Biodiversity, the tree of life, and science communication

Abstract

The usual approach to organising human knowledge in any field is to invent an intuitive, often hierarchical system of classification. Perhaps uniquely to natural history, humans did not so much invent such a system as discover one: the tree of life. This now iconic object has utility, not only in biodiversity research but also in conservation and science communication. For example, engagement in conservation requires highlighting the scale of biodiversity and what we stand to lose; this can be communicated very effectively by showing people the complete tree of life. Here we discuss the challenges involved in making the complete tree of life accessible to a broad audience. The first challenge relates to data curation, which is marred by the lack of a universally recognised database of species names. Different species can have the same name, different names can refer to the same species, and spelling errors are rife. The second challenge is tree visualisation. While many visualisation methods already exist, few are able to represent the complete tree of life. We argue that scaling up any method to the extent necessary for showing the whole tree of life is bound to expose inescapable trade-offs in the prominence given to each aspect of the underlying data. For example, should topology or species richness be prioritised when displaying clades that contain an insignificant proportion of species but which occupy a prominent position in the tree topology? We conclude with an optimistic outlook for using the tree of life in science communication.