Why Are Some Evolutionary Trees in Natural History Museums Prone to Being Misinterpreted?

Abstract

Today, the picture of an evolutionary tree is a very well-known visual image. It is almost impossible to think of the ancestry and relationships of living beings without it. As natural history museums play a major role in the public understanding of evolution, they often present a wide variety of evolutionary trees. However, many studies have shown (Baum and Offner 2008;Baum et al. 2005;Catley and Novick 2008;Evans 2009;Gregory 2008;Matuk 2007;Meir et al. 2007b;Padian 2008) that even though evolutionary trees have the potential to engage visitors of natural history museums with the phenomena of evolution, many of them unwittingly might lead to misunderstandings about the process. As valuable research and educational institutions, one of the museum's important missions should be the careful design of their exhibits on evolution considering, for example, common preconceptions visitors often bring, such as the notion that evolution is oriented from simple toward complex organisms (incarnating the idea of a single ladder of life amidst the extraordinary diversity of organisms) and that humans are at the pinnacle of the evolutionary story, as well as naïve interpretations of phylogenies. Our aim in this article is to show from history where many of these misunderstandings come from and to determine whether five important Western natural history museums inadvertently present "problematic" evolutionary trees (which might lead to non-scientific notions).

From Tree to Map: Using Cognitive Learning Theory to Suggest Alternative Ways to Visualize Macroevolution

“…Tree diagrams vary greatly in structure, orientation, and the types of information they depict. For example, cladograms and phylograms are based upon cladistic analysis, while other types of phylogenies incorporate additional non-cladistic information into the visualization (Torrens and Barahona 2012). Most cladistic phylogenetic "trees" developed today have little in common with early depictions of the tree of life, and are tree-like only in general outline.…”

“…For example, including a time scale on diagrams may help viewers better conceptualize evolutionary time (Catley and Novick 2009). Presenting diagrams oriented horizontally or radically may help viewers avoid the misconception that taxa at the top of the tree are superior to those below them (e.g., Catley and Novick 2008;Torrens and Barahona 2012). Finally, careful consideration of branching topology can help avoid misconceptions about evolutionary advancement and primitiveness among taxa (e.g., Gregory 2008;Catley et al 2010).…”

“…Many of the affordances described in Table 1 suggest important aspects of the theory of evolution. For example, one affordance that tree diagrams can depict well, depending upon the specific tree, is the significance of shared descent and a macroevolutionary pattern that shows a unitary origin of life (Torrens and Barahona 2012). Another positive feature of tree diagrams is their emphasis on cladogenesis as a key feature in macroevolution (Catley and Novick 2008;Gregory 2008).…”

“…The second is quantitative and represents formal phylogenetic hypotheses about the relationships among organisms. Both qualitative tree diagrams and quantitative cladograms are used in evolution education (e.g., Catley et al 2010;Torrens and Barahona 2012), and the ability to interpret trees is an important skill for professional biologists. This paper is chiefly concerned with the more qualitative aspects of tree visualizations and does not propose to rethink the assumptions behind phylogenetic analysis.…”

“…While text in the visualization does describe some evolutionary processes, the pictorial (Catley and Novick 2008;Gregory 2008;Catley and Novick 2009;Catley et al 2010;MacDonald 2010;Torrens and Barahona 2012). Therefore, this comparison is necessarily focused on features that are found across a range of diagrams.…”