JELLYFISH- Structure

Jellyfish have drifted through the Earth’s oceans for some 540 million years. They’re also some of the simplest creatures in the animal kingdom- which may be part of the reason for the species’ success. I’m Jim Metzner, and this is the Pulse of the Planet, presented by the American Museum of Natural History.

Dave Wrobel is Senior Aquarist at the Monterey Bay Aquarium where Jellyfish are raised and displayed in large tanks.

“Jellyfish do not have true organs. They’re at what’s called the tissue level of organization. They don’t have any kind of a heart or a brain or anything that you could consider an organ. They do have sensory structures, so they can determine their orientation. Some of them can sense light. Very limited sensory capability, but they do have a few things that they can sense in their environment. But they don’t have eyes that they can form an image with. They don’t hear sounds. So it’s a very different world compared to what we experience.”

But there are some advantages to not having organs: jellyfish have the ability to shrink or grow in response to changes in the availability their food supply.

“When food is not around, they can live for long periods without eating, and they’ll actually start to shrink. It’s a nice feature for them, they can go for long periods without eating and then when food is abundant, they’ll actually start to grow again. So they can go through periods where they’re shrinking and then periods where they’re actually growing, depending on the availability of food.”

But, as far as humans are concerned, one of the jellyfish’s main attractions may be the way it looks:

“I don’t think people realize how beautiful jellies really are. I think they just think of them as the helpless blobs that are thrown up on beaches. And one of the things we’re doing here at the Monterey Bay Aquarium is to show people how beautiful and amazing the jellies really are.”

Pulse of the Planet is presented by the American Museum of Natural History. Additional funding for this series has been provided by the National Science Foundation. I’m Jim Metzner.

JELLYFISH- Structure

They're some of the simplest creatures in the animal kingdom- but, to those who admire jellyfish, they're also some of the most beautiful.
Air Date:10/08/1999
Scientist:
Transcript:

Jellyfish have drifted through the Earth's oceans for some 540 million years. They're also some of the simplest creatures in the animal kingdom- which may be part of the reason for the species' success. I'm Jim Metzner, and this is the Pulse of the Planet, presented by the American Museum of Natural History.

Dave Wrobel is Senior Aquarist at the Monterey Bay Aquarium where Jellyfish are raised and displayed in large tanks.

"Jellyfish do not have true organs. They're at what's called the tissue level of organization. They don't have any kind of a heart or a brain or anything that you could consider an organ. They do have sensory structures, so they can determine their orientation. Some of them can sense light. Very limited sensory capability, but they do have a few things that they can sense in their environment. But they don't have eyes that they can form an image with. They don't hear sounds. So it's a very different world compared to what we experience."

But there are some advantages to not having organs: jellyfish have the ability to shrink or grow in response to changes in the availability their food supply.

"When food is not around, they can live for long periods without eating, and they'll actually start to shrink. It's a nice feature for them, they can go for long periods without eating and then when food is abundant, they'll actually start to grow again. So they can go through periods where they're shrinking and then periods where they're actually growing, depending on the availability of food."

But, as far as humans are concerned, one of the jellyfish's main attractions may be the way it looks:

"I don't think people realize how beautiful jellies really are. I think they just think of them as the helpless blobs that are thrown up on beaches. And one of the things we're doing here at the Monterey Bay Aquarium is to show people how beautiful and amazing the jellies really are."

Pulse of the Planet is presented by the American Museum of Natural History. Additional funding for this series has been provided by the National Science Foundation. I'm Jim Metzner.