Request to add terms for phylogenetic distance, its measurement method, and invasion success

[timalamenciak]

I can add these terms but wanted to open an issue to check the semantics and get feedback.

phylogenetic distance - def: a data item that describes the amount of time since two species diverged from a common ancestor.
 def source - Velland et al. 2010
 is_a data item

mean weighted phylogenetic distance - def: An assay of the mean phylogenetic distance between two species weighed by the amount of biomass produced by one species.
 def source - Yannelli et al. 2017
 is_a assay

invasion success - def: The capacity for a species to establish, dominate and spread in a non-native ecosystem.
 def source - O'Loughlin & Green 2017
 is_a data item

[timalamenciak]

On reflection, I think phylogenetic distance and invasion success should be is_a realizable entity