Daily Static MCQs for UPSC & State PSC Exams - Environment & Ecology (15 July 2023)

Daily Static MCQs Quiz for UPSC, IAS, UPPSC/UPPCS, MPPSC. BPSC, RPSC & All State PSC Exams

Subject : Environment & Ecology

1. Consider the following statements:

1. In the aquatic environment, the sediment-characteristics often determine the type of benthic animals that can thrive there.
2. Like humans, plants also have mechanisms to maintain internal temperature.
3. Very small animals are rarely found in polar regions since thermoregulation is energetically expensive for these animals.

How many of the above statements are correct?

(a) Only one
(b) Only two
(c) All three
(d) None

Answer: (B)

Explanation:

  • The mechanisms used by most mammals to regulate their body temperature are similar to the ones that we humans use. We maintain a constant body temperature of 370C. In summer, when outside temperature is more than our body temperature, we sweat profusely.
  • The resulting evaporative cooling, similar to what happens with a desert cooler in operation, brings down the body temperature. In winter when the temperature is much lower than 370C, we start to shiver, a kind of exercise which produces heat and raises the body temperature. Plants, on the other hand, do not have such mechanisms to maintain internal temperatures. Hence, statement 2 is incorrect.
  • Thermoregulation is energetically expensive for many organisms. This is particularly true for small animals like shrews and humming birds. Heat loss or heat gain is a function of surface area. Since small animals have a larger surface area relative to their volume, they tend to lose body heat very fast when it is cold outside; then they have to expend much energy to generate body heat through metabolism. This is the main reason why very small animals are rarely found in polar regions. Hence, statement 3 is correct.

2. Consider the following statements regarding ocean acidification:

1. It largely occurs due to the high absorption of nitrogenous based acidic compounds.
2. Introduction of sea grasses can reduce the impact of acidification.

Which of the above statements is/are correct?

(a) 1 only
(b) 2 only
(c) Both 1 and 2
(d) Neither 1 nor 2

Answer: (B)

Explanation:

  • Ocean acidification refers to a reduction in the pH of the ocean over an extended period of time, caused primarily by uptake of carbon dioxide (CO2) from the atmosphere. Nitrogenous compounds contribute fraction to ocean acidification. Hence, statement 1 is incorrect.
  • Sea grass has ability to control ocean acidification. Hence, statement 2 is correct.

3. Birds following Army Ants is an example for which of the following types of symbiotic relationship between organisms?

(a) Mutualism
(b) Parasitism
(c) Commensalism
(d) Competition

Answer: (C)

Explanation:

  • Commensalism is a type of symbiotic relationship between organisms in which one organism benefits without harming the other.
  • Many birds form a commensal relationship with some species of ants like the army ants. A great number of army ants trail on the forest floor, and while moving, stir up many insects lying in their path. The birds follow these army ants and eat up the insects that try to escape from them. The birds benefit by catching their prey easily, while the army ants are totally unaffected. Hence, option (c) is correct.

4. Consider the following statements about life forms:

1. Epiphytic: plants which derive nutrients from fungi that are attached to the roots of a vascular plant
2. Terrestrial: plants growing on land and climbers
3. Mycoheterotrophic: plants growing on another plants

Which of the above are correctly matched?

(a) 1 and 2 only
(b) 2 and 3 only
(c) 2 only
(d) 1, 2 and 3

Answer: (C)

Explanation:

  • Epiphytic - plants growing on other plants including those growing on rock boulders and often termed lithophytes.
  • Terrestrial - plants growing on land and climbers.
  • Mycoheterotrophic - plants which derive nutrients from mycorrhizal fungi that are attached to the roots of a vascular plant.

Hence, option (c) is correct.

5. In dry areas of low rainfall, thorny shrubs and scrubs grow. How do such plants adapt to the low level of moisture?

1. Such plants generally have shallow roots to utilize water more efficiently.
2. Some plant leaves have thorny and waxy surface to reduce loss of moisture by transpiration.

Which of the above statements is/are incorrect?

(a) 1 only
(b) 2 only
(c) Both 1 and 2
(d) Neither 1 nor 2

Answer: (A)

Explanation:

  • They have adapted to desert conditions by developing extremely long root systems to draw water from deep underground near the water table. The mesquite’s roots are considered the longest of any desert plant and have been recorded as long as 80 feet. Hence, statement 1 is incorrect.
  • Some have succulent leaves to store moisture. Some have thorny leaves to reduce water loss by transpiration. Waxy leaves protect soil moisture beneath the coating. Hence, statement 2 is correct.