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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…)

Pregnant Primates Miscarry When New Male Enters Group

By Guest PostFebruary 24, 2012Nature, Scienceamy lu, anthropology, baboons, bachelor males, breeding primate, bruce effect, clay wilton, eila roberts, ethiopia, female geladas, fertility, geladas, gestation, jacinta beehner, jared wadley, lactation, mammals, miscarriage, national park, offspring, old world monkeys, pregnant, reproduction, rodents, science express, simien mountains, thore bergman, unfamiliar male, university of michigan

ANN ARBOR, Mich.— Pregnant female geladas show an unusually high rate of miscarriage the day after the dominant male in their group is replaced by a new male, a new University of Michigan study indicates.

The “Bruce effect” – in which pregnant females spontaneously miscarry after being exposed to an unfamiliar male – has been found repeatedly in laboratory rodents. However, no conclusive evidence for this effect had ever been demonstrated in a wild population prior to this study. Geladas are Old World monkeys that are close relatives of baboons. (more…)

Building A Better Trap

By Guest PostFebruary 19, 2012Naturebuilding a trap, collecting insects, led modified trap, leds, light emitting diodes, new trap, sand flies

Fieldwork in Peru’s Andes Mountains is demanding, especially when it involves hauling heavy equipment to remote sites that are accessible only by traversing the region’s rugged terrain. (more…)

Fish of Antarctica Threatened by Climate Change

By Guest PostFebruary 16, 2012Environment, Natureantarctic fish, antarctic fish lineage, anti freeze proteins, antifreeze glycoproteins, climate change, evolution of antifreeze, polar conditions

A Yale-led study of the evolutionary history of Antarctic fish and their “anti-freeze” proteins illustrates how tens of millions of years ago a lineage of fish adapted to newly formed polar conditions – and how today they are endangered by a rapid rise in ocean temperatures. (more…)

Scared of a Younger Rival? Not for Some Male Songbirds

By Guest PostFebruary 14, 2012Naturemale birds, male songbirds, mature sparrow, nesting territory

COLUMBUS, Ohio — When mature male white-crowned sparrows duel to win a mate or a nesting territory, a young bird just doesn’t get much respect. (more…)

Bird Count

By Guest PostFebruary 12, 2012Naturebackyard feeder, baltimore oriole, bird count, bird nerd, boreal forests, charles shattuck, chris williams, delaware nature society, derek stoner, kennett square, laysan albatross, margo mcdonough, pine siskins, red breasted nuthatches, red clay creek, screech owl

*Birds aren’t flocking to backyard feeders this winter*

What’s in short supply this winter? If you said snow you guessed the first (and obvious) answer. But you may not have noticed what else has been scarce — birds at backyard feeders.

“Our customers are talking about the fact that fewer birds are coming to feeders this winter,” says Charles Shattuck who, with his wife, Kathy, owns Wild Birds Unlimited in Hockessin. “I’ve heard reports of fewer birds at feeders across the East Coast.” (more…)

Redder Ladybirds More Deadly, Say Scientists

By Guest PostFebruary 7, 2012Natureavian predator, ladybird colour, ladybirds, pigment levels, pigmentation, warning signals

A ladybird’s colour indicates how well-fed and how toxic it is, according to an international team of scientists. (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…)

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