(EEAR - 2020/2)
The idea of evolution (which is gradual change) was not a new one. The Greeks had thought of it, so Erasmus Darwin, the grandfather of Charles, and also the Frenchman, Lamarck. It is one thing to have an idea; we can all of us guess and sometimes make a lucky guess.
The pronoun one, in the text, is classified as:
object pronoun
relative pronoun
indefinite pronoun
possessive pronoun