Meet the new entry in biology's "What in fuck is THAT?" sweepstakes.
The green sea slug, known by Serious Folks as Elysia chlorotica. The green? It's due to CHLOROPHYLL. Scientists announced this week that they'd found a critter (other than sponges) that uses chlorophyll. Only, see, it's freakier than that. Unlike most animals who use parts of other critters in their physiology, the sea slugs don't use the whole cells. No, the slugs break down the cells, somehow filter out ONLY the chloroplasts (the organelle in plant cells that do photosynthesis) and then park the chloroplasts in their guts where they produce 'food' on a cellular level. But it gets weirder. The researchers figured out that if they kept the slugs in light for twelve hours a day, they don't need to eat at all. Yet somehow the chloroplasts kept 'running' - meaning the animal physiology has somehow figured out a way to 'feed' the chloroplasts and keep them operating. Even though the chloroplasts aren't in cells. And are in animals instead of plants. Truly, the world is a weird place. (Article here.)
Some other fun entrants in the "What the fuck?" taxonomy contest:
Oh, sure, you've probably got the skeletons of a couple sponges laying around the house, and so you think they're common. Let me tell you, these things are weirder than you realize. Did you know sponges are classified as animals? They are. Even though they reproduce like plants. Some even have chlorophyll in them. Sponges are found world wide, from the tropics to the poles, in fresh and salt water, from shallows to over five miles (!) deep. They produce hordes of odd chemicals - toxins, antimicrobials, you name it. For something that looks uncomplicated, they're extremely complicated.
Meet Fuligo septica, or in folk/common names, "Dog Vomit Slime Mold". (Sure, taxonomy is less confusing, but I fuckin' love folk names. So much more descriptive.) Slime molds used to be classified with fungi, hence the name. But unlike fungi, which have organized cellular tissue, slime molds "composed of an acellular mass of naked protoplasm with no cell walls in its vegetative state". (Quotes from here.) In layman's terms, that means in part of a slime mold's life cycle, IT IS A PUDDLE OF GOO. No cells. No kind of tissue organization that we associate with living creatures. Nada. Just a freakin' puddle. IS THAT COOL, OR WHAT? It reproduces by sexual reproduction (usually considered an advanced adaptation), and when in the mood (and proper portion of their life cycle), they can ooze around "in amoeboid fashion". Except amoeba are amoeba, and these suckers grow up to the size of dinner plates. Here's some video of them sliming about; I don't speak the language, but the visuals of the mold can't be beat. I think the 'raspberries flying through the air' animation is to represent the 'fruiting' or 'spore' portion of the life cycle, when it sort of seeds itself. You see how screwed up these things are? No one knows what to call the reproduction phase of the life cycle - you've got 'fruiting' from angiosperm plants and 'spore' from fungi, and scientists agree they aren't really either one, but DON'T HAVE A WORD for what it really is. Think about that a minute. How a critter reproduces is a major point used to classify a critter, and scientists are still LOOKING FOR WORDS to simply describe these things.
So far as I know, slime molds live entirely on vegetable matter - bark, leaf rot, that sort of thing. One lab was feeding them oats (the same lab that had a slime mold escape a petri dish; cracks me up). If a meat-eating slime mold turns up, let me know, 'cause I'm moving to the moon.
Meet one of the few critters on the planet not to run on sunlight. You know how we were taught in school that everything runs on sunlight? That if you trace the food chain back far enough, EVERYTHING always traces back to photosynthesizing plants? Guess again. (Though the whole ecosystem was only discovered in 1977, so depending, your biology teacher may be forgiven for getting it wrong.) These guys run on chemosynthesis. They live around "black smokers", hydrothermal vents on the ocean floor. The 'smoke' is actually a soup of sulfur and hydrocarbons and god-knows. Tube worms contain bacteria that metabolize those chemicals into organic molecules that the tube worm then feeds on. Other critters in the black smoker mini ecosystem either graze directly on similar bacteria that live in mats around the black smokers, or graze on critters who graze on critters that... well, it's just like solar food chains, but not. Cool, yet utterly fucked up.
So there you go. I wonder if they don't teach this stuff in biology because it confuses that taxonomy 'tree of life' thing they're trying to teach in a classroom, or if they don't think they have time to teach the weird shit. But it's a shame, because it's stuff just like this that gets kids curious and interested, and I don't know about you, but I think a good argument on whether sponges are plants or animals would be great to make them think.
There you go, geeking out for the sheer fun of it.