Wednesday, November 15, 2006

The Sessile Life

Sessile organisms are living things who attach to a spot and never leave it. If you are a parent of teenagers, you might be picturing your kid on the couch right now, but that is not entirely accurate. The teen CAN actually move when stimulated.(examples: pizza delivery guy at the door, "supper's ready", "WHO LEFT THE MILK OUT?!")

The oysters and barnacles below are true sessile critters. After a short stint as free-swimming planktonic larvae, they attach to some hard surface and are forever part of it.

This presents some challenges.

Food has to come to you if you are sessile. Most sessile sea creatures are filter-feeders for that reason. You suck, grab, stick to, or slurp whatever tiny nutrients happen to float by.

Shelter is either provided by a shell of some sort, or by simply choosing the right spot to attach to when you were a larva. Low tide with it's extreme temperature changes and lack of water for hours presents another challenge. Again, a good shell or lucky choice will be the ticket to survival.

Sex, becomes another challenge when you are rooted to one spot. You can't really go out on a date. The oysters in the top photo get around this problem by spawning. Everybody just agrees to dump their eggs and sperm into the water all at once. This productivity party is triggered by water temperature and light levels.

The barnacles solve the sex problem in two ways. First, each barnacle is a hermaphrodite, so your neighbor is always a possible mate. Their other solution is to have what amounts to the longest (relative to their size) male reproductive organ in the animal kingdom.

This allows them to "reach out and touch someone" even if they don't live next door.

Posted by Picasa


Carina said...

I know people like that....sessile. My new word of the week!

rick said...

time for an oyster roast.who has the datil sauce?

Wayne said...

...the longest (relative to their size) male reproductive organ in the animal kingdom.

I'm relieved to read this, for my own selfish reasons. Here I was feeling like I might be crossing the line talking about menopause.

Anonymous said...


Your posts are so educational, and funny too. I learn more from your blog than I did in all my years of college, and I have a Master's Degree!

Rurality said...

I only knew the term "sessile" as it relates to botany (especially trilliums), so the use was new to me.

BTW, any mention of barnacles starts me humming "Barnacle Bill the Sailor" over and over again for hours. Thanks SOOO much!

vicki said...

As I've been considering hibernating since returning to Chicago from Florida, this doesn't sound all bad either. Now I'll be humming Barbacle Bill the Sailor all day.

I like the Cedar Key pictures. And I always like the dog. Do you have piglets yet? I'm learning all about piglets because part of training to be a docent at the Lincoln Park Zoo involves working at the John Deere Farm in the Zoo Project. A pound a day! Wow! And they're such tidy little things.

Did you know cows give about a 100# of milk a day if they're doing they're modern dairy farm part for society? You probably did. Wayne is talking about menopause??? Gotta go!

Laura said...

This has got to be the funniest educational post I've ever read online. I will never look at them the same way again.

LOL.. you're crazy!

robin andrea said...

So, Rurality, Vicki, and I are all singing "Barnacle Bill the Sailor." Thanks, fc!

Great information on those sessiles. Interesting evolutionary trend on those barnacles.

roger said...

i have found many oysters here in port townsend bay, part of puget sound, unattached to anything. just sitting out at low tide on gravel or mud or the tons of bark which line the shore in places. and also the rock bound ones.

Deb said...

I have a lot more respect for barnacles now! :)

Floridacracker said...

Me too!

I was just sprinkling some datil vinegar on a bowl of sausage pilau.

I enjoyed your menopause mystery item post... even if I guessed wrong.
I should be a menopause expert by now.

Thank you! I am blushing.

Good thing I didn't mention "99 Bottles Of Beer ...)

Easy pound a day even more on the high protein showpig feed we give 'em. We should be getting a pig right after Thanksgiving.

My kids and students agree with you.

Survival of the "fittest" and all that. Crazy barnacles.

our oysters are always attached to something here. each other, a log, a rock, a post, etc. any hard substrate.

Never judge a barnacle by it's cover.

Abandoned in Pasadena said...

How interesting...I always learn something when I visit you...and in this case I think I learned more than I needed to know. hahaha

Floridacracker said...

Well, now you have some new trivia to share.

Missourimadness said...

Thanks, flacracker; I am a true Aquarian and love learning about marine life. As other folks said, this is a great place to come and larn!

Missourimadness said...

My editor would probably love it if I would learn how to spell; course then he might be out of a job! Meant "learn" on my previous post (sheesh).

Floridacracker said...

Glad you got something out of it!
As for larn, I thought you were just being creative :)

missourimadness said...

Oh man, in this business you can get fired for too much of that kind of "creativity." Had to cover a speech by the U.S. Ag Sec. here in town yesterday. Darndest, coldest blusteriest day of the year so far. Sick with a head cold-nose running, eyes watering; right ear stopped up. I could only hope I hear him right when he said "If you ate today, you should go out and hug a farmer." That the way I quoted him and no complaints, yet!

Floridacracker said...

I saw a similar bumpersticker yesterday.
Hope you feel better!