Darwinian Evolution: Descent & Selection — NEET Biology

Correct answer: B — S1, S3 and S5

Let's evaluate each statement regarding natural selection and evolution: S1: This statement is correct. Darwin's theory emphasizes that natural selection operates on heritable variations, meaning traits that can be passed from parents to offspring. S2: This statement is incorrect. According to Darwin, fitness refers ultimately and only to reproductive fitness, meaning the ability to produce more progeny. It does not refer to the acquisition of new traits during an individual's lifetime, which is a Lamarckian concept. S3: This statement is correct. Individuals with characteristics that enable them to survive better in natural conditions (better adapted) are said to be more fit and leave more progeny, thus increasing the prevalence of those advantageous traits. S4: This statement is incorrect. The concept of inheritance of acquired characters was proposed by Lamarck, not Darwin. Darwin's theory focuses on the inheritance of pre-existing heritable variations. S5: This statement is correct. NCERT describes evolution as a stochastic process, meaning it is influenced by chance events in nature and random mutations in organisms, rather than being deterministic. Therefore, statements S1, S3, and S5 are correct. The correct option is B because it accurately identifies S1, S3, and S5 as correct statements. Options A, C, and D include incorrect statements or exclude correct ones.