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Costasiella kuroshimae – Solar Powered animals, that do indirect photosynthesis

124 points by vinnyglennon 4 days ago | 49 comments

iwd 9 hours ago

I just got to see a different species of kleptoplastic sea slugs in the wild last month, on a kayak tour of the mangroves around Key West. Our guide scooped some lettuce sea slugs up in a plastic container (and then returned them safely). They were bigger, about 3 inches long, with a wavy/frilly green border. It made my biologist heart very happy!

throwup238 8 hours ago

That was likely a sea slug from the Nudibranchia order (they resemble lettuce sea slugs sometimes) which are a bit different from Sacoglassa order slugs like the one in TFA in that they carry symbiotic algae colonies, rather than digesting them and keeping the chloroplasts like Sacoglassa.

Ericson2314 9 hours ago

I remember as a kid wondering if we could give humans chlorolaplasts.

rustyhancock 8 hours ago

I believe that mitochondria and chloroplast both were originally independent single celled organisms.

So kind of funny that, chloroplast is being "stolen" again by this sea slug.

morphle 4 hours ago

Yes, it is funny that biological history repeats itself.

https://en.wikipedia.org/wiki/Symbiogenesis

gus_massa 7 hours ago

Somewhat related https://what-if.xkcd.com/17/

The surface is too small and you only get like 4% of the energy you need (Assuming you like being naked under full sunlight all day long. The article is for cows, but I guess the number is similar for humans.) 4% of 2400 kcal is almost 100 kcal, that is the content of a small diet treat or 2 apples.

These sea slugs can survive because they move very slowly. For a human, I think it's not enough energy to survive even if all the activity is to watch TV inside a hot swimming pool.

eigenspace 5 hours ago

Dietary need scales with volume, whereas incident sunlight would scale with surface area.

Assuming a spherical cow and a spherical human, the calories needed would scale with the radius cubed, whereas the calories gained from sunlight would scale with the radius squared. So while I agree this wouldn't be very many calories, even if you sat under the sun all day, I think the 4% figure is probably quite pessimistic.

pfdietz 4 hours ago

The square cube law pops up all over the place, my favorite being in fusion reactors, where it is a two edged sword.

corygarms 6 hours ago

This is exactly why pokemon devs are looking for biologists! (seriously) https://www.nature.com/articles/d41586-026-00960-8

hackerbeat 8 hours ago

We‘re all solar—powered animals.

morphle 4 hours ago

Many bacteria and animals are chemically-powered or electrically-powered. Just one group: https://www.whoi.edu/oceanus/feature/lost-city-pumps-life-es...

jimbokun 8 hours ago

You know what they meant.

infogulch 3 hours ago

Well it says "indirectly". How much indirect do they mean?

stavros 11 hours ago

Life is amazing.

squigz 11 hours ago

Stuff like this really makes you wonder what life might look like out in the universe.

ljf 10 hours ago

https://www.eastoftheweb.com/short-stories/UBooks/TheyMade.s... - love this short story and its take on that question.

squigz 10 hours ago

A classic, and regularly shared here on HN :)

I really like this version of it personally: https://www.youtube.com/watch?v=T6JFTmQCFHg

explodes 10 hours ago

Some things on Earth (especially in the ocean) you'd think were extraterrestrial... What a gift to still be able to find such amazing animals out there.

pfdietz 4 hours ago

They all, so far, share the same basic biochemistry, derived from the Last Universal Common Ancestor (LUCA).

What would be extraordinarily interesting would be if we could find life on Earth with a fundamentally different biochemstry. Very different genetic code, even. This would be sign that Origin of Life is not the Great Filter. And we don't even have to go to another planet to conduct this search for "alien" life.

squigz 6 hours ago

Some of those things down in the ocean are almost too extraterrestrial... they can stay undiscovered!

morphle 10 hours ago

Isn't life on this planet also life out in the universe? It depends on your point of view.

[1] Pale blue dot - Carl Sagan https://www.youtube.com/watch?v=wupToqz1e2g

squigz 10 hours ago

Do you consider things that are inside a house to also be outside a house?

morphle 10 hours ago

All things are moving in space and time and in relation to other objects so inside or outside are relative points of view.

[1] https://en.wikipedia.org/wiki/Special_relativity

[2] Point of view is worth 80 IQ points - Alan Kay. He didn't specify the sign....

squigz 10 hours ago

I wonder if life elsewhere in the universe is pedantic too.

morphle 10 hours ago

QED.

[1] Why people hate smart individuals: Studies reveal it's linked to your own intelligence level https://www.gq.com.au/health/wellness/studies-say-who-you-ha...

[2] On the importance of being pedantic https://medium.com/@lfloridi/on-the-importance-of-being-peda...

[3] Pedantic definition https://dictionary.cambridge.org/dictionary/english/pedantic

[4] Pedantic opinion https://www.vocabulary.com/dictionary/pedantic

parineum 7 hours ago

If you were so smart, you'd probably find better sources than GQ and Medium to prove your point.

morphle 7 hours ago

Or Hacker News for that matter. Never trust anything on the internet [1] on face value. Start by asking qui bono? Is this a reputable source, like a scientist[2]?. Be critical and sceptical.

[1] https://en.wikipedia.org/wiki/On_the_Internet,_nobody_knows_...

[2] https://youtu.be/NV0Z6vlIJig?t=216

parineum 6 hours ago

> sceptical

How can I trust someone who can't use spell check?

morphle 5 hours ago

I used four spell checkers including Apple, Wikipedia and Google search.

Don't trust anything you read on the internet, including your comment.

AftHurrahWinch 5 hours ago

I regret to inform you that is the preferred spelling in British English.

bregma 7 hours ago

Is the coffee actually in the mug or only on top of it?

pests 5 hours ago

Well, can you walk around inside of a coffee cup? If so, you are on it. If not, you are in it.

treyd 7 hours ago

In Spanish I don't care.

gus_massa 5 hours ago

I'm confused, in es-ar, it can be:

* "El café está en la taza." [preferred]

* "El café está sobre la taza." [I'd never use this.]

* "El café está adentro de la taza."

I'd probably use "en(in?)" for a cup, "sobre(over?)" for a plate an "adentro de (inside?)" for a jar.

tbrownaw 9 hours ago

Things inside this house are indeed outside that house.

Sardtok 7 hours ago

An apartment inside an apartment complex is still inside the same building. Earth is in the Universe. There's a difference between "in the Universe" and "outside of Earth".

A superset also includes everything in all its subsets.

latexr 7 hours ago

Sounds like you might be interested in “The Zoologist’s Guide to the Galaxy”.

https://en.wikipedia.org/wiki/The_Zoologist%27s_Guide_to_the...

makoai 9 hours ago

Real Life Bulbasaur

katspaugh 6 hours ago

Probably more like モンメン (Cottonee).

idiotsecant 10 hours ago

Makes you imagine a world with high solar power density and maybe lower gravity or something where larger land animals might be realistically supplemented by solar energy as well.

tbrownaw 9 hours ago

Closer to the sun (high solar power density) and smaller (lower gravity)... I think we actually have one of those nearby?

lukan 9 hours ago

Some infinite water supply would be probably helpful there.

tbrownaw 8 hours ago

Infinite indeed, need to keep it topped off as it all boils away.

lukan 8 hours ago

Now I think of a scifi setting, where rich people use massive ressources to feed their artificial gardens on Merkur with water from comets, so the genetically engineered solar powered green butterflies in their garden can keep flying.

(But there might be more expensive adjustments needed, like rotation speed)

thinkingtoilet 8 hours ago

This is one of those times evolution doesn't make sense to me. It's clear how a giraffe's neck evolves, the ones that could reach higher leaves in trees had an advantage. In examples like this, how does this evolve when there is no gradual change? An animal had to exist that had an offspring that somehow both absorbed the chloroplasts of the food it ate in a way that it could use (not just simple digestion), then have a place to store them, then have a mechanism to move the chloroplasts to the storage space, then have the mechanisms in their body to use the energy the stored chloroplasts create. How does that happen gradually when each step is totally useless without the others?

(please note I am not challenging the scientific truth of evolution, I simply do not understand how something like this happens)

crustaceansoup 7 hours ago

The article notes that the chloroplasts are like a larder that the slug can digest when needs be, so storage could have come well before photosynthesis was actually utilized.

Or maybe it was photosynthesis first. The chloroplasts just did their thing for a while, and slugs that digested them slower (and eventually ones that stored them) got more benefit than ones that didn't.

largbae 8 hours ago

They look kind of translucent to me, maybe the first of this kind of slug just had a digestive problem that didn't break down the chloroplasts, and the minimal energy through their bodies made those individuals more successful because they didn't need to eat as often as those who digested theirs. Yada yada other errors among the indegestible-chloroplast population showed further advantages when it's closer to the skin, they outcompeted their peers, etc.

andy99 7 hours ago

> please note I am not challenging the scientific truth of evolution

Evolution isn’t a matter of faith, you’re welcome to challenge it and try to poke holes in it.

dekhn 2 hours ago

While true, the predominance of evidence for evolution has reached the point that anybody attempting to argue against it would have to produce absolutely enormous amounts of self-consistent evidence that explains our observations better than modern theories of evolution. It's sort of like the laws of thermodynamics, or relativity, or quantum physics- if you found convincing evidence that any one of those was not accurate, and came up with a better explanation, it would both completely transform science, and open up new avenues for discovery.

And if you want to do that, you should probably get a deep set of experience; otherwise, it's not much different from a flat earther.

ethan_smith 22 minutes ago

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redsocksfan45 6 hours ago

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