CBSE Class 10 Science 2019 · Paper 31/4/3 · Question 17

(a) Differences between acquired and inherited traits (any two; set out as a table in step 3): 1. Acquired traits are developed by an individual during its lifetime (e.g. loss of weight of a starving beetle); inherited traits are received from the parents (e.g. eye colour). 2. Acquired traits do not change the DNA of the germ cells, so they are not passed on to the next generation; inherited traits are coded in the DNA of the germ cells and are passed on. 3. Acquired traits cannot direct evolution; inherited traits can direct evolution. (b) Homologous organs, for example the forelimbs of a human being, a cat, a whale and a bat. They have the same basic structure (humerus, radius and ulna, wrist bones, hand and finger bones) but are modified to perform different functions: grasping, walking, swimming and flying. This common design has been inherited from a common ancestor, so homologous characteristics show how closely species are related: the more of them two species share, the closer they are in evolution.