All comparative zoology stories

Leading scientists announce creation of Encyclopedia of Life

50443248 — Tue, 02 Oct 2007 12:00:45 -0400

Realizing a dream articulated in 2003 by renowned biologist E.O. Wilson, Harvard and four partner institutions have launched an ambitious effort to create an Encyclopedia of Life (EOL), an unprecedented project to document online every one of Earth's 1.8 million known species. For the first time in history, the EOL would grant scientists, students, and others multimedia access to all known living species, even those just discovered.

The effort, announced today (May 9), will be supported by a new $10 million grant from the John D. and Catherine T. MacArthur Foundation and $2.5 million from the Alfred P. Sloan Foundation.

Primates expect others to act rationally

50443248 — Mon, 01 Oct 2007 16:11:22 -0400

When trying to understand someone’s intentions, nonhuman primates expect others to act rationally by performing the most appropriate action allowed by the environment, according to a new study by researchers at Harvard University.

The findings appear in the Sept. 7 issue of the journal Science. The work was led by Justin Wood, a graduate student in the Department of Psychology in the Faculty of Arts and Sciences (FAS), with David Glynn, a research assistant, and Marc Hauser, professor of psychology at Harvard, along with Brenda Phillips of Boston University.

A tale of two scholars: The Darwin debate at Harvard

50443248 — Tue, 02 Oct 2007 10:41:37 -0400

Few people have left a more indelible imprint on Harvard than Louis Agassiz.

An ambitious institution-builder and fundraiser as well as one of the most renowned scientists of his generation, he founded the Museum of Comparative Zoology (MCZ) and trained a generation of naturalists in the precise methods of observation and categorization developed in Europe. His wife Elizabeth Cary Agassiz, the other half of this Harvard power couple, was co-founder and first president of the Society for the Collegiate Instruction of Women, the precursor of Radcliffe.

Opossum genome shows 'junk' DNA source of genetic innovation

50443248 — Wed, 09 May 2007 16:51:38 -0400

A tiny opossum's genome has shed light on how evolution creates new creatures from old, showing that change primarily comes by finding new ways of turning existing genes on and off.

The research, by an international consortium led by the Broad Institute of MIT and Harvard, revises our understanding of genetic evolution. Scientists previously thought that evolution slowly changed the genes that create specific proteins. As the proteins changed, so did the creatures that owned them.

The current research shows that opossum and human protein-coding genes have changed little since their ancestors parted ways, 180 million years ago. It has been the regulation of their genes - when they turn on and off - that has changed dramatically.

"Evolution is tinkering much more with the controls than it is with the genes themselves," said Broad Institute director Eric Lander. "Almost all of the new innovation ... is in the regulatory controls. In fact, marsupial mammals and placental mammals have largely the same set of protein-coding genes. But by contrast, 20 percent of the regulatory instructions in the human genome were invented after we parted ways with the marsupial."

The research, released May 9 also illustrated a mechanism for those regulatory changes. It showed that an important source of genetic innovation comes from bits of DNA, called transposons, that make up roughly half of our genome and that were previously thought to be genetic "junk."

The research shows that this so-called junk DNA is anything but, and that it instead can help drive evolution by moving between chromosomes, turning genes on and off in new ways.

When fish first started biting

Tue, 10 Jul 2007 14:20:30 -0400

Before fish began to invade land, about 365 million years ago, they had some big problems to solve. They needed to come up with new ways to move, breathe, and eat.

Take the latter, for example. Fish usually pucker up and suck prey into their mouths. But air is 900 times less dense than water, so land-livers must bite into their food to get a meal. Researchers at Harvard University have just completed a study that gives a clear picture of how that change was made.

Despite their heft, many dinosaurs had surprisingly tiny genomes

Wed, 11 Jul 2007 09:46:11 -0400

They might be giants, but many dinosaurs apparently had genomes no larger than those of a modern hummingbird.

So say scientists who've linked bone cell and genome size among living species and then used that new understanding to gauge the genome sizes of 31 species of extinct dinosaurs and birds, whose bone cells can be measured from fossilized bones.

The researchers, at Harvard University and the University of Reading, were led by Chris Organ and Scott V. Edwards at Harvard. They report their findings this week in the journal Nature.

Seeing the forest, from the trees

50443248 — Wed, 03 Oct 2007 09:17:48 -0400

It was Valentine’s Day 2000 and Alain Houle was not quite sure what to do. He was alone in a fruit tree and the chimps were coming back.

“I thought I’d be killed,” Houle said later. “They climbed up, looked at me, barked at me, and then settled down to eat.”

After Houle climbed down that day, he returned to the research station in Uganda’s Kibale National Park and met Richard Wrangham, Ruth Moore Professor of Biological Anthropology, who has studied the park’s chimpanzees since 1987.

Though Houle was in the park studying the diets of monkeys for his doctoral work at the University of Quebec at Montreal, Wrangham expressed interest in Houle’s experience and said that chimpanzees had never been studied at eye-level in the treetops before.

Big brains better for birds

Wed, 11 Jul 2007 14:50:32 -0400

As you might guess, big-brained birds survive better in the wild than those less cerebral for their size. Scientists guessed that too, but they had to prove it to themselves.

"The supposition that large brains are associated with reduced death rates has not been tested in any group of animals," notes Tamás Székely, a visiting fellow at Harvard's Museum of Comparative Zoology and Department of Organismic and Evolutionary Biology.

Big brains have their disadvantages, biologists admit. They exact a high cost from their owners in the form of development time and upkeep demands. Evolution would eliminate them if they did not provide benefits to offset that cost. The benefit is obvious when you see a large-brained red-tail hawk capture a small-brained pigeon for its lunch.

Eclipsed for decades, Harvard's glass animals step out

50443248 — Thu, 04 Oct 2007 09:46:42 -0400

Long overshadowed by their famed floral kin, some of the exquisite 19th century glass animals housed at Harvard's Museum of Comparative Zoology (MCZ) have finally hit the road for a Minnesota exhibit - the first time in Harvard's nearly 130-year ownership that the rare sculptures are known to have left Cambridge.

The exhibit of 29 invertebrate models, dubbed "The Glass Sea Treasures of Harvard: The Age of Darwin," continues through next February at the Underwater Adventures Aquarium in Bloomington, Minn. At that time, the newly cleaned and restored creatures are expected to migrate eastward en masse for a possible exhibition on campus.

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.

Wing color not just for looks

70652986 — Mon, 26 Mar 2007 05:41:13 -0400

Harvard and Russian researchers have documented natural selection's role in the creation of new species through a process called reinforcement, where butterfly wing colors differ enough to avoid confusion with other species at mating time, helping the butterflies avoid creating less-fit hybrid offspring.

Though more distantly related species tend to be more physically distinct, researchers found this was not the case with species of the blue butterfly Agrodiaetus, found in a broad swath across much of Central Asia and Europe. Researchers found instead that species that might be expected to have the most trouble telling each other apart had the greatest differences in wing color.

That meant that newly diverged species living in the same area that could still mate and have hybrid young had more distinctive wing colors than other closely-related species that had diverged at an earlier time, as well as those living in different areas from each other.

Hessel Professor of Biology Naomi Pierce said a critical factor in this research is the fact that the butterflies are still closely related enough that they can - and sometimes do - interbreed. The hybrids created by this interbreeding, however, are less fit than the parents. That makes it advantageous for parents to ensure more offspring will survive by developing distinguishing characteristics, such as male wing color, and thereby avoiding the costly mistake of mating outside their own species.

"The fact that the hybrids are less viable drives the divergence between the parent species," Pierce said. "Wing colors must be one of the first traits the butterflies use to recognize the right mate."

The research was published in the July 21, 2005 issue of the journal Nature.

A tale of a venomous dispute

70652986 — Mon, 26 Mar 2007 05:41:16 -0400

Sea spiders as large as a foot across have been seen crawling along the deep ocean floor from the windows of submersible research vessels. Most of them, however, including those in a Harvard study, are a scant millimeter (.04 inch) in size. But big or small, they boast long snouts, on either side of which grow pincerlike claws.

Zoologists classify them as arthropods, a group that includes all the insects, land-loving spiders, and crustaceans from flea-size shrimp to lobsters. Together they make up the largest class of animals on Earth.

"In all other arthropods, the front section of the brain bears only eyes," notes Amy Maxmen, 27, a Harvard graduate student who studies sea spiders for her Ph.D. thesis. "Our observation is the first ever of a clawlike appendage arising from that part of the brain. The finding supports assumptions by others that some ancestors of living arthropods once had a pair of pincers or antennae, along with their eyes, extending from the forward parts of their brains."

"At first sight, this is a rather esoteric finding," according to two scientists who commented on the discovery as it is reported in the Oct. 20, 2005 issue of the science journal Nature. "But if it is correct, it will shake up the field of arthropod evolution."

"The evolutionary status of the front part of the brain has been a point of contention for a long time," Maxmen notes. Prior to her study, no living arthropods had anything but eyes growing out of this part of the head. However, it appeared that some extinct arthropods did. Thus, sea spiders, rather than being odd, water- living relatives of ordinary house spiders, may be the only surviving relatives of arthropods who walked the oceans' floors some 500 million years ago with appendages attached to the front of their heads.

Zoologist says in animal kingdom, less is more

70652986 — Mon, 26 Mar 2007 05:41:22 -0400

Harvard researcher Piotr Naskrecki hopes his new book, "The Smaller Majority" (Harvard University Press, 2005), will win over some new advocates for the tiny creatures he has spent his life studying. It is a gorgeous book, featuring hundreds of photographs from Naskrecki's expeditions in Latin America, Africa, Australia, and the South Pacific.

Naskrecki has trained his macro lens on some of the rarest and most unusual living creatures on the planet. Some of them are still unclassified and, until now, unphotographed. And while some of the reproductions may show a tiny ant or spider enlarged to many times its original dimensions, Naskrecki says that his real aim is not to confer the gift of size on his tiny subjects.

"In my photography, I'm not trying to make them bigger.

How ant (and human) societies might grow

70652986 — Mon, 26 Mar 2007 06:22:31 -0400

Pellegrino University Professor Emeritus Edward O. Wilson remains fascinated with the highly organized societies of ants, bees, wasps, termites, and humans. He and Bert Holldobler, with whom he shared a Pulitzer Prize for their book "The Ants," have published a paper about how such societies originate, which appears in the Sept. 20, 2005 issue of Proceedings of the National Academy of Sciences. The original colonies of humans, like those of ants and termites, they propose, could have arisen in much the same way.

Both ants and humans have achieved "spectacular ecological success," they write. For humans, this includes winning out over competing forms of humanlike creatures who evolved from apelike ancestors.

The tale of the tail

70652986 — Mon, 26 Mar 2007 05:35:29 -0400

Sharks' tails have always mystified biologists. Their relatives, hundreds of different species of fish, happily push themselves through the water with symmetrical tails that move from side to side. But most sharks are asymmetrical; the top part of their tails is larger than the bottom part, sometimes grossly so. George Lauder and Cheryl Wilga decided to look into this uneven enigma. Lauder is a professor of biology at Harvard University who has a life-long interest in the design of animals that live in water. He often works with Wilga, a biologist at the University of Rhode Island. The Navy helps support their research because the things they learn could lead to robotic submarines that move more like fish and less like robots. Using a complicated setup of laser light sheets that four dogfish swim through, high-speed video cameras, and sophisticated computer software, the researchers studied the flow of water over their asymmetric tails. Wilga and Lauder described this setup and their results in the Aug. 19, 2004, edition of the journal Nature. While a symmetrical fish tail leaves a one-part wake behind, the shark experiments clearly show a two-part wake. The larger upper lobe of a shark's tail cuts the oncoming water slightly before the smaller lower lobe. This creates a wake within a wake, giving the shark both thrust and lift, both forward and upward motion.