Category Archives: Nature

Pollination with Precision: How Flowers Do It

By Guest PostMay 23, 2012Naturearabidopsis plants, brown university, chaotic frenzy, female gametes, fertilization, gamete fusion, hap2, kristin beale, logistical efficiency, mark johnson, mechanism, microscope, model, mothers day, mutant sperm, ovule, pollen grains, pollen tubes, pollination, polytubey, precision, reproduction, sex cells, sperm

Pollination could be a chaotic disaster. With hundreds of pollen grains growing long tubes to ovules to deliver their sperm to female gametes, how can a flower ensure that exactly two fertile sperm reach every ovule? In a new study, Brown University biologists report the discovery of how plants optimize the distribution of pollen for successful reproduction.

PROVIDENCE, R.I. [Brown University] — Next Mother’s Day, say it with an evolved model of logistical efficiency — a flower. A new discovery about how nature’s icons of romance manage the distribution of sperm among female gametes with industrial precision helps explain why the delicate beauties have reproduced prolifically enough to dominate the earth.

In pollination, hundreds of sperm-carrying pollen grains stick to the stigma suspended in the middle of a flower and quickly grow a tube down a long shaft called a style toward clusters of ovules, which hold two female sex cells. This could be a chaotic frenzy, but for the plant to succeed, exactly two fertile sperm should reach the two cells in each ovule — no more, no less. No ovule should be left out, either because too many tubes have gone elsewhere, or because the delivered sperm don’t work. (more…)

Ancient Giant Turtle Fossil Revealed

By Guest PostMay 18, 2012Nature, Scienceamazon river delta, ancient, behemoth, carbonemys cofrinii, carlos jaramillo, cerrejon formation, coal mine, coal turtle, Colombia, crocodiles, dan ksepka, edwin cadena, fossil, giant turtle, jonathan bloch, national science foundation, orinoco, paleontologist, pelomedusoides, reptiles, skull, south american giant, Titanoboa cerrejonensis

Picture a turtle the size of a Smart car, with a shell large enough to double as a kiddie pool. Paleontologists from North Carolina State University have found just such a specimen – the fossilized remains of a 60-million-year-old South American giant that lived in what is now Colombia.

The turtle in question is Carbonemys cofrinii, which means “coal turtle,” and is part of a group of side-necked turtles known as pelomedusoides. The fossil was named Carbonemys because it was discovered in 2005 in a coal mine that was part of northern Colombia’s Cerrejon formation. The specimen’s skull measures 24 centimeters, roughly the size of a regulation NFL football. The shell which was recovered nearby – and is believed to belong to the same species – measures 172 centimeters, or about 5 feet 7 inches, long. That’s the same height as Edwin Cadena, the NC State doctoral student who discovered the fossil. (more…)

Counting Horseshoe Crabs

By Guest PostMay 17, 2012Nature, Sciencecensus, crab line, crab population, delaware bay, dover, eadoh reshef, fertilization, field research, horseshoe crab, joanna york, jonathan dinman, kayla krenitsky, marine science, megan nogan, migration, pvc pipe, st jones reserve, tammy beeson, teresa messmore, university of delaware, will goldman

Marine science majors conduct field research with horseshoe crab census

Wearing sneakers and rain boots, University of Delaware freshmen got their feet wet as marine biologists recently while counting horseshoe crabs along the Delaware Bay. The students participated in a monitoring effort to gain firsthand experience in field research with their fellow marine science majors.

“Where else can you go on a Saturday night to count horseshoe crabs?” freshman Will Goldman said. (more…)

First Satellite Tag Study for Manta Rays Reveals Habits And Hidden Journeys of Ocean Giants

By Guest PostMay 15, 2012Naturebaleen whales, brenden j godley, caribbean sharks, chinese medicinal trade, dan w castellanos, devilfish, ecological needs, fish eggs, francisco remolina, gill rakers, government of mexico, howard rosenbaum, iucn, lucy a hawkes, manta ray, matthew witt, Mexico, mysterious ocean giant, mythic fish, plankton, rachel graham, sara maxwell, satellite telemetry, satellite tracking technology, university of exeter, whale sharks, Wildlife Conservation Society, yucatan peninsula, zooplankton

Using the latest satellite tracking technology, conservationists from the Wildlife Conservation Society, the University of Exeter and the Government of Mexico have completed a ground-breaking study on a mysterious ocean giant: the manta ray.

The research team has produced the first published study on the use of satellite telemetry to track the open-ocean journeys of the world’s largest ray, which can grow up to 25 feet in width.

Researchers say the manta ray—listed as ‘Vulnerable’ by the International Union for the Conservation of Nature (IUCN)—has become increasingly threatened by fishing and accidental capture and now needs more protection. (more…)

Five-Limbed Brittle Stars Move Bilaterally, Like People

By Guest PostMay 14, 2012Natureanimals, belize, bilateral symmetry, bilaterally symmetrical, brain, brittle stars, brown university, bushnell foundation, david orenstein, direction, five limbed, henry astley, humans, locomotion, mark bertness, move bilaterally, ophiocoma echinata, pentaradially symmetrical, radial symmetrical

Brittle stars and people have something in common: They move in fundamentally similar ways. Though not bilaterally symmetrical like humans and many other animals, brittle stars have come up with a mechanism to choose any of its five limbs to direct its movement on the seabed. It’s as if each arm can be the creature’s front, capable of locomotion and charting direction. Results appear in the Journal of Experimental Biology.

PROVIDENCE, R.I. [Brown University] — It appears that the brittle star, the humble, five-limbed dragnet of the seabed, moves very similarly to us.

In a series of first-time experiments, Brown University evolutionary biologist Henry Astley discovered that brittle stars, despite having no brain, move in a very coordinated fashion, choosing a central arm to chart direction and then designating other limbs to propel it along. Yet when the brittle star wants to change direction, it designates a new front, meaning that it chooses a new center arm and two other limbs to move. Brittle stars have come up with a mechanism to choose any of its five limbs to be central control, each capable of determining direction or pitching in to help it move. (more…)

Construction of New Rock Spawning Reefs Will Help Great Lakes Native Fish

By Guest PostMay 13, 2012Environment, Naturebelle isle, boat traffic, boulder, bruce manny, center of excellence, connecting channel, crevices, delta, detroit, detroit river, erie, fighting island, great lakes, huron erie, huron erie corridor, jennifer read, lake sturgeon, lake whitefish, lakes huron, michigan, michigan sea grant, middle channel, middle channel reefs, mooneye, native fish, northern madtom catfish, physical characteristics, reef project, river bottom, river redhorse sucker, rock spawning reefs, rock structure, sport fish, st clair river, U.S. Geological Survey, walleye

ANN ARBOR, Mich.—The first of nine rock reefs is under construction in the St. Clair River delta northeast of Detroit. The goal of the project, which is led by Michigan Sea Grant, is to boost populations of lake sturgeon and other rare native fish by providing river-bottom rock structures where they can spawn.

The rock reefs are designed to assist several native species that are considered threatened or endangered in Michigan, including lake sturgeon, mooneye, the northern madtom catfish and the river redhorse sucker. Walleye, a popular sport fish, and commercially important lake whitefish should also benefit. (more…)

Ecosystem Effects of Biodiversity Loss Could Rival Impacts of Climate Change, Pollution

By Guest PostMay 10, 2012Environment, Natureacid deposition, air pollution, algae, bacteria, biodiversity loss, biological diversity, bradley cardinale, california, canada, climate change, david hooper, ecosystem, environmental change, environmental stress, environmental stressors, extinction, forests, fungi, global warming, henry gholz, impact, leslie gonzalez, nutrient pollution, oxygen, ozone pollution, pollution, san josé, serpentine grasslands, Sweden, united states, university of michigan

ANN ARBOR, Mich.— Loss of biodiversity appears to impact ecosystems as much as climate change, pollution and other major forms of environmental stress, according to a new study from an international research team.

The study is the first comprehensive effort to directly compare the impacts of biological diversity loss to the anticipated effects of a host of other human-caused environmental changes.

The results highlight the need for stronger local, national and international efforts to protect biodiversity and the benefits it provides, according to the researchers, who are based at nine institutions in the United States, Canada and Sweden. (more…)

Biologists Turn Back the Clock to Understand Evolution of Sex Differences

By Guest PostMay 9, 2012Nature, Scienceabderrahman khila, antlers, battle, darwin, ehab abouheif, evolution, hooks, locke rowe, male guppies, mating, mcgill university, moose, peacocks, plumage, rheumatobates rileyi, rna interference, sex differences, sexes, traits in nature, tusks, university of toronto, walruses, water striders, wild colours

Battles of sexes shown to spur adaptive sex differences

Sex differences account for some of the most of the spectacular traits in nature: the wild colours of male guppies, the plumage of peacocks, tusks on walruses and antlers on moose. Sexual conflict – the battle between males and females over mating – is thought to be a particularly potent force in driving the evolution of traits that differ in males and females.

However, the genetic processes responsible for producing such traits are not well understood, nor how they evolved from their simpler less elaborate ancestral forms. We tend to assume that each tiny step in evolution is an advantage. But are they really? (more…)