CreatureCast – Pattern Shifting Snails

posted by Sophia Tintori / on December 29th, 2009 / in molluscs, Podcast (Student Contribution), Science & Art

This is the fourth of four contributions from undergraduates in Casey Dunn’s Bio0041 Invertebrate Zoology class. This episode is inspired by the fascinating behavior of the flamingo tongue snail, Cyphoma gibbosum, which is described in further detail in Casey Dunn’s earlier post.

Video, music, and narration by Chris Vamos. This podcast is licensed under a Creative Commons Attribution-Noncommercial-No Deriviatives 3.0 United States License.

CreatureCast – Comb Jellies

posted by Sophia Tintori / on December 21st, 2009 / in Comb Jellies, Podcast (Student Contribution)

This is the third of four contributions from undergraduates in Casey Dunn’s Bio0041 Invertebrate Zoology class. In this episode, Daniella Prince describes the many wonders of comb jellies.

Video by Daniella Prince, with music by Ben Esposito. This podcast is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 United States License.

Stack of plates in action

posted by Sophia Tintori / on December 17th, 2009 / in Development, Jellies, lab, lifecycles

Look what we caught happening in our refrigerator.

While doing a fridge clean-out in the Dunn Lab, graduate student Rebecca Helm took a look at a forgotten bowl of Chrysaora colorata polyps from our friends Chad Widmer and Wyatt Patry at the Monterey Bay Aquarium. These creatures were left over from an RNA extraction we had done earlier for the Cnidarian Tree of Life Project, and were hidden in the back of the fridge, despite the labs strict ‘no pets’ rule.

Upon inspection, Rebecca noticed that the polyps were strobilating! This is a spectacular type of asexual reproduction, which is explained in more depth in Perrin Ireland’s post on the scyphozoan life cycle.

In this video, a polyp has pinched off into a stack of plate-like discs, called ephyrae. When they pop off of the end of the polyp, they each become a free swimming individual, and a direct clone of the parent polyp. Each ephyra will mature into adult bell-shaped jellyfish. Even before they break away from the poly, they are strongly pulsating as they flex their newly developed swimming muscles before birth.

Video by R. Helm and S. Siebert.

CreatureCast – Marine Worms

posted by Sophia Tintori / on December 16th, 2009 / in Annelids, Podcast (Student Contribution)

This installment of CreatureCast is the second of several contributions that were done as final projects by undergraduate students in Casey Dunn’s Invertebrate Zoology class at Brown University. In episode 4, sophomore Noah Rose delves into the bottom half of the circle of life, where dead things decompose and elements that can then be incorporated into other living organisms are liberated. Noah discusses how the many-legged worms we tend to think of as fish bait impact this process.

This podcast is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 United States License. The video and sound work was done by Noah Rose, with music by Noah Rose.

Making babies like a stack of plates

posted by Perrin Ireland / on December 10th, 2009 / in Jellies, lifecycles

aurelia500

Our own lifecycles are pretty simple. Making babies requires sex. Sex creates offspring with new unique combinations of genes. Many organisms are also capable of asexual reproduction, which doesn’t involve sex (as the name implies) and involves only one parent. In most types of asexual reproduction, genes aren’t reshuffled and the offspring are genetic clones of their parent.

Unlike ourselves, many species have lifecycles that combine both  sexual and asexual reproduction. Take the moon jelly, for example. Moon jellies, also known as Aurelia aurita, are perhaps the quintessential jellyfish, with a typical umbrella-like medusa that travels on ocean currents. There is more to their lifecyle, though, than this swimming organism. The swimming medusa does use sex to make babies—but the babies don’t grow directly into swimming medusae. Medusae release their eggs and sperm into the water and these combine to form a zygote (the fertilized egg). The zygote then develops into a planula larva. The planula eventually sinks to the ocean floor and develops into a polyp, an organism that looks nothing like a medusa. Polyps are attached to the ocean floor, usually on a rock or other hard surface, and stay in one place their whole life. They have a mouth surounded by tentacles, just like the more familiar polyps of sea anemones and Hydra. These polyps, however, are incapable of having sex—they cannot make eggs and sperm. Instead, they reproduce asexually. They can asexually produce other polyps, but they can also asexually produce miniature medusae called ephyra. These are pinched off from the polyp’s mouth as if they were a stack of plates, with the most mature medusa on top. The ephyra then swim away, grow into mature medusae, and complete the lifecycle.

CreatureCast – Comb Jelly Movement

posted by Sophia Tintori / on December 6th, 2009 / in Comb Jellies, locomotion, Podcast (Student Contribution)

This installment of CreatureCast is the first of several contributions that were done as final projects by undergraduate students in Casey Dunn‘s Bio0410 Invertebrate Zoology class at Brown University. In episode 3 sophomore Lee Stevens discusses how comb jellies move the same way that many single-celled organisms do, which is remarkable given how much bigger comb jellies are.

This podcast is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 United States License. Narrated and animated by Lee Stevens, with music by Tracky Birthday (this song, and also this one).