We can perhaps understand the apparently quicker rate of change in terrestrial and in more highly organised productions compared with marine and lower productions, by the more complex relations of the higher beings to their organic and inorganic conditions of life, as explained in a former chapter.
Lehorreko izakiak eta goragoko organizazioa dutenek, itsas izakiekin eta beheragoko organizazioa dutenekin konparaturik, aldaketa nabariki azkarragoak izatea, agian honako honengatik uler genezake, alegia, goi-izakiek beren bizi-baldintza organiko eta ezorganikoekin harreman konplexuagoak dituztelako, aurreko kapitulu batean azaldu den moduan.