Add to ORKGThis paper aims at discussing some difficulties regarding the species definition problem in biology. I will try to show that typological concept defines species as fixed, immutable entities. After this, I will consider some passages of Origin of Species in the attempt to characterize Darwinian species as populations that may be modified, through natural processes, into new species. Besides, I will present the biological concept of species, trying to discuss problems of not making distinctions between species as classes and species as concrete individuals. Then, I will point out some different definitions, alternative to the biological concept. Finally, I will delineate some consequences of species definition discussion to own human species ...