Revision summary
Erect posture frees the hands for tools and carrying. It favours endurance walking and a high visual field. Costs include lumbar strain, difficult birth, and venous problems. The obstetric dilemma pits a narrow pelvis against a large brain. Selection kept the bargain because making and ranging paid.
Model answer
Introduction
Bipedal erect posture is the hominin hallmark. It freed the hands and strained the spine, pelvis, and birth canal. Gains and losses are one design.
Body
Gains
- Hands free for tools, carrying, and gesture. Washburn and Darwin already tied bipedalism to culture.
- A high, scanning eye-line and endurance walking, later used by Homo erectus on open landscapes.
- Thermoregulation in savanna sun is argued: less surface to noon radiation, more sweating skin.
Losses
- Lumbar lordosis, slipped discs, and osteoarthritis of the lower back and knees.
- A narrow pelvic inlet versus a large neonatal brain: the obstetric dilemma, with rotational birth and risk to mother and child.
- Inguinal hernia, varicose veins, and haemorrhoids from vertical viscera and valves.
- Foot arches and fallen arches; a locked knee that saves energy but fails in injury.
Balance
- Natural selection kept the posture because foraging and making paid more than a perfect back.
Flow diagram
flowchart TD BP[Bipedalism] --> G[Hands tools endurance] BP --> L[Spine pelvis veins feet] L --> OB[Obstetric dilemma]
Conclusion
Erect posture bought tools, range, and a scanning stance. It cost backs, births, and veins. The human body is that bargain.
Quick related
Students also ask
-
Is race a valid and biologically meaningful concept?
Next question in the 2021 paper (Q5). View answer →
-
Was bipedalism for running first?
Early hominins walk. Endurance running is clearer later, with erectus-grade bodies.
-
Can culture remove the losses?
Midwifery, chairs, and surgery mitigate. They do not rewrite the skeleton.
PYQ trend
When UPSC asked this
Related PYQs from other years, newest first. Open a question to read it.
-
2025 · Q1(d) · Anthropology GS 1 · 10 marks
Smell as a signal among non-human primates. -
2025 · Q2(a) · Anthropology GS 1 · 20 marks
Discuss the Miocene hominoid remains and their significance in evolution -
2022 · Q2(b) · Anthropology GS 1 · 15 marks
Discuss different forms of primate social organisation -
2016 · Q8(c) · Anthropology GS 1 · 15 marks
Explain the skeletal changes due to erect posture and their implications.
More from this paper
Q1(a) · UPSC Mains 2021 · Anthropology GS 1 · 10 marks
Animism and Deep Ecology
Religion
Tylor’s animism is belief in spiritual beings as the minimum of religion. Later work reads animism as relating to animals and places as persons. Naess’s Deep Ecology gives nature intrinsic worth beyond human use. The two meet as critiques of a dead, owned environment. They are not the same theory and must not revive Tylor’s ladder.
Q1(b) · UPSC Mains 2021 · Anthropology GS 1 · 10 marks
Marriage Regulations and Alliance Theory
Family
Marriage regulations forbid and prefer categories of spouse. Alliance theory reads marriage as exchange that constitutes society. Lévi-Strauss contrasted restricted and generalised exchange. Kachin and Dravidian systems illustrate positive alliance. Weiner’s Trobriand work shows women as givers, not only gifts.
Q1(c) · UPSC Mains 2021 · Anthropology GS 1 · 10 marks
Historical Particularism and Franz Boas
Historical particularism (Boas)
Historical particularism treats each culture as a unique historical product. Boas rejected Morgan–Tylor unilinear stages. Diffusion and invention must be proved, not assumed from similarity. Race, language, and culture are independent. Heirs used culture areas and texts; the risk is trait-listing.
Toppers' copies
Toppers' copies for this question will be uploaded soon.