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Nearly One-Tenth of Hemisphere’s Mammals Unlikely to Outrun Climate Change

By Guest PostMay 15, 2012Environment, Natureanteaters, armadillos, Berkeley, caribou, carnivore, carrie schloss, cedar tree foundation, climate change, coyotes, deer, emission scenario, generation, global climate, greenhouse gas, habitat, hemisphere, howler monkeys, human influence, joshua lawler, mammal, marmosets, model, nature conservancy, sexually mature, species of primates, spider monkeys, tamarins, tristan nunez, tropics, university of california, university of washington, vulnerability, western hemisphere, wolves

A safe haven could be out of reach for 9 percent of the Western Hemisphere’s mammals, and as much as 40 percent in certain regions, because the animals just won’t move swiftly enough to outpace climate change.

For the past decade scientists have outlined new areas suitable for mammals likely to be displaced as climate change first makes their current habitat inhospitable, then unlivable. For the first time a new study considers whether mammals will actually be able to move to those new areas before they are overrun by climate change. Carrie Schloss, University of Washington research analyst in environmental and forest sciences, is lead author of the paper out online the week of May 14 in the Proceedings of the National Academy of Sciences. (more…)

Low Quality Genes May Cause Mutational Meltdown

By Guest PostApril 19, 2012Scienceaneil agrawal, chromosome, DNA, dna damage, drosophila melanogaster, eeb, environmental stress, evolutionary biologist, extinction, fruit fly, genetic deficiencies, high quality gene, low quality gene, mammal, mutation, nathaniel sharp, poor genetic quality, repairing dna, species, university of toronto

Deficiencies compound over time, researchers say

Evolutionary biologists at the University of Toronto have found that individuals with low-quality genes may produce offspring with even more inferior chromosomes, possibly leading to the extinction of certain species over generations.

Their study, published in Proceedings of the National Academy of Sciences, predicts that organisms with such genetic deficiencies could experience an increased number of mutations in their DNA, relative to individuals with high-quality genes. The research was done on fruit flies whose simple system replicates aspects of biology in more complex systems, so the findings could have implications for humans. (more…)

Scientists Trace Evolutionary History of What Mammals Eat

By Guest PostApril 17, 2012Nature, Scienceanimal ecology, antelope, bats, big cats, carnivory, cows, darwin, davis, deer, duke university, environmental biology, evolutionary race, evolutionary time, extinct, feeding habit, george gilchrist, herbivory, louise roth, macroevolutionary diversification, mammal, meat, national science foundation, omnivore, plant eater, primates, rabbits, rodents, samantha hopkins, samantha price, ungulates, university of california, university of oregon

*Feeding habits haven’t always been what they are today*

The feeding habits of mammals haven’t always been what they are today, particularly for omnivores.

Some groups of mammals almost exclusively eat meat–take lions and tigers and other big cats as examples.

Other mammals such as deer, cows and antelope are predominantly plant-eaters, living on a diet of leaves, shoots, fruits and bark. (more…)

Some Mammals Used Highly Complex Teeth to Compete With Dinosaurs

By Guest PostMarch 19, 2012Nature, Science3 d images, alistair evans, angiosperms, australia, back teeth, bumps, computed tomography, ct, cusps, dinosaur extinction, dinosaurs, event, extinction, finland, food, fossil, gregory p wilson, ian corfe, insect pollinators, jukka jernvall, mammal, mesozoic era, mikael fortelius, monash university, mountain range, multituberculates, Nature, paleontologist, peter smits, rodent, scanning, tooth surface, topography, tubercles, university of helsinki, university of washington, vince stricherz

Conventional wisdom holds that during the Mesozoic Era, mammals were small creatures that held on at life’s edges. But at least one mammal group, rodent-like creatures called multituberculates, actually flourished during the last 20 million years of the dinosaurs’ reign and survived their extinction 66 million years ago.

New research led by a University of Washington paleontologist suggests that the multituberculates did so well in part because they developed numerous tubercles (bumps, or cusps) on their back teeth that allowed them to feed largely on angiosperms, flowering plants that were just becoming commonplace. (more…)

Evolution of Earliest Horses Driven by Climate Change

By Guest PostFebruary 24, 2012Environment, Nature, Scienceaaron wood, atmosphere, bighorn basin, body size, cabin fork area, carbon, carbon dioxide, cause and effect, climate model, clydesdale, concentration, doug boyer, dwarfing phenomenon, earliest horse, evolution, florida museum of natural history, fossil, geochemical analysis, global temperature, h richard lane, horse teeth, industrial revolution, jonathan bloch, mammal, national science foundation, natural selection, North America, nsf, ocean, ornithologist, oxygen levels, paleocene-eocene thermal maximum, petm, prediction, ross secord, sifrhippus sandae, stephen chester, temperature, university of florida, university of nebraska lincoln, worland, yale

*The hotter it gets, the smaller the animal?*

When Sifrhippus sandae, the earliest known horse, first appeared in the forests of North America more than 50 million years ago, it would not have been mistaken for a Clydesdale.

It weighed in at around 12 pounds–and it was destined to get much smaller over the ensuing millennia.

Sifrhippus lived during the Paleocene-Eocene Thermal Maximum (PETM), a 175,000-year interval of time some 56 million years ago in which average global temperatures rose by about 10 degrees Fahrenheit. (more…)

A Bug’s (Sex) Life: Diving Beetles Offer Clues About Sexual Selection

By Guest PostFebruary 6, 2012Nature, Sciencearizona desert, co evolution, dawn higginson, diving beetles, dytiscidae, epifluorescence image, Europe, evolution, evolutionary relationship, female, fertilization, great diving beetle, hygrotus sayi, invertebrate, kari segraves, kelly miller, larva, male, mammal, mollusk, reproductive organ, scott pitnick, sexual evolution, sexual selection, sexual trait, speciation, sperm evolution, sperm storage, spermatheca, syracuse university, thermonectus marmoratus, university of arizona

*Studies of diving beetles suggest sperm evolution may be driven by changes in female reproductive organs, challenging the paradigm of post-mating sexual selection being driven mostly by competition among sperm.*

Studying female reproductive tracts and sperm in diving beetles (Dytiscidae), researchers from the University of Arizona and Syracuse University have obtained a glimpse into a bizarre and amazing world of sperm that can take on a variety of forms – including joining together into conglomerates that navigate the twisted mazes of the female reproductive tract.

Analyses of the evolutionary relationships among diving beetles reveal that sperm form appears to follow function dictated by female reproductive organs. (more…)

Nature’s Backbone at Risk

By Guest PostOctober 31, 20101 commentNature, Sciencealien species, amphibian, biodiversity, biologist, black footed ferret, brown rat, california condor, copsychus sechellarum, ecosystems, edward o wilson, equus ferus, extinction, falco punctatus, global conservation efforts, gymnogyps californianus, humpback whale, kihansi spray toad, logging, magpie robin, mammal, mauritius kestrel, megaptera novaeangliae, mongolia, mustela nigripes, Nature, nectophrynoides asperginis, over exploitation, przewalski horse, rattus norvegicus, red list, ronald nussbaum, science express, seychelles, southeast asia, species, vertebrate, vicugna vicugna, vicuña

ANN ARBOR, Mich.— One-fifth of the world’s vertebrate species are threatened with extinction, but the situation would be worse if not for current global conservation efforts, a new study finds.

University of Michigan biologist Ronald Nussbaum is one of 174 researchers from 115 institutions and 38 countries who authored the study published this week in Science Express.

The study used data for 25,000 species from the International Union for Conservation of Nature’s Red List of Threatened Species to investigate the status of the world’s vertebrates (mammals, birds, amphibians, reptiles and fishes) and how this status has changed over time. The results show that, on average, 50 species of mammal, bird and amphibian move closer to extinction each year due to the impacts of agricultural expansion, logging, over-exploitation, and invasive alien species. (more…)

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