1. Of Shakes and Quakes
- India is located in the Indian Ocean with Sri Lanka beneath it.
- The Indian subcontinent was once attached to Africa and Madagascar.
- Early 20th-century belief was that continents were fixed land masses.
- Alfred Wegener proposed the theory of continental drift in 1912.
- Wegener’s book, The Origin of Continents and Oceans, was published in 1915.
- Wegener argued that present continents originated from one land mass.
- This explained the jigsaw puzzle appearance of the world map.
- It took nearly fifty years to scientifically prove Wegener’s theory.
- In the late fifties and sixties, new geological data confirmed plate tectonics.
- Earth’s crust is a patchwork of plates moving relative to each other.
- A billion years ago, there was a supercontinent called Rodinia.
- Rodinia broke up around 750 million years ago during the Pre-Cambrian period.
- Single-cell organisms like bacteria existed then.
- Around 530 million years ago, complex organisms appeared in the Cambrian Explosion.
- Continents reassembled and formed Pangea about 270 million years ago.
- Dinosaurs appeared on Pangea 230 million years ago.
- Pangea began to break up around 175 million years ago during the Jurassic era.
- It split into Laurasia (North America, Europe, Asia) and Gondwana (Africa, South America, Antarctica, Australia, India).
- Dinosaur remains were found in Raioli village, Gujarat, including Rajasaurus Narmadsensis.
- India, Antarctica, and Madagascar separated from Africa around 158 million years ago.
- India and Madagascar separated from Antarctica around 130 million years ago.
- India separated from Madagascar around 90 million years ago and drifted northwards.
- The Reunion hotspot caused volcanic activity leading to the Deccan Traps.
- Deccan Traps were created by layer-by-layer volcanic eruptions.
- The eruptions possibly led to the extinction of dinosaurs.
- India collided with the Eurasian plate 55-60 million years ago, forming the Himalayas.
- The Himalayas are still rising by about 5 mm per year.
- The region is seismically unstable and prone to earthquakes.
- Fossilized insects in Cambay Shale, near Surat, raise questions about India’s isolation.
- The northward drift of India made the region tectonically active.
- The 2005 earthquake in North Pakistan and Pakistan-occupied-Kashmir had a magnitude of 7.6.
- The 1950 Assam earthquake registered a magnitude of 8.6.
- The Himalayas are dangerous for building large dams.
- The Gangetic plains are among the youngest geological features.
- They started as a marshy depression between the Himalayas and the Vindhyas.
- Silt from the Ganga created a fertile alluvial plain.
- The Ganga’s course changes left oxbow lakes in its path.
- The Ganga’s southward drift was stopped by the Vindhyas near Chunar.
- Chunar fort was strategically important in historical times.
- The fort has remnants from various eras, including Vikramaditya, the Mughals, and the British.
- The national emblem of India, the Mauryan lions of Sarnath, were carved from Chunar stone.
MOVE IT, PEOPLE!
- Similarities between Indian and African mammals are due to geographical reattachment to Eurasia and changing climate zones.
- Elephants, rhinos, and lions migrated to India after separation from Africa during the dinosaur era.
- Genetic study shows Asian elephants are more closely related to mammoths than to African elephants.
- Asian and African elephant genetic lines separated six million years ago, while Asian elephants and mammoths diverged 4,40,000 years ago.
- Many Indian animals, including the tiger, came from the east.
- Tigers possibly originated from Siberia or South China, arriving in India around 12,000 years ago.
- Human beings evolved in Africa around 2,00,000 years ago.
- The San tribe of the Kalahari shows the greatest genetic variation, indicating descent from the earliest modern humans.
- Early modern humans first attempted to leave Africa around 1,20,000 years ago but returned due to climate changes.
- Around 65,000–70,000 years ago, a small group crossed from Africa into southern Arabia.
- All non-Africans descended from this small group.
- Cooler global temperatures during migrations resulted in lower sea levels and different coastlines.
- Early humans migrated along the Arabian coastline and into the Persian Gulf region.
- The Persian Gulf was a fertile plain when sea levels were lower, supporting early human populations.
- Modern humans spread along the Makran coast into the Indian subcontinent.
- The Neanderthals in Europe moved westward and eventually died out.
- Modern humans in the subcontinent spread quickly and reached South East Asia.
- Indigenous tribes of the Andaman and Nicobar Islands may descend from early migrants.
- Ancestors of Australian aborigines reached Australia around 40,000 years ago.
- A 2009 study found genetic traces linking some Indian tribes with native Australians.
- Population near the Persian Gulf remained for thousands of years, contributing to genetic branches.
- Climate changes caused migrations during warmer interglacial periods.
- The last full-blown ice age started around 24,000 years ago, peaked around 18,000–20,000 years ago, and then warmed up.
- The Persian Gulf filled up 12,500 years ago, possibly linked to the Great Flood in Sumerian and Biblical accounts.
- People near the Persian Gulf moved to higher ground around 7500 years ago and began using boats.
- Indian coastline moved inland, flooding large land masses in the Gulf of Khambat and south of the Tamil coast.
- Marine archaeologists found underwater settlements in the Gulf of Khambat, potentially flooded around 7500 years ago.
- Early crops in the subcontinent, such as wheat and barley, were West Asian species.
- Indians may have independently developed farming, including rice cultivation.
- By the end of the Neolithic age, there was a large population in India.
- Researchers are studying the relationship between present-day Indians and ancient populations.
WHAT DO YA MEAN, GENE?
- Up to the early twentieth century, it was believed that India was inhabited by Stone-Age tribes until 1500 BCE when Indo-Europeans called ‘Aryans’ invaded.
- This invasion theory was used to explain similarities between Indian and European languages.
- The theory was politically convenient for British colonizers to appear as latter-day ‘Aryans’ civilizing the local population.
- The discovery of the Harappan civilization showed Indian civilization was advanced before 1500 BCE.
- The ‘Aryan invasion’ theory was modified to suggest Dravidians created Harappan cities, later destroyed by Aryans.
- There is no archaeological or literary evidence of a large-scale Aryan invasion.
- Harappan cities declined slowly due to environmental reasons, not invasion.
- India has a complex mix of castes, tribes, and language groups.
- Some groups, like Jews and Parsis, came to India in historical times.
- Many populations have lived in India for a long time, migrating and settling over thousands of years.
- Most groups have mingled, but some tribes retain unique identities.
- There are no ‘pure’ races in India; variations exist even within families.
- A 2006 study showed India’s population mix has been stable for over 10,000 years, with no major Central Asian gene influx.
- The study suggested the Dravidian population had long lived in southern India.
- A 2009 study explained the Indian population as a mixture of two ancestral groups: Ancestral South Indian (ASI) and Ancestral North Indian (ANI).
- ASIs are older and not related to groups outside the subcontinent.
- ANIs are more recent and related to Europeans.
- ANI genes have a large share in North India and a significant share in South India and some tribal groups.
- ANI-ASI split is not the same as the Aryan-Dravidian theory.
- ANI and ASI are genetic mixes, not ‘pure’ races.
- ‘Aryan’ and ‘Dravidian’ terms carry cultural connotations linked to Vedic and Sangam traditions.
- ANI and ASI emerged well before these traditions and the Harappan civilization.
- Climate change caused ANI and ASI groups to mix rapidly around 4200 years ago.
- Indians are closely related to each other due to thousands of years of mixing.
- Some Indian groups do not fit within the ANI-ASI framework and have other influences.
- North Indian genetic links to Europeans involve the R1a1 gene mutation, specifically the R1a1a subgroup.
- R1a1a is common in North India and Eastern Europe, but rare in Western Europe and parts of Central Asia.
- The oldest strain of R1a1a is found in Gujarat-Sindh-Western Rajasthan, suggesting this area is its origin.
- European carriers of R1a1a have a further mutation, M458, not found in Asian carriers.
- M458 mutation is estimated to be at least 8000 years old, indicating separation before or during the Great Flood.
- Genetic linkages between North Indians and East Europeans are best explained by a common ancestor post-ice age.
- The most common gene in Western Europe is R1b, related to R1a1, possibly originating in the Persian Gulf area.
- India has a low concentration of R1b.
- Two major genetic dispersals may have occurred from the Persian Gulf-Makran-Gujarat region at different climatic points.
- One dispersal during the last ice age involved R1b carriers heading west.
- Another dispersal around the time of the Flood involved R1a1 carriers.
- Some Indian tribes may have moved westward to Iran and beyond during the Bronze Age.
- Cultural linkages may have happened through trade.
- Indian culture spread to South East Asia and English language popularity in postcolonial India show cultural exchanges can happen without war or large-scale migration.
IS THERE A LITHUANIAN IN YOUR FAMILY?
- The caste system is not unique to India and has been seen in Japan, Iran, and Classical Europe.
- The Indian caste system is remarkable for its survival over thousands of years despite changes in technology, political conditions, and religion.
- Despite strong criticism and opposition within Hindu tradition, the caste system has continued to exist.
- It was once thought that the caste system originated from the Aryan influx and imposition of a rigid racial hierarchy.
- Genetic studies have shown a largely South Asian origin for Indian caste communities.
- Indian castes are profoundly influenced by ‘founder events’, where a group separates out and becomes an endogamous tribe.
- This process leads to a varied social environment of groups and subgroups, sometimes combining and sometimes splitting off.
- Intermarriage between different groups was fluid 1900–4000 years ago, coinciding with the mixing of ANI and ASI.
- About 1900 years ago, intermarriage became less common and castes became more exclusive.
- There is a difference between the genetic reality and the rigid, hierarchical ‘varna’ system described in the Manusmriti.
- The Manusmriti’s description of a rigid system may have been a scholarly idea and may never have truly existed.
- Indian society has been very flexible, with people from different castes adapting to changing times by altering their social roles.
- Till 1900 years ago, intermarriage between groups was common.
- After castes became strictly endogamous, the status of different groups remained fluid.
- New castes could be created to accommodate new groups, and groups could be promoted or demoted in status according to social conditions.
- Historical experience, such as the emergence of the Rajputs in medieval times, fits this flexible caste system.
- In the past, groups tried to move forward in the pecking order.
- Now, groups try to be classified as ‘backward’ to benefit from affirmative action.
- The logic of both processes is the same.