Chapter 2 Environment and Human Society

NIOS Class 12 Environmental Science Chapter 2

INTEXT QUESTIONS 2.1

1. Name two natural resources without which life cannot exist.

Ans: Air, water, substratum (any two)

2. State two uses each for (i) land and (ii) metals that are used by humans.

Ans:

(i) Land- to make shelter, for agriculture, pottery, etc.
(ii) Metals – to make tools, ornaments and other things

3. State two uses of animals for humans.

Ans: As food, transport

INTEXT QUESTIONS 2.2

1. Name the first stage of human evolution.

Ans: Australopithecus

2. When did the ‘modern humans’ evolve?

Ans: 2 million years ago

3. What do you mean by “hunters and gatherers”? Answer in one sentence.

Ans: Forage, plucks fruits and uproots plants and hunts animals

4. Where did primitive humans live?

Ans: Caves

5. State the advantage of their being able to walk on their two feet?

Ans: Walking on hind limbs, primitive humans were free to use their hands to

Uproot plants for edible roots,
Pluck fruits and vegetables,
Pick up pebbles from the banks of rivers and stones from other places and
Make tools from them
Hunt animals, skin them and then eat them.

INTEXT QUESTIONS 2.3

1. With what did primitive humans make tools?

Ans: Stone and metals

2. State two uses of these tools.

Ans: Uproot plants, kill animals

3. State two uses of fire by primitive humans.

Ans:

They realised that the use of fire enabled them to colonize the colder parts of the Earth.
Meat becomes tender when cooked in fire, making it more digestible.
Fire was also used to scare away dangerous animals.
Fire brought about “cultural evolution” of humans, as well as increasing exploitation of natural resources.

INTEXT QUESTIONS 2.4

1. According to an archaeological study, how did foragers live?

Ans: In a temporary oval hut shelter, which is often covered with plants.

2. When was primitive agricultural society formed?

Ans: About 10,000 years ago.

3. Which was the first domesticated animal?

Ans: Dog

4. Name three draught animals.

Ans: Bullock, camel, elephant.

5. When and where was wheel invented?

Ans: Around 5000 years ago in Iraq and Syria.

INTEXT QUESTIONS 2.5

1. List some steps towards industrialization.

Ans: Making wheels, constructing buildings, mining ores to make tools and ornaments were steps towards industrialization.

2. Which metals were discovered by the primitive humans?

Ans: Copper, iron and bronze

3. List four factors that led to growth of industrialization.

Ans: Technical development, economic development, the invention of wheel, the beginning of mining, agriculture, etc. (any four)

4. What is the impact of industrialization upon nature?

Ans:

Forests, the original habitat of humans, have dwindled at an alarming rate; wildlife has been threatened with extinction.
Some wild animals have vanished.
Pollution from industries has made the air impure and the water bodies full of filth.
Treasured natural resources such as the soil, the forest, the minerals, metals, the air, the water, plants and animals were increasingly overexploited.
Environmental resources are limited and are fast getting depleted due to overexploitation.
Pollution of air, water and land caused by human activities is posing a serious threat to human survival and well-being.

TERMINAL EXERCISE

1. Name the abiotic and biotic natural resources.

Ans:

Abiotic natural resources: Land, water, energy from the sun, coal, petroleum and natural gas, metal ores and minerals.
Biotic natural resources: Plants, animals, and microorganisms.

2. Of what use are plants and animals to humans?

Ans:

Plants

They provide natural food resources included in the human diet.
Fibre-yielding plants are grown to obtain cotton, jute and flex, etc.
Flowers of various kinds are cultivated for ornamental purposes.
Some plants that have medicinal value have been extensively used from time immemorial.
Industrial raw materials such as rubber, resins, and wood are irreplaceable plant products.

Animals

They are a source of food for human beings.
Horses, bullocks, elephants, oxen, camels, donkeys, yaks, etc., are used for transportation as draught animals.
Yaks and sheep yield wool for woollens.
Silk worms are grown for silk.

3. List 10 uses of water for human beings.

Ans: Water is required for

Irrigation of agricultural crops.
Industries
Building construction
Culture of fish, prawn, aquatic plants (aquaculture)
Drinking,
Bathing,
Cleaning,
Washing,
Gardening,
Pottery making, etc.

4. List the various sources of energy.

Ans:

The prime source of energy is solar radiation.
Primitive humans used firewood and cow dung, and other animal wastes for heating and cooking.
Oil extracted from seeds and fish was used by them to light caves and shelters.
Fossil fuels such as coal.

5. Trace the evolution of humans up to modern man.

Ans:

The earliest human ancestors, the Australopithecines, which walked upright, evolved around 3.5 million years ago in South Africa.
Australopithecines gave rise to Homo habilis, probably around 2 million years ago.
The next stage, Homo erectus, is supposed to have existed between 1.5 million years to 200,000 years ago.
Next to evolve were the Neanderthal man (Homo sapiens neandertalensis), but they belonged to the same species as modern humans, Homo sapiens.
For about 35,000 years, Homo sapiens or modern humans, have been the only living human species.

6. What do you mean by the statement “early men were hunters and gatherers”?

Ans: Primitive humans lived in forests, near water bodies such as rivers and lakes located on the edges of forests. Their main preoccupation in life was to “procure food”. Their diet consisted of seeds, roots and fruits of plants and small animals, which they killed with tools they made from pebbles and stones. They roamed in the forests in search of food during the day and returned to the caves at sunset to save themselves from the attack of wild animals. Walking on hind limbs, primitive humans were free to use their hands to

Uproot plants for edible roots,
Pluck fruits and vegetables,
Pick up pebbles from the banks of rivers and stones from other places and
Make tools from them
Hunt animals, skin them and then eat them.

Thus, primitive humans were ‘hunters and gatherers’.

7. State the purposes for which primitive man made tools.

Ans: To chip wood, hammer bones, to uproot edible roots and other plant parts underground, to cut animal and skin them, and for hunting larger animals.

8. Primitive humans were thrilled to discover fire, and why?

Ans: They realized that the use of fire also enabled them to colonize the colder parts of the earth, and meat becomes tender when cooked in fire, making it more digestible. Fire was also used to scare away dangerous animals. Fire brought about “cultural evolution” of humans as well as increasing exploitation of natural resources.

9. How did humans think of cultivating crops?

Ans: As humans built temporary shelters and began to stay together for three to four months at a place, they discovered that seeds of fruits and grains thrown in front of their huts sprouted into saplings. As intelligent beings, they realized that instead of foraging, they could grow food plants for themselves. Around 12,000 years ago, humans learnt to cultivate crops.

10. What changes took place in the behaviour and lifestyle of primitive humans after they became agriculturists?

Ans: As time passed, humans learnt to use metal tools for agriculture and used plant and animal residues as manure. They also began irrigation of their cultivated fields. Thus evolved the so-called “agro-horticultural societies”.

Soon, in fertile valleys, food became surplus through continuous cultivation. Humans also began the domestication of animals and raising cattle. The first domesticated animal was the dog. They also maintained fisheries. Further improvement in the cultivation and domestication of animals encouraged human settlements by the river banks and valleys. Thus primitive “agrarian society” evolved and practised traditional agriculture.

11. What do you mean by “Bronze Age” and “Iron Age”?

Ans: Humans began to make copper axes and weapons with sharp cutting edges. Soon, smiths mixed metals and produced bronze from copper and tin. This alloy was harder and easier to cast into knives and axes. By 2500 BC, bronze became the dominant metal. This is known as the Bronze Age.

From the 7th and 6th centuries BC, humans began to use iron to make weapons and found it to be much superior to bronze. By 1200 BC, western Asia (Iran, Turkey, etc.) had come out of the Bronze Age and entered the Iron Age. Iron tools and weapons replaced those made from bronze.

12. State the factors which led to industrialization.

Ans: Several factors were responsible for the growth of industrialization.

Technical development: The discovery of metals for making better tools and weapons initiated technology.
Economic development:
- (i) The establishment of agrarian societies engaged people in selling surplus produce or bartering it. This made them economically sound.
- (ii) In the agrarian society, people got busy with occupations other than agriculture.
Invention of the wheel: This led to faster transportation and marked the beginning of the transportation industry.
Beginning of mining: It was related to unearthing flint. Later ores containing copper, iron, and aluminum are mined. This led to the formation of the mining industry. Mining of mineral and metalous fossil fuels like coal and natural gas is common even today.
Agriculture: Agriculture began with primitive humans. They produce food, fibres, and raw materials for industry. Modern farming methods have produced food for the teeming millions. Agriculture itself has become an industry.
Bronze Age and Iron Age: Bronze Age and Iron Age, as well as the discovery of fire much earlier, led to the making of the machine tool industry. Machines for making synthetic cloth, for printing cloth, ushered in the textile industry.
Language: Spoken communication led to the development of language. Language helped in working in groups, which enhanced the pace of economic development.

13. What impact did years of use by a growing population of humans have on environmental resources?

Ans: As humans became more and more ‘civilized’ and created innovative newer technology, the treasured natural resources such as the soil, the forest, the minerals, metals, the air, the water, plants and animals were increasingly overexploited. Coupled with the exploitation was the enormous increase in the human population. In the last decade, environmentalists have made alarming discoveries.

Environmental resources are limited and are fast getting depleted due to overexploitation.
Pollution of air, water and land caused by human activities is posing a serious threat to human survival and well-being.

The relationship between human and their environment has changed, especially since the beginning of the industrial revolution. It has become confrontational, and the consequences have already started surfacing.