The Biology Refugia

A group blog highlighting ecology, evolution and biodiversity, and other aspects of biology.

Sunday, April 17, 2005

Whale-Dolphin Hybrid reproduces!

"Whale-Dolphin Hybrid Has Baby Wholphin." By Jeannette J. Lee. Associated Press, 14 Apr 2005. The World's Only Known Whale-Dolphin Hybrid Gives Birth to Playful Female Calf, a Wholphin.


Excerpts - 'The world's only known whale-dolphin hybrid has given birth to a playful female calf, officials at Sea Life Park Hawaii said Thursday. The calf was born on Dec. 23 to Kekaimalu, the only known living hybrid of a false killer whale and an Atlantic bottlenose dolphin.

The young as-yet unnamed wholphin is one-fourth false killer whale and three-fourths Atlantic bottlenose dolphin. Her slick skin is an even blend of a dolphin's light gray and the black coloring of a false killer whale. She is jumbo-sized compared to purebred dolphins, and is already the size of a one-year-old bottlenose.

"It's very significant in the scientific world that they are able to reproduce because it shakes family and class information on these two species of dolphins and whales."

Kekaimalu was born 19 years ago after a surprise coupling between a 14-foot, 2,000-pound false killer whale and a 6-foot, 400-pound dolphin. Kekaimalu has given birth to two other calves. One lived for nine years and the other, born when Kekaimalu was very young, died a few days after birth. Park researchers suspect the wholphin's father is a 15-foot long Atlantic bottlenose dolphin named Mikioi, who has not shown any behavioral changes since the birth.

False killer whales grow to 20 feet long, weigh up to two tons and have a tapering, rounded snout that overhangs their toothed jaw. Atlantic bottlenose dolphins reach a maximum size of 12 feet and can weigh up to 700 pounds.

Read the complete article here.

Thanks to Huang Danwei for the alert.

Tuesday, April 12, 2005

Caribbean: "Overfishing of Sharks Key Factor in Coral Reef Decline."

"Jordi Bascompte and Carlos Melián of the Integrative Ecology Group, Estación Biológica de Doñana, Consejo Superior de Investigaciones Científicas, in Sevilla, Spain, and Enric Sala of Scripps Institution of Oceanography at the University of California, San Diego, developed an unprecedented model of a Caribbean marine ecosystem and details of its intricate predator-prey interactions.

This food “web” covered 1,000 square kilometers to a depth of 100 meters and included some 250 species of marine organisms. The study, published in the April 12 edition of the Proceedings of the National Academy of Sciences, included an intricate network of more than 3,000 links between these species.

The project was one of the largest and most detailed investigations of marine food webs and the first study to integrate food web structure, dynamics and conservation.

One of the most striking products of the study is a stark picture of human impacts on marine ecosystems and the consequences of targeted fishing. In the Caribbean, overfishing of sharks triggers a domino effect of changes in abundance that carries down to several fish species and contributes to the overall degradation of the reef ecosystem. Overfishing species randomly, the study shows, is not likely to cause these cascading effects.

“It appears that ecosystems such as Caribbean coral reefs need sharks to ensure the stability of the entire system,” said Sala, deputy director of the Center for Marine Biodiversity and Conservation at Scripps.

Red full report: "Overfishing of Sharks Key Factor in Coral Reef Decline." NewsWise, 11 Apr 2005. Based on: Bascompte, J., C. J. Melián & E. Sala, 2005. Interaction strength combinations and the overfishing of a marine food web. Proc. Natl. Acad. Sci. USA, 10.1073/pnas.0501562102. Published online, 31 Mar 2005. Abstract.

Sunday, April 10, 2005

"Specimens still need to be found"

"In Search of Bugs." By Karen Heyman. The Scientist, 19 (6), 28 Mar 2005. On television, everyone's an insect collector. But how does that square with real-life entomology?


This spring's US television season will feature dueling zoologists, as Ruud "Bugman" Kleinpaste (Buggin' With Ruud, premieres on Animal Planet, June 15) takes on Martin "Spiderman" Nicholas (Nature: Deep Jungle, premieres on PBS, April 17). Both come from the "kids, don't try this at home" school of science television. New Zealander Kleinpaste allows himself to be covered in killer bees to demonstrate the power of pheromones. The UK's Nicholas says, "Don't touch this venomous spider," and then, of course, he does.

Both represent a Victorian gentleman's view of science as exotic adventure, which seems anachronistic these days when the only thing one is likely to be chasing is an errant Drosophila in the lab. It's hard to imagine that many real, professional scientists are slogging through jungles collecting insects and arachnids.

Still, the approach taken by Kleinpaste and Nicholas may remind the public, and funding agencies, that good zoology research requires such work. "Neither scientists nor society will support the work of collecting and naming insects," says Malcom Burrows, head of the Zoology Department at Cambridge University. "Yet it's extremely important. Even people who do work on Drosophila don't have the classifications [they need]."

The lack of funding has often left ambitious collecting to amateurs, at least in the United Kingdom, says the Spiderman, who does not hold a graduate degree in biology. He funds his worldwide expeditions through his work designing water treatment systems, and he is paid for his television appearances. "This is only my perspective, but it seems the field-work of scientists from institutions (when actually allowed) is on a tighter and tighter brief, and the concept of doing something as nebulous as 'just looking for something new' would never be funded by any self-respecting university," Nicholas writes in an E-mail.

"The unfortunate reality with amateur collecting in the Victorian era and indeed today is that the driver for the majority of collecting trips is profit," he continues. "In the 19th century this would have been for 'gentlemen' ... collectors back in [Europe], with the collected animals euthanized, formaldehyded, and pinned onto cards. These days the goal is to bring something new into culture in Europe or North America, preferably something new and spectacular whose offspring can be sold for top dollar."

Although the United States invests more money at the professional level, investigators still fear that both the general public and even some fellow scientists are grossly underestimating the challenges left for systematic biology. "We don't know how many species of organisms we have on this planet, even to the nearest order of magnitude," says James B. Woolley of Texas A&M University, and a former program director at the National Science Foundation. "There's a real urgency to this, because a lot of that diversity is disappearing faster than we can get a handle on it. We've got maybe one generation left that can get out there and get some sort of handle on what biological diversity is on this planet."

What underlies their concern is that outside of the field of taxonomy, most people do not understand just how truly complicated is the idea of what a species is. "The [introductory-level] class my students hate the most is the one where I tell them there's six different definitions for what is a species," says Felix Sperling of the University of Alberta, Canada. "In my [advanced] class, I spend weeks on how you decide if things are different species or not." The actual number of definitions is closer to 60.

Talk for long enough with a specialist and you will find flaws in nearly every concept used for species identification. "It's like a set problem; a species is the minimal set that doesn't show variation," says Randall Schuh, curator and chair, Division of Invertebrate Zoology, American Museum of Natural History (AMNH), "but there's no single kind of attribute that allows you to recognize what's a species." Consider what happens to even the most seemingly basic concept, reproductive isolation, if you apply it to plants. This is one reason why Paul Herbert's "DNA barcode" concept, in which specimens could be checked against a genetic database, has generated so much buzz along with cautions that it not be viewed as a definitive tool.

Most importantly, the specimens still need to be found. That leaves Charles Lydeard of the NSF, which does fund-collecting trips, optimistic for "traditional" systematicists. "The molecular types can't survive without the traditional types," he says. "Where are they going to get samples from?" Indeed, underscoring just how much fieldwork remains to be done, Brian Wiegmann of North Carolina State University says, referring to the enormous Kinsey gall wasp collection now housed at AMNH, "If you're interested in species, five million wasps is one data point."

Thansk to Hugh Tan for forwarding this.

Sunday, April 03, 2005

Sex speeds up evolution

An interesting by Goddard et al (2005) using genetically modified yeasts could explain the importance of sex in evolution. This supports Weismann's claims that sex improves genetic variation and thereby promote evolutionary adaptation. Goddard's team created a asexual strain of yeast and subjected it together with a sexual strain to 2 novel environments, harsh and benign. Both strains did equally well in the benign environment. However the sexual strain showed a higher growth in the harsh environment (with elevated temperature). This could be the first experimental evidence to the age old theory that sex promotes the fitness of the species.

See - Goddard, M.R., Charles, N. and Burt A 2005 Sex increases efficacy of natural selection in experimental yeast populations. Nature 434 pp. 636 - 640