300+ TOP Surveying MCQ Questions and Answers

Surveying Multiple Choice Questions (mcqs)

1. During chaining along a straight line, the . leader of the party has 4 arrows in his hand while the follower has 6. Distance of the follower from the starting point is
a) 4 chains
b) 6 chains
c) 120 m
d) 180m
Answer: b

2. A metallic tape is made of
a) steel
b) invar
c) linen
d) cloth and wires
Answer: d

3. For a well-conditioned triangle, no angle should be less than
a) 20°
b) 30°
c) 45°
d) 60°
Answer: b

4. The angle of intersection of the two plane mirrors of an optical square is
a) 30°
b) 45°
c) 60°
d) 90°
Answer: b

5. The allowable length of an offset depends upon the
a) degree of accuracy required
b) method of setting out the perpendiculars and nature of ground
c) scale of plotting
d) all of the above
Answer: d

SURVEYING Mcqs
SURVEYING Multiple Choice Questions

6. Which of the following angles can be set out with the help of French cross staff?
a) 45° only
b) 90° only
c) either 45° or 90°
d) any angle
Answer: c

7. Which of the following methods of offsets involves less measurement on the ground?
a) method of perpendicular offsets
b) method of oblique offsets
c) method of ties
d) all involve equal measurement on the ground
Answer: a

8. The permissible error in chaining for measurement with chain on rough or hilly ground is
a) 1 in 100
b) 1 in 250
c) 1 in 500
d) 1 in 1000
Answer: b

9. The correction for sag is
a) always additive
b) always subtractive
c) always zero
d) sometimes additive and sometimes subtractive
Answer: b

10. Cross staff is an instrument used for
a) measuring approximate horizontal angles
b) setting out right angles
c) measuring bearings of the lines
d) none of the above
Answer: b

11. Normal tension is that pull which
a) is used at the time of standardising the tape
b) neutralizes the effect due to pull and sag
c) makes the correction due to sag equal to zero
d) makes the correction due to pull equal to zero
Answer: b

12. Which of the following is not used in measuring perpendicular offsets ?
a) line ranger
b) steel tape
c) optical square
d) cross staff
Answer: a

13. If the length of a chain is found to be short on testing, it can be adjusted by
a) straightening the links
b) removing one or more small circular rings
c) closing the joints of the rings if opened out
d) all of the above
Answer: a

14. The maximum tolerance in a 20 m chain is
a) ±2 mm
b) ±3 mm
c) ±5 mm
d) ±8 mm
Answer: c

15. For accurate work, the steel band should always be used in preference to chain because the steel band
a) is lighter than chain
b) is easier to handle
c) is practically inextensible and is not liable to kinks when in use
d) can be easily repaired in the field
Answer: c

16. The length of a chain is measured from
a) centre of one handle to centre of other handle
b) outside of one handle to outside of other handle
c) outside of one handle to inside of other handle
d) inside of one handle to inside of other handle
Answer: b

17. Select the incorrect statement.
a) The true meridians at different places are parallel to each other.
b) The true meridian at any place is not variable.
c) The true meridians converge to a point in northern and southern hemispheres.
d) The maps prepared by national survey departments of any country are based on true meridians.
Answer: a

18. If the true bearing of a line AB is 269° 30′, then the azimuth of the line AB is
a) 0° 30′
b) 89° 30′
c) 90° 30′
d) 269° 30′
Answer: c

19. In the prismatic compass
a) the magnetic needle moves with the box
b) the line of the sight does not move with the box
c) the magnetic needle and graduated circle do not move with the box
d) the graduated circle is fixed to the box and the magnetic needle always remains in the N-S direction
Answer: c

20. For a line AB
a) the forebearing of AB and back bearing of AB differ by 180°
b) the forebearing of AB and back bearing of BA differ by 180°
c) both (a) and (b) are correct.
d) none is correct
Answer: a

21. Local attraction in compass surveying may exist due to
a) incorrect levelling of the magnetic needle
b) loss of magnetism of the needle
c) friction of the needle at the pivot
d) presence of magnetic substances near the instrument
Answer: d

22. In the quadrantal bearing system, a whole circle bearing of 293° 30′ can be expressed as
a) W23°30’N
b) N66°30’W
c) S113°30’N
d) N23°30’W
Answer: b

23. The prismatic compass and surveyor’s compass
a) give whole circle bearing (WCB) of a line and quadrantal bearing (QB) of a line respectively
b) both give QB of a line and WCB of a line
c) both give QB of a line
d) both give WCB of a line
Answer: a

24. The horizontal angle between the true meridian and magnetic meridian at a place is called
a) azimuth
b) declination
c) local attraction
d) magnetic bearing
Answer: b

25. A negative declination shows that the magnetic meridian is to the
a) eastern side of the true meridian
b) western side of the true meridian
c) southern side of the true meridian
d) none of the above
Answer: b

26. If the magnetic bearing of the sun at a place at noon in southern hemisphere is 167°, the magnetic declination at that place is
a) 77° N
b) 23° S
c) 13° E
d) 13° W
Answer: c

27. The graduations in prismatic compass
i) are inverted
ii) are upright
iii) run clockwise having 0° at south
iv) run clockwise having 0° at north
The correct answer is
a) (i) and (iii)
b) (i) and (iv)
c) (ii) and (iii)
d) (ii) and (iv)
Answer: a

28. Agate cap is fitted with a
a) cross staff
b) level
c) chain
d) prismatic compass
Answer: d

29. The temporary adjustments of a prismatic compass are
i) Centering
ii) Levelling
iii) Focusing the prism
The correct order is
a) (0, (iii), 00
b) (0, (ii), (iii)
c) (ii), (iii), 0)
d) (in), (i), (ii)
Answer: b

30. Theodolite is an instrument used for
a) tightening the capstan-headed nuts of level tube
b) measurement of horizontal angles only
c) measurement of vertical angles only
d) measurement of both horizontal and vertical angles
Answer: d

31. The process of turning the telescope about the vertical axis in horizontal plane is known as
a) transiting
b) reversing
c) plunging
d) swinging
Answer: d

32. Size of a theodolite is specified by
a) the length of telescope
b) the diameter of vertical circle
c) the diameter of lower plate
d) the diameter of upper plate
Answer: c

33. Which of the following is not the function of levelling head ?
a) to support the main part of the instrument
b) to attach the theodolite to the tripod
c) to provide a means for leveling the theodolite
d) none of the above
Answer: d

34. If the lower clamp screw is tightened and upper clamp screw is loosened, the theodolite may be rotated
a) on its outer spindle with a relative motion between the vernier and graduated scale of lower plate
b) on its outer spindle without a relative motion between the vernier and gra-duated scale of lower plate
c) on its inner spindle with a relative motion between the vernier and the graduated scale of lower plate
d) on its inner spindle without a relative motion between the vernier and the graduated scale of lower plate
Answer: c

35. A telescope is said to be inverted if its
a) vertical circle is to its right and the bubble of the telescope is down
b) vertical circle is to its right and the bubble of the telescope is up
c) vertical circle is to its left and the bubble of the telescope is down
d) vertical circle is to its left and the bubble of the telescope is up
Answer: a

36. The cross hairs in the surveying telescope are placed
a) midway between eye piece and objec¬tive lens
b) much closer to the eye-piece than to the objective lens
c) much closer to the objective lens than to the eye piece
d) anywhere between eye-piece and objective lens
Answer: b

37. For which of the following permanent adjustments of theodolite, the spire test is used ?
a) adjustment of plate levels
b) adjustment of line of sight
c) adjustment of horizontal axis
d) adjustment of altitude bubble and vertical index frame
Answer: c

38. The adjustment of horizontal cross hair is required particularly when the instrument is used for
a) leveling
b) prolonging a straight line
c) measurement of horizontal angles
d) all of the above
Answer: a

39. Which of the following errors is not eliminated by the method of repetition of horizontal angle measurement ?
a) error due to eccentricity of verniers
b) error due to displacement of station signals
c) error due to wrong adjustment of line of collimation and trunnion axis
d) error due to inaccurate graduation
Answer: b

40. The error due to eccentricity of inner and outer axes can be eliminated by
a) reading both verniers and taking the mean of the two
b) taking both face observations and taking the mean of the two
c) double sighting
d) taking mean of several readings distributed over different portions of the graduated circle
Answer: a

41. In the double application of principle of reversion, the apparent error is
a) equal to true error
b) half the true error
c) two times the true error
d) four times the true error
Answer: d

42. Which of the following errors can be eliminated by taking mean of bot face observations ?
a) error due to imperfect graduations
b) error due to eccentricity of verniers
c) error due to imperfect adjustment of plate levels
d) error due to line of collimation not being perpendicular to horizontal axis
Answer: d

43. Which of the following errors cannot be eliminated by taking both face observations ?
a) error due to horizontal axis not being perpendicular to the vertical axis
b) index error i.e. error due to imperfect adjustment of the vertical circle vernier
c) error due to non-parallelism of the axis of telescope level and line of collimation
d) none of the above
Answer: d

44. If a tripod settles in the interval that elapses between taking a back sight reading and the following foresight reading, then the elevation of turning point will
a) increase
b) decrease
c) not change
d) either ‘a’ or ‘b’
Answer: a

45. If altitude bubble is provided both on index frame as well as on telescope of a theodolite, then the instrument is levelled with reference to
i) altitude bubble on index frame
ii) altitude bubble on index frame if it is to be used as a level
iii) altitude bubble on telescope
iv) altitude bubble on telescope if it is to be used as a level The correct answer is
a) only (i)
b) both (i) and (iv)
c) only (iii)
d) both (ii) and (iii)
Answer: b

46. A’level line’is a
a) horizontal line
b) line parallel to the mean spheriodal surface of earth
c) line passing through the center of cross hairs and the center of eye piece
d) line passing through the objective lens and the eye-piece of a dumpy or tilting level
Answer: b

47. The following sights are taken on a “turning point”
a) foresight only
b) backsight only
c) foresight and backsight
d) foresight and intermediate sight
Answer: c

48. The rise and fall method of levelling provides a complete check on
a) backsight
b) intermediate sight
c) foresight
d) all of the above
Answer: d

49. If the R.L. of a B.M. is 100.00 m, the back- sight is 1.215 m and the foresight is 1.870 m, the R.L. of the forward station is
a) 99.345 m
b) 100.345 m
c) 100.655m
d) 101.870m
Answer: a

50. In an internal focussing type of telescope, the lens provided is
a) concave
b) convex
c) plano-convex
d) plano-concave
Answer: a

51. Which of the following errors can be neutralised by setting the level midway between the two stations ?
a) error due to curvature only
b) error due to refraction only
c) error due to both curvature and re-fraction
d) none of the above
Answer: c

52. Height of instrument method of levelling is
a) more accurate than rise and fall method
b) less accurate than rise and fall method
c) quicker and less tedious for large number of intermediate sights
d) none of the above
Answer: c

53. The rise and fall method
a) is less.accurate than height of instrument method
b) is not suitable for levelling with tilting levels
c) provides a check on the reduction of intermediate point levels
d) quicker and less tedious for large number of intermediate sights
Answer: c

54. If the staff is not held vertical at a level¬ling station, the reduced level calculated from the observation would be
a) true R.L.
b) more than true R.L.
c) less than true R.L.
d) none of the above
Answer: c

55. The difference between a level line and a horizontal line is that
a) level line is a curved line while horizontal line is a straight line
b) level line is normal to plumb line while horizontal line may not be normal to plumb line at the tangent point to level line
c) horizontal line is normal to plumb line while level line may not be normal to the plumb line
d) both are same
Answer: a

56. The sensitivity of a bubble tube can be increased by
a) increasing the diameter of the tube
b) decreasing the length of bubble
c) increasing the viscosity of liquid
d) decreasing the radius of curvature of tube
Answer: a

57. With the rise of temperature, the sensitivity of a bubble tube
a) decreases
b) increases
c) remains unaffected
d) none of the above
Answer: a

58. Refraction correction
a) completely eliminates curvature correction
b) partially eliminates curvature correction
c) adds to the curvature correction
d) has no effect on curvature correction
Answer: b

59. The R.L, of the point A which is on the floor is 100 m and back sight reading on A is 2.455 m. If the foresight reading on the point B which is on the ceiling is 2.745 m, the R.L. of point B will be
a) 94.80 m
b) 99.71 m
c) 100.29 m
d) 105.20 m
Answer: d

60. As applied to staff readings, the corrections for curvature and refraction are respectively
The above table shows a part of a level field book. The value of X should be
a) 98.70
b) 100.00
c) 102.30
d) 103.30
Answer: b

63. If the horizontal distance between the staff point and the point of observation is d, then the error due to curvature of earth is proportional to
a) d
b) 1/d
c) d2
d) 1/d2
Answer: c

64. Sensitiveness of a level tube is designated by
a) radius of level tube
b) length of level tube
c) length of bubble of level tube
d) none of the above
Answer: a

65. Which of the following statements is in-correct ?
a) Error due to refraction may not be completely eliminated by reciprocal levelling.
b) Tilting levels are commonly used for precision work.
c) The last reading of levelling is always a foresight.
d) All of the above statements are incorrect.
Answer: d

66. Dumpy level is most suitable when
a) the instrument is to be shifted frequently
b) fly levelling is being done over long distance
c) many readings are to be taken from a single setting of the instrument
d) all of the above
Answer: c

67. The difference of levels between two stations A and B is to be determined. For best results, the instrument station should be
a) equidistant from A and B
b) closer to the higher station
c) closer to the lower station
d) as far as possible from the line AB
Answer: a

68. Contour interval is
a) inversely proportional to the scale of the map
b) directly proportional to the flatness of ground
c) larger for accurate works
d) larger if the time available is more
Answer: a

69. An imaginary line lying throughout the surface of ground and preserving a constant inclination to the horizontal is known as
a) contour line
b) horizontal equivalent
c) contour interval
d) contour gradient
Answer: d

70. The suitable contour interval for a map with scale 1 : 10000 is
a) 2 m
b) 5m
c) 10 m
d) 20 m
Answer: a

71. Select the correct statement.
a) A contour is not necessarily a closed curve.
b) A contour represents a ridge line if the concave side of lower value con¬tour lies towards the higher value contour.
c) Two contours of different elevations do not cross each other except in case of an overhanging cliff.
d) All of the above statements are correct.
Answer: c

72. A series of closely spaced contour lines represents a
a) steep slope
b) gentle slope
c) uniform slope
d) plane surface
Answer: a

73. Direct method of contouring is
a) a quick method
b) adopted for large surveys only
c) most accurate method
d) suitable for hilly terrains
Answer: c

74. In direct method of contouring, the process of locating or identifying points lying on a contour is called
a) ranging
b) centring
c) horizontal control
d) vertical control
Answer: d

75. In the cross-section method of indirect contouring, the spacing of cross-sections depends upon
i) contour interval
ii) scale of plan
iii) characteristics of ground
The correct answer is
a) only (i)
b) (i)and(ii)
c) (ii) and (iii)
d) (i), (ii) and (iii)
Answer: d

76. Which of the following methods of con-touring is most suitable for a hilly terrain ?
a) direct method
b) square method
c) cross-sections method
d) tacheometric method
Answer: d

77. Select the correct statement.
a) Contour interval on any map is kept constant.
b) Direct method of contouring is cheap¬er than indirect method.
c) Inter-visibility of points on a contour map cannot be ascertained.
d) Slope of a hill cannot be determined with the help of contours.
Answer: a

78. Closed contours, with higher value inwards, represent a
a) depression
b) hillock
c) plain surface
d) none of the above
Answer: b

79. Contour interval is
a) the vertical distance between two con-secutive contours
b) the horizontal distance between two consecutive contours
c) the vertical distance between two points on same contour
d) the horizontal distance between two points on same contour
Answer: a

80. Benchmark is established by
a) hypsometry
b) barometric levelling
c) spirit levelling
d) trigonometrical levelling
Answer: c

81. The type of surveying which requires least office work is
a) tacheomefry
b) trigonometrical levelling
c) plane table surveying
d) theodolite surveying
Answer: c

82. Intersection method of detailed plotting is most suitable for
a) forests
b) urban areas
c) hilly areas
d) plains
Answer: c

83. Detailed plotting is generally done by
a) radiation
b) traversing
c) resection
d) all of the above
Answer: a

84. Three point problem can be solved by
a) Tracing paper method
b) Bessels method
c) Lehman’s method
d) all of the above
Answer: d

85. The size of a plane table is
a) 750 mm x 900 mm
b) 600 mm x 750 mm
c) 450 mm x 600 mm
d) 300 mm x 450 mm
Answer: b

86. The process of determining the locations of the instrument station by drawing re sectors from the locations of the known stations is called
a) radiation
b) intersection
c) resection
d) traversing
Answer: c

87. The instrument used for accurate centering in plane table survey is
a) spirit level
b) alidade
c) plumbing fork
d) trough compass
Answer: c

88. Which of the following methods of plane table surveying is used to locate the position of an inaccessible point ?
a) radiation
b) intersection
c) traversing
d) resection
Answer: b

89. The two point problem and three point problem are methods of
a) resection
b) orientation
c) traversing
d) resection and orientation
Answer: d

90. The resection by two point problem as compared to three point problem
a) gives more accurate problem
b) takes less time
c) requires more labour
d) none of the above
Answer: c

91. The methods used for locating the plane table stations are
i) radiation
ii) traversing
iii) intersection
iv) resection
The correct answer is
a) (i) and (ii)
b) (iii) and (iv)
c) (ii) and (iv)
d) (i) and (iii)
Answer: c

92. After fixing the plane table to the tripod, the main operations which are needed at each plane table station are
i) levelling
ii) orientation
iii) centering
The correct sequence of these operations is
a) (i), (ii),.(iii)
b) (i), (iii), (ii)
c) (iii), (i), (ii)
d) (ii), (Hi), (i)
Answer: b

93. Bowditch rule is applied to
a) an open traverse for graphical adjustment
b) a closed traverse for adjustment of closing error
c) determine the effect of local attraction
d) none of the above
Answer: b

94. If in a closed traverse, the sum of the north latitudes is more than the sum of the south latitudes and also the sum of west departures is more than the sum of the east departures, the bearing of the closing line is in the
a) NE quadrant
b) SE quadrant
c) NW quadrant
d) SW quadrant
Answer: b

95. If the reduced bearing of a line AB is N60°W and length is 100 m, then the latitude and departure respectively of the line AB will be
a) +50 m, +86.6 m
b) +86.6 m, -50 m
c) +50m, -86.6 m
d) +70.7 m,-50 m
Answer: b

96. The angle between the prolongation of the preceding line and the forward line of a traverse is called
a) deflection angle
b) included angle
c) direct angle
d) none of the above
Answer: a

97. Transit rule of adjusting the consecutive coordinates of a traverse is used where
a) linear and angular measurements of the traverse are of equal accuracy
b) angular measurements are more accurate than linear measurements
c) linear measurements are more accurate than angular measurements
d) all of the above
Answer: b

98. Which of the following methods of theodolite traversing is suitable for locating the details which are far away from transit stations ?
a) measuring angle and distance from one transit station
b) measuring angles to the point from at least two stations
c) measuring angle at one station and distance from other
d) measuring distance from two points on traverse line
Answer: b

99. Subtense bar is an instrument used for
a) levelling
b) measurement of horizontal distances in plane areas
c) measurement of horizontal distances in undulated areas
d) measurement of angles
Answer: c

100. Horizontal distances obtained by thermometric observations
a) require slope correction
b) require tension correction
c) require slope and tension corrections
d) do not require slope and tension corrections
Answer: d

101. The number of horizontal cross wires in a stadia diaphragm is
a) one
b) two
c) three
d) four
Answer: c

102. If the intercept on a vertical staff is ob-served as 0.75 m from a tacheometer, the horizontal distance between tacheometer and staff station is
a) 7.5 m
b) 25 m
c) 50
d) 75 m
Answer: d

103. For a tacheometer the additive and multi-plying constants are respectively
a) 0 and 100
b) 100 and 0
c) 0 and 0
d) 100 and 100
Answer: a

104. If the focal length of the object glass is 25 cm and the distance from object glass to the trunnion axis is 15 cm, the additive constant is
a) 0.1
b) 0.4
c) 0.6
d) 1.33
Answer: b

105. Overturning of vehicles on a curve can be avoided by using
a) compound curve
b) vertical curve
c) reverse curve
d) transition curve
Answer: d

106. Different grades are joined together by a
a) compound curve
b) transition curve
c) reverse curve
d) vertical curve
Answer: d

SURVEYING Objective type Questions and Answers pdf free download ::

[PDF Notes] International Finance Corporation (IFC) was established in July 1956

International Finance Corporation (IFC) was established in July 1956 as an affiliate of the World Bank to provide finance to the private sector. The World Bank grants loans to the governments of the member countries or provides loan capital to the private enterprises on the guarantee of the member governments.

Moreover the World Bank does not provide risk capital. The IFC was established with the specific purpose of providing risk capital to the private enterprises in the less developed countries without government guarantee.

Though the IFC is affiliated to the World Bank, but it is a separate legal entity with separate fund and functions. The membership of the Corporation is open only to the members of the World Bank.

The organisation of the Corporation is the same as that of the World Bank. The Board of Governors and the Executive Directors of the World Bank also function as the Board of Governors and the Executive Directors of the IFC.

The Corporation started with the initial authorised capital of $100 million which has been increased from time to time. The subscription quota of each member is proportionate to its share of subscription to the capital of the World Bank.

[12 Class Notes] ECOSYSTEM – Biology CBSE

ECOSYSTEM – Biology CBSE :-

British ecologist Arthur Tansley first defined the term Ecosystem.ECOSYSTEM :- the functional unit of nature, where living organisms interact among themselves and with the surrounding physical environment.

Types of Ecosystems:

New Species Discovered in Different Ecosystems:
·         Pinocchio: long nosed frog found in Indonesia
·         Bald headed parrot in Amazon
·         Yeti Crab (Kiwa hirsuta) near Easter islands.Structure of Ecosystems
An Ecosystem has two components:
·         Biotic components and
·         Abiotic components

Stratification:

This is the Vertical Distribution of Different Species occupying Different Levels.

The levels are called STRATA.

Aspects Affecting the Functioning of an Ecosystem are:

1. PRODUCTIVITY
The rate of synthesis of organic matter (biomass) during a given period of time. It is measured as weight (g-2) or as energy (kcal m-2). It is used to compare productivity of different ecosystems.

  • Primary productivity:

It is the amount of biomass produced per unit area in a given time period by Plants during Photosynthesis.
GPP – R = NPP
*GPP-Gross Primary Productivity             *NPP-Net Primary Productivity

  • Secondary productivity

It is the amount of biomass produced at any of the Consumer levels in a given period of time.

2. DECOMPOSITION

It is the process of breaking down of dead organic matter into smaller organic molecules and inorganic molecules by Decomposers (bacteria, fungi)

DETRITUS: Dead remains of plants and animals is called detritus.

DETRITIVORES: Animals that feed on decaying organic matter (detritus).

Examples: earthworms, termites, snails etc

Mechanism of Decomposition:

  1. Fragmentation of Detritus: Detritivores feed on detritus —breakdown — increases the surface area of detritus particles for microbial action.
  2. Leaching: Soluble inorganic nutrients dissolve in water -– percolate through the soil —removed due to leaching action.
  3. Catabolism: Decomposers (bacteria, fungi) release enzymes — decompose detritus — simpler inorganic compounds.
  4. Humification: Simplified detritus— converted to HUMUS

– Humus is a Dark, Amorphous substance.
– Highly resistant to Microbial Action
– Undergoes Decomposition very Slowly.
– Reservoir of nutrients (due to colloidal nature)

5. Mineralisation: Humus is degraded – releases inorganic substances
( CO2, H2O etc) and nutrients (Ca2+, Mg2+,K+ etc)

Factors affecting rate of Decomposition:

    • Chemical composition – decomposition rate will be slow when detritus is rich in lignin and chitin and rate increases when detritus is rich in nitrogen and water soluble substances like sugsrs.
    • Climatic conditions – warm and moist environment favour decomposition and low temperature and anaerobiosis inhibit decomposition.


3. ENERGY FLOW

►     SUN- Main Source of energy
►     50% of incident light is PHOTOSYNTHETICALLY ACTIVE  RADIATION (PAR)
►     2- 10 % of PAR is captured by plants.
►     Only a small fraction of this (stored as organic compounds) is transferred to consumers; the rest is used up in respiration and other life-supporting activities of the plants.
►     As energy is transferred as food, most part is lost as heat at each stage (10% LAW)

Unidirectional flow of Energy:
Sun        ->    Producers   ->   Consumers

Transfer of energy / food from the producer through a series of organisms is known as FOOD CHAINS.

FOOD CHAINS

  • Food chains represent energy flow through ecosystems.
  • Different steps in a food chain are TROPHIC LEVELS
  • Basic terms:

Producers, Herbivores, Carnivores, Omnivores.

1.GRAZING FOOD CHAIN (GFC)

  • Primary source of energy – Solar radiations.
  • First trophic level includes – All Herbivores.
  •  -GFCs are Long-sized chains

2) DETRITUS FOOD CHAIN (DFC)
·         Primary source of energy is Detritus.
·         First trophic level includes Detritivores.
·         Detritus Food Chains are small-sized chains.

SAPROPHYTES:These include decomposers (fungi, bacteria) which feed on detritus.

FOOD WEBS
•       The Natural Interconnection of Several Food Chains forms a FOOD WEB.
•       Provides alternate pathways for food availability.
•       Unlike food chains, food webs are never straight.
•       Help in ecosystem development and stability.

TEN PERCENT LAW:

Ø  By Lindemann in 1942

Ø  States that : during transfer of energy from one trophic level to another, only about 10% is stored at higher levels; remaining 90% is lost in respiration (heat)

4. ECOLOGICAL PYRAMIDS

  • Developed by Charles Elton in 1927.
  • Pyramids are an expression of the relationship between organisms at different trophic levels in terms of their number, biomass or energy.
  • Three types of pyramids:

1.       Pyramid of Number
2.       Pyramid of Biomass
3.       Pyramid of energy

  1. Pyramid of Number:  The relationship between producers and consumers in an ecosystem can be represented in the form of a pyramid in terms of number called pyramid of number.
  2. Pyramid of Biomass:  The relationship between producers and consumers in an ecosystem can be represented in the form of a pyramid in terms of biomass called pyramid of biomass.  It can be of two types:

a)      Upright (in case of grassland ecosystem)
b)      Inverted (in case of pond ecosystem)

3.      Pyramid of energy:  The relationship between producers and consumers in an ecosystem can be represented in the form of a pyramid in terms of flow of energy called pyramid of energy.  It is always upright.
Learn more from your teachers in class along with diagram

Limitations of Ecological Pyramids:

  • ž  It does NOT consider the same species belonging to two or more trophic levels.
  • ž  It is based on simple food chains, which hardly exist. It does NOT accommodate food webs.
  • ž  Saprophytes (decomposers) are NOT given any place in the ecosystem.

Climax Community:

  • Changes that lead finally to a community that is in near equilibrium with the environment.
  • It remains stable as long as the environment remains unchanged.

The Rainforest is an example of climax community ecosystem.

Ecological Succession:

  • Refers to predictable and orderly change in the composition or structure of a community.
  • May be initiated either by formation of new, unoccupied habitat or by some form of disturbance of an existing community.
  • Sere – entire sequence of community that successively change in a given area.
    • Seral stages – individual transitional communities.


Seral Communities
:

Hydrosere – Community in freshwater
Lithosere – Community on rock
Pssamosere – Community on sand
Halosere – Community in saline body
Xerosere – Community in dry area
Primary Succession

  • If the development begins on an area that has not been previously occupied by a community.
  • Pioneer species – lichens, phytoplankton, etc.
  • Examples:

– newly exposed rock or sand surface
–  a lava flow
–  glacial tills
–  newly formed lake,

Secondary Succession

  • If the community development is proceeding in an area from which a community was removed.
  • Pioneer species – grasses, wildflowers, algae.
  • Examples:

–  an abandoned crop field
–  cut-over forest
–  natural forces such as wind storms and floods

Succession in Plants:

Hydrarch succession

  • It takes place in wetter areas and the successional series progress from hydric to the mesic conditions.

Phytoplankton in pond -> Submerged plant stage-> Submerged free floating plant stage -> Reed – swamp stage -> Marsh – meadow stage – scrub stage -> Forest

Xerarch succession

  • It takes place in dry areas and the series progress from xeric to mesic condition.

Bare rock -> Lichens and mosses -> Annual grasses -> Perennial grasses -> Shrubs -> Tall Trees

The Nutrient Cycle

  • Also known as biogeochemical cycle.
  • Environmental factors like soil, moisture, temperature, etc. regulate the rate of release of nutrients into the atmosphere.
  • Standing state – amount of nutrients, such as C, N, P, Ca, etc. present in the soil at any given time.
  • Nutrients are never lost from the ecosystem; they are recycled time an again indefinitely.
  • There are two types:

–  Gaseous cycle
–  Sedimentary cycle

Ecosystem Services

  • Humankind benefits from a multitude of resources and processes that are supplied by natural ecosystems. Collectively, these benefits are known as ecosystem services.
  1. Purify air and water
  2. Decomposition of waste materials
  3. Cycle nutrients
  4. Pollinate crops
  5. Maintain biodiversity
  • Researchers have put an average price tag of US $33 trillion a year on these fundamental ecosystems services, which is largely taken for granted because they are free.

[PDF Notes] What are the main Objectives and Functions of ADB?

The main objectives of ADB, as laid down in its Charter, are “to foster economic growth and cooperation in the region of Asia and Far East, and to contribute to the acceleration of the process of economic development of the developing members in the region, collectively and individually.” The Bank aims at achieving this broad objective through the following functions:

(i) Mobilisation and promotion of investment of private and public capital for productive purposes.

(ii) Utilisation of its resources for financing those development projects which contribute most to the harmonious economic growth of the region as a whole, with special emphasis on the needs of the smaller or less developed members.

(iii) Coordination of plans and policies of the member countries with a view to achieving better utilisation of their resources, making them economically more complementary, and expanding their foreign trade.

(iv) Provision of technical assistance to the member countries for the preparation, financing and execution of development projects.

(v) Cooperation with the United Nations and its various organs and other international organisations with the objective of persuading them to make investments in this region.

(vi) Undertaking of such other activities which may help to achieve its main objectives.

[12 Class Notes] ORGANISMS & POPULATIONS – Biology CBSE

ORGANISMS AND POPULATIONS – Biology CBSE :-

ECOLOGY:Branch of Science which deals with relationship between organisms & their physical & biological environment.

LEVELS OF ORGANISATION:
• Organisms- every individual of a species
• Population- individuals of the same species at a given place
• Communities- assembly of population of all different species living in an area and interacting.
• Biomes- large unit of flora and fauna in a specific climatic zoneENVIRONMENT
Sum of all biotic and abiotic factors that surround and influence an organism in it’s survival and reproduction.Factors affecting environment:
• Rotation of earth
• Seasonal and annual variation in temperature and precipitation
• HabitatsMAJOR BIOMES
1. Artic & Alpine Tundra
2. Coniferous Forest
3. Temperate Forests
4. Grassland
5. Tropical Forest
6. Desert
MAJOR  ABIOTIC FACTORS
•          Temperature
•           Water
•           Light
•           Soil
Temperature
•          Ecologically most imp. Factor
•          Decreases progressively from equator towards pole and from plane to mountain tops
•           Polar Region and high altitudes- sub zero level Tropical deserts > 50°C
•          Organisms survive only in suitable range of temperature
•          Based on tolerance to temperature

–   Eurythermal
Organisms that tolerate wide range of temperature
–   Stenothermal
Organisms that tolerate only narrow range of temperature

Water
•          Life on earth originated in water
•           Productivity and distribution of plants depends on water

Based on tolerance to salinity
– Euryhaline
Organisms that can tolerate wide range of salinity
– Stenohaline
Organisms that can only tolerate narrow range of salinity

•          Freshwater animals cannot live in sea water and vice versa because of osmotic problems.

Light
•          sunlight source of energy- photosynthesis
•           Small plants (canopied by tall plants) adapted to photosynthesize at low light conditions.
•           Flowering dependent on sunlight
•           Foraging, Reproductive and migratory activities of animals depend on seasonal variation in light intensity
•           UV component – harmful to organisms

Soil
Nature of soil depends on
I.            climate
II.           weathering process
III.          sedimentary or transported
IV.          soil development

Characteristics of soil
a.       soil composition
b.      grain size
c.       aggregation- determine percolation and water holding capacity of soil

RESPONSES TO ABIOTIC FACTORS
Homeostasis: The ability of an organism to maintain the constancy of its internal environment despite varying external environmental conditions.

Q: How does Homeostasis occur?

1. Regulate: maintain homeostasis by ensuring constant body temp (thermoregulation), and constant osmotic concentration (osmoregulation). Examples – mammals regulate temperature by  shivering in cold and sweating in heat

2. Conform: internal environment of conformers changes with external environment

Q:Why small animals are rarely found in polar regions?

A: Small animals have large surface area compared to volume so they lose heat easily in cold and have to expend energy to generate body heat.

But, if stressful external conditions are localized or remain for short duration, then alternatives are migrate / suspend.

3. Migrate: Move from stressful habitat temporarily to hospitable area and return when stressful period over.

E.g.- Migration of birds to Keolado National Park, Rajasthan from Siberia

4. Suspend: Organisms develop mechanisms to deal with stressful situation

Examples- Spores (bacteria and fungi)

– Seeds (angiosperms)- dormancy
– Hibernation (Bears)
– Aestivation ( snails)
– Diapause (stage of suspended development) in zoo plankton

Adaptation

Any ability of an organism that enables an organism to survive and reproduce in its habitat

ADAPTATIONS IN ORGANISMS

1. Kangaroo rat: internal fat oxidation to produce water as by product- concentrated urine
2.Desert plants: thick cuticle, stomata in deep pits to minimize transpiration and special photosynthetic pathway (CAM).  Ex. OPUNTIA – leaves reduced to spines, photosynthetic stems
3. Cold climate mammals: short ears and limbs to minimize heat loss. This is Allen’s Rule.
4. People living at high altitude: increased RBC production and increased breathing rate
5. Desert lizards: bask in sun when cold and move to shade when hot.

POPULATION

Group of individuals living in a well defined area which share or compete for similar resources and potentially interbreed

Example: Lotus plants in a pond

Bacteria in a culture plate

Population ecology is therefore, an imp. area of ecology because it links ecology to population genetics and evolution

POPULATION ATTRIBUTES

1.Birth rate- Average no. of young ones born in  a period of time with reference to the  members of the population.
2. Death rates- Average no. of deaths in a period of time with reference to the members of the population.
3.Sex Ratio- No. of females and males per 1000 individuals
4. Age pyramid: Plot of age distribution (% individuals of a given age or age group)

It reflects whether growth is
(i)            Expanding
(ii)           Stable
(iii)          Declining

POPULATION DENSITY:
Number of individuals present per unit area at a given time.POPULATION GROWTH
Factors affecting change in population density

  1. Food availability
  2. Predation pressure
  3. Weather

Density changes by change in four basic processes
(a)    Natality              –     Increase population
(b) Immigration      –    Increase population
(c)  Mortality           –    Decrease population
(d) Emigration        –    Decrease population

1.Natality (B) : Number of births during given period in the population that are added to the initial density
2.Mortality (D) : Number of deaths in the population during a given period.
3.Emigration (E) : Number of individuals of the population who left the habitat and went elsewhere during the given period
4. Immigration (I) : Number of individuals of the same species that have come into the habitat from elsewhere during the time under consideration.

  • If N is the population density at time ‘t’, then its density at time ‘t+1’

Nt+1 = Nt + [(B + I) – (D + E)]

  • Population density will increase if (B+I) > (D+E)

GROWTH MODELS

  • EXPONENTIAL
  • LOGISTIC

EXPONENTIAL GROWTH

•           When resources are unlimited, each species realizes its innate potential to grow in no. – population grows exponentially
•           N – Population size
b – Birth rates( per capita births)
d – Death rates (per capita deaths
dN/dt – increase/decrease in N during time t

Then,   dN/dt = (b – d)*N
Let (b – d) = r, then
dN/dt = r*N
Where, r – intrinsic rate of natural increase
For human population in 1981, r = 0.0205

Integral form of exponential growth eq.

                  Nt = N0ert

Where Nt = Population density after t
N0 =Initial population density
r   = Intrinsic rate of natural increase
e  = base of natural logarithms

•           Species growing exponentially under unlimited resources reaches enormous population density in short time.

LOGISTIC GROWTH
•           No population has unlimited resources-leads to competition for resources
•          Fittest individual survive and reproduce
•          Carrying capacity (K)- Maximum population density a habitat’s resources can support
•          When a population has limited resources it shows

  1. lag phase
  2. phase of acceleration
  3. asympote- population density = K

Verhulst Pearl Logistic Growth

                          dN/dt = rN [(K – N)/K]

Where   N = Population density at time t
r = Intrinsic rate of natural increase
K = Carrying capacity

•           As resources for most organisms are finite logistic growth more realistic

LIFE HISTORY VARIATIONS

•          Darwinian fitness – Reproductive fitness
•          Organisms adopt most efficient reproductive strategy suited to their habitat

Examples:

1. Breed once in lifetime – pacific salmon fish ,Bamboo
2. Breed many times in life time – birds,  mammals
3. Produce large no. of small sized offspring  – Oysters, pelagic fishes
4. Produce small no. of large sized offspring – birds, mammals

Ecologists say life history traits depend on constraints of biotic and abiotic parts

 
Population Interactions

Minimum requirement of species- one more species to feed on.

Interspecific interactions – Interactions of populations of two different species.

Types of Interactions:

Name of Interaction        Species A       Species B

Mutualism                         +                   +
Competition                       –                    
Predation                          +                   
Parasitism                         +                   
Commensalism                   +                   0
Ammensalism                     –                    0

+   Positive effect                    –  Detrimental effect                      0  Neutral effect 

PREDATION

It is an Interspecific Interaction where one animal kills and consumes the other weaker animal.

Roles of Predators

  • Transfer energy from plants to higher trophic levels (position of organism in food chain)
  • Control Prey population – Prickly pear cactus- moth
  • Biological control of Agricultural pest
  • Maintain species diversity by reducing intensity of competition among competing prey species

Q: Why predators are prudent?

A: Over exploitation of prey by the predators results in extinction of prey and predator.

Defense to lessen impact of predation

  • Insects and frog – camouflage
  • Monarch butterfly – poisonous


PLANTS MORPHOLOGICAL AND CHEMICAL DEFENCES

  • Thorns- cactus and Acacia
  • Produce and store chemical – Calotropis
  • Nicotine, Caffeine, Quinin, Strychnine, opium – against grazers & browsers

COMPETITION
Interaction either among individuals of same species or between individuals of different species.

Occurs among closely related species but not always true

1. Unrelated species also compete- flamingo & fish compete for zooplankton
2. Feeding efficiency of a species reduce due to other species even if resources are plenty – Abingdon tortoise.

Evidence for competition
Competitive release – species distribution restricted to small areas due to competitively superior species.

GAUSE’S COMPETITION EXCLUSION PRINCIPLE
“Two closely related species competing for same resources cannot coexist as the competitively inferior one will be eliminated.”

Resource partition- Two competing species avoid competition by diff. feeding and foraging patterns-Mc Arthur (warblers foraging activities)

PARASITISM
It is the interaction where one species (parasite) depends on the other species (host) for food and shelter, host is harmed.

  • Parasites and host self-evolve.
  • Adaptations of parasites

– Loss of unnecessary sense organs
– Hooks and sucker
– Loss of digestive system
– High Reproductive capacity

  • Parasites-

(i) Reduce the survival of host
(ii) Growth and reproductive rate are reduced
(iii) Render the host vulnerable to its predators by making them weak

Types of parasite

ECTOPARASITESdepend on external surface of host
Example – head lice on humans, ticks on dogs

ENDOPARASITEStake shelter within the body of the host organism
Example – Liverfluke, Plasmodium

MUTUALISM
It is interaction in which both the interacting species are benefited

Examples
1. Lichen – fungi and algae
2. Mycorrhizae – fungi and roots of higher plants
3. Pollination of plants by insects
4. Mediterranean orchid- sexual deceit for pollination- appears as female bee

AMENSALISM
Interaction between two different species, in which one species is harmed and the other species is neither harmed nor benefited. Example.  Bacterial culture, after few days fungus growth will be there on it like Pencillium, and its secretions of chemical will kill bacteria, but no benefits to fungi.

[PDF Notes] What are the Fundamental Principles of GATT?

The ultimate aim of GATT is the establishment of a free multilateral trading system and liberalisation of international trade through removal of discrimination in international trade and reduction in trade barriers.

For the achievement of this objective, GATT has adopted the following fundamental principles. These principles forbid unfair trade practice and set a code of conduct for the participants.

(i) Trade should be on non-discriminatory basis.

(ii) Quantitative restrictions on trade are prohibited.

(iii) Settlement of trade disputes should be achieved through consultations within the framework of GATT.

(iv) Tariff reductions are to be accomplished in a series of multilateral negotiations, or GATT rounds.