[HN Gopher] In Praise of Subspecies
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       In Praise of Subspecies
        
       Author : Petiver
       Score  : 19 points
       Date   : 2025-02-03 22:17 UTC (5 days ago)
        
 (HTM) web link (aeon.co)
 (TXT) w3m dump (aeon.co)
        
       | ginko wrote:
       | The definition of what's a species or subspecies starts getting
       | fun when you consider ring species[0].
       | 
       | [0] https://en.wikipedia.org/wiki/Ring_species?useskin=vector
        
       | ralusek wrote:
       | As someone who has recently been dealing with taxonomic
       | classification, this world is a complete mess. For one, there
       | isn't even a singular authority on classification. Secondly, the
       | "data model" we have for classification isn't even capable of
       | actually representing proper lineages.
       | 
       | Linnaean classification, i.e. Domain > Kingdom ... Genus >
       | Species is a tree data structure, wherein each node has one
       | parent. Now what happens if you have something like a Leyland
       | Cypress, a hybrid?
       | 
       | A Leyland Cypress is a very popular tree that is the product of
       | hybridizing an Alaskan Cypress and a Monterey Cypress. Let's
       | begin analyzing all of the problems with this:
       | 
       | 1.) As mentioned, we can only choose one parent, even though all
       | species have 2. Which lineage to choose?
       | 
       | 2.) We know the _exact_ parents of this new species, and yet the
       | fact that Linnaean taxonomy uses a fixed number of ancestor node
       | ranks means we can 't classify this under a parent, but rather go
       | to the parent's genus
       | 
       | 3.) The idea of "species" being the only thing that can produce
       | viable offspring is completely incorrect, so being stuck with a
       | parent's genus as a foolproof way of reparenting a node is not
       | reliable. While an Alaskan Cypress and Monterey Cypress used to
       | both be classified as Cypresses (Cupressus nootkatensis and
       | Cupressus macrocarpa, respectively), they've now each been
       | reclassified multiple times into multiple different genuses, and
       | are now Callitropsis nootkatensis and Hesperocyparis macrocarpa
       | respectively. So we've created a viable offspring not just from
       | two different species, but two different genuses.
       | 
       | 4.) Many of these classifications were come up with purely
       | phenotypically and have nothing to do with genetic lineages.
       | 
       | So is a Leyland Cypress classified as Callitropsis or
       | Hesperocyparis, or the former Chamaecyparis or Cupressus? Just
       | choose an arbitrary grandparent node, and throw away the
       | information of half of its lineage, as well as the information of
       | its species-level parentage.
       | 
       | And then _within_ the species level, as mentioned by the original
       | article, we have subspecies (or infraspecific ranks). Subspecies,
       | varieties, subvarieties, forms, subforms, proles, cultivars, etc.
       | If you think there 's sanity found in that world, you'd be
       | mistaken.
       | 
       | Fortunately scientists dealing with actual genetic lineages have
       | begun switching to a different system which is not only founded
       | in genetics, but also has a proper data model to represent it,
       | which is a graph wherein any node can be associated with a
       | particular ancestor. So a Leyland Cypress could be parented to an
       | Alaskan cypress _and_ a Monterey cypress. It can also be parented
       | to ancestors of any rank, and this parentage can be any number of
       | levels deep. Each of these assertions of parentage puts a
       | particular entity in what is referred to as a  "clade," making
       | this form of classification referred to as "cladistic" or
       | "phylogenetic."
        
         | thejohnconway wrote:
         | Interestingly, vertebrate palaeontology switched to clade-based
         | taxonomy a while ago (although genus and species cling on).
         | Wikipedia tries to attach ranks to the clades of extinct
         | animals such as dinosaurs, which have no basis in the
         | scientific literature to normalise them with the taxonomy of
         | extant animals.
         | 
         | Palaeontology make the notion of species kinda silly, as all
         | organisms can be followed as a smooth grade all the way to the
         | origin of life.
        
         | dieselgate wrote:
         | Being a human of mixed race seems similar
        
       | pnut wrote:
       | Clicked the link thinking, "Finally Radu Vladislas has his day".
        
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