Blog posts describing the history of trees and networks as displays of phylogenetic relationships

The first phylogenetic network (1755)
The second phylogenetic network (1766)

The first gene transfer (HGT) network (1910)
The first paper on HGT in plants (1971)
HGT networks
The earliest tree / network of languages (1671)
The first HGT network

An outline history of phylogenetic trees and networks
The first royal pedigree
The first known pedigree of a non-noble family
Another early noble pedigree

Is this the first network from conflicting datasets?
An early phylogenetic classification (1884)
The dilemma of evolutionary networks and Darwinian trees

Books about the history of trees and networks
More literature on trees and networks

The ultimate phylogenetic network?
Metaphors for evolutionary relationships
Rivers of Life, instead of trees

Ngrams and phylogenetics
Who first used the term "phylogenetic network"?

Networks of genealogy
Networks of affinity rather than genealogy
Affinity networks updated
Phylogenetic networks 1900-1990

Charles Darwin's unpublished tree sketches
Charles Darwin's unpublished tree sketches, Part 2
Charles Darwin's unpublished tree sketches, Part 3
Update to Charles Darwin's unpublished tree sketches

Evolutionary trees: old wine in new bottles?
Who published the first phylogenetic tree?
Relationship trees drawn like real trees
An early tree of languages
The first Darwinian evolutionary tree
Fritz Müller and the first phylogenetic tree

Buffon's genealogical ideas
Buffon and the origin of the tree and network metaphors

Why do we still use trees for the dog genealogy?
Trees, networks and dogs
Why do we still use trees for the Neandertal genealogy?

Youngest contributor to phylogenetic networks
Anna Maria Redfield — the first woman to draw a tree of biodiversity

Human races, networks and fuzzy clusters

What is "Haeckel's Tree of Life"?
The kabbalistic Tree of Life is a network

Pierre Trémaux, the unknown phylogeneticist

The role of biblical genealogies in phylogenetics
The first infographic was a genealogy (c. 400 AD)
How confusing were the first genealogies?

Predecessors of Charles Darwin
Naudin, Wallace and Darwin — the tree idea
Charles Darwin and the coalescent
Darwin, hybridization and networks


  1. Does anyone know who was the first to
    formally state (and maybe also prove?) what is arguably the most basic result in phylogenetics, which in today's language would say:

    A set H of subsets of X equals the set of clusters of a rooted phylogenetic X-tree if and only if H is a hierarchy (i.e. any two sets in H are disjoint or one contains the other).

  2. Mike
    The obvious place to start looking is in Willi Hennig's work, since an explicit non-mathematical statement of the principle is always credited to him. However, Hennig compiled his ideas from those of several other people, so it probably goes back much farther. Hennig's treatment of the equivalence between phylogeny and hierarchy is discussed by Eric B. Knox (1998) The use of hierarchies as organizational models in systematics. Biological Journal of the Linnean Society 63: 1-49.

  3. Thanks David,
    that's helpful.
    I wondered if it might be in the writings of Linneaus? Or earlier (Aristotle et al?). I can find definite mathematical statements of it in the 1960s, but again there's maybe references from 1860 too! (related to some other problem, perhaps in physics, or pure maths)...

  4. Equating hierarchical relationships (ie. a tree) and phylogeny is something that is usually attributed to Darwin, although he explicitly calls it a "simile" rather than treating it as a formal model. Before that time, tree models were used in a non-phylogenetic context (I have an upcoming blog post on this). Linné, for example, said that relationships were "like countries on a map" rather than like a tree (his hierarchical taxonomic classification was a separate thing entirely); and I am not sure that Aristotle was much interested in phylogenetic relationships. So, your query most likely refers to someone between Darwin and Hennig in time, and probably closer to Hennig.

  5. Yes, I agree that the phylogenetic interpretation of what these trees mean comes much later, but the mathematical principle (that nested subsets are equivalent to a tree-like relationship) must surely have been stated earlier - perhaps in some totally different discipline, or context. It's not a deep result, of course, but it seems quite foundational in some sense.