relationship ?
(a) Tiger eating a deer
(b) Plant Nepenthes trapping an insect
(c) Bacteria decomposing organic matter
(d) Crocodile killing a man
Answer:
(c) Bacteria decomposing organic matter
Question 53.
Competitive exclusion principle stating that inferior species is eliminated eventually after prolonged competition was given by
(a) Allen
(b) Pearl-Verhulst
(c) Gause
(d) Darwin.
Answer:
(d) Darwin.
Question 54.
Two different species cannot live for long duration in the same niche or habitat. This law is called
(a) Allen’s law
(b) Glogerrule
(c) Competitive exclusion principle
(d) Weisman’s theory.
Answer:
(b) Glogerrule
Question 55.
When two similar species live in the same area, they may evolve to become more different in order to
(a) drive the other species to extinction
(b) reduce competition
(c) use up the other species resources
(d) reduce genetic variation.
Answer:
(c) use up the other species resources
Question 56.
An interaction between two individuals where one is benefitted while the other is neither benefitted nor harmed is called as
(a) predation
(b) symbiosis
(c) amensalism
(d) commensalism.
Answer:
(d) commensalism.
Question 57.
Which of the following exhibits mutualism ?
(a) Mycorrhizae living on the roots of higher plants.
(b) Wasps pollinating fig inflorescence.
(c) Sea anemone often found on the shell of hermit crab.
(d) All of these
Answer:
(d) All of these
Question 58.
The interdependent evolution of flowering plants and pollinating insects together is known as
(a) mutualism
(b) co-evolution
(c) commensalism
(d) co-operation.
Answer:
(b) co-evolution
Question 59.
Autocology is the
(a) relation of heterogenous population to its environment
(b) relation of an individual to its environment
(c) relation of a community to its environment
(d) relation of a biome to its environment.
Answer:
(a) relation of heterogenous population to its environment, (b) relation of an individual to its environment
Question 60.
Ecotone is
(a) a polluted area
(b) the bottom of a lake
(c) a zone of transition between two communities
(d) a zone of developing community.
Answer:
(c) a zone of transition between two communities
Question 61.
Biosphere is
(a) a component in the ecosystem
(b) composed of the plants present in the soil
(c) life in the outer space
(d) composed of all living organisms present on earth which interact with the physical environment.
Answer:
(d) composed of all living organisms present on earth which interact with the physical environment.
Question 62.
Ecological niche is
(a) the surface area of the ocean
(b) an ecologically adapted zone
(c) the physical position and functional role of a species within the community
(d) formed of all plants and animals living at the bottom of a lake.
Answer:
(c) the physical position and functional role of a species within the community
Question 63.
Salt concentration (salinity) of the sea measured in parts per thousand is
(a) 10 – 5
(b) 30 – 70
(c) 0 – 5
(d) 30 – 37.
Answer:
(d) 30 – 37.
Question 64.
Formation of tropical forests needs mean annual temperature and mean annual precipitation as
(a) 18 – 25°C and 150 – 400 cm
(b) 5 – 15°C and 50 – 100 cm
(c) 30 – 50°C and 100 – 150 cm
(d) 5 – 15°C and 100 – 200 cm.
Answer:
(a) 18 – 25°C and 150 – 400 cm
Question 65.
Which of the following forest plants controls the light conditions at the ground ?
(a) Lianas and climbers
(b) Shrubs
(c) Tall trees
(d) Herbs
Answer:
(c) Tall trees
Question 66.
What parameters are used for tiger census in our country’s national parks and sanctuaries ?
(a) Pug marks only
(b) Pug marks and faecal pellets
(c) Faecal pellets only
(d) Actual head counts
Answer:
(b) Pug marks and faecal pellets
Question 67.
Which of the following would necessarily decrease the density of a population in a given habitat ?
(a) Natality > mortality
(b) Immigration > emigration
(c) Mortality and emigration
(d) Natality and immigration
Answer:
(c) Mortality and emigration
Question 68.
A protozoan reproduces by binary fission. What will be the number of protozoans in its population after six generations ?
(a) 128
(b) 24
(c) 64
(d) 32
Answer:
(c) 64
Question 69.
Lichens are the associations of
(a) bacteria and fungus
(b) algae and bacterium
(c) fungus and algae
(d) fungus and virus.
Answer:
(c) fungus and algae
Question 70.
Which of the following is a partial root parasite ?
(a) Sandal wood
(b) Mistletoe
(c) Orobanche
(d) Ganoderma
Answer:
(a) Sandal wood
Question 71.
Which one of the following organisms reproduces sexually only once in its life time ?
(a) Banana plant
(b) Mango
(c) Tomato
(d) Eucalyptus
Answer:
(c) Tomato