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Comment by beeforpork | Hacker News Reader

> All eukaryotes have mitochondria.

To be picky: that's only 99.9...% true, because some have lost them again, like Monocercomonoides and Henneguya zschokkei. And they lost the mitochondria by two different mechanisms!

https://en.wikipedia.org/wiki/Monocercomonoides https://en.wikipedia.org/wiki/Henneguya_zschokkei

EDIT: typo

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Relatedly, some animals can steal chloroplasts.

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

and to complete the circle, many plants - usually the parasites and the carnivorous plants - have lost some or most of their chloroplasts.

Rafflesia (a parasite) might have lost the entire chloroplast: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3969568/

Here's one 'in the middle' that lost a bunch of genes from the chloroplasts: https://journals.plos.org/plosone/article?id=10.1371/journal...

let's keep it going because "parasites" are fascinating. Dodder plants are usually generalized obligate plant parasites. Dodders have "stolen" at least 108 genes from various plants its parasitized.

Bonus, dodder plants also seem to be able to double as a sort of above-ground mycorrhizal network, allowing plants (even across species) to communicate with each other and send warning signals about pests/stressors/etc

I'm not aware of any carnivorous plant that lost chloroplasts, could you share which species it is?

Only parts; Drosera (sundews) usually lost all of their ndh genes https://academic.oup.com/gbe/article/11/2/472/5284917

your second example is particularly fascinating. Myxosporeans were basically once more complex animals that had gradually evolved towards simpler and simpler structures until they became unicellular organisms again. Henneguya zschokkei seems to have taken this to the extreme — going where not even bacteria ever go

Looking into it, there's a theory that this parasite started out as a cancer cell of a more complex organism: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6343361/

I remember the shock when they identified that things as cnidarians

On that note, man o wars are thought to be an example of a complex multicellular organisms partnering so closely that they lose their individualism. Basically every organ of this thing seems to at once have been a separate animal and can still survive on its own for a while

https://en.wikipedia.org/wiki/Portuguese_man_o%27_war

not separated animals. Is a colony but the members are not independent. Many cnidarians are able to bud and the buds can vary the phenotype later.

I suppose a better example of what I meant to talk about are lichen. Which are single species but technically a partnership between types of fungi and an algae.

In siphonophores, each specimen is actually a colony of minute asexually reproducing organisms called zooids that have to work together for survival. They are not "independent" in the sense that they would die without each other, but given the fact that they can reproduce independently, there's definitely some sort of independence there. It's like if all your organs were able to independently reproduce themselves.

What I mean is that in Physalia each individual in the floating city is still a clone of the other members of the colony. All members of the floating city came from an unique larva. This mean also that each Physalia is either male or female but not both.

Fascinating. I had no idea, thank you.

I wonder how these eukaryotes that lost their mitochondria get their energy?

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