Building a phylogenetic tree 134567

Several artificial organisms are shown on the cards. These drawings have been prepared so that it is easy to find differences and to distinguish between the characteristics of each organism. No numerical data are needed to distinguish between characteristics such as long and short birds’ tails. In contrast, with real organisms a researcher must usually collect numerical data and subjectively decide how to group characteristics or, alternatively, use advanced mathematical tools. Such problems do not exist when analysing molecular data. Phylogenetic trees for even distantly-related organisms may be prepared using amino acid or nucleotide sequence data. The differences between the sequences in different organisms indicate evolutionary distances. Wojciech Grajkowski