Darwin Meets Graph Theory on a Strange Planet: Counting Full \(n\)-ary Trees with Labeled Leafs
Johnathan Barnett, Hannah Correia, Peter D. Johnson, Michael Laughlin, Kathryn M. Wilson · 2015
Some time in April 2009, the third author ran across some numbers in Chapter 10 of The Blind Watchmaker Dawkins (1996), a popular explanation of evolution by the great evolution explainer Richard Dawkins, that he (the third author) could not verify. These numbers were counts of different “family trees” indicating degrees of “cousinhood” or order of descent, among categories of living things. For example, if we are interested in (relative) cousinly relations among 3 species, say lions and tigers and bears (assuming those to be species), there are 3 hypothetical trees to consider: