Chapter Overview & Weightage
- Marks in Boards: 6–10 marks (usually 1–2 questions + numerical/theory)
- Repeated Topics: Darwin's theory of natural selection, Lamarckism, evidences of evolution (homologous/analogous organs, fossils, embryology), Hardy-Weinberg principle, adaptive radiation, speciation, human evolution.
- Difficulty: Moderate • Heavy on theory (theories, evidences) + numerical (Hardy-Weinberg allele frequency).
- Trend (2021–2025): 1 numerical (3 marks) on Hardy-Weinberg + 1 long answer (5 marks) on evidences/Darwinism + MCQs on human evolution.
Most Important & Repeated Questions (2021–2025)
- Repeated 5–6 times: Explain Darwin's theory of natural selection with examples. (5 marks)
- Repeated 4–5 times: Differentiate between Lamarckism and Darwinism. Give limitations of each. (3 marks)
- Repeated 4 times: Give evidences of evolution: homologous & analogous organs, fossils, embryological, biochemical. (5 marks)
- Repeated 3–4 times: Explain Hardy-Weinberg principle. Calculate allele frequency in a population. (3 marks)
- Repeated 3 times: What is adaptive radiation? Give example (Darwin's finches). (3 marks)
- Repeated 3 times: Describe origin & evolution of man (stages: Australopithecus → Homo erectus → Neanderthal → Homo sapiens). (5 marks)
- Repeated 2–3 times: What is speciation? Explain allopatric & sympatric speciation. (3 marks)
- Assertion-Reason (2023–2025): Assertion: Homologous organs show divergent evolution. Reason: They have common ancestry but different functions. (Both true, reason explains – repeated 2x)
Important Keywords & Concepts to Memorize
- Evolution, natural selection, Darwinism, Lamarckism, acquired characters, struggle for existence, survival of the fittest, homologous organs, analogous organs, vestigial organs, fossils, embryological evidence, biochemical evidence, adaptive radiation, convergent evolution, divergent evolution, speciation (allopatric, sympatric), Hardy-Weinberg principle, allele frequency, genetic drift, founder effect, bottleneck effect, human evolution (Australopithecus, Homo habilis, Homo erectus, Neanderthal, Homo sapiens), Neanderthal man, Cro-Magnon man.
Exam Strategy for Chapter 7 (2026 Boards)
- Focus: Evidences of evolution (homologous/analogous organs, fossils) – practice 3 tables daily
- High-scoring: Darwinism vs Lamarckism comparison (3 marks) + Hardy-Weinberg numerical
- Time: 8–10 minutes per 5-mark question (theory + diagram)
- Tip: Draw labelled diagrams of homologous/analogous organs – neatness = full marks
- Repeated: Human evolution stages (3–5 marks)
This is Chapter 7 complete PYQ analysis.
If you want Chapter 8 or any other chapter, just say the chapter number or name.