and as these specific characters have varied and come to differ since the period when the species branched off from a common progenitor, it is probable that they should still often be in some degree variable-at least more variable than those parts of the organisation which have for a very long period remained constant.
eta ezaugarri espezifikook espezieak arbaso komunarengandik abartu zirenetik aldatu eta ezberdinak izatera heldu direnez gero, daitekeena da gaur egun ere maiz aldagarriak izatea graduren batean; aldi oso luzez aldagabe iraun duten organismoaren atalak baino aldagarriagoak.