The Natural History Museum in Los Angeles, Redesigned LOS ANGELES - The traditional natural history museum is powerful and familiar, but it is also strange. It is weighty, ponderous, pieced together from relics of lost worlds. It evolved in the 19th century, displaying the geological cataclysms that molded the earth's surface, the creatures that clambered into habitats and the indigenous cultures that were once considered closer to nature. No other museum genre has changed so glacially. But the pace of evolution has been quickening. Last month, just in time for its centennial this fall, the Natural History Museum of Los Angeles County completed a $135 million multiyear refashioning: a transformation that has doubled its program space and added new exhibitions and reworked others, including a mammals hall in 2010 and a compelling dinosaur hall in 2011. Its new entrance is a six-story-high glass pavilion designed by CO Architects in which a hanging skeleton of a 63-foot-long fin whale is silhouetted by 33,000 LED lights. Outside, a 3.5-acre "urban wilderness" designed by Mia Lehrer & Architects has replaced concrete parking lots. Some 31,000 plantings and a 27,000-gallon pond lure dragon flies and hummingbirds, while a curving stone wall harbors smaller samplings of urban wildlife. Indoors, other examples of the region's creatures, including tarantulas, harvester ants and rats, appear as part of a new interactive Nature Lab that readily attracts parents along with their charges. And in what may be the greatest departure from archetype, "Becoming L.A.," a permanent 14,000-square-foot exhibition - the largest in the museum - surveys the history of Los Angeles. But what kind of evolution is this, and what does it portend? Unlike the new Perot Museum of Nature and Science in Dallas, the Los Angeles museum has not embraced the style of the contemporary "science center." Under the guidance of the institution's president, Jane G. Pisano, its natural history heritage is preserved as well as transformed. The stunning dioramas that were mounted in the 1920s and "30s remain graciously intact. So do the museum's greatest fossils. The original 1913 Beaux-Arts rotunda still makes its antique promise of nobility and grandeur. What natural history museum, though, would display, as we find here, one of the first crucifixes to make its way to California in the 18th century? Or the carefully scuffed shoes and torn clothes of Charlie Chaplin's tramp from "City Lights"? And while we would expect to see the skeletal remnants of a baby Tyrannosaurus, why the chassis of an equally extinct Tourist, a 1902 wooden car that was the best-selling automobile in California before World War I? Including those items is part of the museum's effort at redefinition, although the curators were drawing on an eccentric set of collections that were never really part of the natural history tradition. The facade of the building still bears its original title: Los Angeles County Historical and Art Museum. In fact, the art collection became the heart of the Los Angeles County Museum of Art in the early 1960s, when the "natural history" title was adopted. The name remains appropriate. But what is the nature of the museum's redefinition? We get some hints in the halls devoted to mammals and dinosaurs, where explanations, interpretations and uncertainties accompany dramatic displays. The emphasis is on how paleontologists learn and on how our understanding has changed. Scientists appear in videos and panels, outlining arguments and demonstrating procedures. This is quite different from the monumental mounts of old, or the slice-of-nature dioramas that are so haunting partly because there is no sign of a human presence. It really is a transformation of the genre. We used to see a history of life's forms laid out before us, presumably culminating in the achievements of ... those who created the museum. Now we see something different. "Natural history" becomes not the history of nature but the history of human interactions with nature. And the focus narrows from the universal to the local. This is the approach taken by the Natural History Museum of Utah, which opened last year in Salt Lake City; its site in the foothills of the Wasatch Mountains provides the focus for its explorations. That institution, like many others (including the Quai Branly in Paris), also replaces the natural history museum's traditional condescension toward indigenous cultures with an idealization that is equally distorting. The Los Angeles museum's American Indian collection has been in temporary storage while its own strategy is worked out. And there are weaknesses in this new approach. The Los Angeles museum's garden, for example, is enchanting, but I would have wanted something more systematic, with clear labels and more apparent organization. Instead, the emphasis is on the overall experience of urban nature. Edible plants are gathered together, including a clutch of varied species that manage to produce lemonlike smells. South American floss silk trees are here to provide habitats for parrots, which, we learn inside, are onetime pets that now flourish in Los Angeles's urban wild. The new Nature Lab finds a better balance with its attentiveness to the city's animal life. Los Angeles County, we learn, has more bird species than any other county in the nation. Displays whimsically outline staff members" experiences in learning about their surroundings. Nature is not somewhere else, but always right here: "Houses, bridges and office buildings," we read, "can turn out to be great homes for wildlife." The visitor is lured in as a participant. "Help us map L.A."s nature by doing what you love," a wall label reads, soliciting Web contributions. "Send us a photo of road kill (it doesn't count if you kill it on purpose)," is one example, with contributions to go to a Web site. The museum's "citizen science" program, we learn, has "discovered two lizard species that had not been previously recorded in the Greater L.A. Area." The lab's exhibits are among the most successful I have seen for children in a science museum. They also reinforce the implications of the reworked fossil hall with emphases on interaction and interpretation. The old museum genre has been turned on its head: this is not a narrative of an all-seeing culture evolving out of the wilds of nature, but of a culture tentatively trying to find its way into nature. The museum's major new "Becoming Los Angeles" exhibition could have served as a foundation for this change, showing the city evolving out of the natural world while transforming it. And, indeed, that is its stated theme: we are told that the "relationship between human activity and the land" is the "prism" through which the history is told. So we learn that indigenous Southern California cultures regularly cleared undergrowth and grew food in small plots, but that 18th-century Spanish missions transformed agriculture. We learn how shifts in property law under the Spanish, the Mexicans and then the United States led to alterations in the landscape. And we learn how water became crucial: we see a half-filled bottle with the date Nov. 5, 1913, a souvenir from the opening of Los Angeles's first aqueduct, which enabled the growth of a modern city. This museum opened the following day. But unfortunately, for all its intelligence and flashes of illumination, the exhibit seems thin, not offering enough context or explanation, making it difficult to sense a continuous, coherent narrative. No matter, because the transformation of the natural history genre is evident and its effects lingering. When I return to the museum's imposing dioramas, I fruitlessly search for human tracks in the carefully crafted earth.