Smithsonian Science » National Museum of Natural History

Slide Show: Smithsonian’s National Museum of Natural History is 100!

John Barrat — Tue, 22 Jun 2010 17:24:14 +0000

Since its doors first opened in 1910, the National Museum of Natural History has inspired curiosity and learning about the natural world and our place in it. Building upon the strong foundation of our extensive collections, the staff of the museum have been at the forefront of essential scientific exploration and research, and groundbreaking public exhibition and education. This slideshow and the website (www.mnh.si.edu/onehundredyears/) is a living documentary of the Museum’s 100-year history.

Killing of methane-producing megafauna may have caused cooling 13,000 years ago

John Barrat — Fri, 04 Jun 2010 14:42:06 +0000

The mechanisms for global warming are relatively well understood, but what does it take to cool the planet? According to new research, a taste for large game by the prehistoric inhabitants of the Americas may have caused the Earth to cool some 13,000 years ago.

Image right: Mastadon, painting by Charles R. Knight

As reported in the June issue of the journal Nature Geoscience, ancient settlers to North and South America may have significantly reduced atmospheric levels of methane – a much more problematic greenhouse gas than carbon dioxide – by relentlessly hunting large herbivores of their day. “This may be the first measurable impact of humans on the greater environment,” says S. Kathleen Lyons, co-author and researcher in paleobiology at the Smithsonian’s National Museum of Natural History.

Image left: Prehistoric megafauna, painting by Jay Matternes.

New world megafauna such as mammoths, bison and camelids that were alive at the end of the Pleistocene epoch (some 13,000 years ago) would have produced massive amounts of methane-rich flatulence and belching, thanks to the cellulose-digesting microbes in their guts. Human hunting activities likely made a sizable dent–anywhere from 12.5 to 100 percent–in the level of atmospheric methane at that time. As a result, a cooling in transregional temperatures of the Younger Dryas period may be attributable in part to the rapid eradication of some 100 herbivorous species.

“The timing of the extinction aligns perfectly with the arrival of humans in the Americas,” Lyons says, “and their hunting may have contributed to this famous cool-down.” A drop of 9 to 12 degrees Celsius is believed to have occurred within the Younger Dryas stadial, or the “Big Freeze,” which came between the Pleistocene and Holocene epochs.

Chart right: The extinction of megafauna (indicated by red shaded region) closely coincides with an abrupt drop in atmospheric methane concentration at the onset of the Younger Dryas (indicated by blue shaded region). Time is given in kiloannum. Scientists estimate that prior to the extinction event, large-bodied herbivores in the Americas released about 9.6 Tg of methane to the atmosphere annually. The loss of these species could be responsible for 12.5 to 100% of the overall methane decline. Atmospheric methane concentrations during the past 15,000 years are derived from the Greenland ice core samples.

Ice core samples and fossil and archaeological records, combined with body mass and gut size calculations of these ancient animals, informed the methane estimates derived by the authors.

The research team, which was led by Felisa A. Smith of the University of New Mexico, and assisted by Scott M. Elliott of Los Alamos National Laboratory and Lyons, also found the Intergovernmental Panel on Climate Change is likely undervaluing the amount of methane emitted by non-domesticated animals.

As a result of their findings, the authors propose that the beginning of the ‘Anthropocene’ be recalibrated to 13,400 years ago instead of 8,000 years ago when ancient farmers are known to have cleared forests to grow crops. –Brian Ireley

“MEanderthal,” National Museum of Natural History’s first ever mobile application

John Barrat — Wed, 19 May 2010 15:40:25 +0000

“MEanderthal” is a new mobile application that makes the morphing technology used in the Smithsonian National Museum of Natural History’s David H. Koch Hall of Human Origins available for free on mobile devices. Users are able to use an existing portrait of themselves or take a new portrait and morph it into a verison of how they might appear as one of humankind’s early relatives. Download it at: itunes.apple.com/us/app/meanderthal/id370710977?mt=8

May Smithsonian symposium marks research contributions of scuba

John Barrat — Wed, 19 May 2010 12:16:04 +0000

Organisms are best understood by observing them directly in their habitat. For marine organisms, however, their salt water surroundings makes this a challenge to scientists. Scuba has changed that. For example, initially coral was believed to be a plant. Eighteenth-century scientists used microscopes to classify coral as an animal, but it was not until scuba was developed that researchers were able to study coral in its natural habitat for long periods of time. This led to a much clearer understanding of coral, its communities and ecosystems.

Right: Smithsonian Scientific Diving Officer Michael Lang in Florida.

Allowing scientists to stay underwater for extended periods has made scuba equipment an invaluable tool for the study of marine and freshwater environments. Since its development in 1943, scuba (self-contained underwater breathing apparatus) has enabled researchers to dive longer and deeper and closely study millions of underwater species and their vibrant ecosystems.

To mark scuba’s important contribution to underwater science, the Smithsonian Institution is convening dozens of scientists on May 24 – 25 at the National Museum of Natural History for a special symposium: “Research and Discoveries: The Revolution of Science through Scuba.” Open to the public, anyone wishing to attend this symposium should register online at the Web site: www.si.edu/sds/

Photo left: Brown elegance coral

“Without scuba our dive times would be restricted to the few minutes we can hold our breath, clearly not long enough to make scientific observations or collect samples,” says Michael Lang, director of the Smithsonian’s Marine Science Network and the Smithsonian’s Science Diving Program. “With thorough entry-level training, scientific scuba is a simple enough tool to enable its effective and safe use at many remote research sites.”

Photo right: A Smithsonian dive team. (Photo by Dan Miller)

Scuba is not a finished product, however. As technological advancements are made, scuba will continue to grow and be an even greater resource to science and discovery. “As our knowledge of decompression sickness increases and engineering solutions for scuba regulators and dive computers evolve, the envelope of our working window in the underwater world will likely expand, opening up new depths and habitats for research and exploration,” Lang says.

Geologist Liz Cottrell puts Eyjafjallajökull’s eruption into perspective

John Barrat — Mon, 17 May 2010 15:13:37 +0000

Smithsonian volcanologist Rick Wunderman talks about volcanos and the recent eruptions in Iceland

John Barrat — Fri, 30 Apr 2010 00:11:41 +0000

Keeper Tracey Barnes talks about the National Zoo’s Andean bear, Billie Jean, and her two new cubs

New Acquisition: Clay vessels by Native American potter Jeri Redcorn added to Smithsonian collections

John Barrat — Thu, 29 Apr 2010 03:30:22 +0000

The Smithsonian’s National Museum of Natural History recently acquired three contemporary pieces of Caddo pottery from well-known modern Native American artist, Jeri Redcorn.

Image left: Caddo potter Jeri Redcorn

“One of the greatest strengths of the anthropology collections at NMNH is their historical depth,” says Daniel Rogers, anthropology department chairman at the Natural History Museum. “Ms. Redcorn’s contemporary pottery is providing NMNH anthropologists with a modern connection to early Caddo traditions.”

The Caddo people of Arkansas, Louisiana, Texas and Oklahoma have maintained many of their traditional ways and actively work to preserve their unique tribal cultural today. One example is the pottery of Jeri Redcorn.

“Ms. Redcorn’s pottery represents the modern reflection of a tradition that goes back more than 1,200 years,” says Rogers.

Redcorn, a native of Oklahoma, began her study of the legendary Caddo pottery after many years of admiring the work of her native people. In 1991, she vowed to learn how to carry on the tradition and officially began her study of the Caddo pottery.

Early Caddo pottery was made of coiled clay commonly mixed with a temper (a material that strengthens the clay) made of bone or pottery shards. The shape of the vessels varied considerably in form and decoration, but as seen in Redcorn’s work, pottery was commonly decorated with incised (drawn into wet clay) lines forming complex circular and rectangular designs that covered a large portion of the vessel.

Image right: These three vessels by Jeri Redcorn were recently added to the collections of the Anthropology Department of the National Museum of Natural History. (Photo by James DiLoreto)

In 2007 Ms. Redcorn was commissioned to make three pots for the National Museum of Natural History. The end result was three beautiful examples that represent a combination of traditional designs with a modern interpretation. The three pots were brought to the Smithsonian in 2009. Ms. Redcorn has also participated in the Smithsonian’s National Museum of the American Indian programs and in 2009 First Lady Michelle Obama chose one of Ms. Redcorn’s pots for display in the White House.

“Ms. Redcorn is a modern-day cultural interpreter of a very long tradition,” says Rogers, “We’re happy to have Ms. Redcorn’s pottery join the Smithsonian collection.”--Jessica Porter

Thepytus carmen, a newly described species of butterfly from Brazil

John Barrat — Tue, 13 Apr 2010 12:49:41 +0000

Thepytus carmen, a newly described species of butterfly from Brazil, was recently named in memory of Carmen Lúcia Buck in recognition of the gracious support of science that she and her husband Peter have provided to the Smithsonian Institution’s National Museum of Natural History. Described by Smithsonian entomologist Robert K. Robbins and Marcelo Duarte, Museum of Zoology, University of São Paulo. (Illustration by Vichai Malikul)

A well-defended territory is what some female hummingbirds find most attractive in a mate

John Barrat — Wed, 31 Mar 2010 17:20:21 +0000

When it comes to attracting a mate, flowers and sweets often do the trick—even for one of the world’s smallest birds—the purple throated carib, a hummingbird species native to the mountainous islands of the Eastern Caribbean. Scientists recently discovered that it is in the best interest of male purple-throated caribs to defend and maintain a territory with a high density of nectar-producing flowers. Why? Because it is the quality of this territory—rather than flashy plumage or elaborate courtship displays—that attracts the most females.

Image right: A male purple-throated carib perches on a Caribbean heliconia plant. Click to enlarge. (Photo by John Kress)

John Kress, a botanist at the Smithsonian’s National Museum of Natural History, and Ethan Temeles, an ornithologist and biology professor at Amherst College in Massachusetts, have spent several years researching purple throated caribs (Eulampis jugularis) in the wild on the island of Dominica. What they observed was unique among all bird species: successful male caribs maintained and defended territories with nectar supplies that were two to five times greater than their daily needs and also isolated part of their crop for the exclusive feeding rights of visiting females. The key to this female-only feeding area was the presence of heliconia flowers.

“This is the first time such behavior has ever been observed in a bird species,” said Kress. “Not only is the male defending a huge territory from competing males, but he’s also defending a big chunk of it exclusively for females who he is trying to attract as potential mates. He is farming the nectar for these dual purposes.”

Image left: A female purple-throated carib (Photo by Ethan Temeles)

Male and female purple throated caribs are alike in plumage, but males are considerably larger and have longer wings than females. Females, however, have bills that are 20 percent longer and 30 percent more curved than the bills of the males, meaning that they are physically able to feed from flowers that males cannot. This is also known as “sexual resource partitioning” and for the purple throated carib it applies to two species of Heliconia, a primarily neotropical genus of plants. Male caribs feed from the Caribbean heliconia (Heliconia caribaea), while females feed primarily from the lobster claw heliconia (Heliconia bihai).

This close correspondence between the physical traits of the two different heliconia flowers and the bill morphology of each sex of purple-throated carib strongly suggests that the process of coevolution (the evolution of two or more species that interact closely with one another, with each species adapting to changes in the other) is the cause of this fit between the birds and the flowers. Furthermore, this process is strongly reinforced by the fact that the different energy requirements of the male and female carib are uniquely matched by the energy rewards in the nectar of their respective heliconia flowers.

Image right: A male purple-throated carib sips nectar from a Caribbean heliconia plant. (Photo by Ethan Temeles)

The scientists report that a female’s choice of a male depends on the nectar supplies within his territory, which in turn depended on his prevention of nectar losses to competing male purple-throated caribs and other nectar feeding intruders.

“One of the most important aspects of maintaining an abundant nectar crop for the male carib is keeping intruders out,” Temeles said. “We found that males that were most successful at defending their territories from intruders also were the ones that were most successful at dominating neighboring males and at feeding on neighbors’ territories.”

The male’s reward for spending the time and energy in defending his territory was, of course, the attraction of potential mates. Temeles and Kress observed that the rates of female intrusions to feed on defended territories were highest in late morning and early afternoon, at times when the amount of nectar in undefended plants was lowest. “Once the females are in the territories they are allowed to “sip from the male’s wine cellar.” If she likes what she is sampling, then mating takes place,” Temeles said.

Kress and Temeles plan to extend their studies to other islands in the Eastern Caribbean to test how this plant-pollinator system has evolved in different regions and in different ecosystems. —Johnny Gibbons

New Hall of Human Origins points to environmental change as major force in evolution of hominins

John Barrat — Mon, 29 Mar 2010 14:31:29 +0000

Among the many treasures on view in the new David H. Koch Hall of Human Origins at the Smithsonian’s National Museum of Natural History is the only original fossil Neanderthal skeleton in the United States. The skeleton is from the Smithsonian’s human fossil collection and is part of the enormous range of archeological material assembled from around the world for this exhibition. Also on view are two original fossil skulls of Cro-Magnon and the La Ferrassie Neanderthal on temporary loan from the Musée de l’Homme in France.

Image left: A hyper-realistic bust of Homo neanderthalensis by artist John Gurche in the David H. Koch Hall of Human Origins.

Based on decades of cutting-edge research, the 15,000-square-foot Hall of Human Origins offers visitors an immersive, interactive journey through 6 million years of human evolution that spells out how defining characteristics of the human species have evolved during millions of years in response to a changing world. Inside are stories of survival, extinction and evidence of how environmental change may have shaped the evolution of new adaptations and the origin or extinction of early hominin species, as well as the emergence of our species, Homo sapiens. Visitors connect with their distant ancestors through life-size forensically reconstructed faces of early human species and learn about major milestones in the origins of human beings.

Other key features in the exhibition include interactive snapshots in time based on actual field sites where research is being conducted, a display of more than 75 skulls (exact replicas), an interactive human family tree showcasing 6 million years of evolutionary evidence from around the world, a “One Species Living Worldwide” amphitheater show and a special “Changing the World” gallery, in which visitors can address questions and issues surrounding climate change and the impact of humans on the Earth.

Video: Curator Rick Potts talks about the new David H. Koch Hall of Human Origins

“The theme of the exhibition, ‘What Does It Mean to Be Human?,’ is one of the most profound questions humans have asked over thousands of years and is informed by philosophy, religion and the arts and sciences,” said Rick Potts, director of the Human Origins Program and curator of anthropology at the museum. “Our goal is to provide a solid foundation for the public to explore the scientific contributions to answering this question.”

Image right: A bust of Australopithecus afarensis by John Gurche.

“What our exhibit does, is something that no other exhibit in the world does,” Potts continues. “ It’s not just about the discovery of a particular fossil human, it’s not just about debates that rage in scientific circles about our family tree and who was related to whom of the early species of fossil humans.” Rather this exhibit is “about the emergence of human characteristics, the things that define every single human being on earth today and it allows people the chance to explore the antiquity of walking upright on two legs, when we started making tools and the changes in technology over time, when our brains became large, the origins of art and our ability to use symbols and language. It allows the visitor to explore that deep antiquity and to see that everything didn’t happen all at once but rather things occurred over a 6-million year period in accumulating the characteristics of what it means to be a human being today.”

Image left: An evolutionary comparison (from left to right: Homo erectus, 1 million years old; Australopithecus afarensis, 2.5 million years old; Homo neanderthalensis, 100,000 – 32,000 years old)

Also, the exhibition contains a series of interactive stations to help visitors explore scientific evidence about the lives of early human ancestors and have fun while doing it. For example, there is a face-morphing station where visitors can see their faces transform into an ancient species of their choosing. Other features include interactive snapshots in time using the actual field sites where research is conducted; an interactive human family tree showcasing 6 million years of evolutionary evidence; a “One Species Living Worldwide” theater show; and a special “Humans Change the World” gallery.

Visitors can dig deeper online through the Human Origins Web site, http://humanorigins.si.edu, which features the Human Origins research program, collections and field sites—including podcasts and diaries from the field. They can engage onsite and online with science and scientists and go behind the scenes into the field, the lab or a unique, interactive museum experience that illuminates the major milestones in the origin of human beings.

By presenting the scientific findings and process of discovering how our species has evolved over time, the exhibition, “Human Origins: What Does It Mean to Be Human?,” takes the most comprehensive perspective on human beings of any Smithsonian exhibition.