1) The basis of modern systematics are ideas about the unity of origin of living organisms and the evolution of the organic world.
2) Guided by such ideas, modern science constructs a natural system based on phylogenetic kinship (i.e., the common origin, proximity and distance of kinship between different species) of classified organisms.
3) The degree of kinship of the compared species is established on the basis of their morphological, anatomical, biochemical, genetic, etc. similarities and differences.
Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.