博彩平台推荐研究生’s work deepens understanding of evolution and extinction 

在80年代末, just as another group of scholars was preparing a 2,500页的, two-volume text cataloging the unique flora of the Hawaiian Islands, 哈罗德·圣. 约翰, 曾经是植物学的先驱教授, long-time chair of the Botany Department and director of the arboretum at the University of Hawai’i at Mānoa from 1929 to 1958, 90多岁时, published 37 articles describing 894 new plant species in the islands, 这几乎是前所未有的数字, 包括157种新薄荷. 

Under the international code of scientific nomenclature, first publication takes priority. But the researchers on the other project found some small errors in his work, and the scientific community dismissed and then ignored St. 约翰的杰作. 

“人们不看好他. They just thought he was this old guy who’d done sloppy work,贾斯汀·威廉姆斯说。, a graduate student in museum and field studies at the 博彩平台推荐 自然历史博物馆. 威廉姆斯认为St. 约翰’s few errors might have been due to his intentionally rushing to press in the race for publication priority.

快进三十年. Botany has been revolutionized by molecular DNA work, which has led researchers to re-examine and, 在很多情况下, 重写, long-held taxonomies for Hawai’ian flora. And Williams’s own research on mints in the Hawaiian Islands has led him to a surprising revelation: “Preliminary data is suggesting that 哈罗德·圣. 约翰说对了.”

But that’s just one wrinkle in Williams’ gradual unraveling of mysteries surrounding Hawai’i’s mint species. 它们是真正的薄荷糖, but like so much of the islands’ flora and fauna, they are quite distinct from their generic continental relatives you might pluck from your garden for iced tea or other continental species. 

For one thing, they don’t have that familiar minty odor. Rather than evolving into trees like Hawai’ian violets and lobeliads, they are either dainty herbs or enormous woody vines. And unlike any other mint, they produce fleshy fruits. 

“Hawaiian mints seem to be an oddball when we evaluate them under traditional … evolution theory,威廉姆斯说。, who has been working with two of the 157 species described by St. 约翰, courtesy of the botany department at the world-famous Bishop Museum. 

“Preliminary molecular results strongly support that these two specimens are unique taxa, 支持圣. 约翰’s species hypothesis and refuting previous claims that his work was rushed and sloppy.”

Williams’ molecular sleuthing indicates that while Hawaiian mints likely came to the islands from North America, 约,500英里外, 他们后来驱散了超过3人,距离汤加岛500英里, unusual for a species that evolved fleshy fruit—which sinks, 而不是浮动, 在海水中, a factor that has limited long-distance dispersal of several other Hawaiian species. 

The mints also seem to violate Hennig’s “progression rule” in evolution, which states that the most primitive species of any group will be found in the earliest, 最中心位置. 

最后, the currents and prevailing winds don’t support the case for “extra-Hawaiian dispersal,“但DNA就是这么说的.

“These mints have the potential to redefine how we think of insular evolution, as well as regular evolution and the speciation and extinction process,威廉姆斯说.

Of the currently parsed 59 mint species, all but two are found in Hawai’i. 另外两个, only found on that islands of Tahiti and Tonga, 是在19世纪末首次被收集的吗. Williams notes that the Tongan species was collected only once, in 1958 … by 哈罗德·圣. 约翰.

围绕St的谜团. 约翰 and Hawaiian mint species fascinate Williams. But he hopes his systematics research—properly describing and placing species on the taxonomic tree—will have a real-world impact for the islands known as “the endangered species capital of the world,” where two-thirds of species are considered threatened, 濒临灭绝，甚至灭绝.

“Refining our systematic understanding of what the species are will inform immediate conservation action, but also provide a foundation from which to answer interesting evolutionary and ecological questions,威廉姆斯说. He hopes that persistent fieldwork will lead to the rediscovery of species thought to be extinct, as well as new populations of rare and endangered plants.

“在全球大规模物种灭绝的时代, any efforts to refine our knowledge of these processes, 尤其是博彩app推荐灭绝的, could significantly contribute to us reversing that trend,威廉姆斯说.