Organisms and Populations MCQs with Answers

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

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

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

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

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. Natality
2. Mortality
3. Immigration
4. Emigration

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

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

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

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

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

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

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

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

1. one species is benefitted and other is unaffected
2. both the species are harmed
3. one species is harmed and other is benefitted
4. one species is harmed 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. Parasite
2. Predator
3. Both
4. None of these

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

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

Question-11. Autecology is the

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

Question-12. Biosphere is

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

Question-13. Biotic factors include

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

Question-14. Competition is most fierce between

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

Question-15. Ecological niche is

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

Question-16. Ecotone is

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

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

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

Question-18. Fossorial refers to

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

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. 100 per hour
2. 5 per hour
3. 200 per hour
4. 50 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. 200
2. 100
3. 50
4. 150

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

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

Question-23. Lichens are the associations of

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

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

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

Question-25. Mimicry is

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

Question-26. Most animals are tree dwellers in a

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Question-40. Xerocoles are

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

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

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

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

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

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

Question-44. Bulk CO2 fixation occurs in

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

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. ATP
2. photosynthesis
3. sun
4. light

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

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

Question-47. Desert plants are generally

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

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

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

Question-49. Eutrophication is often seen in

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

Question-50. Homeostasis is

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

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

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

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

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

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

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

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

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

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

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

Question-56. Plants adapted to low light intensity have

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

Question-57. River water deposits

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

Question-58. Soil best suited for plant growth is

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

Question-59. Soil particles determine its

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

Question-60. Soil water available to roots is

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

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

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

Question-62. Species diversity increases as one proceeds from

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

Question-63. Sunken stomata is the characteristic feature of

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

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

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

Question-65. The benthic organisms

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

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

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

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

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

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

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

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

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

Question-70. The term ‘precipitation’ includes

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

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

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

Question-72. Velamen is found in

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

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

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

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

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

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

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

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

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

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

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

Question-78. Xeric environment is characterized by

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