In looking at many small points of difference between species, which, as far as our ignorance permits us to judge, seem quite unimportant, we must not forget that climate, food, etc., have no doubt produced some direct effect.
Espezieen artean dauden alde txiki ugariak, gure ezjakintzak erizten uzten digun heinean, bat ere garrantzirik gabekoak diruditenak ikustean, ez dugu ahantzi behar klimak, janariak eta abarrek horiengan dudarik gabe ondoren zuzenik eragin dutela.