Revision summary
Some traits are heritable and locally selected. Most genetic variation is within groups, not between classical races. Environment and plasticity change the growing phenotype. Boas showed that ‘racial’ head form shifts with place. Populations form by clines and admixture, not pure types.
Model answer
Copper italics in this answer — like this — are the key facts. Each one is unpacked in the Facts & figures rail.
Introduction
Classical ‘races’ were treated as hereditary types. Living human variation is clinal, polygenic, and always jointly shaped by genes and environment.
Body
Heredity
- Skin colour, some body proportions, and many blood polymorphisms have a genetic component.
- Bergmann and Allen trends, sickle cell, and lactase alleles show selection in place, not a three-race Noah’s ark.
- Lewontin showed most genetic diversity is within continental groups. Race as a few boxes fails the genome.
Environment
- Sun, diet, altitude, and disease shape phenotype through growth: Tanner secular trends, Andean and Tibetan hypoxia answers.
- Plasticity: the same genotype yields different stature in famine and plenty. Boas immigrant studies already showed head form is not a fixed race mark.
- Culture is environment: clothing, marriage networks, and caste endogamy structure gene flow.
Formation, not types
- Populations form by isolation, selection, drift, and admixture. They do not form as pure races.
- Forensic ancestry estimates are statistical. They are not a return to colonial race science.
Flow diagram
flowchart TD VAR[Human variation] --> H[Alleles selection drift] VAR --> E[Climate diet culture] H --> P[Populations clines] E[E] --> P[P]
Conclusion
Heredity supplies alleles under selection and drift. Environment and culture shape both gene frequencies and the growing body. Races as fixed hereditary types are a poor model of that process.
Quick related
Students also ask
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Does denying race deny biology?
No. It denies a few-box typology. Biology is real as clines and local adaptation.
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Is caste a race?
Caste is a social endogamy system. It can structure genes without being a biological race.
Same topic · past papers
UPSC has asked this before
These previous-year questions sit on the same topic. Open one to practise the earlier ask.
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2026 · Q2(b) · Anthropology GS 1 · 15 marks
How do religious beliefs help people to devise cultural mechanisms to adapt to their environment? Discuss in detail with appropriate examples -
2023 · Q2(b) · Anthropology GS 1 · 15 marks
Discuss the Paleolithic environment in light of available evidences with special reference to India.
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Race as a few fixed stocks fails Boas’s plasticity evidence and Lewontin’s genetic apportionment. Race still organises inequality as a social category. Ethnicity is a maintained boundary of language, history, and politics, as Barth argued. Cohen showed ethnicity at work in urban competition. In India the same people may be sorted by caste, tribe, or language depending on the boundary in play.