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Evolution is the gradual change in the inherited characteristics of a population across generations. The fact that species change was accepted long before anyone could explain how, and that gap is where this chapter lives.
That is also why exams ask it as name-matching. Three men proposed three different mechanisms, each in a different century of thought, and only one of the three survived being tested. Store each theory with the test that was run on it, and the questions stop being memory work.
Lamarck said organisms change during their own lifetime and pass the change on. Darwin said organisms vary from birth and the environment selects among them. De Vries said change comes in sudden jumps rather than gradually.
The second half of the chapter is evidence — homologous organs, vestigial organs, fossils, embryology and biochemistry. Evidence questions are easier than theory questions, because each kind of evidence comes with two or three standard examples that are asked again and again.
SSC CGL and CHSL, RRB NTPC and Group D, BPSC TRE-4 general science, UPSC Prelims and CTET science all ask from here.
1. Who proposed the theory of inheritance of acquired characters, illustrated by the lengthening of the giraffe's neck?
2. Which book, published by Charles Darwin in 1859, set out the theory of natural selection?
3. The forelimbs of a man, a whale and a bat have the same basic bone structure but perform different functions. Such organs are called what?
4. Archaeopteryx is regarded as a connecting link between which two groups?
5. Which of the following is a vestigial organ in human beings?
6. Whose experiment on the tails of rats over many generations disproved the theory of inheritance of acquired characters?
7. The mutation theory of evolution, based on work with the evening primrose, was proposed by whom?
8. The phrase 'survival of the fittest' was coined by whom?