All biology stories

Biologists remember landmark theory

404132862 — Tue, 16 Oct 2007 17:12:41 -0400

Forty years ago, Edward O. Wilson and Robert H. MacArthur described how size and isolation determine how many species an island can support. Last week, biologists gathered to mark the theory’s anniversary, calling it a “pivotal point” in ecology’s relatively short history.

Professor Lord Robert May of Oxford University said the word “ecology” — which describes the interaction between an organism and its environment — was coined just a little more than a century ago. By the 1960s, he said, the science of ecology was still mainly a descriptive one, lacking theories to tie together the observations by scientists in the field.

Losos’ lizards give evolutionary clues in island experiments

50443248 — Mon, 01 Oct 2007 15:41:16 -0400

Tiny islets in the Bahamas have proven useful laboratories to illustrate natural selection’s effects on island lizards, which saw their legs lengthen, then shorten as ground-dwelling predators drove them into the trees.

The experiments capped years of research into a type of lizard called an anole on the Caribbean islands. The research, conducted by Jonathan Losos, the Monique and Philip Lehner Professor of the Study of Latin America, examined the relationships between lizards that shared similar habitats and characteristics but lived on different islands.

Losos described his research Tuesday (Sept. 18) during the kickoff talk in this year’s lecture series sponsored by the Harvard Museum of Natural History (HMNH).

Major progress toward cell reprogramming

Tue, 10 Jul 2007 09:34:31 -0400

Two Harvard Stem Cell Institute (HSCI) researchers and scientists at Whitehead Institute and Japan's Kyoto University have independently taken major steps toward discovering ways to reprogram cells in order to direct their development - a key goal in developmental biology and regenerative medicine.

Additionally, the group led by Kevin Eggan, an HSCI principal faculty member - whose study is featured on the cover of the latest issue of the journal Nature - has disproved a long-held view of developmental biologists by demonstrating in mice that it is possible to use previously fertilized ova to produce disease-specific stem cell lines using somatic cell nuclear transfer (SCNT) - commonly referred to as therapeutic cloning.

Wilson urges alliance to save species

50443248 — Wed, 03 Oct 2007 10:01:31 -0400

Edward O. Wilson sees a future in which science and religion join forces to save the natural world.

Without such an alliance, said the legendary Harvard biologist and author, an alternative future is in store for the human race: one of accelerating environmental cataclysm fueled by overpopulation, deforestation, declining fisheries, and climate change.

If nothing is done, by the end of the century one-half of all species will be gone, or nearly gone, said Wilson, Pellegrino University Professor Emeritus. In the next 50 years, a quarter of those species will become extinct because of climate change alone. That's a fast blow to Earth's biodiversity, which took 3.5 billion years to evolve.

Arctic hit by global warming first

50443248 — Wed, 03 Oct 2007 10:28:30 -0400

Scientists from the eight nations bordering the Arctic recently enlisted representatives of the region's native peoples to help assess climate change there. What they found put a human face on a debate often involving distant projections and abstract numbers.

Less snow, less sea ice, freezing rain in winter, and the appearance of mosquitoes and robins, creatures so foreign the native residents have no word for them.

The experience of the Arctic peoples is a harbinger of things to come, according to James McCarthy, the Alexander Agassiz Professor of Biological Oceanography.

"It's the canary in the mine, a glimpse of what's going to happen at lower latitudes," McCarthy said.

Mode of seed dispersal shapes placement of rainforest trees

Thu, 12 Jul 2007 09:21:43 -0400

The apple might not fall far from the tree, but new research shows that how it falls might be what is most important in determining tree distribution across a forest. A recent study of the seed dispersal methods of rainforest trees demonstrates that these methods play a primary role in the organization of plant species in tropical forests.

Joshua B. Plotkin, a junior fellow in the Faculty of Arts and Sciences at Harvard University, and co-author Tristram Seidler published the results of their study on seed dispersal methods in the journal Public Library of Science - Biology (PLoS Biology).

Students search for Thompson Island's hoppers

70652986 — Mon, 26 Mar 2007 05:46:41 -0400

Education met hands-on science on Boston Harbor's Thompson Island on Oct. 9, 2006, as roughly 100 Harvard undergraduates fanned out from beach to beach collecting insects to be included in a new database of Harbor Island insect life.

The students, part of biology professors Brian Farrell and Missy Holbrook's OEB 10 class, "Foundations of Biological Diversity," spent a warm and sunny October day combing the island, literally beating the bushes and scooping up all types of insects in nets.

Farrell, who led the excursion, said the trip served several purposes. First, it exposed students studying biological diversity to the most diverse group of animals on the planet.

Spring in your step helps avert disastrous stumbles

Thu, 12 Jul 2007 10:48:17 -0400

From graceful ballerinas to clumsy-looking birds, everyone occasionally loses their footing. New Harvard University research suggests that it could literally be the spring, or damper, in your step that helps you bounce back from a stumble.

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.

Sweeping changes in life sciences education approved

Wed, 18 Jul 2007 11:30:18 -0400

Professors at Harvard University have overwhelmingly approved a plan that will reinvent the experience of the University's undergraduate life sciences students, broadening degree options to better track modern biology and its related fields as it is practiced by scientists while boosting student advising and strongly encouraging undergraduate research.

Following a Tuesday (April 18) vote by the Faculty of Arts and Sciences (FAS), implementation will begin next fall, differentiating Harvard's life sciences degree options and making students in the current freshman class the last Harvard undergraduates with the option of receiving a general "biology" degree.

"Harvard has a stellar record of achievement and innovation in the life sciences, but our current life sciences curriculum neither reflects nor capitalizes on that inherent strength," says William C. Kirby, Edith and Benjamin Geisinger Professor of History and dean of the Faculty of Arts and Sciences. "We hope and expect that our redesign of undergraduate life sciences education will produce a strong and imaginative new generation of leaders in biomedicine, neuroscience, biotechnology, and other life science fields."

The newly adopted programs will expand the number of life sciences concentrations (commonly known as "majors") from five to eight, mirroring more accurately the natural categories of inquiry inhabited by modern scientists. In addition to shrinking the number of students in each life science concentration, which will enable more intensive, small-group learning experiences, the expansion of degree offerings is expected to greatly strengthen student advising, as faculty align themselves with undergraduate degree programs that more closely parallel their own interests and research. The new organization will also grant students greater flexibility and fewer, more targeted degree requirements; and make research experiences more integral to undergraduate life sciences education at Harvard.

"The last decade has seen an explosion of new life sciences knowledge and methods, which has led to new fields such as genomics, systems biology, neuroscience, and evolutionary-developmental biology," says Douglas A. Melton, Thomas Dudley Cabot Professor of the Natural Sciences and chair of FAS's Life Sciences Council. "These innovations are having profound impacts on fields spanning the breadth of life sciences, from the social sciences to the physical sciences. While Harvard faculty are actively engaged in research in these new directions, our current curriculum is not appropriately designed to permit undergraduates to learn about and get involved in these new fields."

Some 19 percent of Harvard undergraduates are now enrolled to receive degrees in one of the five current concentrations touching on the life sciences: Anthropology (via a Biological Anthropology track), Biochemical Sciences, Biology, Chemistry, and Psychology. These five will be replaced by a menu of eight degree options that more closely reflect current major disciplines within the life sciences: concentrations in Chemical & Physical Biology, Chemistry, Human Evolutionary Biology, Molecular & Cellular Biology, Neurobiology, and Organismic & Evolutionary Biology; a Biological Anthropology track in Anthropology and a Social & Cognitive Neuroscience track in Psychology.

Melton first convened the Life Sciences Education Committee 18 months ago, charging the group with making Harvard's undergraduate instruction in the life sciences as strong as possible. Before developing its proposal to revamp the University's life sciences degrees, the committee implemented new, team-taught Life Sciences 1A and 1B courses, which have radically altered introductory biology and chemistry instruction at Harvard from traditional textbook-based course work aimed at covering a broad range of topics to classes that engage major questions in the life sciences: What are the fundamental features of living systems? What are the molecules that impart these features, and how do their chemical properties explain their biological roles? Why is there so much variation among individuals? Why are species so different?

All current biology concentrators will have the option to switch into a new life science degree if their course work allows, but no new students will be allowed to declare a concentration in the current biology track after May 31.

Among other shifts prompted by these changes, the number of concentrations available for study specifically in the fast-growing field of neuroscience will increase from one to two, and the human-oriented Human Evolutionary Biology and the Biological Anthropology track in Anthropology could produce more biologists with an interest in studying human biology outside of clinical trials, where most research on human biology takes place today.

The new life sciences concentrations will be reviewed within five years, and a report presented to the faculty.

Eating plants that grow on plants

70652986 — Mon, 26 Mar 2007 06:26:23 -0400

Parasitic plants are not just a biological curiosity. Every year, parasitic plants damage farmers' fields, particularly in Africa. Kristin Lewis, a junior fellow at the Rowland Institute at Harvard, is learning more about plants and their parasites.

For instance, in Africa, seeds of parasitic plants blow in from surrounding environments or are deposited in bird droppings. The plants that grow from those seeds attach to roots and stems, sucking vital nutrients, stunting the crop plants' growth, and reducing yields.

To foil the parasites, African farmers have adopted the practice of planting fields twice, first with plants that are resistant to the parasites and then, after the parasites germinate and die, with their desired crop, such as sorghum.

"Most of them are very problematic plants," Lewis said.

Lewis became interested in parasitic plants while studying plant defenses. Though they can't fight back as an animal would, plants can generate a wide variety of substances that are toxic or distasteful to insects and other browsers.

In fact, some of our best-known commercial plants are popular exactly because of the unique qualities of the plant's chemical defenses. Caffeine and nicotine, for example, as well as the hot spices contained in pepper plants, are all intended by the plant to discourage herbivores.

After studying plants' reactions to insects eating their leaves, Lewis became interested in the interaction of a plant and its parasite.

She already knew that in some cases a parasitic plant shares the host plant's defensive chemicals, as well as nutrients and carbohydrates. What she wants to find out is how much the two plants communicate.

If an insect attacks a parasitic plant, that insect is just a short distance from the host plant. Though normally the host wouldn't benefit from helping its parasite, it's possible the parasite could manipulate the host into shifting more defensive chemicals into the parasite to keep the leaf-eating insect at bay - over there. That would require some sort of communication from the parasite to the host saying, in essence: "Send help fast. It's BITING me!"

Lewis said she's still gathering data, but she remains fascinated by the active responses to the environment of plants, which on the surface seem so passive.

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.

Dominican insects make natural art

50443248 — Wed, 18 Jul 2007 14:08:52 -0400

It's the brilliant colors and otherworldly shapes of the Dominican insects that catch the eye and draw a viewer in. It's the alien forms magnified for all to see clearly that keeps one standing before the images hung at the Cambridge Multicultural Arts Center, studying them.

The digital images are one-third of the center's show "Tre: Dominican Contemporaneity," which is the result of a collaboration by three Dominican artists, sociologist Soraya Arecena, and Harvard entomologist Brian D. Farrell, professor of biology and curator of entomology in the Museum of Comparative Zoology (MCZ).

Science losing war over evolution?

50443248 — Thu, 19 Jul 2007 12:41:17 -0400

This just in from the front lines of the battle between evolution and intelligent design: evolution is losing.

That's the assessment of Randy Olson, a Harvard-trained evolutionary biologist turned filmmaker who explored the debate in a new film, "Flock of Dodos: The Evolution - Intelligent Design Circus," which was screened Monday (Feb. 6) at the Harvard Museum of Natural History.

Featuring Harvard faculty as well as scenes shot within the museum, the 90-minute film strikes a humorous tone as it explores the debate, poking a bit of fun at both intelligent design and the scientific community.

Drug prevents spread of genital herpes

50443248 — Thu, 19 Jul 2007 15:21:22 -0400

A new type of treatment has been found to protect mice against a nasty strain of herpes virus common in humans. Because this genital virus is an important co-factor for the transmission of AIDS, the discovery could lead to inexpensive protection against the ongoing epidemic that will kill more than 3 million people this year.