Beginning of Life and Early Civilisations

Human ancestors are defined as the early human species that evolved into modern humans through the process of natural selection and biological development.
Key Features of Human Ancestors:
- Bipedalism: The ability to walk on two legs.
- Larger Brain Development: Increasing cranial capacity over time.
- Ability to Use Tools: Developing the manual dexterity to manipulate the environment.
Evolutionary Stages of Key Species:
- Australopithecus:
  - Recognized as the first upright walkers.
  - These were the earliest hominins to adopt bipedalism, which is the act of walking on two legs.
- Homo habilis:
  - Commonly known as the "Handy Man."
  - This species was responsible for crafting the first simple stone tools.
- Homo erectus:
  - Notable for the mastery of fire.
  - Possessed a larger brain than previous ancestors and utilized more sophisticated tools.
- Homo sapiens:
  - Anatomically modern humans.
  - Characterized by a highly-developed brain and complex social structures.

Human history is categorized based on the types of tools used and the prevailing lifestyle of the period.
The Stone Age:
- Palaeolithic Age: Also known as the Old Stone Age. Characterized by crude stone tools and a nomadic lifestyle.
- Mesolithic Age: Also known as the Middle Stone Age. Characterized by the use of microliths (small, refined tools).
- Neolithic Age: Also known as the New Stone Age. Defined by the use of polished stone tools, the beginning of agriculture, and the shift from nomadic life to permanent settlements.
The Metal Age:
- Bronze Age: People began using tools made from bronze, an alloy consisting of copper and tin ( $\text{Copper} + \text{Tin}$ ).
- Iron Age: Tools were made of iron, which was stronger and cheaper than bronze.

Start of Agriculture: Early humans began cultivating crops such as wheat, barley, and rice.
Domestication of Plants and Animals: Humans began to domesticate animals for various uses, including dogs, sheep, goats, and cattle.
Permanent Settlements: The development of farming led to the creation of villages, as people needed to stay near their crops.
Lifestyle Changes: Humans transitioned to living in houses or huts made of mud and straw.
Technological Advancement: The shift included the beginning of tool-making and the eventual use of metals.
Social Impact: Surplus food production led to the development of towns, cities, storage systems, and complex social structures including trade and commerce.

Geography: One of the earliest urban civilizations in the world, developed along the Indus River and its tributaries in present-day Pakistan and North-western India.
Major Cities:
- Harappa: One of the first cities discovered.
- Mohenjo-Daro: Famous for the "Great Bath."
Key Features:
- Planned Cities: Built on a grid system.
- Advanced Drainage and Sanitation: Systems designed for waste and water management.
- Thriving Trade and Crafts: Significant economic activity and craftsmanship.

What does culture include?
- Answer: (c) Practices, ideas, and creations of a society.
Which was the earliest form of human communication?
- Answer: (b) Gestures and primitive sounds.
Which species is known as the "Handy Man"?
- Answer: (d) Homo habilis.
What was a major achievement of Homo erectus?
- Answer: (c) Mastery of fire.
Which age is known for crude stone tools and a nomadic lifestyle?
- Answer: (c) Palaeolithic Age.
What were microliths?
- Answer: (c) Small refined tools.
What major change occurred during the Neolithic Age?
- Answer: (b) Beginning of agriculture.
Which metal was used in the Bronze Age?
- Answer: (c) Bronze ( $\text{copper} + \text{tin}$ ).
What is bipedalism?
- Answer: (b) Walking on two legs.
The Neolithic Revolution refers to:
- Answer: (c) Shift from hunting to farming.
Which was the first domesticated animal?
- Answer: (c) Dog.
Which cities were part of the Harappan Civilization?
- Answer: (b) Harappa and Mohenjo-Daro.
Mesopotamia is located between which two rivers?
- Answer: (c) Tigris and Euphrates.
What led to the development of towns and cities?
- Answer: (b) Surplus food production.
What was the barter system?
- Answer: (b) Exchange of goods without money.

Options for this section:
- (a) Both A and R are true, and R is the correct explanation of A.
- (b) Both A and R are true, but R is not the correct explanation of A.
- (c) A is true, but R is false.
- (d) A is false, but R is true.

Assertion (A): Early humans lived in groups. Reason (R): Group living helped in protection and sharing of resources.
- Answer: (a)
Assertion (A): Homo habilis is called the "Handy Man." Reason (R): It was the first species to use fire.
- Answer: (c) [Note: Homo erectus was the first to use fire].
Assertion (A): The Neolithic Age is known as the New Stone Age. Reason (R): People started using polished stone tools.
- Answer: (a)
Assertion (A): The discovery of fire improved human life. Reason (R): Fire helped in cooking food and protection from animals.
- Answer: (a)
Assertion (A): Agriculture led to the growth of permanent settlements. Reason (R): People needed to stay near their farms.
- Answer: (a)

Mechanical/Biological Weathering: A rock on a mountainside might break due to frost action (water freezing in joints) and biological weathering (tree roots widening cracks).
Chemical Weathering: Rainwater dissolving minerals within the rock.
Erosion Process: Rock fragments are eroded when they loosen and are transported by rivers, wind, or gravity.