But we can see that species, owing to their struggle for existence with numerous competitors, will have been exposed during long periods of time to more uniform conditions, than have domestic varieties; and this may well make a wide difference in the result. For we know how commonly wild animals and plants, when taken from their natural conditions and subjected to captivity, are rendered sterile; and the reproductive functions of organic beings which have always lived under natural conditions would probably in like manner be eminently sensitive to the influence of an unnatural cross.
eta honek alde handia eragin lezake ondorioan. Jakin ere, badakigu zein eskuarki bihurtzen diren antzu basoko animalia eta landareak, beren natur baldintzetatik atera eta hesiperatzen direnean; eta natur baldintzetan beti bizi izan diren izaki organikoen ugal-funtzioak badaiteke era berean oso sentiberak izatea gurutzaketa eznaturalen eraginarekiko.