In this article we present a synthesis of the organisational system of living organisms. It describes the structure of five kingdom system accepted by the majority of biologists. We present a couple of arguments that prove that this particular system most accurately explains the main characteristics of evolution. In the description of the main groups of acellular and cellular organisms (prokaryotic and eukaryotic) we use systemic units ordered in hierarchical series. The image of the phylogenetic tree is a great explanatory material which helps in the understanding of classification of the living organisms established during the evolution process. This study is meant for biology teachers and students. We hope that the evolutionary tree will be studied, discussed and used during biology classes.