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> We'll see if the inflation in ancient human species stands up to scrutiny. Not in that business, but could it be simply that a new way of measuring taxonomy

> We'll see if the inflation in ancient human species stands up to scrutiny. Not in that business, but could it be simply that a new way of measuring taxonomy is needed? From the outside, it appears that the whole business inherits from a Victorian need for orderly tree structures.

HelloNurse 5y ago
While not a tree, there is an indisputable orderly structure: the directed acyclic graph of individuals descending from other individuals. Then we can collapse nodes to obtain species that evolved from one another or more realistic arrangements, respecting some constraints (for example, if A is an ancestor of B and B is an ancestor of C, putting A and C in the same species should imply that B belongs to that species too).
- deleted 5y ago
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- AlotOfReading 5y ago
  The problem is that grouping individuals -> species is highly nontrivial. Even your constraint fails with bidirectional admixture. Imagine individuals from species A interbreed with people of species B. The admixture survives in B for a couple hundred thousand years and then back-admixture occurs, producing descendants in A who have intermediate ancestors of a different species. This is a common pattern in genus Homo, which is part of why human taxonomy is insanity. Bonus points if you can explain how to decide which species name to give to the immediate descendants of the admixture event from A->B. There's an older paper by Holliday on this subject that you might find interesting: https://doi.org/10.1086/377663 https://doi.org/10.1086/377663
  - HelloNurse 5y ago
    The idea of species is quite meaningless in any case. Boundaries are arbitrary, genetic similarity can arise by chance, interbreeding is situational, reproductive isolation is rarely perfect, populations are vague; of the different definitions of species surveyed in the article, the "cohesion"-based one is the closest to admitting that taxonomy is a rough model of cohesive genealogical and evolutionary patterns.

HelloNurse 5y ago

While not a tree, there is an indisputable orderly structure: the directed acyclic graph of individuals descending from other individuals. Then we can collapse nodes to obtain species that evolved from one another or more realistic arrangements, respecting some constraints (for example, if A is an ancestor of B and B is an ancestor of C, putting A and C in the same species should imply that B belongs to that species too).

deleted 5y ago
[deleted]
AlotOfReading 5y ago
The problem is that grouping individuals -> species is highly nontrivial. Even your constraint fails with bidirectional admixture. Imagine individuals from species A interbreed with people of species B. The admixture survives in B for a couple hundred thousand years and then back-admixture occurs, producing descendants in A who have intermediate ancestors of a different species. This is a common pattern in genus Homo, which is part of why human taxonomy is insanity. Bonus points if you can explain how to decide which species name to give to the immediate descendants of the admixture event from A->B. There's an older paper by Holliday on this subject that you might find interesting: https://doi.org/10.1086/377663 https://doi.org/10.1086/377663
- HelloNurse 5y ago
  The idea of species is quite meaningless in any case. Boundaries are arbitrary, genetic similarity can arise by chance, interbreeding is situational, reproductive isolation is rarely perfect, populations are vague; of the different definitions of species surveyed in the article, the "cohesion"-based one is the closest to admitting that taxonomy is a rough model of cohesive genealogical and evolutionary patterns.