all organismic biology stories

Boning up on frogs' defenses

404132862 — Tue, 24 Jun 2008 14:13:51 -0400

Harvard biologists have determined that some African frogs carry concealed weapons: when threatened, these species puncture their own skin with sharp bones in their toes, using the bones as claws capable of wounding predators.

The unusual defense mechanism is described by Harvard's David C. Blackburn, James Hanken, and Farish A. Jenkins, Jr., in a forthcoming issue of the journal Biology Letters.

Sensory organ differentiates male/female behavior in some mammals

50443248 — Mon, 01 Oct 2007 16:50:40 -0400

For years, scientists have searched in vain for slivers of the brain that might drive the dramatic differences between male and female behavior. Now biologists at Harvard University say these efforts may have fallen flat because such differences may not arise in the brain at all.

Rather, they say, the epicenter of sex-specific behavior in many species may be a small sensory organ found in the noses of all terrestrial vertebrates except higher primates. Their work, appearing this week in the journal Nature, indicates that defects in this organ, known as the vomeronasal organ, lead female mice to adopt male behaviors such as mounting and pelvic thrusting while abandoning female behaviors such as nesting and nursing.

Some like it hot: Deep-sea worms favor a fiery 45-55° c

Wed, 18 Jul 2007 11:01:17 -0400

Scientists have found that worms dwelling at deep-sea hydrothermal vents opt for temperatures of 45-55 degrees Celsius (113-131 degrees Fahrenheit) when provided a choice of conditions, giving them the highest thermal preference of any animal studied to date. This unique preference for extreme temperatures may be the undersea worms' meal ticket, because they are apparently the only animals able to access - and feast on - lush mats of bacteria that thrive around deep-sea vents.

The research was described last week in the journal Science.

Evolution follows few possible paths to antibiotic resistance

50443248 — Wed, 18 Jul 2007 12:33:28 -0400

Darwinian evolution follows very few of the available mutational pathways to attain fitter proteins, researchers at Harvard University have found in a study of a gene whose mutant form increases bacterial resistance to a widely prescribed antibiotic by a factor of roughly 100,000. Their work indicates that of 120 harrowing, five-step mutational paths that theoretically could grant antibiotic resistance, only about 10 actually endow bacteria with a meaningful evolutionary advantage.

The research is described this week in the journal Science.

Missing link crawls out of muck

50443248 — Wed, 18 Jul 2007 13:19:36 -0400

Paleontologists have discovered fossils of a species that provides the missing evolutionary link between fish and the first animals that walked out of water onto land about 375 million years ago. The newly found species, Tiktaalik roseae, has a skull, a neck, ribs, and parts of the limbs that are similar to four-legged animals known as tetrapods, as well as fishlike features such as a primitive jaw, fins, and scales.

Harvard students build Dominican insect database

70652986 — Mon, 26 Mar 2007 05:20:17 -0400

Over spring break, a group of Harvard students led by biology Professor Brian Farrell collected specimens representing 500 insect species, including perhaps 200 new ones, and helped establish an insect database for the Museo Nacional de Historia Natural in Santo Domingo. The trip was a collaboration between several organizations and many individuals, Farrell said. His Dominican colleagues helped teach the students about the local insect life, and the students and the staff of Harvard's Museum of Comparative Zoology, in turn, explained and helped set up digital databases that can be used for the Museo's entire 55,000-specimen collection and that can expanded to accommodate future collections.