Life on the Earth Class 11 Important Extra Questions Geography Chapter 15
Life on the Earth Important Extra Questions Very Short Answer Type
Question 1.
Name three natural realms of the earth.
Answer:
The three natural realms of the earth are the atmosphere, lithosphere, and hydrosphere.
Question 2.
What is ecology?
Answer:
Ecology is the science that studies the interaction of organisms with their environment.
Question 3.
Who is known as the father of Ayurveda?
Answer:
Charak is known as the father of Ayurveda.
Question 4.
What is ‘Charak Samhita’?
Answer:
It is the book of Indian medicine written by Charak, the first century A.D. scholar, who has listed over 200 kinds of animals and, about 340 kinds of plants in this book,
Question 5.
How many species of living organisms exist today?
Answer:
Over 5 million species of living organisms exist in the world today.
Question 6.
What is the science of classification of organisms called?
Answer:
The science of the classification of organisms is called taxonomy.
Question 7.
Define ecosystem.
Answer:
The biotic community along with the physical environment forms an interacting system is called the ecosystem.
Question 8.
Name the positive biotic interactions.
Answer:
Mutualism and communalism are two positive biotic • interactions.
Question 9.
Name some abiotic factors of the environment.
Answer:
Temperature, water, light, humidity, wind, topography and mineral elements,
Question 10.
Give two examples of fungi.
Answer:
Yeast and mushrooms are two examples of fungi.
Question 11.
Give two examples of herbivores and carnivores each.
Answer:
Cattle and deer are herbivores, whereas tigers and lions are carnivores.
Question 12.
What are the major determinants of nature and the extent of a biome?
Answer:
Rainfall, temperature range, nature, soil, barriers, latitude, and altitude are the major determinants of the nature and extent of a biome.
Question 13.
Where would you find the greatest variety of hoofed herbivore species?
Answer:
The greatest variety of hoofed herbivorous species is found in tropical savanna.
Question 14.
Give some examples of hoofed herbivore species.
Answer:
They include zebra, giraffe, elephant, kangaroos, and several kinds of antelopes.
Question 15.
Which areas in the world consist of deciduous forests?
Answer:
The deciduous forests are found in the temperate region of north-central Europe, eastern Asia, and the eastern United States.
Question 16.
Name the principal grasslands of the world.
Answer:
The principal grasslands of the world include prairies of Canada and the USA, the pampas of South America, the steppes of Europe and Asia, and veldts of Africa.
Question 17.
What constitutes the dominant vegetation of Taiga?
Answer:
Pine, fir, cedar, hemlock, and spruce constitute the dominant vegetation of Taiga.
Question 18.
What kind of topography characterizes Tundra?
Answer:
Tundra is a region characterized by snow, ice, and frozen soil for the most part of the year.
Question 19.
Identify the important determinants 6f marine ecosystems.
Answer:
The important determinants of marine ecosystems are depth of water, distance from the snow, and drainage of glaciers and rivers.
Question 20.
Mention three vertical zones of the ocean on the basis of the availability of light for photosynthesis.
Answer:
The three zones of oceans on the basis of availability of light for photosynthesis are: photic, aphotic, and abyssal.
Question 21.
Name the water bodies which form the freshwater environment.
Answer:
The freshwater environment is formed by stagnant water bodies like lakes and ponds, and flowing water bodies like rivers and streams.
Question 22.
Name the major grasslands of the world.
Answer:
Prairies, pampas, steppes, veldts, and downs.
Question 23.
What is an estuary?
Answer:
The estuary is a zone of mixing of fresh and salty water.
Question 24.
What are lianas?
Answer:
The jungle edge is a tangle of sun-loving woody climbers called lianas.
Question 25.
What are xerophytes?
Answer:
Plants that are able to survive in dry regions are called xerophytes.
Life on the Earth Important Extra Questions Short Answer Type
Question 1.
What is a bio in?
Answer:
Natural ecological groups of plants and animals extend over large areas. Each of these major terrestrial ecosystems or distinctive terrestrial areas with their group of plants and associated animals are recognized as biomes. A biome is, therefore, the largest terrestrial community of plants and associated animals in interaction with the environment.
Question 2.
What kind of animals live in tropical rain forests?
Answer:
The animals living in tropical rain forests include monkeys, snakes, ant-eaters, tropical birds, bats, large carnivorous animals, and a variety of fish in the rivers. Of all the species of insects known nearly 70 to S0% occur in the tropical rain forests.
Question 3.
What kind of flora and fauna characterize the deserts?
Answer:
Deserts are characterized by scanty flora and fauna. Desert plants include different kinds of acacias, cacti, euphorbias, and other succulents. Ants, locusts, wasps, scorpions, spiders, lizards, rattlesnakes, a large number of insect-eating birds such as swifts and swallows, seed-eating quails, doves, desert rats, rabbits, foxes, jackals, and various cats are the common desert animals.
Question 4.
What kind of plant and animal life is supported by tropical savanna?
Answer:
Savannas are characterized by coarse grass and scattered trees on the margins of the tropics where rainfall is seasonal. Wet seasons alternate with dry seasons. Plants and animals are drought-tolerant and do not show much diversity. This biome supports the greatest variety of hoofed herbivore species including the zebra, giraffe, elephant, and several kinds of antelopes. Kangaroos are found in the savannas of Australia.
Question 5.
What are the important features of the Mediterranean scrub forest as a biome?
Answer:
This biome is also known as Chapparal. This is marked by very limited winter rain followed by drought in the rest of the year. The temperature is moderate under the influence of the cool, moist air of the oceans. The biome is characterized by broad-leaved evergreen vegetation. It is made up of fire-resistant resinous plants and drought-adapted animals.
Question 6.
Write a note on deciduous forests.
Answer:
The deciduous forests are found in the temperate regions of north-central Europe, eastern Asia, and the eastern United States. The annual precipitation ranges between 75-150 cm. With the onset of autumn, most of the trees and shrubs become leafless. The vegetation comprises broad-leaved, hardwood trees such as oak, elm, beech, maple, and hickory. The fauna includes frogs, salamanders, turtles, snakes, lizards, squirrels, rabbits, deer, bears, raccoons, foxes, and songbirds.
Question 7.
Describe various vertical zones of the ocean.
Answer:
The vertical zones of the ocean can be determined by the availability of light for photosynthesis. The lighted upper 200 meters form the photic or euphotic zone. The next zone, up to the depth of 2000 meters, gets less light which is insufficient for photosynthesis. This layer is called an aphotic zone. Below 2000 meters is the area of perpetual darkness, called the abyssal zone.
Question 8.
Distinguish between food chain and food web.
Answer:
The food relation in its simplest form representing a producer, a primary consumer (herbivore), a secondary consumer (carnivore), and a decomposer is called a food chain. The next circle of such a food chain is called the food web.

Question 9.
Describe various structural components of an ecosystem.
Answer:
Various structural components of an ecosystem are classified into two main groups:
biotic or living, and
abiotic or non-living.
The biotic component of an ecosystem comprises the kinds, numbers, and distribution of living organisms. The abiotic component consists of the kinds, quantity, and distribution of physical and chemical factors such as light, temperature, water, oxygen, carbon, nitrogen, and minerals.
Question 10.
Define ‘ecosystem’ with examples.
Answer:
The biotic community, along with the physical environment, forms an interacting system called the ecosystem. An ecosystem can be natural or artificial, temporary or permanent. A large grassland or a forest, a small tract in a forest or a single log, an edge of the pond, a village, an aquarium, or a manned spaceship can all be regarded as ecosystems.
Question 11.
Distinguish between biotic and abiotic factors.
Answer:
They are two components of an ecosystem. The biotic component comprises the kinds, numbers, and distribution of living organisms. The abiotic component, on the other hand, consists of the kinds, quantity, and distribution of physical and chemical factors such as light, temperature, water, oxygen, carbon, nitrogen, and minerals.
Question 12.
Explain with examples the role of members of the fungi kingdom of organisms.
Answer:
The fungi kingdom includes diverse kinds of multicellular heterotrophic organisms. There are over 100,000 species of fungi. Some are unicellular like yeast, others are complex like mushrooms. The fungi are the major decomposers and their activity is essential for the recycling of inorganic resources in the biosphere.
Question 13.
What do you understand by biogeochemical cycles?
Answer:
The balance of the chemical elements in the atmosphere and hydrosphere is maintained by a cyclic passage through the tissues of plants and animals. The cycle starts by absorbing chemical elements by the organism and returned back to air, water, and soil through decomposition. These cycles are energized by solar insolation. These cyclic movements of chemical elements of the biosphere between the organism and the environment are referred to as biogeochemical cycles.
Question 14.
What is the hydrologic cycle?
Answer:
All living organisms, the atmosphere, and the lithosphere maintain between them a circulation of water in solid, liquid, or gaseous form, referred to as water or hydrologic cycle.
Question 15.
What is denitrification?
Answer:
Herbivorous animals feeding on plants in turn consume some of it. Dead plants and animals, excreted nitrogenous wastes are converted into nitrites by the attachment of bacteria present in the soil. Some bacteria can even convert nitrites into nitrates that can be used again by the green plants. There are still other types of bacteria capable of converting nitrates into free nitrogen, a process known as denitrification.
Life on the Earth Important Extra Questions Long Answer Type
Question 1.
“Food chains are not isolated linear chains of trophic levels.” Comment.
Answer:
In nature, the food relationship cannot be explained only in terms of a single food chain. A herbivore consumes many types of plants or plant products. Many kinds of animals, other than tiger, derive food from herbivorous animals. Ticks and mites, leeches, and blood-sucking insects are dependent on herbivores and even on carnivores. Thus, food chains are not isolated linear chains of trophic levels.
Depending upon the availability and choice of food, different organisms at each level have a food relationship with more than one organism at the lower levels. A rat, for example, feeds on various kinds of stem, roots, fruits, and grains. In turn, it is consumed by a snake which is eaten by a falcon. The snakes feed on both, frogs and rats. Then, a network of food chains exist, which is called a food web. The food web becomes more complicated when taste and preference, availability, and compulsion are involved.
Question 2.
Describe the functions of various biotic components.
Answer:
Various biotic components include producers, herbivores, carnivores, and decomposers. All organisms require energy for their life processes. Food supplies both energy and materials for the sustenance of life. Green plants produce carbohydrates by photosynthesis and also synthesize proteins and fats. The green plants, therefore, are called producers. The animals that consume this energy are called consumers.
The herbivores like cattle, deer, and goats derive their food or energy directly from plants and are called the first-order consumers. The carnivores like tiger and lion depend on herbivores for their food and energy and are therefore called the secondary or second-order consumers. The non-green organisms like fungi and some bacteria, which do not produce their own food, live on the dead and decaying plants or animals and are consumers of a special type called decomposers.
Question 3.
Distinguish between Taiga and Tundra biome.
Answer:
Question 4.
Describe the energy flow in the biosphere.
Answer:
Energy from the sun enters the living world through photosynthetic organisms and passes on from one organism to another in the form of food.

The organisms which trap solar energy and act as producers also use some energy for their own life processes. Only a portion of the energy trapped is taken by the primary consumers. Animals being more active than plants use much of the energy acquired before they are consumed by the next trophic level. At each stage of energy transfer, some amount of energy is lost from the food chain. The amount of energy transferred to the next higher level thus gradually decreases. The decomposition of dead organisms also releases chemical energy. Eventually, all this solar energy that entered the living system through the producers goes back into the non-living world, not as light but as heat.
Question 5.
Describe the carbon cycle in brief.
Answer:
Carbon is one of the basic elements of all living organisms. It forms the basic constituent of all organic compounds. The biosphere contains over half a million carbon compounds. The carbon cycle is mainly the conversion of carbon dioxide. This conversion is initiated by the fixation of carbon dioxide from the atmosphere through photosynthesis. Such conversion results in the production of carbohydrates, glucose that may be converted to other organic compounds such as starch, cellulose, etc. Here, some of the carbohydrates are utilized directly by the plant itself. During this process, more carbon dioxide is generated and is released through its leaves or roots during the day. The remaining unutilized carbohydrates become part of the plant tissue.
The plant tissues are either eaten by the herbivorous animals or get decomposed by micro-organisms. The herbivores convert some of the consumed carbohydrates into carbon dioxide for release into the air through respiration. The micro-organisms decompose the remaining carbohydrates after the animal dies. The carbohydrates that are decomposed get oxidized into carbon dioxide and are returned back to the atmosphere.
