Organisms and Populations MCQs with Answers

Question-1. In growth pattern, (1 – N/K) is

1. intrinsic rate of natural increase
2. environmental resistance
3. biotic potential
4. carrying capacity

Question-2. _____ is any attribute of the organism (morphological physiological, behavioural) that enables the organisms to survive and reproduce in its habitat.

1. Acclimatization
2. Adaptation
3. Mutualism
4. Exponential growth

Question-3. _______________ is the number of individuals of the population who left the habitat and have gone elsewhere during the time period under consideration.

1. Mortality
2. Immigration
3. Emigration
4. Natality

Question-4. A few organisms can tolerate and thrive a wide range of temperature. Such animals are called

1. eurythermal
2. thermophilic
3. ectothermal
4. stenothermal

Question-5. A group of populations of two or more species occupying the same geographical area during a particular time is called

1. Interaction
2. Commensalism
3. None of these
4. Community

Question-6. A population has more young individuals compared to the older individuals. What would be the status of the population after some years?

1. It will first decline and then stabilise
2. It will stabilise
3. It will decline
4. It will increase

Question-7. According to Allen’s Rule, the mammals from colder climates have

1. shorter ears and shorter limbs
2. longer ears and shorter limbs
3. shorter ears and longer limbs
4. longer ears and longer limbs

Question-8. Amensalism is an association between two species where:

1. both the species are harmed
2. one species is harmed and other is benefitted
3. one species is harmed and other is unaffected
4. one species is benefitted and other is unaffected

Question-9. An organism that lives in or on another organism and derives nutrients for itself at the expense of the host organism is called

1. Predator
2. Both
3. None of these
4. Parasite

Question-10. Asymptote in a logistic growth curve is obtained when

1. K > N
2. K < N
3. None of these
4. K = N

Question-11. Autecology is the

1. Relation of a community to its environment
2. Relation of a biome to its environment
3. Relation of a population to its environment
4. Relation of an individual to its environment

Question-12. Biosphere is

1. life in the outer space
2. composed of the plants present in the soil
3. a component in the ecosystem
4. composed of all living organisms present on earth which interact with the physical environment

Question-13. Biotic factors include

1. Water temperature, fish
2. Plants, animals and physical environment
3. All of these
4. Plants and animals

Question-14. Competition is most fierce between

1. Two or more closely related species in a different environment
2. Unrelated species in the same environment
3. None of these
4. Two or more closely related species in the same environment

Question-15. Ecological niche is

1. formed of all plants and animals living at the bottom of a lake
2. an ecologically adapted zone
3. the surface area of the ocean
4. the physical position and functional role of a species within the community

Question-16. Ecotone is

1. A zone of developing community
2. The bottom of a lake
3. A polluted area
4. A zone of transition between two communities

Question-17. Formation of tropical forests needs mean annual temperature and mean annual precipitation as

1. 5 – 15°C and 50 – 100 cm
2. 30 – 50°C and 100 – 150 cm
3. 5 – 15°C and 100 – 200 cm
4. 18 – 25°C and 150 – 400 cm

Question-18. Fossorial refers to

1. Animals that are adapted to climbing
2. Animals that turned into fossils
3. None of these
4. Animals that are adapted to burrowing

Question-19. If a population of 50 Paramoecium present in a pool increases to 150 after an hour, what would be the growth rate of population?

1. 5 per hour
2. 200 per hour
3. 50 per hour
4. 100 per hour

Question-20. If a population of 50 Paramoecium present in a pool increases to 150 after an hour, What would be the per cent growth or birth rate per individual per hour of population?

1. 100
2. 50
3. 150
4. 200

Question-21. If the age distribution (per cent individuals of a given age or group) is plotted for the population, the resulting structure is called a/an

1. ecological pyramid
2. population growth
3. age pyramid
4. population density

Question-22. In 2005, for each of the 14 million people present in a country, 0.028 were born and 0.008 died during the year. Using exponential equation, the number of people present in 2015 is predicted as

1. 20 millions
2. 18 millions
3. 25 millions
4. 17 millions

Question-23. Lichens are the associations of

1. fungus and virus
2. bacteria and fungus
3. algae and bacterium
4. fungus and algae

Question-24. Microbes present in hydrothermal vents where the temperature far exceed 100°C is

1. archaebacteria
2. eubacteria
3. none of these
4. cyanobacteria

Question-25. Mimicry is

1. An adaptation made for finding mates
2. An adaptation for surviving temperature fluctuations
3. None of these
4. An evolved resemblance between an organism and an object

Question-26. Most animals are tree dwellers in a

1. coniferous forest
2. thorn woodland
3. temperate deciduous forest
4. tropical rain forest

Question-27. Percolation and water holding capacity of soil is dependent upon

1. grain size
2. aggregation
3. all of these
4. soil composition

Question-28. Plants which produce characteristic pneumatophores and show vivipary belong to

1. Mesophytes
2. Psammophytes
3. All of these
4. Halophytes

Question-29. Salt concentration (Salinity) of the sea measured in parts per thousand is

1. 0 – 5
2. 30 – 70
3. 10 – 15
4. 30 – 35

Question-30. Seals have a thick layer of fat (blubber) below their skin that acts as an

1. capacitor
2. resistor
3. insulator
4. thermostat

Question-31. The age of pyramid with narrow base indicates

1. low number of young individuals.
2. high number of old individuals.
3. low number of old individuals.
4. high number of young individuals.

Question-32. To avoid summer - related problems such as heat and dessication fish undergoes

1. diapause
2. aestivation
3. none of these
4. hibernation

Question-33. What parameters are used for tiger census in our country’s national parks and sanctuaries?

1. Actual head counts
2. Faecal pellets only
3. Pug marks only
4. Pug marks and faecal pellets

Question-34. What will happen to a well growing herbaceous plant in the forest if it is transplanted outside the forest in a park?

1. It grows very well because the plant gets more sunlight
2. It will grow well because it is planted in the same locality
3. It will grow normally
4. It may not survive because of change in its micro climate

Question-35. Which of the following forest plants controls the light conditions at the ground?

1. Herbs
2. Shrubs
3. Lianas and climbers
4. Tall trees

Question-36. Which of the following is a partial root parasite?

1. Mistletoe
2. Orobanche
3. Ganoderma
4. Sandal wood

Question-37. Which of the following parameter is not a part of population growth?

1. Mortality
2. Metapopulation
3. Emigration
4. Natality

Question-38. Which of the following would necessarily decrease the density of a population in a given habitat?

1. Natality and immigration
2. Immigration > emigration
3. Natality > mortality
4. Mortality and emigration

Question-39. Which one of the following organisms reproduces sexually only once in its life time?

1. Tomato
2. Banana plant
3. Mango
4. Eucalyptus

Question-40. Xerocoles are

1. Animals adapted to live in the deep sea
2. Animals adapted to a nocturnal lifestyle
3. All of these
4. Animals adapted to live in deserts

Question-41. A fertile agricultural soil appears dark coloured at the surface as compared to soil one metre down. The reason for colour of top soil is

1. rich in organic matter
2. rich in iron, calcium and magnesium
3. recent formation
4. more moisture

Question-42. Animals that can tolerate a narrow range of salinity are

1. euryhaline
2. anadromous
3. catadromous
4. stenohaline

Question-43. Annual migration does not occur in the case of

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

Question-44. Bulk CO2 fixation occurs in

1. oceans
2. tropical rain forests
3. Temperate forests
4. crop plants

Question-45. Deep (>500m) in the oceans, the environment is perpetually dark and its inhabitants are not aware of the existence of a celestial source of energy called_________.

1. photosynthesis
2. sun
3. light
4. ATP

Question-46. Deep black soil is productive due to high proportion of

1. gravel and calcium
2. clay and humus
3. silt and earthworm
4. sand and zinc

Question-47. Desert plants are generally

1. succulent
2. herbaceous
3. heterophyllus
4. viviparous

Question-48. Diffuse porous woods are characteristic of plants growing in

1. tropics
2. alpine region
3. cold winter regions
4. temperate climate

Question-49. Eutrophication is often seen in

1. Fresh water lakes
2. Ocean
3. Mountains
4. Deserts

Question-50. Homeostasis is

1. tendency of biological systems to resist change
2. disturbance of self regulatory system and natural controls
3. biotic materials used in homeopathic medicines
4. tendency of biological system to change with change in environment

Question-51. In desert grasslands, which type of animals are relatively more abundant?

1. Arboreal
2. Aquatic
3. Fossorial
4. Diurnal

Question-52. In which one of the following habitats does the diurnal temperature of soil surface vary most ?

1. Forest
2. Desert
3. Grassland
4. Shrubland

Question-53. In which one of the following pair is the specific characteristic of soil not correctly matched?

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

Question-54. More than 70% of world’s fresh water is contained in

1. glaciers and mountains
2. greenland
3. polar ice
4. Antarctica

Question-55. Organisms that are restricted to a narrow range of salinity, are called

1. osmoconformer
2. euryhaline
3. stenohaline
4. ectohaline

Question-56. Plants adapted to low light intensity have

1. higher rate of CO2 fixation than the sun plants
2. more extended root system
3. leaves modified to spines
4. larger photosynthetic unit size than the sun plants

Question-57. River water deposits

1. alluvial soil
2. laterite soil
3. sandy soil
4. loamy soil

Question-58. Soil best suited for plant growth is

1. loamy
2. sandy
3. gravel
4. clay

Question-59. Soil particles determine its

1. field capacity
2. water holding capacity
3. soil flora
4. texture

Question-60. Soil water available to roots is

1. hygroscopic water
2. gravitational water
3. capillary water
4. surface water

Question-61. Special kinds of roots called pneumatophores are characteristics of the plants growing in

1. saline soils
2. marshy places and salt lakes
3. dryland regions
4. sandy soils

Question-62. Species diversity increases as one proceeds from

1. low altitude to high altitude and high latitude to low latitude
2. low altitude to high altitude and low latitude to high latitude
3. high altitude to low altitude and low latitude to high latitude
4. high altitude to low altitude and high latitude to low latitude

Question-63. Sunken stomata is the characteristic feature of

1. mesophyte
2. xerophyte
3. halophyte
4. hydrophyte

Question-64. Temperature changes in the environment affect most of the animals which are

1. aquatic
2. poikilothermic
3. desert living
4. homeothermic

Question-65. The benthic organisms

1. found in open water.
2. always live at the depth of 50-100 m.
3. live outside water.
4. live near the sea bottom.

Question-66. The process in which the body’s internal environment is kept stable is known as

1. adaptation
2. geometry
3. acclimatization
4. homeostasis

Question-67. The response of different organisms to the environmental rhythms of light and darkness is called

1. phototropism
2. vernalization
3. photoperiodism
4. phototaxis

Question-68. The salinity in sea water in parts per thousand (ppt) ranges between

1. 30-35%
2. 50-75%
3. more than 100%
4. 5-15%

Question-69. The slow rate of decomposition of fallen logs in nature is due to their

1. poor nitrogen content
2. anaerobic environment around them
3. low cellulose content
4. low moisture content

Question-70. The term ‘precipitation’ includes

1. snow
2. hails
3. all forms of water that fall to the ground.
4. rain

Question-71. There is no life on moon due to absence of

1. water
2. light
3. temperature
4. O2

Question-72. Velamen is found in

1. aerial and terrestrial roots of orchids
2. leaves of Ficus elastica
3. aerial roots of orchids
4. roots of screwpine

Question-73. What are the key elements that lead to so much variations in the physical and chemical conditions of different habitats?

1. Light and soil
2. Only temperature
3. Temperature, water, light and soil
4. Temperature and water

Question-74. What is the best pH of the soil for cultivation of plants?

1. 6.5-7.5
2. 4.5-8.5
3. 5.5-6.5
4. 3.4-5.4

Question-75. Which of the following does not have stomata?

1. Mesophytes
2. Xerophytes
3. Submerged hydrophytes
4. Hydrophytes

Question-76. Which of the following is the stage of suspended development?

1. Hibernation
2. Aestivation
3. Diapause
4. Dormancy

Question-77. Which of the following pair is correctly matched?

1. Parasitism — intra-specific relationship
2. Excessive perspiration — xeric adaptation
3. Stream lined body — aquatic adaptation
4. Uricotelism—aquatic habitat

Question-78. Xeric environment is characterized by

1. low atmospheric humidity
2. extremes of temperature
3. high rate of vapourization
4. precipitation