Wednesday, January 13, 2010

And you thought biology was boring.

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.


Emily said...

Oh boy. No wonder I love your blog!!!

sheknitupthat said...

I love these biology posts!

Amy Lane said...

So cool-- I love it! And I'm a little freaked out about it too... (ooh... give the urban fantasy writer weirdo things to write about... good idea!)

spamword: sploinda

Narelle said...

Slime moulds are awesome. I got to see Dictyostelium go in a Biology lab at uni.

And it turns out they can solve mazes too:

Bunny Queen said...

And here I thought rabbits were weird for their double digestion.

On a similar, weird but amazing and cool, topic... have you ever looked into all the things raw honey is supposedly composed of and can do? I thought it was largely folk remedy but it turns out there is actual science behind putting raw honey on wounds!

BB said...

I found some dog vomit slime mold once.
Oh wait, that was the real McCoy.
Thanks for the nice post.

Alwen said...

I think I'm stealing "Schleimpilze" as my new fave insult.

There was a schleimpilze in the news when I was a kid that grew to a huge size in Tennessee or someplace - people thought it was an alien. No, it's from HERE! Be amazed.

Louiz said...


Anonymous said...

Hey Julie, I'm Australian and a science teacher and at my school we do teach the weird stuff like this (although the green sea slug was new to me) because we want the students to understand that science still has more to study and explain. It isn't all done so we mustn't get complacent - or bored. The students just love that we don't have all the answers and probably never will. It fires them up to make their own contribution.

Love the biology posts. Thanks.


Cindy said...

Fun post and congrats on un-nerving the editor of Vogue Knitting! I'm curious though as to why you describe the sponges as reproducing like plants? Most sponges are sequential hermaphrodites and broadcast spawn (releasing sperm and oocytes) with fertilization occurring in the water column. A few species do practice vivipary (which is totally cool) with embryos released as free swimming larvae.

Julie said...

Cindy, I fear I wrote that because I didn't let you proof-read me. I should stick to real plants. Thanks for the extra info!

TinkingBell said...

I like nudibranches - go on - say it - 'nudibranch' - now go behind the bike-sheds and snigger - 'nooooodibranch'

and we have some sort of riverine slime amoeba called 'river snot' - kid you not - apparently Tasmania caught it from New Zealand - see - how could you not love science.....

Galad said...

I've been waiting for your blog on slime molds which must make me a major geek :-)

Always love seeing what you come up with.

Barbara said...

Now you're talking my language! I'm a total geek about underwater plants and animals. I love that sponges are animals, and colonial ones at that. Slugs that eat stinging cells and then park them on their outsides to deter predation, oh yeah. Worms that live in poison water, bring it. I'd kill to be underwater right now watching a damselfish defend its algae garden.

I found info while researching a story about a micologist about a fungi/slime mold that cows excrete after eating the spores, then it catapults its new spores out of the cow pats about 8 feet so that it can infect more cows. What's not to love?

I agree, if they'd have taught a few of the biological oddities I'd have paid a lot more attention in school.

Roxie said...

Did you ever see that 1950s sci-fi flick, "The Blob?" They would up freezing it and dropping it somewhere neqr the north pole. But slime mold never dies. Bwahahahaha!

I LOVE your bio posts. Green sea slug? Way to go, sluggo!