About Our Logo
The Global ESD logo represents a phylogenetic network graph including the impact of lateral and oblique transmission of heritable information. We use it as an icon of perspectives in cultural evolution science that integrate human genetic evolution with the more complex flow of cultural information through social learning networks.
For a deeper explanation, please see highlights from the work of Johann-Mattis et al (2013) below.
Johann-Mattis List, Shijulal Nelson-Sathi, Hans Geisler, William Martin. 2013. Networks of lexical borrowing and lateral gene transfer in language and genome evolution. Bioessays 36: 141-150 https://onlinelibrary.wiley.com/doi/epdf/10.1002/bies.201300096
"In this diagram, the tree explicitly represents the phylogenetic history of the languages while the evolutionary network represents possible borrowings of words, with thicker lines representing more borrowed words. Clearly, the network also contains phylogenetic information of some sort. For example, the connection of the root of the Romance languages to English reflects the conquest of Britain by the French-speaking Normans, which modified the Old-German heritage of Old English. However, the diagram as a whole is a hybrid, rather than being a coherent phylogenetic network in the simplest sense (ie. a reticulation network).
To see this clearly, note that the phylogenetic tree is not fully resolved and that the evolutionary network does suggest possible resolutions for several of polychotomies, such as the relationship of Armenian and Greek, the relationship of Albanian to the Romance languages, and the relationship of the Gaelic languages to the Romance languages. So, in some cases the evolutionary network helps resolve the phylogenetic tree rather than forming a reticulating network.
It would be possible to derive a phylogenetic network from this minimal lateral network, but as it stands it is a combination of a phylogenetic tree and a so-called evolutionary network. "
