CBSE Class 10 Science 2017 · Paper 31/1 · Question 21

Acquired traits: developed during an individual's lifetime because of its surroundings, use or experience; they change body (non-reproductive) tissue, not the DNA of the germ cells, and are not passed on to the offspring. Example: the low weight of a beetle that has been starved (or a skill such as swimming). Inherited traits: received from the parents through the DNA (genes) of their germ cells, and passed on to the offspring. Example: a beetle that is green because of a change in its DNA has green progeny (or the colour of the eyes, which a child inherits). Reason: only the DNA of the germ cells enters the zygote, and changes in non-reproductive tissues cannot be passed on to the DNA of the germ cells, so an acquired trait does not reach the next generation. Example: if the tails of mice are cut off by surgery in every generation, their progeny are still born with tails, because removing the tail does not change the genes of the germ cells.