1. Competition for light, nutrients and space is most severe between
(a) closely related organism growing in different niches
(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
2. A mutually beneficial association necessary for survival of both partners is
(a) mutualism/symbiosis
(b) commensalism
(c) amensalism
(d) both A and B
3. 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.
4. Deep black soil is productive due to high proportion of
(a) sand and zinc
(b) gravel and calcium
(c) clay and humus
(d) silt and earthworm
5. 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
6. A fertile agricultural soil appears deep coloured at the surface as compared to soil one metre down. The reason for colour of top soil is
(a) more moisture
(b) rich in organic matter
(c) rich in iron, calcium and magnesium
(d) recent formation
7. Soil particles determine its
(a) texture
(b) field capacity
(c) water holding capacity
(d) soil flora
8. The sum total of the populations of the same kind of organisms constitute
(a) colony
(b) genus
(c) community
(d) species
9. Soil best suited for plant growth is
(a) clay
(b) loam
(c) sandy
(d) gravel
10. Association of animals when both partners are benefitted
(a) colony
(b) mutualism
(c) commensalism
(d) amensalism
11. Xeric environment is characterised by
(a) precipitation
(b) low atmospheric humidity
(c) extremes of temperature
(d) high rate of vapourisation
12. Animals that can tolerate a narrow range of salinity are
(a) stenohaline
(b) euryhaline
(c) anadromous
(d) catadromous
13. In a food chain, the largest population is that of
(a) producers
(b) decomposers
(c) secondary consumers
(d) primary consumers
14. Tropical forests occur in India
(a) Jammu and Kashmir
(b) Rajasthan
(c) Kerala and Assam
(d) The forests do not occur in India
15. Sunken stomata is the characteristic feature of
(a) hydrophyte
(b) mesophyte
(c) xerophyte
(d) halophyte
16. Which of the following pairs is correctly matched?
(a) uricotelism – aquatic habitat
(b) parasitism – intra-specific relationship
(c) excessive perspiration – xeric adaptation
(d) stream lined body – aquatic adaptation
17. The concept that population tends to increase geometrically while food supply increases arithmetically was put forward by
(a) Stuart Mill
(b) Adam Smith
(c) Charles Darwin
(d) Thomas Malthus
18. In India, human population is heavily weighed towards the younger age groups as a result of
(a) short life span of many individuals and low birth rate
(b) long life span of many individuals and low birth rate
(c) short life span of many individuals and high birth rate
(d) long life span of many individuals and high birth rate
19. Human population growth in India
(a) tends to follow a sigmoid curve as in case of many other animal species
(b) tends to reach a zero population growth as in case of some animal species
(c) can be reduced by permitting natural calamities and enforcing birth control measures
(d) can be regulated by following the national programme of family planning
20. The nature of climax community ultimately depends on
(a) climate
(b) bed rock
(c) soil organisms
(d) pool of available nutrients.
21. In increasing order of organizational complexity, which one of the following is the correct sequence?
(a) Population , species , community ecosystem
(b) Population, variety, species, ecosystem
(c) Population , ecosystem, species community
(d) Species, variety, ecosystem, community
22. Keystone species in an ecosystem are those
(a) present in maximum number
(b) that are most frequent
(c) attaining a large biomass
(d) contributing to ecosystem properties
23. What is the most important factor for the success of animal population?
(a) Natality
(b) Unlimited food
(c) Adaptability
(d) Inter-species activity
24. The present population of the world is about
(a) 500 million
(b) 100 billion
(c) 6 billion
(d) 15 billion
25. Plants such as Prosopis, Acacia and Capparis represent examples of tropical
(a) thorn forests
(b) deciduous forests
(c) evergreen forests
(d) grasslands
26. An interesting modification of flower shape for insect pollination occurs in some orchids in which a male insect mistakes the pattern on the orchid flower for the female of his species and tries to copulate with it, thereby pollinating the flower. This phenomenon is called
(a) mimicry
(b) pseudopollination
(c) pseudocopulation
(d) pseudoparthenocarpy
27. 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 to it is called
(a) mortality
(b) fecundity
(c) biotic control
(d) environmental resistance.
28. Which of the following communities is more vulnerable to invasion by outside animals and plants?
(a) Tropical evergreen forests
(b) Oceanic island communities
(c) Mangroves
(d) Temperate forests.
29. Which part of the world has a high density of organisms?
(a) Grasslands
(b) Savannahs
(c) Deciduous forests
(d) Tropical rain forests
30. In a population unrestricted reproductive capacity is called as
(a) biotic potential
(b) fertility
(c) carrying capacity
(d) birth rate
31. Choose the correct sequence of stages of growth curve for bacteria
(a) Lag, log, stationary, decline phase
(b) Lag, log, stationary phase
(c) Stationary, lag, log, decline phase
(d) Decline, lag, log phase
32. The semilog of per minute growing bacteria is plotted against time. What will be the shape of graph?
(a) Sigmoid
(b) Hyperbolic
(c) Ascending straight line
(d) Descending straight line
33. 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
(a) environmental resistance
(b) morbidity
(c) fecundity
(d) biotic potential
34. Diffuse porous woods are characteristic of plant growing of
(a) tropics
(b) alpine region
(c) cold winter regions
(d) temperate climate
35. What is a keystone species?
(a) A species which makes up only a small proportion of the total biomass of a community, yet has a huge impact on the community‘s organization and survival
(b) A common species that has plenty of biomass, yet has a fairly low impact on the community‘s organization
(c) A rare species that has minimal impact on the biomass and on other species in the community
(d) A dominant species that constitutes a large proportion of the biomass and which affects many other species.
36. 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
37. The maximum growth rate occurs in
(a) stationary phase
(b) senescent phase
(c) lag phase
(d) exponential phase
38. 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
39. Which one of the following pairs is mismatched?
(a) Tundra – permafrost
(b) Savanna – acacia trees
(c) Prairie – epiphytes
(d) Coniferous forest – evergreen trees
40. Niche overlap indicates
(a) two different parasites on the same host
(b) sharing of one or more resources between the two species
(c) mutualism between two species
(d) active cooperation between two species
41. The formula for exponential population growth is
(a) dN/rN = dt
(b) rN/ dN = dt
(c) dN/ dt = rN
(d) dt/ dN = rN
42. Praying mantis is a good example of
(a) warning colouration
(b) social insects
(c) camouflage
(d) mullerian mimicry
43. Geometric representation of age structure is a characteristic of
(a) population
(b) landscape
(c) ecosystem
(d) biotic community.
44. 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?
(a) The food plants mature and die at the end of the rainy season
(b) Its population growth curve is of J-type
(c) The population of its predators increases enormously
(d) S-shaped or sigmoid growth of this insect.
45. Two plants can be conclusively said to belong to the same species if they
(a) have more than 90 per cent similar genes
(b) look similar and possess identical secondary metabolites
(c) have same number of chromosomes
(d) can reproduce freely with each other and form seeds.
46. A high density of elephant population in an area can result in
(a) intra specific competition
(b) inter specific competition
(c) predation on one another
(d) mutualism.
47. What is true about the isolated small tribal populations?
(a) There is a decline in population as boys marry girls only from their own tribe
(b) Hereditary diseases like colour blindness do not spread in the isolated population
(c) Wrestlers who develop strong body muscles in their life time pass this character on to their progeny
(d) There is no change in population size as they have a large gene pool
48. What is a keystone species?
(a) A species which makes up only a small proportion of the total biomass of a community, yet has a huge impact on the community‘s organization and survival
(b) A common species that has plenty of biomass, yet has a fairly low impact on the community‘s organization
(c) A rare species that has minimal impact on the biomass and on other species in the community
(d) A dominant species that constitutes a large proportion of the biomass and which affects many other species.
49. In the case of peppered moth (Biston betularia) the black – coloured form became dominant over the lightcoloured form in England during
industrial revolution. This is an example of:
(a) appearance of the darker coloured individuals due to very poor sunlight
(b) protective mimicry
(c) inheritance of darker colour character acquired due to the darker environment
(d) natural selection whereby the darker forms were selected
50. Two plants can be conclusively said to belong to the same species if they
(a) have more than 90 per cent similar genes
(b) look similar and possess identical secondary metabolites
(c) have same number of chromosomes
(d) can reproduce freely with each other and form seeds.
51. Which one of the following is one of the characteristics of a biological community?
(a) Stratification
(b) Natality
(c) Mortality
(d) Sex ratio
52. What is a keystone species?
(a) A species which makes up only a small proportion of the total biomass of a community, yet has a huge impact on the community‘s organization and survival
(b) A common species that has plenty of biomass, yet has a fairly low impact on the community‘s organization
(c) A rare species that has minimal impact on the biomass and on other species in the community
(d) A dominant species that constitutes a large proportion of the biomass and which affects many other species.
53. Large woody vines are more commonly found in:
(a) temperate forest
(b) mangroves
(c) tropical rainforests
(d) alpine forests
54. Consider the following four conditions (i) – (iv) and select the correct pair of them as adaptation to environment in desert lizards. The
conditions: (i) Burrowing in soil to escape high temperature (ii) Losing heat rapidly from the body during high temperature (iii) Bask in sun when
temperature is low (iv) Insulating body due to thick fatty dermis Options:
(a) (iii), (iv)
(b) (i)
(c) (iii), (ii), (iv)
(d) (i), (ii)
55. Which one of the following statements is correct for secondary succession?
(a) It begins on a bare rock
(b) It occurs on a deforested site
(c) It follows primary succession
(d) It is similar to primary succession except that it has a relatively fast pace
56. Cuscuta is an example of
(a) ectoparasitism
(b) brood parasitism
(c) predation
(d) endoparasitism
57. A sedentary sea anemone gets attached to the shell lining of hermit crab. The association is:
(a) Symbiosis
(b) Commensalism
(c) Amensalism
(d) Ectoparasitism
58. A biologist studied the population of rats in a barn. He found that the average natality was 250, average mortality 240, immigration 20 and emigration The net increase in population is:
(a) 15
(b) 05
(c) zero
(d) 10
59. Benthic organisms are affected most by
(a) Water-holding capacity of soil
(b) Light reaching the forest floor
(c) Surface turbulence of water
(d) Sediment characteristics of aquatic ecosystem
60. The age pyramid with broad base indicates
(a) High percentage of young individuals
(b) High percentage of old individuals
(c) Low percentage of young individuals
(d) A stable population
61. Which one of the following is not a parasitic adaptation?
(a) Loss of unnecessary sense organs
(b) Development of adhesive organs
(c) Loss of digestive organs
(d) Loss of reproductive capacity
62. Parasitic animal which is part of bio-geo community and included as zoo planktons and mesofauna of tenestrial ecosystem is …….
(a) Moles
(b) mites
(c) Earthworms
(d) leech
63. Plants which produce characteristic pneumatophores and show vivipary belong to
(a) hydrophytes
(b) mesophytes
(c) halophytes
(d) psammophytes
64. 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) Cuscuta (dodder) growing on other – flowering plants – Epiphytism
(d) Orchids growing on trees – Parasitism
65. The principle of competitive exclusion was stated by
(a) Mac Arthur
(b) Verhulst and Pearl
(c) C. Darwin
(d) G.F. Gause
66. 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) steady state
(d) homoeostasis
67. Average human population in a certain time area is 5000 in which 1111 children are produced during an years, find out the birth rate ?
(a) 0.1111
(b) 0.3333
(c) 0.2222
(d) 0.4444
68. 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 is exactly one
(b) when N nears the carrying capacity of the habitat.
(c) when N/K equals zero
(d) when death rate is greater than birth rate
69. If the mean and the median pertaining to a certain character of a population are of the same value, the following is most likely to occur
(a) a bimodal distribution
(b) a normal distribution
(c) a Tshaped curve
(d) a skewed curve
70. Mycobiont Supplies X to phycobiont and phycobiont supplies Y to mycobiont, then what is true for X and Y ?
(a) X : Mineral element ; Y : Habitat
(b) X : organic nutrients ; Y : Inorganic Nutrient
(c) X : Habitat Y : protection
(d) X : Minerals Y : organic nutrients
71. Just as a person moving from Delhi to Shimla to escape the heat for the duration of hot summer, thousands of migratory birds from Siberia and other extremely cold northern regions move to
(a) Corbett National Park
(b) Western Ghat
(c) Meghalaya
(d) Keolado National Park
72. In which one of the following pairs is the specific characteristic of a soil not correctly matched?
(a) Terra rosa most suitable for roses
(b) Chernozems richest soil in the world
(c) Laterite contains aluminium compound
(d) black soil rich in calcium carbonate
73. What is true for both the organism showing interspecific compitition ?
(a) Both are benefited
(b) more or less harmful effect to both
(c) one is benefited where as other is at loss
(d) None of these
74. The age pyramid with broad base indicates
(a) high percentage of old individuals
(b) high percentage of young individuals
(c) low percentage of young individuals
(d) a stable population
75. The salinity in sea water in parts per thousand (ppt) ranges between
(a) 5-15%
(b) 30-35%
(c) 50-75%
(d) more than 100%
76. Large woody vines are more commonly found in
(a) temperate forests
(b) mangroves
(c) tropical rainforests
(d) alpine forests.
77. What is the vital Index, if Birth rate is 0 and Death rate = 5 ?
(a) 0
(b) 100
(c) 1
(d) None of these
78. Which one of the following is categorised as a parasite in true sense?
(a) The female Anopheles bites and sucks blood from humans
(b) The cuckoo (koel) lays its eggs in crow’s nest
(c) Human foetus 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
79. 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
80. Which one of the following is one of the characteristics of a biological community?
(a) Mortality
(b) Stratification
(c) Natality
(d) Sex ratio
.
81. Reduction in vascular tissue, mechanical tissue and cuticle is characteristic of
(a) hydrophytes
(b) xerophytes
(c) mesophytes
(d) epiphytes
82. Asymptote in a logistic growth curve is obtained when :
(1) K = N
(2) K > N
(3) K < N
(4) The value of ‘r’ approaches zero
83. Plants which produce characteristic pneumatophores and show vivipary belong to :
(1) Halophytes
(2) Psammophytes
(3) Hydrophytes
(4) Mesophytes
84. Select the correct route for the passage of sperms in male frogs:
(1) Testes → Vasa efferentia → Kidney → Seminal Vesicle → Urinogenital duct → Cloaca
(2) Testes → Vasa efferentia → Bidder’s canal → Ureter → Cloaca
(3) Testes → Vasa efferentia → Kidney → Bidder’s canal → Urinogenital duct → Cloaca
(4) Testes → Bidder’s canal → Kidney → Vasa efferentia → Urinogenital duct → Cloaca
85. Presence of plants arranged into well defined vertical layers depending on their height can be seen best in:
(1) Tropical Rain Forest
(2) Grassland
(3) Temperate Forest
(4) Tropical Savannah
86. In a growing population of a country,
(1) pre-reproductive individuals are more than the reproductive individuals.
(2) reproductive individuals are less than the post-reproductive individuals.
(3) pre-reproductive individuals are less than the reproductive individuals.
(4) reproductive and pre-reproductive individuals are equal in number.
87. Which one of the following population interactions is widely used in medical science for the production of antibiotics?
(1) Commensalism
(2) Mutualism
(3) Amensalism
(4) Parasitism
88. Offsets are produced by
(1) Meiotic divisions
(2) Mitotic divisions
(3) Parthenogenesis
(4) Parthenocarpy (2018)
89. Which of the following flowers only once in its life-time?
(1) Bamboo species
(2) Jackfruit
(3) Papaya
(4) Mango
90. Niche is
(1) all the biological factors in the organism’s environment
(2) the physical space where an organism lives
(3) the functional role played by the organism where it lives
(4) the range of temperature that the organism needs to live
91. Natality refers to
(1) Death rate
(2) Birth rate
(3) Number of individuals entering a habitat
(4) Number of individuals leaving the habitat
92. Pneumatophores occur in
(1) Halophytes
(2) Free-floating hydrophytes
(3) Submerged hydrophytes
(4) Carnivorous plants
93. In some plants, the female gamete develops into embryo without fertilization. This phenomenon is known as
(1) Autogamy
(2) Parthenocarpy
(3) Syngamy
(4) Parthenogenesis
94. The process of growth is maximum during
(1) Senescence
(2) Dormancy
(3) Log phase
(4) Lag phase
95. Which of the following is not an attribute of a population?
(1) Mortality
(2) Species interaction
(3) Sex ratio
(4) Natality
96. Secondary metabolites such as nicotine, strychnine and caffeine are produced by plants for their
(1) Defence action
(2) Effect on reproduction
(3) Nutritive value
(4) Growth response
97. Inspite of interspecific competition in nature, which mechanism the competing species might have evolved for their survival?
(1) Predation
(2) Resource partitioning
(3) Competitive release
(4) Mutualism
98 Amensalism can be represented as:
(1) Species A (+); Species B (0)
(2) Species A (–); Species B (0)
(3) Species A (+); Species B (+)
(4) Species A (–); Species B (–)
99. In the exponential growth equation Nt = N0ert , e represents
(1) The base of geometric logarithms
(2) The base of number logarithms
(3) The base of exponential logarithms
(4) The base of natural logarithms
100. Assertion (A): A person goes to high altitude and experiences ‘altitude sickness’ with symptoms like breathing difficulty and heart palpitations.
Reason (R): Due to low atmospheric pressure at high altitude, the body does not get sufficient oxygen. In the light of the above statements, choose the correct answer from the options given below
(1) (A) is false but (R) is true
(2) Both (A) and (R) are true and (R) is the correct explanation of (A)
(3) Both (A) and (R) are true but (R) is not the correct explanation of (A)
(4) (A) is true but (R) is false
(2021)
Solutions :
1.Solution: (b) Competition is most severe between the members of a population belonging to same niches.
2.Solution: (a) Symbiosis or mutualism is a mutually beneficial association necessary for the survival of both the partners.
3.Solution: (b) Homeostasis is the property of an open system, especially living organisms, to regulate its internal environment to
maintain a stable, constant condition, by means of multiple dynamic equilibrium adjustments, controlled by interrelated regulation mechanisms.
4.Solution: (c) Deep black soil has high content of clay and humus, which makes it more fertile and so productive. Humus is amorphous
and colloidal mixture of complex organic substances. It provides fertility to the soil.
5.Solution: (b) When the interaction is useful for both the populations.
6.Solution: (b) High organic matter darkens the colour of soil. This is soil.
7.Solution: (a) Soil particles size defines its texture. The mineral particles present in soil, vary enosmously in size the fire fiagments. (consisting of sand, silt and clay particles) and coarse fiagments (gravel, copples and stones). The relative proportion’s of sand, silt and clay in a soil is referred as soil texture. Fine textured soil have more of clay particles. Water holding capacityLarger soil particles like sand, gravel have large pores. This have high less holding capacity and higher percolotion rate field capacity is the of soil moisture or water content held in soil after excess water has drained away.
8.Solution: (d) A species is a group of individuals of same kind of phenotypic characters and can interbreed easily.
9.Solution: (b) Loam soil is best suited for plant growth because it possesses good aeration, nutritive salts and good water retaining capacity.
10.Solution: (b) Mutualism type of interactions are shown in plant roots in mycorrhizal region.
11.Solution: (b) Xeric environment is found in deserts where temperature remains high in the day and low during the night and air humidity
is very low.
12.Solution: (a) Stenohaline: Steno meaning narrow and haline meaning salt. A fish cannot handle a wide fluctuation in salt content in water.
Many fresh water fish tend to be stenohaline and die in environments of high salinity such as the ocean. Fish living in coastal estuaries and tide pools are often euryhaline (tolerant to changes in salinity) as are many species which have life cycle requiring tolerance to both fresh water and
sea water environments such as Salmon.
13.Solutions : (a) Producers. Number of individuals decrease at successive tropic level.
14.Solution: (c) Kerala & Assam. Tropical forests-are highly productive terrestrial ecosystem. Their environment conditions are not
climate and wel moisture which causes for their higher productivity.
15.Solution: (c) Sunken stomata is the characteristic feature of xerophytes which help in reducing reducing loss of water from leaf surface.
These type of stomata are found in oleander or pine.
16.Solution: (d) The correctly matched pair is streamlined body for aquatic adaptation. Parasitisminter specific relationship in which one
species (parasite) benefits for growth and reproduction and ollic species (host) harmed. Parasite live on or inside the body of host.
17.Solution: (d) Thomas R. Malthus put forward a theory of human population growth in 1778. He told that population grows in geometrical
progression, whereas the means which support it, grow only in arithmetical progression.
18.Solution: (c) In India, there is short life span of individuals and high birth rate as compared to other countries. That is why, the human population is heavily weighed towards the younger age groups.
19.Solution: (d) Human population growth in India can be regulated by following the national programme of family planning.
20.Solution: (a) In ecological succession, climax community is a stable, self perpetuating biotic community developing towards the
end of biotic succession in an area and is in harmony with the climate of the region.
21.Solution: (a) Population is an aggregation or grouping of individuals of the same species at the same time in a particular area. Species is a
grouping of individuals of one or more populations resembling each other in important morphological, anatomical and biochemical characters and can potentially interbreed. Biotic community is an assemblage of interdependent, and ecosystem is a self sufficient and self regulating segment of nature comprising of a biotic community and its physical environment, both interacting and exchanging materials. The basic level of ecological organisation starts with the individual, the next more complex levels are populations, species, community and then ecosystem.
22.Solution: (d) The keystone species in an ecosystem are those who are the main contributors to the ecosystem.
23.Solution: (c) Natality refers to the rate at which new individuals are born. Adaptability refers to the capacity of the organisms to adapt
themselves to their environment.
24.Solution: (c) Human population in world is estimated to have crossed 6 billion in the year 1999.
25.Solution: (a) Deciduous forests are present in both northern and southern hemisphere contain broad leaved, hardwood deciduous trees –
oak, maple, chestnut etc. evergreen forests occur in equatorial and subequatorial regions important plants are- Rosewood Ebony, Mahogany, fig, etc. Grass lands are large plains covered by grasses. Prosopis, Acacia and Capparis are non succulent, thorny hot desert plants.
26.Solution: (a) Mimicry is resemblance of an organism to its natural surrounding, a non-living object or another organism for concealing itself
from its enemies. Flowers of Ophrys muscifera resemble the female wasps of Colpaaurea so that the male wasp tries to copulate with the flowers and pollinate them.
27.Solution: (d) Mortality is the average number of natural deaths per unit population per unit time. Fecundity refers to the biotic potential of
the organism. Environmental resistance is the sum total of all limiting factors that prevents a population to realize its full potential.
28.Solution: (b) This is so because oceanic islands are normally cut off from other habitats.
29.Solution: (d) Tropical rain forests occur in equatorial and subequatorial regions. The forests receive all the external inputs for optimum
plant growth. Due to abundant plant growth, a large number of animals live in tropical rain forests. In grasslands fire occur periodically which prevent tree growth. In savannahs periods of drought are common. In deciduous forests are found predominantly broad leaved hard wood deciduous trees.
30.Solution: (a) Carrying capacity refers to the maximum number of individuals that can be sustained by the environment. Birth rate
refers to number of births per unit population.
31.Solution: (a) The growth curve for bacteria is sigmoid. First phase is the phase of slow growthLag phase. Second phase is the period of
accelerated growth – Log phase. Third phase is the phase when growth rate becomes stable – Stationary phase. Finally growth rate declines.
32. Solution: (c) Semilog of per minute growing bacterium when plotted against time, would yield ascending straight line.
33.Solution: (a) Biotic potential is the inherent ability of an organism to reproduce. Resistance refers to the sum total of all the limiting factors that
inhibit further growth of population.
34.Solutions : (a) Diffused porous wood have vessels irregularly arranged within in the wood. In tropics, there is no sharp distinction between the seasons; hence, there is not much difference in the activity of cambium.
35.Solution: (a) A keystone species is the one which makes up only a small proportion of the total biomass of a community, yet has a huge
impact on the community‘s organization and survival.
36.Solution: (c)Desert show maximum difference between day and night temperature.
37.Solution: (d) In the sigmoid growth curve growth is slow in the lag phase. Growth rate remains stable during the stationary phase and it
declines during the senescent phase. Growth increases logarithmically during the exponential phase.
38.Solution: (a) Demography is the study of population in all aspects. Fertility refers to the number of children per couple. Mortality rate is the
average number of natural deaths per unit population per unit time. Age distribution refers to the proportionate occurrence of individuals of the three age groups. Developing countries usually have high rate of population growth, because of increasing fertility and declining mortality.
39.Solution: (c) Prairies is a grass land and epiphytes and ephemerals are found in desert. In Tundra much of the ground stays frozen round the
year, this condition is called permafrost. The Acacia trees are common in African savannas. In coniferous forest all plants do not shed their leaves at the same time hence forest remain ever green.
40.Solution: (b) Niche indicate the habitat of a particular species and the interaction of that species with the resources present in the habitat.
Niche overlap means that two or more species sharing the resources present in a particular niche.
41.Solution: (c) The formula of exponential growth is dNdt = rN where dNdt is the rate of change in population size, r is the biotic potential and
N is the population size.
42.Solution: (c) Praying mantis is a good example of camouflage. Camouflage is the natural colouring of an animal which enables it to
blend in with its surroundings. A praying mantis, or praying mantid, is the common name for an insect of the order Mantodea. Often mistakenly spelled preying mantis (a tempting mistake, as they are notoriously predatory) they are in fact named for the typical ―prayer-like‖ stance. The word mantis derives from the Greek word mantis for prophet or fortune teller. A praying mantis from India
43.Solution: (a) Geometric representation of age structure a characteristic of population.
44.Solution: (b) If a population (e.g reindeer population) is allowed to grow in a predator free environment, the population grows beyond
carrying capacity and there occurs population crash due to sudden shortage of food. Such growth curves also occur in insect populations during rainy season, and in algal blooms.
45.Solution: (d) When the members of a species are inter – fertile and produce fertile offsprings.
46.Solution: (a) It is competition between individuals of same species. The intraspecific competition may be very severe because all the
members of a species have similar requirements of food, habitat mate, etc and they also have similar adaptations to get their needs.
47.Solution: (a)
There is a decline in population as boys marry girls only from their own tribe in the isolated small tribal populations.
48.Solution: (a) A keystone species is the one which makes up only a small proportion of the total biomass of a community, yet has a huge
impact on the community‘s organization and survival.
49.Solution: (d) In the case of peppered moth (Biston betularia) the black coloured form became dominant over the light coloured form in
England during industrial revolution. This is an example of natural selection. This group is about species that gain protection from predators due to selection caused by nature.
50.Solution: (d) When the members of a species are inter – fertile and produce fertile offsprings.
51.Solution: (a) Stratification is one of the characteristics of biological community. Natality, mortality, age, structure and sex ratio are basic
characteristics of a population.
52.Solution: (a) A keystone species is the one which makes up only a small proportion of the total biomass of a community, yet has a huge
impact on the community‘s organization and survival.
53.Solution: (c) Large woody vines are more commonly found in tropical rain forests. This is a common concern in the high humidity
climatic condition.
54.Solution: (b) Some species make permanent burrows deep into the soil to escape high temperature or sunlight and some cold
blooded animals often like to bask in the sun to warm up their body.
55.Solution: (b) Secondary succession refers to the regrowth of a habitat in the area where disruptive event has occurred and
eliminated the existing, above ground plant life of the natural habitat. So, it occurs on a deforested site.
56.Solution: (a) Cuscuta, or Dodder plant, is a parasitic plant that wraps around other plants for nourishment. Cuscuta is found on outer
side of the host and is total stem parasite. Cuscuta a parasite of Acacia.
57.Solution: (b) Commensalism is a interaction where one species is benefitted and other is neither benefitted nor harmed.
58.Solution: (c) Net increase in population = (Natality + Immigration) –(Mortality + Emigration)
(250 + 20) – (240 + 30) = 270 – 270 = 0
59.
Solutions : (d) The sediment characteristics often determine the type of benthic animals that can thrive there.
60.Solution: (a) Age pyramid is a graphic representation of different age groups of population with prereproductive groups at the base,
reproductive ones in the middle and postreproductive groups at the top. In Triangular age pyramid, the number of prereproduction individual is very large while reproductive are moderate and postreproductive are fewer.
61.Solution: (d) In parasitism, one species (parasite) is benefitted and the other (host) is harmed. Parasites have very high reproduction
capacity. The life cycles of parasites are often complex, involving one or two intermediate hosts or vectors to facilitate parasitisation of its primary host
62.(b) Parasitic animal which is part of bio-geo community and included as zoo planktons and mesofauna of tenestrial ecosystem is mites.
63.(a) Hydrophytes are those plants which live in water and adjust with their surroundings. They either remain fully submerged in the water like Hydrilla, Valisineria, etc. or most of their body parts remain under the water like trapa, lotus, etc. water lilies, sedges, crow foots are other important water plants.
64.(b) Like all fungi, lichen fungi require carbon as a food source; this is provided by their symbiotic algae and/or cyanobacteria, that are photosynthetic. The lichen symbiosis is thought to be a mutualism, since both the fungi and the photosynthetic partners, called photobionts, benefit.
65.(d) In ecology, the competitive exclusion principle, sometimes referred to as Gause’s law, is a proposition named for Georgy Gause that two species competing for the same limited resource cannot coexist at constant population values.
66.(d) Homeostasis is any self-regulating process by which an organism tends to maintain stability while adjusting to conditions that are best for its survival. If homeostasis is successful, life continues; if it’s unsuccessful, it results in a disaster or death of the organism.
67.(c) 0.2222
68.(a) when N/K is exactly one
69.(b) a normal distribution
70.(d) X : Minerals Y : organic nutrients
71.(d) Keolado National Park , bharatpur rajasthan
72.(d) Black soil is dark or dark brown in colour. It is formed from basaltic rock under semi-arid condition. Black soil logically known as regur or black cotton soil.
73.(b) Interspecific competition is a form of competition between different species of the same ecological area. An example of interspecific competition is between lions and leopards that vie for similar prey
74.(b) The age of pyramid is a model representing geometrically the proportions of different age groups in the population of any organism. A pyramid with broad base indicates a high percentage of young individuals. An umshaped age pyramid indicates a low percentage of young individuals.
75. (b) Salinity of water bodies is generally measured in parts per thousand. It determines what kind of organisms can live in it. Salinity of the sea is 30-35 parts per thousand, while for inland waters and some lagoons is less than 55 and more than 100, respectively. Fresh water animals generally cannot live for long in sea water and vice versa because of osmotic problems.
76.(c) Large woody vines are more commonly found in tropical rain forests. Lianas are large climbing woody vines that drape tropical rainforest trees. They have adapted to life in rainforest by having their roots in the ground and climbing high onto the tree canopy to reach available sunlight. Many lianas start life in the rainforest canopy and send roots down to the groun
77(a) 0 is the vital Index, if rate is 0 and Death rate = 5.
78.(c) Parasitism is an association in which one organism (the parasite) lives on (eetoparasitism) or in (endoparasitism) the body of another (the host), from which it obtains its nutrients. They also produce vast numbers of eggs there e.g., head louse living on the human scalp.
79.(c)The rate at which food energy is assimilated at the trophic level of consumers is called secondary productivity. In other words, the rate of synthesis of organic matter by consumers is called as secondary productivity.
80.(c) The characteristics of biological community are dominance, species diversity, trophic organisation, stratification, dynamism and stability
81.(a) hydrophytes
82. (a)A logistic growth curve is an S-shaped (sigmoidal) curve that can be used to model functions that increase gradually at first, more rapidly in the middle growth period, and slowly at the end, leveling off at a maximum value after some period of time.
For logistic growth = rN =
If K= N then = 0
The = 0
The population reaches asymptote.
83 (a)Halophytes are salt-tolerant plants that grow in waters with high salinity, such as in mangrove swamps, marshes, seashores and saline semi-deserts. Only two per cent of the plant species found on the Earth are halophytes. As they are able to tolerate high salinity through different adaptation methods like tolerance, resistance and avoidance, they have less competition in saline environments. Halophytes are classified into aqua-halines, terrestro-halines and aero-halines.
84. (3) In male frog the sperms will move from
Testes → Vasa efferentia → Kidney → Bidder’s canal → Urinogenital duct → Cloaca.
85 (a) The tropical rainforest is a hot, moist biome where it rains all year long.
86 (a) Pre-Reproductive: Birth to age 14 years – These are ages when most girls are pre-pubescent and unlikely to have the ability to bear children. These are commonly referred to as the child-bearing years. Reproduction is defined as a biological process in which an organism gives rise to young ones (offspring) similar to itself.
87(c) Amensalism, association between organisms of two different species in which one is inhibited or destroyed and the other is unaffected. There are two basic modes: competition (q.v.), in which a larger or stronger organism excludes a smaller or weaker one from living space or deprives it of food, and antibiosis, in which one organism is unaffected but the other is damaged or killed by a chemical secretion
88 (b) Offset is a vegetative part of a plant, formed by mitosis.
– Meiotic divisions do not occur in somatic cells.
– Parthenogenesis is the formation of embryo from ovum or egg without fertilisation.
– Parthenocarpy is the fruit formed without fertilisation, (generally seedless)
89 (a) Bamboo species are monocarpic . generally only once in its life-time after 50- 100 years.
90 (c) In ecology, a niche is the match of a species to a specific environmental condition. It describes how an organism or population responds to the distribution of resources and competitors and how it in turn alters those same factors
91(b) The crude birth rate or natality in a period is the total number of live births per 1,000 population divided by the length of the period in years. The number of live births is normally taken from a universal registration system for births; population counts from a census, and estimation through specialized demographic techniques.
92 (a) Pneumatophores are specialized aerial roots stemming from a subterranean root system, which enable plants to utilize air in waterlogged soil habitats. Halophytes like mangrooves have pneumatophores. Apogeotropic (–vely geotropic) roots having lenticels called pneumathodes to uptake O2
93 (d) arthenogenesis is a form of reproduction in which an egg can develop into an embryo without being fertilized by a sperm. several insect species including aphids, bees, and ants are known to reproduce by parthenogenesis.
94 (c) The log phase is a period characterized by cell doubling. The number of new bacteria appearing per unit time is proportional to the present population. If growth is not limited, doubling will continue at a constant rate so both the number of cells and the rate of population increase doubles with each consecutive time period.
95(b) Following are the lists of attribute of a population
- Birth and Death Rates
- Sex Ratio
- Age Distribution
- Population Density
Natality is the rate of production of new individuals per unit area of population per unit time. Simply it is called birth rate
96 (a) Defence action
97 (b) Resource partitioning
98 (b) Species A (–); Species B (0)
99 (d) The integral form of the exponential growth equation as Nt=N0ert Where,
Nt = Population density after time t
N0= Population density at time zero
r = intrinsic rate of natural increase
e= the base of natural logarithms (2.71828)
100 (b) Both (A) and (R) are true and (R) is the correct explanation of (A)
