for unknown reasons there is a semi-retarded belief that no animal phyla will evolve from a simpler animal phyla but phylum are set in stone ever since 400 million years or so and no longer there can be new phyla but old ones can occasionally go extinct>no other phyla evolved from cnidarians lol, they just resemble some of the earliest animals but none of them are related to the direct ancester of other animal groupsmeanwhile this is held true:>fish evolved into amphibians>amphibians evolved into lizards>lizards made several branhces, one of which is mammal and another one which is birdsso you see, inside a phyla animals can evolve but no new phyla can appear from old ones, an animal will not change so much it becomes a new phylum, this is hold true now and also 450 million years ago altough perhaps not 800 million years ago
>>17004923It's more of an issue of unequal hierarchies, I mean look at this mess.Porifera is a phylum even though it's an offshoot of the kingdom Animalia/Metazoa, and sister clade to the subkingdom Eumetazoa/HistozoaCtenophora is a phylum even though it's an offshoot of the subkingdom MetazoaPlacozoa is a phylum even though it's an offshoot of a clade two nodes above BilateriaCnidaria is a phylum even though it's an offshoot of a clade above BilateriaXenocoelomorpha is a phylum even though it's a sister clade of Nephrozoa, the node above the super-phyla Deuterostomia and ProtostomiaChordata is a phylum even though its sister clades are all groups of many phyla, etcThe thing you're gesturing at (bilaterians being descended "from" Cnidarians) is represented as them sharing a common "Planulozoan" ancestor, who was probably very Cnidarian-like, but minus the cnidocyte innovation which is kind of a key characteristic you know.By the way, recent phylogeny work has shown that while protostomy is definitely monophyletic, deuterostomy is more likely to be basal to all bilaterians, so in theory protostomes are offshoots of deuterostome lineages.
>>17004923You are mostly seething at a language issue. People name things and then retroactively create a narrative that fits names. Naming of species, species groupings and their hierarchies is largely arbitrary and does not follow a set standard that you can measure objectively. Instead it's based on groupings of species that have some feature that other groupings lack. The particular statement you are whining about is definitionally true but it's not somehow objective.
low iq thread #35920590
i think you're right about this, yeah
>>17004961snail @°°
