
The Jellyfish Problem - gruseom
https://www.historytoday.com/archive/natural-histories/jellyfish-problem
======
ncmncm
We still have the problem of the ctenophores. "Comb jellies", they used to be,
until it turned out they have practically nothing in common with jellyfish
except transparency and radial symmetry. Or with anything else.

They use proteins similar to those used by other animals, but for different
things. Some people think they evolved muscles and nerves entirely
independently of other animals. Some people think they fell from the sky.

Whatever you think, they are astonishing in every detail. Watch videos of
Beroe if you have any doubts.

~~~
pvaldes
> Some people think they fell from the sky.

Ctenophores are a nigthmare to study. They self-disintegrate at the slightest
touch and aren't well adapted to low pressure environments. Pieces of an
animal being dragged from a storm before to fall again does not count as a
realistic way to spread.

If you mean that they could have an extraterrestrial origin, is really
unprobable IMHO. If there is an animal badly adapted to survive in the space
is this.

~~~
ncmncm
Nobody really thinks they are storm-borne or extraterrestrial. They are just
weird enough to make you wonder.

------
frabbit
A good tour of the problems of phenotypic classifications -- which reached
their heyday in the funfair of cladism. Always reminds me of Terry Pratchett's
jokes about banana classification:

[https://www.goodreads.com/quotes/6870748-yes-sir-but-the-
lib...](https://www.goodreads.com/quotes/6870748-yes-sir-but-the-librarian-
likes-bananas-sir-very-nourishin)

------
divbzero
The article didn’t mention phylogenetic analysis of jellyfish genes or
genomes, _e.g._ using 16S rRNA. [1]

[1]:
[https://en.wikipedia.org/wiki/16S_ribosomal_RNA](https://en.wikipedia.org/wiki/16S_ribosomal_RNA)

A brief search didn’t yield anything on jellyfish phylogeny for me, would be
curious if anyone else has information on this.

~~~
frabbit
Use "cnidaria" as your keyword?

[https://oceanexplorer.noaa.gov/fsts/media/DNAbarcodingCnidar...](https://oceanexplorer.noaa.gov/fsts/media/DNAbarcodingCnidarians.pdf)

------
perl4ever
"Since nothing could will itself to move without some sense of where it wanted
to go"

[https://www.farmersalmanac.com/maple-copters-
everywhere-2158...](https://www.farmersalmanac.com/maple-copters-
everywhere-21588)

------
cortesoft
There is no 'true' category for anything.

The Categories Were Made For Man, Not Man For The Categories

[https://slatestarcodex.com/2014/11/21/the-categories-were-
ma...](https://slatestarcodex.com/2014/11/21/the-categories-were-made-for-man-
not-man-for-the-categories/)

~~~
huffmsa
> Thus Abraham Lincoln’s famous riddle: “If you call a tail a leg, how many
> legs does a dog have?” And the answer: “Four – because a tail isn’t a leg
> regardless of what you call it.”

Enter the kangaroo.

------
naringas
reminds me of
[https://meaningness.com/eggplant/definition](https://meaningness.com/eggplant/definition)

