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!
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.
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.
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.
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.
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.
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.
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.
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.
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)
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)
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.
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.
So kind of funny that, chloroplast is being "stolen" again by this sea slug.
https://en.wikipedia.org/wiki/Symbiogenesis
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.
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.
I really like this version of it personally: https://www.youtube.com/watch?v=T6JFTmQCFHg
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.
[1] Pale blue dot - Carl Sagan https://www.youtube.com/watch?v=wupToqz1e2g
[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....
[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
[1] https://en.wikipedia.org/wiki/On_the_Internet,_nobody_knows_...
[2] https://youtu.be/NV0Z6vlIJig?t=216
How can I trust someone who can't use spell check?
Don't trust anything you read on the internet, including your comment.
* "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.
A superset also includes everything in all its subsets.
https://en.wikipedia.org/wiki/The_Zoologist%27s_Guide_to_the...
(But there might be more expensive adjustments needed, like rotation speed)
(please note I am not challenging the scientific truth of evolution, I simply do not understand how something like this happens)
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.
Evolution isn’t a matter of faith, you’re welcome to challenge it and try to poke holes in it.