Home/Class 12/Biology/

Question and Answer

Write a short note on :
(a) Adaptations of desert plants and animals
(b) Adaptations of plants to water scarcity
(c) Behavioural adaptations in animals
(d) Importance of light to plants
(e) Effect of temperature or water scarcity and the adaptations of animals.

Answer

(a) Adaptations of desert plants and animals
Plants found in deserts are well adapted to cope with harsh desert conditions such as water scarcity and scorching heat. Plants have an extensive root system to tap underground water. They bear thick cuticles and sunken stomata on the surface of their leaves to reduce transpiration. In Opuntia, the leaves are entirely modified into spines and photosynthesis is carried out by green stems. Desert plants have special pathways to synthesize food, called CAM (\({C}_{{{4}}}\) pathway). It enables the stomata to remain closed during the day to reduce the loss of water through transpiration.
Adaptations of desert animals
Animals found in deserts such as desert kangaroo rats, lizards, snakes, etc. are well adapted to their habitat. The kangaroo rat found in the deserts of Arizona never drinks water in its life. It has the ability to concentrate its urine to conserve water. Desert lizards and snakes bask in the sun during early morning and burrow themselves in the sand during afternoons to escape the heat of the day. These adaptations occur in desert animals to prevent the loss of water.
(b) Adaptations of plants to water scarcity
Plants found in deserts are well adapted to cope with water scarcity and scorching heat of the desert. Plants have an extensive root system to tap underground water. They bear thick cuticles and sunken stomata on the surface of their leaves to reduce transpiration. In Opuntia, the leaves are modified into spines and the process of photosynthesis is carried out by green stems. Desert plants have special pathways to synthesize food, called CAM (\({C}_{{{4}}}\) pathway). It enables their stomata to remain closed during the day to reduce water loss by transpiration.
(c) Behavioural adaptations in animals
Certain organisms are affected by temperature variations. These organisms undergo adaptations such as hibernation, aestivation, migration, etc. to escape environmental stress to suit their natural habitat. These adaptations in the behaviour of an organism are called behavioural adaptations. For example, ectothermal animals and certain endotherms exhibit behavioral adaptations.
Ectotherms are cold blooded animals such as fish, amphibians, reptiles, etc. Their temperature varies with their surroundings. For example, the desert lizard basks in the sun during early hours when the temperature is quite low. However, as the temperature begins to rise, the lizard burrows itself inside the sand to escape the scorching sun. Similar burrowing strategies are exhibited by other desert animals. Certain endotherms (warm-blooded animals) such as birds and mammals escape cold and hot weather conditions by hibernating during winters and aestivating during summers. They hide themselves in shelters such as caves, burrows, etc. to protect against temperature variations.
(d) Importance of light to plants
Sunlight acts as the ultimate source of energy for plants. Plants are autotrophic organisms, which need light for carrying out the process of photosynthesis. Light also plays an important role in generating photoperiodic responses occurring in plants. Plants respond to changes in intensity of light during various seasons to meet their photoperiodic requirements for flowering. Light also plays an important role in aquatic habitats for vertical distribution of plants in the sea.
(e) Effects of temperature or water scarcity and the adaptations of animals.
Temperature is the most important ecological factor. Average temperature on the Earth varies from one place to another. These variations in temperature affect the distribution of animals on the Earth. Animals that can tolerate a wide range of temperature are called eurythermals. Those which can tolerate a narrow range of temperature are called stenothermal animals. Animals also undergo adaptations to suit their natural habitats. For example, animals found in colder areas have shorter ears and limbs that prevent the loss of heat from their body. Also, animals found in Polar regions have thick layers of fat below their skin and thick coats of fur to prevent the loss of heat.
Some organisms exhibit various behavioural changes to suit their natural habitat. These adaptations present in the behaviour of an organism to escape environmental stresses are called behavioural adaptations. For example, desert lizards are ectotherms. This means that they do not have a temperature regulatory mechanism to escape temperature variations. These lizards bask in the sun during early hours when the temperature is quite low. As the temperature begins to increase, the lizard burrows itself inside the sand to escape the scorching sun. Similar burrowing strategy is seen in other desert animals.
Water scarcity is another factor that forces animals to undergo certain adaptations to suit their natural habitat. Animals found in deserts such as desert kangaroo rats, lizards, snakes, etc. are well adapted to stay in their habitat. The kangaroo rat found in the deserts of Arizona never drinks water in its life. It has the ability to concentrate its urine to conserve water. Desert lizards and snakes bask in the sun during early morning and burrow in the sand as the temperature rises to escape the heat of the day. Such adaptations can be seen to prevent the loss of water.
To Keep Reading This Answer, Download the App
4.6
star pngstar pngstar pngstar pngstar png
Review from Google Play
To Keep Reading This Answer, Download the App
4.6
star pngstar pngstar pngstar pngstar png
Review from Google Play
Correct20
Incorrect0
Watch More Related Solutions
What letters of the English alphabet have reflectional symmetry (i.e., symmetry relatedto mirror reflection) about.(a) a vertical mirror (b) a horizontal mirror(c) both horizontal and vertical mirrors
Let \(\vec{{C}}=\vec{{A}}+\vec{{B}}\)
(A) \({\left|\vec{{C}}\right|}\) is always greater than \({\left|\vec{{A}}\right|}\)
(B) It is possible to have \({\left|\vec{{\left|\lt\right|}}\vec{{A}}\right|}{\quad\text{and}\quad}{\left|\vec{{C}}\right|}\lt{\left|\vec{{B}}\right|}\)
(C) C is always equal to A+B
(D) C is never equal to A+B
Let E,G and N represent the magnitudes of electromasgnetic, gravitational and nkuclear forces between two electrons at a given separation. Then
(A) \({N}\gt{E}\gt{G}\)
(B) \({E}\gt{N}\gt{G}\)
(C) \({G}\gt{N}\gt{E}\)
(D) \({E}\gt{G}\gt{N}\)
A bullet hits a lock kept at rest on a smooth horizontal surface andgets embedded into it. Which of the following does not change?
(A) a linear momentum of the block
(B) kinetic energy of the block
(C) gravitational potential energy of the block
(D) temperature of the block
The motor of an engine is erotating about its axis with an angular velocity of 100 rev/minute. It comes to rest in 15 s, after being switched off. Assumgn cnstant angular decelertion, calculate the number of revolutions made by it before coming to rest.
A parallel beam of light of wavelength 560 nm falls on a thin film of oil (refractive index = 1.4). What should be the minimum thickness of the film so that it strongly
S4 T z reflects the light ?
A Galilean telescope is constructed by an objective of focal length 50 cm and a eyepiece of focal length 5.0 cm a. find the tube length and magnifying power when it is used to see n object at a large distancei normal adjustment b. if the telescope is to focus an object 2.0 m away from the objective what should be the tube length and angular magnification, the image again forming at infinity?
If aperture diameter of the lens of a telescope is 1.25 m and wavelength of light used is 5000 Å its resolving power is ( )
A. \({2.05}\times{10}^{{{6}}}\)
B. \({2.5}\times{10}^{{{5}}}\)
C. \({4.1}\times{10}^{{{5}}}\) 
D. \({4.1}\times{10}^{{{6}}}\)
An electric current of \({0.4}{A}\) is passed through a silver voltameter fro half an hour.Find the amount of silver deposited on the cathode. \({E}{C}{E}\) of silver \(={1.12}\times{10}^{{-{4}}}{k}{g}{C}^{{-{1}}}\)
The coil of an electric bulb takes 40 watts to start glowing. If more than 40 W is supplied, 60% of the extra power is converted into light and the remaining int heat. The bulb consumes 100 W at 220 V. Find the percentage drop in the light intensity at a point if the supply voltage changes from \({220}{V}\to{200}{V}\).

Load More