[HN Gopher] Arthropod head problem
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Arthropod head problem
Author : raattgift
Score : 44 points
Date : 2023-05-13 12:09 UTC (1 days ago)
(HTM) web link (en.wikipedia.org)
(TXT) w3m dump (en.wikipedia.org)
| ftxbro wrote:
| weird I put this one last month
| https://news.ycombinator.com/item?id=35635187
| andai wrote:
| Yeah, sometimes stuff will get reposted like 5 times in a row
| before anyone notices it.
| mjewkes wrote:
| Worth checking out the talk page. Looks like this whole article
| is out of date and that much of the problem is resolved.
| tempaway12644 wrote:
| I read about this somewhere recently and now I remember - it was
| "User: Junnn11" on the front page of HN a few weeks ago for their
| arthropod illustrations (see
| https://news.ycombinator.com/item?id=35630423 )
|
| Arthropod Head Problem is a really good name for a band
| NoZebra120vClip wrote:
| Wow, my eyes fully glazed over trying to just skim that article.
| Wikipedia has a rule about not over-using jargon, especially in
| highly technical articles. It looks like some expert attention is
| needed there to tone that down and translate all that to common
| English.
| bigbillheck wrote:
| I'm not a biologist but it seemed fine to me.
| andai wrote:
| I wanted to redirect you to the Simple English version, but
| there is only Esperanto...
| tedunangst wrote:
| The whole article reads like it was paraphrased by somebody who
| doesn't actually know anything about the subject.
| happytoexplain wrote:
| I mean, there is only so much you can simplify on some topics,
| and this is a _really specific_ topic. Making every domain-
| specific term a hyperlink is about as good as you can hope to
| get sometimes.
| icegreentea2 wrote:
| I don't actually think it's really a jargon problem per-se in
| this case. I think there's some minor changes that would help
| a lot.
|
| For example, the very first sentence: "The (pan)arthropod
| head problem[4] is a long-standing zoological dispute
| concerning the segmental composition of the heads of the
| various arthropod groups, and how they are evolutionarily
| related to each other". So even if you understand the jargon
| more or less, the way this is written makes it feel like
| "there's a lot more essential detail" that's not covered in
| this sentence. But once you read the background section, and
| you get to this sentence "The challenge that the arthropod
| head problem has to address is to what extent the various
| structures of the arthropod head can be resolved into a set
| of hypothetical ancestral segments", you realize that
| actually the initial summary is actually fairly complete, but
| just strangely uncommital.
|
| Rewriting the first sentence to be more direct might result
| in: "The arthropod head problem is a zoological dispute over
| the extent that the various structures of the arthropod head
| amongst different types of arthropods can be resolved into a
| set of hypothetical ancestral structures". Or maybe a less
| aggressive change: "The (pan) arthropod head problem is a
| zoological dispute over the segments that make up the heads
| of the various arthropod groups, and how these different
| segments are evolutionary related to each other".
|
| The background section itself could probably be improved by
| moving the first sentence deeper into the section, and
| probably doing a paragraph break right before the "The
| challenge that the arthropod head problem has to address.."
| sentence to make it easier for skimmers (or glazed out
| readers) to pick out a significant segment.
|
| In fact, maybe the problem with the beginning section is that
| it's focused on the "meta". Every single sentence contains
| information about the history and development of "the
| problem", while only one sentence directly talks about
| "problem", and like two sentences talk about the scope and
| some of the tools used to address the problem. Perhaps
| portions of the "Background" section should be raised to the
| top level, and the history stuff moved to a history (or even
| the background...) section.
|
| I think it's reasonable for some articles to be pretty jargon
| dense, but the opening bits should make some accommodations
| to less specialized audiences.
| brazzy wrote:
| Bravo.
|
| Most people suck _so very much_ at writing clearly and
| concisely.
|
| And that usually has little to do with assuming knowledge
| in the audience; people who have the requisite knowledge
| are just better able to penetrate the bad writing, but
| would still be able to digest a better article much more
| quickly.
| martinpw wrote:
| SGTM. How about you make some of those changes to the
| article? Of course you may end up with possessive authors
| who revert, but the Edit button is there for a reason :-)
| ansgri wrote:
| This should have some simpler overview though. I actually
| have some background in morphology of insects and
| crustaceans, and skimming first screens for a couple of
| minutes gave me no idea what is it about.
|
| Looks like it's about the evolution of arthropod head from
| segmented worms, with disagreements on what arthropod parts
| are homologous (evolutionary correspondent) to which parts of
| segmented worms. Please correct me if I'm wrong.
| stavros wrote:
| Well, from the comments here, it looks like "there's a lot of
| debate on which parts of various insects' heads evolved from
| the same ancestral parts" about covers it.
| pvaldes wrote:
| In short, animal bodies can be constructed either as a chain of
| repeated basic structures called segments or otherwise. We
| could think for example in an earthworm and a jellyfish.
|
| All segmented animals can be represented as a list of ordered
| segments. Different lists can have different lengths, but the
| number of elements inside each type of animal is very stable.
| We are segmented animals also.
|
| An hypothetical animal with five segments in its body plan,
| would be represented as:
|
| '(1 2 3 4 5)
|
| Each element in (cdr '(1 2 3 4 5)) has the ability to grow a
| couple of structures called appendix. The first segment will
| bear another special type of sensors designed to detect light,
| the eyes. Animals use chemical gradients to modulate the
| appendix separately and turn them into everything that will
| need, in the right place.
|
| The concept of chemical gradients is not difficult to
| understand. Drop some chemical in the first segment and let it
| to diffuse towards the end of the chain. The first part will
| receive much more chemicals than the tail, activating different
| genes. Our embryo now looks like this:
|
| '(head torax abdomen)
|
| Rinse and repeat for each element, nesting lists. This very
| smart process is all that we need to make an animal while
| guaranteeing that our embryo will never develop a couple of
| ears in the legs [1].
|
| [1](... Unless is an arthropod, because each type of animals
| have their own ways to solve the problems)
| pvaldes wrote:
| Arthropods are a very species rich and very diverse group of
| animals, but using this system we can safely classify them
| into several big categories by the type, class and position
| of its appendix in the list.
|
| In the real life this translates to:
|
| '( antenna leg leg leg)
|
| This is an hexapod, for example an ant, but:
|
| '( fake-antenna leg leg leg)
|
| This is Myrmarachne a spider mimicking an ant. It moves its
| first pair of legs to simulate an antenna and trick its
| preys, but we know that the structure is different. If you
| are an ant, you would be dead by now.
|
| '( antenna antenna antenna leg leg)
|
| This animal does not exist. Not in this planet. Is an alien.
|
| If we have a partial fossil with one leg and a couple of
| wings, we can say that this was a modern insect. Wings
| developed only in the modern insects.
|
| The appendix and its location are so different among the main
| groups of arthropods and so fixed inside the groups that we
| can safely say that trilobytes didn't fall in any known
| category of alive arthropod. Those were not crustaceans and
| all went extinct.
|
| We also know that spiders are not just crustaceans that lose
| a couple of legs and a couple of antennas. Its legs are
| placed in different segments, and the auxiliar structures in
| its head are totally different.
| xipho wrote:
| While not exactly related a significant contribution has recently
| been published- https://pubmed.ncbi.nlm.nih.gov/37094905/ in a
| journal. Tools like this help tease out what things "really" are,
| as they give a hypothetical context (as opposed to claiming one-
| true-truth) to help one _think_ about things. Evolution has
| repeatedly converged on what people would say are the "same"
| thing many times, this is well understood. Deeply understanding
| the vastness of biologically diversity, as others have alluded to
| in the comments, is still relegated to such a tiny minority of
| human minds that finding a common language to express the nuances
| discovered with the rest of humanity remains a challenge.
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