Pathikrit Bhattacharyya (aka Po), from Casey Dunn’s Invertebrate Zoology (Biol 0410) course at Brown University, tells the story of how the lancet liver fluke gets through life.

The hand-drawn animations were photographed at the Brown University Science Center. Thanks also to the Granoff Center for the Creative Arts.

The songs Staccato and Spooky are by Alastair Cameron.

We are pleased to present our first pamphlet – an illustrated guide to the lifecyles of some fascinating organisms. These lifecycles were selected and illustrated by Manvir Singh, a student in Casey Dunn’s Invertebrate Zoology course at Brown. Manvir is also the author of The Evolutionist’s Doodlebook.

Lifecycles is released under a creative commons license, and available for download at archive.org. If you’re interested in purchasing a printed tabloid version of this pamphlet (11.25″ by 15″), contact manvir_singh@brown.edu.

Here is a little plant that starts it’s life high up in the tree tops, where it can find more light than the dark understory of the rainforest. As it grows though, soon getting enough water becomes limiting factor, and the plant will drop a shoot to the ground.

Matt Ogburn, a graduate student in Erika Edwards’ lab at Brown University, describes this little plant, the strangler fig, and explains how it eventually grows to take over the whole host tree and strangle it to death.

Artwork and editing by Sophia Tintori. Original score by Amil Byleckie. Thanks to Jo Dery for use of her studio. Video released under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 license.

Symbion pandora is a microscopic animal that lives exclusively on the mouth-parts of lobsters. When we think of a life-cycle, we usually think of a baby growing into an adult, a female mating with a male, and then the female giving birth to a baby. But as Symbion pandora demonstrates, this isn’t always the case. Symbion pandora undergoes both asexual and sexual reproduction. Its life cycle is especially interesting because the timing of its sexual reproduction matches the moulting of its lobster host. This allows Symbion pandora to move from the lobster’s old shell to its new one, a remarkable solution to the problem of a temporary home. First described in 1995 by Peter Funch and Reinhardt Kristensen, Symbion pandora’s life-cycle provides insight on the incredible diversity and range in the ways organisms grow and reproduce.

Video and narration by Natividad Chen. The background music is a compilation of Bach’s Cello Suite 1 Prelude and Bach’s Flute Sonata 2, both played by Felipe Sarro.  This podcast is released under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 License.

This is a really nice video that was published in the Journal of Plankton Research this past February, as a part of this article about krill.

Even though krill make up a large fraction of the living mass of the ocean (and are also the food for large charismatic sea mammals), many aspects of their biology is unknown, including the way they reproduce. Recently Dr. Kawaguchi and his colleagues filmed the process happening near the sea floor, which was surprising because krill are notorious for living their lives swimming around up higher in the water, far from the floor.

The footage that the researchers collected was a bit chaotic (above, left), and so they gave it to Lisa Roberts, an animator (and CreatureCast contributor), to illustrate the process. She traced the motions of the crustaceans from the videos, and also practiced the moves with some shrimp from the market (above, right).

The original video footage from the deep sea is also really nice to watch, and can be found here, at the Journal of Plankton Research website.

The animation at the top of the post, and the drawing at the bottom, were made by Lisa Roberts and released under a Creative Commons Attribution Noncommercial Share-Alike 3.0 license. The soundtrack to the animation is by Graeme Ewing.

Rebecca Helm, a Dunn lab graduate student, left a couple of bowls of salt water and hydroids out on the table overnight, instead of the refrigerator where they usually live at around 50 or 60 degrees fahrenheit. The next day she came in and found them doing this:

This particular animal is called Podocoryna carnea. Like most jellies and close relatives of jellies, it has a pretty elaborate life cycle. This one involves a free swimming jellyfish, and a larva that swims around then lands on the back of a hermit crab’s shell. Then the larva metamorphoses into a polyp, which buds more polyps, growing into a whole colony on the crab’s back. The colony is made up of lots of polyps that are all connected and share fluid through a web of tubes that circulate partially digested food. Some members of this colony will eventually bud new swimming jellyfish.

The video at the top is of one of the colonies we have growing in our lab. These polyps were given to us by friends, but they can also be collected from hermit crabs at the beach, then grafted onto slides. They seem to grow well on slides, and slides are much easier to take care of then crabs.

Some of the polyps in the video have pink balls growing around the top. These are the buds that will mature to become free-swimming jellyfish. If you look closely, you can see jellies of all stages of maturity growing, including some that are ready to break free. After they swim off they will continue growing. We’ll try to follow up on how that goes.

Video by Sophia Tintori, life cycle drawing by Perrin Ireland, both released under a Creative Commons Attribution-Noncommercial-Share Alike license. Thanks to Diane Bridge and Neil Blackstone for the Podocoryna colonies. Check out this earlier post of the other polyps we saw budding jellyfish in our lab.

Early last year, at the Australian Antarctic Division (AAD), I saw an unusual sight: the birth of a live Antarctic krill, Euphausia superba.
The newborn appeared on a video screen that projected the view of a camera poised over a petri dish. A tremulous form emerged from its egg with its legs beating furiously!
This event began a continuing conversation with krill research leader, So Kawaguchi.
Back in my Sydney studio, I worked with So’s words and images. He explained (by email) how krill grow, and sent me diagrams by John Kirkwood to work with. I also found data sets online of how krill appendages move (Uwe Kils). Piano music was improvised by an 11 year old friend, Sophie Green.
This is the first of some animations that I am making to more fully describe this elusive and most important creature.
Krill are central to the marine life food web. Their health is endangered as a result of oceans becoming more acidic (as carbon increasingly enters the atmosphere and then dissolves into the water).
A new research project at the AAD is to record changes in normal krill development in increasingly acid water. Next month (June 2010) I return to the AAD krill nursery to find out more about this research.
I will also record So Kawaguchi describe what he has identified as a circling krill mating dance. What a fine gesture of continuity!

This video is released by Lisa Roberts under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 license. More animations can be found at AntarcticAnimation.com.

In 2002, while out roaming the depths in Monterey Bay Canyon with the remote operated vehicle (ROV) Tiburon, MBARI scientist Robert Vrijenhoek stumbled upon a whale carcass on the ocean floor, and noticed that it had its own little ecosystem. When a whale has died, its skeleton drops to the ocean floor, creating a habitat island in the depths. Creatures apparently gather from far and wide to use the whale carcass’ nutrients and living space.

Scientists have categorized four stages of whale carcass ecosystems- first the “mobile scavengers” show up, such as sharks, crabs, hagfish. These guys pick away at what luscious meat remains. Snails, slugs and worms show up next to make use of the nutrient-rich poo (in science speak, “organically rich sediment”) the larger scavengers have left behind. The third stage is comprised of animals that rely on hydrogen sulfide gas emitted from the decomposing bones and organic sediments. These animals, like vesicomyid clams, depend on symbiotic bacteria that live inside their cells to make energy for the animal from sulfur based compounds. Free-living bacteria that also live off sulfur form in mats that coat the bones. The final stage of a whale bone’s community succession is the reef stage, when most of the nutrients the whale bone can provide have been exhausted, and the minerals remaining in the bone provide a surface for suspension and filter feeders, who rely on the ocean currents to bring food their way.

When Vrijenhoek and his colleagues were at depth checking out whalebone world, they noticed little red worms that they were unable to identify all over the remaining whalebones. They collected a sample and send the worms to worm expert Greg Rouse, who informed them they had discovered a new species. Related to tube worms that live at the mouths of hydrothermal vents, Osedax grow at their longest to be about the length of your index finger, and as thick as a pencil. Penetrating deep into the marrow cavities of the whalebones are their elaborate root systems. These roots house bacteria that help the worms extract and digest nutrients from the bone, as they lack stomachs and digestive tubes.

Perhaps most bizarre and enticing about the Osedax worm is that all the worms the scientists first discovered appeared to be reproductive females, with no males in sight. Eventually they found the tiny males living in tubes along the female’s trunk. An Osedax female essentially has a harem of up to fourteen males that do nothing else but provide sperm for the eggs she produces. Osedax males feed for their entire lives on yolk provisioned by the egg from which they hatched, like forty year olds living at home on Mom’s meatloaf. The males look strikingly similar to Osedax larva, suggesting that they are larva in arrested development that began producing sperm.

Most of the eggs exiting the female are already fertilized. But how do those little guys lying along her trunk scoot their sperm up to catch the eggs as they’re on the way out? And how, then, do larvae being flung into the dark beyond know whether to become male or female? It could be possible that sex determination depends on whether a larva lands on bone or lands on another female. Perhaps similar to hydrothermal vent worms, a juvenile becomes a male if it lands on a female and she releases a chemical, enticing it into her little harem, to do her reproductive bidding.

Mushrooms may look mundane, but they’ve got a lot going on underneath the surface.  In animals, each cell in a body contains one nucleus, and each nucleus has 2 copies of the genome, one from the mother, and one from the father, which fused at fertilization. Unlike in animals, where the nuclei of the egg and sperm quickly join after the cells combine, the nuclei in mushroom cells stay separate. The reason for the difference boils down to the particular way fungi have sex.

Frisky fungi creep through the soil with long filaments.  These moldy structures occupy the spaces between dirt, and allow the organisms to digest organic matter.  They’re also great for mating. Fungi spend much of their lives with only a single nucleus.  Except, that is, when two filaments cross paths.

When two lonely filaments find each other, the cells at the tip of the filaments fuse, and form new structures that have two nuclei per cell. This cell with two nuclei takes on a life of it’s own and divides many times to form a mushroom.  Each mushroom cell contains a copy of each of the parent nucleus.  The nuclei only fuse in the mushroom gills (pictured), just prior to the formation of mushrooms spores, which are then carried away by the breeze, off to seed the next generation of fungi.

Photographs of the basidiomycete Agaricus bisporus by Rebecca Helm.

A couple of weeks ago the Dunn lab went out after work, and we got to talking. There’s this thing that usually happens whenever we get together after a day in the lab or field– being a group where everyone focuses in one way or another on the diversity and evolution of reproduction and development, we start to tell stories about how animals reproduce. Someone mentions some surprising tidbit of reproductive biology they recently heard, and that sets it off. Then someone else remembers a weirder story, and tells it. This spurs someone else’s memory, and so on, and then I start feeling overwhelmed.

Well, this time we got caught up on the issue of female choosiness. It takes more energy and resources to make an egg packed with resources, or to raise offspring, or to carry a baby inside the womb, than it does to make sperm. This often leads females to be more selective about their mates than males are. We started talking about ways in which female choosiness manifests itself; sometimes through behavior, sometime through anatomy, and sometimes at the level of the cell. And then sometimes it is all for naught.

In this episode of CreatureCast Rebecca Helm, a graduate student in the Dunn Lab, recounts a few short stories about the many levels of reproductive selection.

Editing and animation by Sophia Tintori. We Want To Be Old by Bird Names. Photos of bowers by Mila Zinkova and Peter Halasz. Duck story from the research of Richard Prum and Patricia Brennan. Video of the inside of a comb jelly egg by Christian Sardet, Danielle Carré and Christian Rouviere, from the BioMarCell group. This video is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 United States License.