Bioinformatics, biological databases, and the worldwide use of computers have accelerated biological research in many fields, such as evolutionary biology. Here, we describe a primer of nucleotide sequence management and the construction of a phylogenetic tree with two examples; the two selected are from completely different groups of organisms: hominids and cyanobacteria. The hominid group involves genetic information not only of recent species, but also from fossilised ancestors of modern humans. Nucleotide sequences are used to construct phylogenetic trees. In the case of the cyanobacteria group, the nucleotide sequences obtained from fossilised cyanobacteria were searched across databases to find similar sequences and identify recent relatives. This demonstration of evolutionary history provides real examples of the bioinformatics approach in biological research; additionally, it can be utilised as practical exercises in biological studies, suitable for secondary or tertiary-level classes. (Contains 1 table and 8 figures.)