speciation

From Michael Le Page at New Scientist: The number of known species of geckos has just jumped upwards, with 15 new species being formally described this week. … The 19 species all live in a small area of Myanmar just 90 by 50 kilometres in size. “That’s the really amazing thing about it,” says Grismer. “They all come from such a small area.” It’s common to find lots of closely-related species of invertebrates like snails or insects in such a small area, but it is unprecedented for a backboned animal, say Grismer. “For lizards, it is remarkable.”More. A friend asks why no criteria are offered in the article as to how the scientists determined that the groups of lizards are Read More ›

Convergent evolution of mimetic species confounds classification. From ScienceDaily: The scientists discovered numerous cryptic species-two or more species erroneously classified as one species-as well as single species mistakenly described as two or three. Frequently, species discriminated with genetic data are each others’ closest relatives, but can be distinguished by stark genetic differences; this suggests a lack of interbreeding — a hallmark of species distinctiveness. However, in Elymnias, Lohman and his associates found that cryptic species were unrelated to each other and resulted from a novel cause: mimicry. Different species on different islands of the Indo-Australian Archipelago frequently evolved to resemble a single, widespread model species, and different Elymnias species therefore evolved to resemble each other. Lohman and his colleagues conducted Read More ›

From Leah Burrows at Harvard SEAS: Even Charles Darwin, the author of “The Origin of Species”, had a problem with species. “I was much struck how entirely vague and arbitrary is the distinction between species and varieties,” Darwin wrote in his seminal 1859 work. His followers have been exploiting the concept ever since, to confuse discussions about evolution with an all-knowing sneer. Indeed, nothing says “Darwin snob” like indifference to the mess that the entire concept of speciation is in. In a paper published in Physics Review E, Tikhonov outlines a framework for rethinking the language of species classification. Classical models of biology start from the assumption that the differences between species are, for the most part, clearly defined, and Read More ›

From ScienceDaily: Evolutionary biologists long have supposed that when species colonize new geographic regions they often develop new traits and adaptations to deal with their fresh surroundings. They branch from their ancestors and multiply in numbers of species. Apparently, this isn’t the story of “true frogs.” The frog family scientists call Ranidae are found nearly everywhere in the world, and their family includes familiar amphibians like the American Bullfrog and the European common frog. New research from the University of Kansas appearing in Royal Society Biology Letters shows, in contrast to expectations, “the rapid global range expansion of true frogs was not associated with increased net-diversification.” … Rather, the rich diversity of species in the Ranidae family comes from millions Read More ›

Or are they just exposing the flaws in the system? From Benjamin Jones at Smithsonian Mag: To study life on Earth, you need a system. Ours is Linnaean taxonomy, the model started by Swedish biologist Carl Linnaeus in 1735. Linnaeus’s two-part species names, often Latin-based, consist of both a genus name and a species name, i.e. Homo sapiens. Like a library’s Dewey Decimal system for books, this biological classification system has allowed scientists around the world to study organisms without confusion or overlap for nearly 300 years. But, like any library, taxonomy is only as good as its librarians—and now a few rogue taxonomists are threatening to expose the flaws within the system. Taxonomic vandals, as they’re referred to within Read More ›

This article is remarkable for its honest look at the mess the “biological species concept,” rammed into high schoolers’ heads since forever, has become. From Jordana Cepelewicz at Quanta: In 2006, a hunter shot what he thought was a polar bear in the Northwest Territories of Canada. Closer examination, however, revealed brown patches on its white fur, uncharacteristically long claws and a slightly hunched back. The creature was in fact a hybrid, its mother a polar bear, its father a grizzly. Although this cross was known to be possible — the two species had mated in captivity before — this was the first documented case found in the wild. Since then, it has become clear that this was not an Read More ›

  Did Darwin really explain the origin of species?   My quote of the month is now up on my blog. This is an interesting one as it comes from an evolutionary biologist and critic of ID. I also focus on comments of a similar nature that have been made in more recent years. Surprise, surprise, Darwin’s work isn’t all it is cracked up to be.                                                H. Allen Orr on Darwin’s Failure    

A sponsored and funded mess, due to the Darwinian obsession with speciation. From ScienceDaily: New research from Dartmouth College raises questions over how scientists should interpret observed groupings of bacteria. The study advises caution with the assumption that bacterial clusters are always a result of ecological and genetic forces. The research, appearing in the Proceedings of the National Academy of Sciences, says random diversification and extinction of cells could organize bacteria into taxonomic units just as effectively as classification based on selection-driven ecological forces. “A reliable classification system is the key to understanding microbial biodiversity,” said Olga Zhaxybayeva, assistant professor of biological sciences at Dartmouth College. “Through our research, we found that organizing microorganisms is even trickier than previously thought.” Read More ›

From Diana Yates at U Illinois: New research reveals that a species of giant elephant that lived 1.5 million to 100,000 years ago – ranging across Eurasia before it went extinct – is more closely related to today’s African forest elephant than the forest elephant is to its nearest living relative, the African savanna elephant. The study challenges a long-held assumption among paleontologists that the extinct giant, Palaeoloxodon antiquus, was most closely related to the Asian elephant. The findings, reported in the journal eLife, also add to the evidence that today’s African elephants belong to two distinct species, not one, as was once assumed. … “We’ve had really good genetic evidence since the year 2001 that forest and savanna elephants Read More ›

From ScienceDaily: Now scientists around Ludwig-Maximilians-Universitaet (LMU) in Munich paleontologist Professor Bettina Reichenbacher have described a new fossil cichlid discovered in Upper Miocene strata in East Africa, which provides new insights into the evolutionary history of the group. Moreover, the results are consistent with molecular genetic data relating to the ongoing diversification of the family in the Great Lakes region of East Africa, which have indicated that hybridization between members of related species or even genera has played a major role in cichlid speciation. The work also sheds light on the environmental conditions that prevailed in the Rift Valley of East Africa in the Upper Miocene period, 9-10 million years ago. The new findings appear in the Journal of Vertebrate Read More ›

From Rachel Cernansky at Nature: Biodiversity moves beyond counting species Ecologists are increasingly looking at how richness of traits — rather than number of species — helps set the health of ecosystems. From the article: Biodiversity, it states, doesn’t have to be just about the number of a species in an ecosystem. Equally important to keeping an ecosystem healthy and resilient are the species’ different characteristics and the things they can do — measured in terms of specific traits such as body size or branch length. … “Just going for species numbers basically doesn’t allow us to harness all this incredibly rich information we have of how the real world operates,” says Sandra Díaz, an ecologist with Argentina’s National Scientific Read More ›

From ScienceDaily: Now, the first genetic study of the diversity of clinging jellyfish populations around the globe has discovered some surprising links among distant communities of jellies and also revealed there may be more than one species of the infamous stinger. … The new study shows that the story is much more complex than previously thought. The researchers uncovered a genetic match between populations of clinging jellyfish in the Vladivostok, Russia-area — specifically the area well known to cause severe sting reactions — and those found along the U.S. East Coast in the Northwest Atlantic. “We know the two regions share one genetic variant or haplotype,” Govindarajan says. “In the Northwest Atlantic, this variant was actually most frequently found in Read More ›

Readers may remember the Darwinian icon of the Galapagos finches that were supposed to be turning into new species but then just drifted back and forth. One would think the finches didn’t give a hoot about Science. From Evolution News & Views: In a new Perspective piece in Science Magazine, “Watching Speciation in Action,” they show that they are not the only ones who have witnessed the origin of species. Beginning with the Darwin quote about “grandeur in this view of life” that evolves, they describe a number of studies like theirs that illustrate organisms that have varied and diversified from parent stock. Let’s begin by listing the examples and what is known about them, both genetically and phenotypically. These Read More ›

From Geoffrey E. Hill at The Scientist: What defines a species? Because the boundaries between species can appear so fluid, pursuing such a question seems, at times, like academic esoterica—little different than discussing how many angels can dance on the head of a pin. But accurate species definitions lie at the heart of biological investigations and management of natural resources (e.g., the US Endangered Species Act). It is troublesome, therefore, that new information on the genetic structure of long-recognized species of birds could jeopardize their status as full species. The problem, in a nutshell, is that the DNA of many familiar species of birds holds signatures of substantial exchange of nuclear genes with other bird species. Such gene exchange matters Read More ›

From ScienceDaily: These new results indicate that the Asian Horned Frogs family may have originated as recently as 77 million years ago in contrast to 100-126 mya as previously estimated, and suggest that scientists might have been also overestimating the age of many other families of frogs by up to 35%. The results have completely changed our understanding of how the different Asian Horned Frog species and their species groups are related. Many of the species that look similar, and so were considered to be closely related, were found to be distant relatives of each other, and those that look different were found to be closely related. Paper. (public access) – Stephen Mahony, Nicole M. Foley, S.D. Biju, Emma C. Read More ›