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Home/Anthropology/Mains PYQ/2020/Paper I/Human Genetics & Human Biology
UPSC MainsAnthropology Optional Paper I 2020 10 Marks Model Answer Available

Senescence — 2020 Paper I

Question · 2020 · Paper I · 10 Marks

Senescence

Model Answer

VAID ICS

Approach

  • Demand of Question: Explain senescence as biological ageing and discuss its major physiological and evolutionary dimensions.
  • Structuring the Response: Define senescence, outline major age-related changes and theories, and distinguish it from chronological ageing.
  • Key Dimensions to Cover: Cellular ageing, homeostasis, telomeres, oxidative damage, mutation accumulation, antagonistic pleiotropy and disposable soma theory.

Model Answer

Introduction

Senescence is the progressive decline in physiological function and biological resilience with advancing age, leading to reduced capacity to maintain homeostasis and increasing vulnerability to disease and mortality. It is a biological process and should not be equated simply with chronological age.

Major manifestations

Senescence involves gradual changes in:

  • muscular strength and bone density;
  • immune competence;
  • cardiovascular efficiency;
  • reproductive function;
  • sensory capacity;
  • tissue repair and recovery.

At the cellular level, ageing is associated with:

  • accumulation of molecular damage;
  • cellular senescence;
  • altered mitochondrial function;
  • changes in telomere dynamics;
  • reduced regenerative capacity.

Evolutionary explanations

  1. Mutation accumulation — Peter Medawar: Harmful mutations expressed mainly at older ages are weakly removed by natural selection.
  2. Antagonistic pleiotropy — George C. Williams: Genes beneficial early in life may have detrimental effects later.
  3. Disposable soma theory — Thomas Kirkwood: Organisms allocate limited energy between reproduction and long-term somatic maintenance.

Thus:

Limited maintenance → Accumulated damage → Functional decline → Senescence

Biocultural dimension

Human ageing varies with:

  • nutrition;
  • disease exposure;
  • physical activity;
  • occupation;
  • socioeconomic environment.

Conclusion

Senescence is therefore a biological and biocultural process, resulting from evolutionary trade-offs interacting with environmental and lifestyle conditions across the life course.

2026 Distinguishing features of nuclear and mitochondrial DNA. 2026 How would you find out that a particular disease/disorder is inherited and, if so, in which manner? Elaborate with suitable examples. 2026 What do you understand by fertility and mortality? How are these influenced by biological and socio-ecological factors? 2026 In what manner is our understanding of serogenetics and cytogenetics useful in reproductive biology? What are the major ethical issues involved in reproductive technology?

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UPSC Anthropology Optional 2020 — Paper I

28 questions

5(d) Ethics and Genetic engineering

10 Marks150 words
Syllabus: Paper I > 12. Applications of Anthropology > Applied human genetics and eugenics
2020Paper IApplied & Forensic AnthropologyModel answer available

5(c) Experiential Ethnography

10 Marks150 words
Syllabus: Paper I > 8.1 Research Methods > Fieldwork tradition and ethnography
2020Paper IResearch Methods in AnthropologyModel answer available

5(b) Genetic drift

10 Marks150 words
Syllabus: Paper I > 9.3 Mendelian population and Hardy-Weinberg law > Genetic drift
2020Paper IHuman Genetics & Human BiologyModel answer available

1(a) Natufian culture

10 Marks150 words
Syllabus: Paper I > 1.8(b) Cultural Evolution: broad outlines of prehistoric cultures > Mesolithic > Natufian
2020Paper IPrehistoric ArchaeologyModel answer available

5(a) Racism and Eugenics

10 Marks150 words
Syllabus: Paper I > 9.5 Race and racism > Racial differentiation; eugenics
2020Paper IHuman Genetics & Human BiologyModel answer available

1(b) Sapir-Whorf hypothesis

10 Marks150 words
Syllabus: Paper I > 7. Culture, language and communication > Language and thought
2020Paper ICulture & SocietyModel answer available

5(e) Senescence

10 Marks150 words
Syllabus: Paper I > 10. Human growth and development > Ageing and senescence
2020Paper IHuman Genetics & Human BiologyModel answer available

1(d) Victor Turner and Liminality

10 Marks150 words
Syllabus: Paper I > 6. Anthropological Theories > Symbolic Anthropology > Turner; liminality
2020Paper IAnthropological TheoriesModel answer available