Basically, I mean an animal evolving to radically simplify its anatomical structure, or losing several major body systems. I will demonstrate some examples in arthropods, a phylum of animals with very complex anatomy and behaviors, in many ways analogous to vertebrates. ‘Degeneration’ as I will ca…

So this genome duplication is unique to teleosts, absent in tetrapods, chondrichthyans, and basal ray finns like sturgeons?

Yes…If nothing has changed in this field of science in the last 20 years. You can try to do a simple google image search with FSGD and fish and you probably find public images where you can see where this additional round of genome duplication has occurred. A search on pubmed will do the same.

SImple, sez you! We see their successful genetic codes overcoming the need for two highly different hosts in environments negotiating climates during continental drift, for 68 million years! Genes are a lot more than bodily morphology. And maybe, the last laugh? I suspect they will somehow surmo…

[image] insectilluminatigetshrekt: an animal evolving to radically simplify its anatomical structure, or losing several major body systems in my mind, transmissible turmors are the ultimate example of this – effectively, multicellular organisms becoming colonial unicellular organsims. in vert…

the important trait of all higher vertebrate is that there is no larva. no larva at all. what you get after hatching/birth you have this makes evolving any kind of sessile, non mobile or super specialized parasite impossible, because you lack any kind of dispersing stage.

I mean, those are examples of cells breaking off the body of the animal. Not the animal gradually evolving to lose all its anntomy to become a nuch simpler organism. But they are cool nonetheless

This is a really interesting point actually. It holds up within arthropods as well. Cristaceans, mites, and holometabolous insects have distinct larval stages and those are the clades with many hyper specialized parasites and degenerated forms. Non mite arachnids, myriapods and non holometabolous in…

Axolotls, olms, and sirens stayed in the juvenile stage of salamanders, and the latter seem to be well established in that form. I’ve seen one example of a bullfrog tadpole that didn’t metamorphose and kept growing to the size of a large adult, but it would take a whole bunch of unlikely coincidence…

Honestly didn’t read thru the entire thread, so someone may have already said this, but salamanders rapidly lose their eyes and pigment in caves, even if the species in general doesn’t exist in that form.

Is anatomical degeneration impossible in vertebrates?

Nature Talk

jasonhernandez74 December 14, 2024, 2:23am 33

So I take it “higher” vertebrates mean reptiles and their descendants. I never was sure where the line was.

Apparently, there is a third kind: Contagious reticulum cell sarcoma in hamsters.

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Is anatomical degeneration impossible in vertebrates?

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