File talk:Darwins first tree.jpg

Somebody has questioned what the text is. It's from page 36 of Notebook B: "I think [sketch] Case must be that one generation then should be as many living as now. To do this & to have many species in same genus (as is) requires extinction. (text below our picture) Thus between A & B immense gap of relation. C & B the finest gradation, B & D rather greater distinction. Thus genera would be formed. — bearing relation

(relevant text on page 37)

to ancient types. — with several extinct forms for if each species an ancient (1) is capable of making 13 recent forms, twelve of the contemporarys must have left no offspring at all, so as to keep number of species constant."

from http://darwin-online.org.uk/content/frameset?viewtype=side&itemID=F1574a&pageseq=14 The Complete Works of Darwin Online