this post was submitted on 22 Oct 2024
99 points (97.1% liked)
Asklemmy
43731 readers
1232 users here now
A loosely moderated place to ask open-ended questions
Search asklemmy ๐
If your post meets the following criteria, it's welcome here!
- Open-ended question
- Not offensive: at this point, we do not have the bandwidth to moderate overtly political discussions. Assume best intent and be excellent to each other.
- Not regarding using or support for Lemmy: context, see the list of support communities and tools for finding communities below
- Not ad nauseam inducing: please make sure it is a question that would be new to most members
- An actual topic of discussion
Looking for support?
Looking for a community?
- Lemmyverse: community search
- sub.rehab: maps old subreddits to fediverse options, marks official as such
- !lemmy411@lemmy.ca: a community for finding communities
~Icon~ ~by~ ~@Double_A@discuss.tchncs.de~
founded 5 years ago
MODERATORS
you are viewing a single comment's thread
view the rest of the comments
view the rest of the comments
There's not enough oxygen in water to support our metabolisms, even if we had gills.
Fish are adapted to conserve and use less oxygen, from slower metabolic rates to more options for anaerobic respiration that doesn't poison oneself from within.
Well thats not really the most relevant thing here even if correct because you could give someone gills and let them keep their lungs too just having the gills to extend how long we can dive would be useful
I don't believe this. Sailfish, barracuda, tuna, huge mass, highly active... I'm sure they use a HELL of a lot more oxygen than I do on a good day. Gills extract MORE oxygen than lungs do, they're more efficient.
My unscientific opinion tho.
This article estimates at a 40kg sailfish uses about 2.7 megajoules per day of energy when hunting. That's about 650 kcal.
An 80kg human weighs about twice as much and needs about 3 times the energy, without even exertion.
Warm blooded animals spend a lot of energy just maintaining body temperature. Plus water doesn't have very much oxygen in it, compared to the atmosphere.
That last line is one reason we're able to fish successfully. Even large fish tire out because they can't pull enough oxygen from the water to struggle forever.
Oh sure, if you're going to use facts and science we may as well not even talk.
Seriously though, thanks for the insight.
This is the whole "if humans were going to have wings we'd have to redesign the whole organism from the ground up" fiasco all over again.
Exactly.
We still theoretically could, I guess, but people already have enough body image problems just from getting wrinkly or kinda bald, let alone being a freak mostly made of human-skin batwings.
Yeah, evolving lungs ended up clearing the way to make use of the much more plentiful oxygen in the air compared to what is dissolved in water. Amphibians and reptiles have pretty low metabolisms, but birds and mammals basically evolved endothermy (aka warm bloodedness), probably in support of much higher muscular power output. Ectotherms (aka cold blooded animals) have metabolisms that are correlated to temperature, which means they can't exert themselves as well when it's cold. Endothermy allowed animals to be warm all the time, and therefore use higher muscular power output in any environment, especially sustained.
That means mammals and birds were able to cover more distance, and survive in places where reptiles and amphibians can't, and all the advantages that carries.