biologists claim that animal phyla have not evolved from other animal phyla, which is retarded claim

for all intents and purposes, it really looks like hydra (species of medusoid) gave eventually birth to polychaete worms

and polychaete worms would give birth to all other phylum

polychaetes -> straight jump to spiralians like snails

flatworms are probably very derived snails

octopus is extremely evolved form of a snail

polychaetes -> the common ancestor of fish and crabs which occuers just before the split of protostomes and deuterostomes

first deuterostomoes -> acorn worms -> later fish

sea stars -> not related to deuterostomes but by pure chance have similar development of fetus (this is also the only thing connecting sea stars to humans, by all other means they are completely different, only the fetus is similar)

so how does sea stars even appear?
medusae -> direct evolution to sea stars without them being worms before that

so in effect the most ancient forms of life after a medusa is sea star which is actually more primitive than any worm altough its not immediately apparent by its form

first protostome -> roundworms -> first arthropod group (nobody knows which came first) -> then appears crabs and spiders out of which crabs evolve into insects and spiders evolve to scorpions at best but do not create more diverse forms than that

>>16723507 (OP)

>sea stars

Aren't these a case where only one side along the body axis develops further? So a case of extreme asymmetry? Just a special EvoDevo branch...

>>16723510
yes but their genes show it must come directly from cnidarian medusoids instead of being related to human/fish lineage altough it is claimed it belonges to deuterostomes

>>16723507 (OP)
>biologists claim that animal phyla have not evolved from other animal phyla, which is retarded claim
Could you tell me who is making this claim and show me where they claim it?

I think you're getting hung up with definitions. By definition a phylum cannot evolve from a phylum. That doesn't mean that the cladistics aren't valid. It would just be called something else.

>>16723525

Might very well be, a bit rusty on the whole topic by now. Still, the organism is not radially different.

>>16723550
>>16723545

>>16723578
So you can't tell me, got it. I'll assume it's not real and you just got your ass twisted by some facebook comment conversation with a bot.

>>16723596
the bot must have been made through various internet sources because it comes to this conclusion

similarly I can eventually find a biologist who has said things are like they be

I will try to find the answer in 24 hours and post it here

>>16723507 (OP)
biologists tend to have this logical blindspot a lot of paleotards have for making up shit and not backing off their mound when it doesn't make sense anymore, you're not wrong OP

>>16723507 (OP)
>>16723545
It's a formality in classification.
When you classify animal clades, this description could fall in one of 3 categories:
>polyphyletic
It arises independently across unrelated lineages. Think "flying animals." Good for functional description but useless for a taxonomic basis.
>paraphyletic
Includes a common ancestor but not all of its descendants. Think "fish." Sort of splits the middle between descriptive utility and taxonomic utility. Biologists avoid these whenever possible.
>monophyletic
Includes a common ancestor and all of its descendants. Pretty much all phyla are classified in this way. It is the gold standard in taxonomy. It removes ambiguity. Once you're in a clade, you can never "evolve out" of it. The only issue is people that don't understand this get confused by questions like these.

I don't know, off the top of my head, anything about the phyla you're discussing here. But what's probably going on is biologists inserted a sort of "proto-taxa" that includes both lineages to maintain a monophyletic system to categorize them.

>biologists claim that animal phyla have not evolved from other animal phyla, which is retarded claim
Evolved from and evolved out of aren't the same thing.

sea stars are deuterostomes tho

>>16724040
why should deuterostomes need to be related to other deuterostomes?

we dont know which is the original animal condition: deuterostomy or protostomy

on the other hand hemichordate worms + fish have a bit too much in common between each other to be unrelated

>>16723550
>By definition a phylum cannot evolve from a phylum

well yeah but there must be an ancestor for a phylum, it doesnt appear out of a thin air

likely a weird worm had few weirder cousins and all of them branched into different phylums

originally this would happen when a worm due to freak mutation loses a lot of its genes, they are lost forever from genome

then somehow it stays viable
it will not be able to reproduce with its cousins but nature could repurpose its remaining genes for whatever features