cnidarians

Dive in Flower Garden Banks National Marine Sanctuary and sometimes you’ll be treated to the beautiful view of an Atlantic sea nettle. (Just don’t get too close – those tentacles sting!) 

Sea jellies like these are classified as cnidarians, a group of animals that also include corals and sea anemones. 

(Photo: G.P. Schmahl/NOAA)

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Scyphozoan Life Cycle

1. Planula : The free-swimming medusa is either female or male and produces eggs or sperm which combine to produce a larva, called a planula. The planula is planktonic and will float around until it finds a substrate to bind to.

2. Scyphistoma : Once the planula binds to a substrate it develops into a scyphistoma. Scyphistoma is a feeding polyp with protruding tentacles on top used to catch food particles.

3. Strobila : The polyp soon turns into a reproductive polyp with stacks of strobilae. The strobilae are immature medusa that are being asexually reproduced by the polyp.

4. Ephyra : When a strobila is mature it breaks away from the reproductive polyp as a planktonic ephyra.

5. Medusa : The ephyra matures into a full grown medusa.

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CNIDARIA!

The lobby outside my lab room at USYD is filled with a collection of preserved animals, I thought you guys might like to take a look at some of the marine-related displays.

Phylum CNIDARIA! Defined by radially symmetrical bodies which either take the medusa (jellyfish) or polyp (corals and sea anemones) form, and contain stinging cells called cnidocytes.

Note the anemones attached to a hermit crab’s shell (image 2), and the Box Jellyfish (image 4)!

Keep reading

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Starting this week, the Museum lets you explore the underwater world of some of the ocean’s most beautiful and bizarre animals: jellies. Come dive into the lives of jellies in an immersive video experience in the Milstein Hall of Ocean Life.* 

But what exactly is a jelly? It’s is a general term for any kind of transparent, gelatinous (or jellylike) animal that floats in the ocean. Jellies belong to two different groups, cnidarians and ctenophores, and while members of the two groups may sometimes look alike, they are not all closely related. 

Hundreds of jelly species live in oceans around the world, from shallow bays to the deep sea. Some even live in fresh water. The most common jellies are true jellyfish (cnidarians) and comb jellies (ctenophores).

Most jellyfish have long stinging tentacles and have oral-arms that help catch and eat food. Comb jellies have oval bodies lined with rows of fluttering cilia. Instead of stinging, they use their tentacles to pull prey into their large mouths.

Whether they’re cnidarians or ctenophores, jellies have bodies that are made of two transparent layers—an outer one for protection and an inner one for digesting food. Between the two layers, you’ll find nothing but a watery gel—in fact, their bodies are more than 95% water! Aside from these few parts, there’s not much more to them. These amazing animals get along with no bones, no head, no legs—not even a brain!

Experience the world of jellies, open now through May 26, 2017. Part of the Milstein Science Series.

Meant to Be (13 Reasons Why Zach Imagine)

Description: In the middle of a study session, Zach tells you his plans for the future.

request: none

I love marine biology a lot, so there is that aspect, just a little bit. :) (Not too much, don’t worry.)

“Babe, we’re in the library,” your boyfriend, Zach laughed in between kisses quietly as he tried to push you away from him gently. “I love you, but ever since you came to these study dates with me, my grades have been slipping. I gotta make sure they’re good if I want to play for the rest of the season.”

“You don’t even want to play basketball in college,” you rolled your eyes.

“I want to play now though,” he laughed as he grabbed his marine biology book from his bag.

“Teach me about fish,” you smiled at him.

“You’re not even taking this class.”

“I like seeing how passionate you are about it though,” you said placing your hand on his arm. “Teach me.”

“Well, we’re learning about cnidarians,” he said as he flipped to the right page. He finally found it and pointed to the jellyfish on the page. “Jellyfish are cnidarians because they have stinging cells so they can keep predators away.”

“So if something is annoying them, they just sting them to death?”

“Kind of,” he laughed. “It’s more for protection.” He grabbed your hand and rubbed it. “Wish I could do that to guys who flirt with you all the time.”

“Jealous much?” you smiled.

“Nah,” he smiled as he kissed your cheek. “I know you don’t care about them because I know we’re meant to be.”

“Really? I mean…how do you know that?”

“Yeah, I mean, when I think about college…I…I think about you a lot, and how you’re gonna fit in the picture.”

“You see me in the picture?” you smiled.

“Yeah,” he blushed looking down at his book.

“What else do you think about?”

“I think about us, wherever we end up…I mean hopefully at the same place, but wherever…I think about how we’re gonna find our Monet’s, and get coffee there in the mornings and have study dates in the afternoons. And how we’re gonna get an apartment together some day, and cuddle a lot because I know you like it.”

“You like it, too, babe,” you laughed as you leaned your head on his shoulder. “You really think about that?”

“All the time, and it never gets old or stale. That’s how I know we’re meant to be,” he smiled as he finally looked at you again.

“That’s the sweetest thing anyone has ever said to me.”

“You deserve the best, (Y/N). I know I’m not perfect, but I will always try my best for you.”

“You’re everything I could want and more,” you whispered as before you kissed him again. “I love you.”

“I love you,” he whispered as he wrapped his arms around you. “I can’t wait for the future with you.”

Behind the scenes at Jelly School

Umbrella jellies on exhibit at the Monterey Bay Aquarium.

Love watching that beautiful display of gently pulsing jellies at your local aquarium? There’s a skilled aquarist behind the scenes who makes this spectacular sight possible! Working with sea life means you’re always learning. That’s why, for the second year in a row, we hosted Jelly School, a three-day workshop where colleagues from around the world gather to share in cnidarian cnowledge-building.

Monterey Bay Aquarium aquarists Tommy Knowles (left) and MacKenzie Bubel (right) shine light on some itty bitty baby jellies at Jelly School.

At Jelly School, aquarists with two to five years of experience come to see how Monterey Bay Aquarium jelly aquarists work. Our aquarists have honed their techniques for culturing jellies and share what they’ve learned through lectures, hands-on labs, and lots of in-depth discussion with participants.

Monterey Bay Aquarium aquarist Wyatt Patry (left) talks shop with a colleague (right) at Jelly School.

Jelly School promotes an ongoing conversation among jelly aquarists who share techniques and tips. Last year’s Jelly School class even created a Facebook group to stay in touch. Together, they continue to share ideas to tackle the challenges of rearing jellyfish!

Jelly School, Class of 2016

So next time you stop to admire a jelly display, take a moment to appreciate all the knowledge and work that went into creating it.

And thank you to everyone who joined us for Jelly School this year!

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The Portuguese man o’ war (Physalia physalis), also known as the Portuguese man-of-war, Man-Of-War, or bluebottle, though often mistaken as a jellyfish, is a marine cnidarian of the family Physaliidae. The man o’ war is not a jellyfish but a siphonophore, which differs from jellyfish in that it is not actually a single organism, but a colonial organism made up of many minute individuals called zooids.  Each of these zooids is highly specialized, and, although structurally similar to other solitary animals, they are attached to one another and physiologically integrated to the extent that they are incapable of independent survival.

The Portuguese man o’ war is composed of four types of polyp. One of the polyps, a gas-filled bladder called the pneumatophore (commonly known as the sail), enables the organism to float. This sail is bilaterally symmetrical, with the tentacles at one end, and is translucent, tinged blue, purple, pink, or mauve. The Portuguese man o’ war generates carbon monoxide in its gas gland, filling its gas bladder with up to 13% carbon monoxide. The sail is equipped with a siphon. In the event of a surface attack, the sail can be deflated, allowing the man o’ war to briefly submerge.

The other three polyp types are known as dactylozooid (defence), gonozooid (reproduction), and gastrozooid (feeding). These polyps are clustered. The dactylzooids make up the tentacles that are typically 10 metres (33 ft) in length but can be up to 50 metres (160 ft). The long tentacles “fish” continuously through the water, and each tentacle bears stinging, venom-filled nematocysts (coiled, thread-like structures), which sting and kill small sea organisms such as small fish and shrimp. Contractile cells in each tentacle drag the prey into range of the digestive polyps, the gastrozooids, which surround and digest the food by secreting enzymes that break down proteins, carbohydrates and fats, while the gonozooids are responsible for reproduction.

The stinging, venom-filled nematocysts in the tentacles of the Portuguese man o’ war can paralyze small fish and other prey. Detached tentacles and dead specimens (including those that wash up on shore) can sting just as painfully as the live organism in the water and may remain potent for hours or even days after the death of the organism or the detachment of the tentacle.

The Portuguese man o’ war is a carnivore. Using its venomous tentacles, a man o’ war traps and paralyzes its prey. Typically, men o’ war feed upon small aquatic organisms, such as fish and plankton.

Stings usually cause severe pain to humans, leaving whip-like, red welts on the skin that normally last 2 or 3 days after the initial sting, though the pain should subside after about an hour. However, the venom can travel to the lymph nodes and may cause, depending on the amount of venom, a more intense pain.

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