speciation

From Andrew Jenner at Atlantic: In July 2008, an American ornithologist named Bret Whitney was researching antbirds in the Brazilian Amazon when he heard a curious bird song. The sound, to his expert ear, clearly belonged a Striolated Puffbird––a big, streaky creature that looks like an owl crossed with a kingfisher. But it also had a smoother quality that struck him as “off-the-charts different” from the slightly warblier songs he knew from elsewhere in the region. He divided the Puffbird into an additional three new species, based on this information but in the ensuing dispute the American Ornithological Society was willing to recognize only one new species: Failing to see the logic behind this decision, Whitney regards it as “just Read More ›

From ScienceDaily: The molecular analysis confirms that all Laparocerus weevils have a common evolutionary ancestor (monophyly), but could not clarify whether that ancient founding species arrived from southern Europe or northwestern Africa. The two extant Moroccan species were found to be the result of a back-colonisation from the Canary Islands to Africa, and not the ancestral source lineage, which unfortunately is still unknown. The evolutionary process responsible for such richness comprises sequential radiation events in these archipelagoes, each generating several monophyletic groups. These groups, 20 in total, have been recognised as subgenera of Laparocerus, and five of them — Aridotrox, Belicarius, Bencomius, Canariotrox, and Purpuranius — are described as new to science in this study. Colonisation routes, habitat shifts, disruption Read More ›

From Science Daily: Lacey Knowles and Jeet Sukumaran investigated the accuracy of inferences made by a mathematical model widely used to quickly determine the boundaries between species without the time-consuming, painstaking process of comparing specimens in museum collections. They found that the genetic approach, formally known as the multispecies coalescent model, can lead to species estimates that are five to 13 times higher than the true numbers. Because the species is the fundamental unit for all evolutionary and ecological studies, their findings are expected to have wide-ranging implications, from biodiversity studies to conservation planning. Their results are scheduled for online publication Jan. 30 in Proceedings of the National Academy of Sciences. “This is an area that has really taken off Read More ›

From science philosophers Adrian Currie and Derek Turner at Aeon: Both Triceratops and Torosaurus lived in what is now western North America near the end of the Cretaceous period. Torosaurus was bigger and had a longer frill on its head, which sported openings or ‘fenestral’. The two species are considered quite distant (different genera). But In 2010, the palaeontologists John Scannella and John Horner challenged this consensus with the so-called ‘Toroceratops’ hypothesis. They argued that Torosaurus and Triceratops were really the same kind of animal, and that the differences were just a question of the creature’s age. As individuals grew up, they got bigger, their frills got longer, and they developed holes. According to this view, a Torosaurus is just Read More ›

From ScienceDaily: Rapid evolution of other species happens all around us all the time — and many of the most extreme examples are associated with human influences. Consider three examples: Commercial fishing. When fishing pressure is high, the fish evolve to reproduce when they are younger and smaller, and thus tend to have fewer, smaller offspring. This evolutionary change can, in turn, reduce fisheries yields and the sustainability. But is this really a form of evolution? That is, are the changes irreversible? Will speciation occur in the affected population, so that the two new groups cannot interbreed with each other? Or, if the bottom fell out of the fish market, would everything be pretty much the same a couple of Read More ›

But in the current mess, how would we know? From Noah K.Whiteman at BigQuestionsOnline: Counting the number of herbivorous insect species that scientists have identified reveals a remarkable possibility: insects that feed on living plants may be the most species-rich group of organisms ever to have evolved in the history of life on the planet. This includes extinct lineages such as the Palaeodictyoptera — among the first herbivorous insects to have evolved. Only unnamed microbes might be more diverse (although this hypothesis is controversial). Parents in some future colony on Mars could someday read to their children the bedtime story The Very Hungry Caterpillar by Eric Carle and with that story illustrate the essential nature of the two most diverse Read More ›

From ScienceDaily: For the new work, Cracraft, Barrowclough, and their colleagues at the University of Nebraska, Lincoln, and the University of Washington examined a random sample of 200 bird species through the lens of morphology — the study of the physical characteristics like plumage pattern and color, which can be used to highlight birds with separate evolutionary histories. This method turned up, on average, nearly two different species for each of the 200 birds studied. This suggests that bird biodiversity is severely underestimated, and is likely closer to 18,000 species worldwide. The researchers also surveyed existing genetic studies of birds, which revealed that there could be upwards of 20,000 species. But because the birds in this body of work were Read More ›

Retro beefalo. From ScienceDaily: Ancient DNA research has revealed that Ice Age cave artists recorded a previously unknown hybrid species of bison and cattle in great detail on cave walls more than 15,000 years ago. The mystery species, known affectionately by the researchers as the Higgs Bison* because of its elusive nature, originated over 120,000 years ago through the hybridisation of the extinct Aurochs (the ancestor of modern cattle) and the Ice Age Steppe Bison, which ranged across the cold grasslands from Europe to Mexico. Research led by the Australian Centre for Ancient DNA (ACAD) at the University of Adelaide, published today in Nature Communications, has revealed that the mystery hybrid species eventually became the ancestor of the modern European bison, Read More ›

See this abstract from Molecular Ecology*: There is increasing evidence that phenotypic plasticity can promote population divergence by facilitating phenotypic diversification and, eventually, genetic divergence. When a ‘plastic’ population colonizes a new habitat, it has the possibility to occupy multiple niches by expressing several distinct phenotypes. These initially reflect the population’s plastic range but may later become genetically fixed by selection via the process of ‘genetic assimilation’ (GA). Through this process multiple specialized sister lineages can arise that share a common plastic ancestor – the ‘flexible stem’. Here, we review possible molecular mechanisms through which natural selection could fix an initially plastic trait during GA. These mechanisms could also explain how GA may contribute to cryptic genetic variation that can Read More ›

No, that’s not the way the ScienceDaily media release puts it, of course: Why do some animals have extravagant, showy ornaments — think elk and deer antlers, peacock feathers and horns on dung beetles — that can be a liability to survival? Charles Darwin couldn’t figure it out, but now a Northwestern University research team has a possible explanation for this puzzling phenomenon of evolution. Just think: The team get to be minor saints in the calendar, for helping the Great One. The researchers developed a mathematical model that made a surprising prediction: In animals with ornamentation, males will evolve out of the tension between natural selection and sexual selection into two distinct subspecies, one with flashy, “costly” ornaments for Read More ›

From ScienceDaily: Deemed as one species spread across different continents, scientists confirm that the Eurasian Hen Harrier and the American Northern Harrier are in fact two distinct species. … “Before the advent of sequencing technology, species were categorised by shared and divergent morphological features. However, new technology allows us to quantify the amount of genetic change between populations and identify divergent lineages.” Paper. (public access) – Graham J. Etherington, Jason A. Mobley. Molecular phylogeny, morphology and life-history comparisons within Circus cyaneus reveal the presence of two distinct evolutionary lineages. Avian Research, 2016; 7 (1) DOI: 10.1186/s40657-016-0052-3 More. On wonders how many other speciation claims will be blown out of the water using such techniques. Nothing says “Darwin snob” like indifference Read More ›

From Bruce Bower at Science: Even more surprising, H. sapiens’ Stone Age dalliances outside their own kind weren’t limited to Neandertals. Ancient DNA shows signs of interbreeding between now-extinct Neandertal relatives known as Denisovans and ancient humans. Denisovans’ DNA legacy still runs through native populations in Asia and the Oceanic islands. Between 1.9 and 3.4 percent of present-day Melanesians’ genes can be traced to Denisovans (SN Online: 3/17/16). Other DNA studies finger unknown, distant relatives of Denisovans as having interbred with ancestors of native Australians and Papuans (see “Single exodus from Africa gave rise to today’s non-Africans”). Genetic clues also suggest that Denisovans mated with European Neanderthals. These findings have renewed decades-old debates about the evolutionary relationship between humans and Read More ›

  Well, not “evolution,” even though it must be marketed that way. From ScienceDaily: For many thousands of years, humans have bred dogs, goats, chickens and other animals to make them suitable for use as domestic animals, in a process known as domestication. Humans have selected the individuals that possess desirable traits and bred them with similar individuals, such that the offspring possess the same traits. The genetic material of the animal has partially changed during the development of the species from its wild form to a domesticated one. The opposite process also takes place, when domesticated animals readapt to life in the wild, in a process known as feralization. By investigating what happens in an animal’s genetic material, we Read More ›

From Ewen Callaway at Nature: Scientists had assumed from fossil evidence that an ancient predecessor called the straight-tusked elephant (Paleoloxodon antiquus), which lived in European forests until around 100,000 years ago, was a close relative of Asian elephants. In fact, this ancient species is most closely related to African forest elephants, a genetic analysis now reveals. Even more surprising, living forest elephants in the Congo Basin are closer kin to the extinct species than they are to today’s African savannah-dwellers. And, together with newly announced genomes from ancient mammoths, the analysis also reveals that many different elephant and mammoth species interbred in the past. More. This is happening so often now that there is clearly something wrong with the way Read More ›

From ScienceDaily: Shimmering carapaces and rattling claws make colourful freshwater crabs attractive to pet keepers. To answer the demand, fishermen are busy collecting and trading with the crustaceans, often not knowing what exactly they have handed over to their client. Luckily for science and nature alike, however, such ‘stock’ sometimes ends up in the hands of scientists, who recognise their peculiarities and readily dig into them to make the next amazing discovery. Such is the case of three researchers from University of New South Wales, Australia, The Australian Museum, Sun Yat-sen University, China, and National Chung Hsing University, Taiwan, who have found a new species and even a new genus of freshwater crab, and now have it published in the Read More ›