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Question
Given below are adaptations seen in organisms that help them to cope with the extremes in their environment.
(i) Desert plants have a thick cuticle on leaf surface and sunken stomata to maximize water loss
(ii) Desert plants have CAM pathway which enables their stomata to remain closed during night time
(iii) Kangaroo rats meet their water requirement through internal oxidation of proteins
(iv) Snails undergo aestivation during summer
How many of the above given statements are incorrect?
Given below are adaptations seen in organisms that help them to cope with the extremes in their environment.
(i) Desert plants have a thick cuticle on leaf surface and sunken stomata to maximize water loss
(ii) Desert plants have CAM pathway which enables their stomata to remain closed during night time
(iii) Kangaroo rats meet their water requirement through internal oxidation of proteins
(iv) Snails undergo aestivation during summer
How many of the above given statements are incorrect?
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Solution
The correct option is C 3
The morphological, physiological or behavioural attributes of the organism that helps them to cope with the extremes in their environment is called adaptation. These adaptations enable the organisms to survive and reproduce in varied habitats.
Adaptations in organisms:
Desert plants are called xerophytic plants as they are adapted to living in hot and dry habitats (xeric habitat). The special adaptations in these plants allow them to prevent the loss of water by the process of transpiration. This is essential because deserts have a major scarcity of water.
Maximum amount of transpiration occurs through tiny pores on the leaves known as stomata. Thus, some desert plants have sunken stomata buried in pits to minimise the loss of water via transpiration. Cuticle is a transparent waxy outer layer that covers the leaves of plants. Presence of a thick cuticle also helps to minimise water loss by reducing the rate of transpiration.
Therefore statement (i) is incorrect as the thick cuticle and sunken stomata do not maximize water loss rather minimise it.
The stomata in most desert plants remain closed during the day to prevent transpiration. This can interfere with the plant’s photosynthetic ability as plants take in carbon dioxide via the stomatal pores. Hence, these plants follow a specialised photosynthetic pathway known as the Crassulacean acid metabolism (CAM) pathway that enables their stomata to be closed during the day, without hampering the process of photosynthesis.
Statement (ii) is incorrect as the stomata of desert plants remain closed during day time.
Kangaroo rat is a rodent inhabiting the deserts of North America.
Even in the absence of an external source of water, they are able to survive as they are capable of meeting the water requirement through the oxidation of fats. Oxidation of fats produces water as a by-product. Also, the kangaroo rats produce highly concentrated urine to minimise water loss.
Hence, statement (iii) is incorrect as the kangaroo rat meets the water requirement through the oxidation of fats but not proteins.
Aestivation (summer sleep) and hibernation (winter sleep) are responses to unfavourable conditions, during which organisms suspend their metabolic activities and go into a period of inactivity. Animals such as snails and fish go into aestivation while hibernation is seen in animals such as polar bears.
Hence, statement (iv) is correct.
Therefore, out of the four statements given, three statements are incorrect.
The morphological, physiological or behavioural attributes of the organism that helps them to cope with the extremes in their environment is called adaptation. These adaptations enable the organisms to survive and reproduce in varied habitats.
Adaptations in organisms:
Desert plants are called xerophytic plants as they are adapted to living in hot and dry habitats (xeric habitat). The special adaptations in these plants allow them to prevent the loss of water by the process of transpiration. This is essential because deserts have a major scarcity of water.
Maximum amount of transpiration occurs through tiny pores on the leaves known as stomata. Thus, some desert plants have sunken stomata buried in pits to minimise the loss of water via transpiration. Cuticle is a transparent waxy outer layer that covers the leaves of plants. Presence of a thick cuticle also helps to minimise water loss by reducing the rate of transpiration.
Therefore statement (i) is incorrect as the thick cuticle and sunken stomata do not maximize water loss rather minimise it.
The stomata in most desert plants remain closed during the day to prevent transpiration. This can interfere with the plant’s photosynthetic ability as plants take in carbon dioxide via the stomatal pores. Hence, these plants follow a specialised photosynthetic pathway known as the Crassulacean acid metabolism (CAM) pathway that enables their stomata to be closed during the day, without hampering the process of photosynthesis.
Statement (ii) is incorrect as the stomata of desert plants remain closed during day time.
Kangaroo rat is a rodent inhabiting the deserts of North America.
Even in the absence of an external source of water, they are able to survive as they are capable of meeting the water requirement through the oxidation of fats. Oxidation of fats produces water as a by-product. Also, the kangaroo rats produce highly concentrated urine to minimise water loss.
Hence, statement (iii) is incorrect as the kangaroo rat meets the water requirement through the oxidation of fats but not proteins.
Aestivation (summer sleep) and hibernation (winter sleep) are responses to unfavourable conditions, during which organisms suspend their metabolic activities and go into a period of inactivity. Animals such as snails and fish go into aestivation while hibernation is seen in animals such as polar bears.
Hence, statement (iv) is correct.
Therefore, out of the four statements given, three statements are incorrect.
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