Herbivores Dine on Toxic Plants, Thanks to Gut Microbes
Woodrats lost their ability to eat toxic creosote bushes after antibiotics killed their gut microbes. Woodrats that never ate the plants were able to do so after receiving fecal transplants with microbes from creosote-eaters, University of Utah biologists found. (more…)
Microbe-eating flies from at least three different locations around the world recently have evolved into herbivores, feeding on some of the most toxic plants on Earth. Fly detectives and UA evolutionary biologists Noah Whiteman and Richard Lapoint are trying to find out what genetic pathways led the flies to such a major change of lifestyle.
For millennia, they buzzed through the woods, contentedly munching yeasts off the surfaces of leaves, bracken and rotting duff on the forest floor. But now, flies in the family Drosophilidae, whose disparate members dwell in areas all across the planet, have evolved into all-out vegetarians with a wicked diet of plants that are deadly to most other organisms.
What, University of Arizona scientists would like to know, has caused these flies, yeast-feeders for nearly 80 million years, to independently go cold turkey with respect to their formerly meaty diets? (more…)
*Climate changes profoundly influenced the rise and fall of six distinct, successive waves of mammal species diversity in North America over the last 65 million years, shows a novel statistical analysis led by Brown University evolutionary biologists. Warming and cooling periods, in two cases confounded by species migrations, marked the transition from one dominant grouping to the next.*
PROVIDENCE, R.I. [Brown University] — History often seems to happen in waves — fashion and musical tastes turn over every decade and empires give way to new ones over centuries. A similar pattern characterizes the last 65 million years of natural history in North America, where a novel quantitative analysis has identified six distinct, consecutive waves of mammal species diversity or “evolutionary faunas.” What force of history determined the destiny of these groupings? The numbers say it was typically climate change.
“Although we’ve always known in a general way that mammals respond to climatic change over time, there has been controversy as to whether this can be demonstrated in a quantitative fashion,” said Christine Janis, professor of evolutionary biology at Brown University. “We show that the rise and fall of these faunas is indeed correlated with climatic change — the rise or fall of global paleotemperatures — and also influenced by other more local perturbations such as immigration events.” (more…)
By examining the type of rock in which dinosaur fossils were embedded, an often unappreciated part of the remains,
Certain dinosaur species liked to live in different habitats, separated by only a few miles. Image credit: Nicholas Longrich
scientists have determined that different species of North American dinosaurs from the Late Cretaceous period 65 million years ago occupied different environments separated by just a few miles.
Hadrosaurs or duck-billed dinosaurs, along with the small ornithopod Thescelosaurus, preferred to live along the edge of rivers, according to the research. Ceratopsians, on the other hand, which include the well-known Triceratops, preferred to be several miles inland.
The findings, which appear in the online edition of the Proceedings of the Royal Society B, give scientists a more complete picture of the distribution of different species and help explain how several large herbivores managed to coexist. (more…)
