Agriculture
Treating peanut allergy bit by bit
Protecting Cows—and People—from a Deadly Disease
Silk’s superpowers
Amphibians
Poison Dart Frogs
Bullfrogs
Newts
Animals
Deep Krill
Cacophony Acoustics
Insects Take a Breather
Behavior
The Disappearing Newspaper
Memory by Hypnosis
Honeybees do the wave
Birds
Turkeys
A Meal Plan for Birds
Crows
Chemistry and Materials
Nanomagnets Corral Oil
Hitting the redo button on evolution
Scientist Profile: Wally Gilbert
Computers
Seen on the Science Fair Scene
Supersonic Splash
Galaxies far, far, far away
Dinosaurs and Fossils
Ferocious Growth Spurts
Mini T. rex
Big Fish in Ancient Waters
E Learning Jamaica
2014 GSAT Results for Jamaican Kids
Results of GSAT are in schools this week
E Learning in Jamaica WIN PRIZES and try our Fun Animated Games
Earth
Earth's Poles in Peril
Getting the dirt on carbon
A Volcano's Deadly Ash
Environment
A 'Book' on Every Living Thing
Missing Tigers in India
Inspired by Nature
Finding the Past
Writing on eggshells
Words of the Distant Past
Stonehenge Settlement
Fish
Megamouth Sharks
Tuna
Great White Shark
Food and Nutrition
Healing Honey
Making good, brown fat
How Super Are Superfruits?
GSAT English Rules
Subject and Verb Agreement
Who vs. That vs. Which
Order of Adjectives
GSAT Exam Preparation Jamaica
2014 GSAT Results for Jamaican Kids
March 21-22, 2013: Over 43,000 students will take the GSAT Exam
GSAT Exam Preparation
GSAT Exams Jamaica Scholarships
2014 GSAT Results for Jamaican Kids
GSAT Scholarship
42,000 students will sit for the GSAT Exam in two weeks
GSAT Mathematics
How to Slice a Cake Fairly
GSAT Practice Papers | GSAT Mathematics | Maths
It's a Math World for Animals
Human Body
Heart Revival
Kids now getting 'adult' disease
Cell Phones and Possible Health Hazards
Invertebrates
Lice
Octopuses
Crustaceans
Mammals
Dingoes
Blue Bear
Dachshunds
Parents
What Not to Say to Emerging Readers
The Surprising Meaning and Benefits of Nursery Rhymes
Choosing a Preschool: What to Consider
Physics
IceCube Science
Extra Strings for New Sounds
One ring around them all
Plants
Flower family knows its roots
Hungry bug seeks hot meal
Tracking the Sun Improves Plant Pollen
Reptiles
Crocodiles
Asp
Pythons
Space and Astronomy
Sun Flips Out to Flip-Flop
Zooming In on the Wild Sun
A Dusty Birthplace
Technology and Engineering
Riding Sunlight
Sugar Power for Cell Phones
Squeezing Oil from Old Wells
The Parts of Speech
What is a Noun
Countable and Uncountable Nouns
Adjectives and Adverbs
Transportation
Morphing a Wing to Save Fuel
Troubles with Hubble
Seen on the Science Fair Scene
Weather
Where rivers run uphill
In Antarctica watch the heat (and your step)
A Change in Climate
Add your Article

When frog gender flips

Several months ago, a California college student working at a university laboratory checked up on a group of frogs and saw some unusual behavior. Some of the frogs were acting like females — which was unusual, since at the beginning of the experiment all of the frogs were males. The student, Ngoc Mai Nguyen, says she told her boss, biologist Tyrone Hayes, “‘I don’t know what’s going on, but I don’t think this is normal.'” Nguyen, a student at the University of California, Berkeley, was working in Hayes’ laboratory. Hayes told Nguyen to keep watching — and write down what she saw each day. Nguyen knew all the frogs had started out as males. She didn’t know, however, what Hayes knew: that there was something in the water of the frog tank. That something was a popular weed killer called atrazine, and since birth the frogs had been raised in water that contained the chemical. Hayes says the experiments in his lab show that 30 percent of the male frogs that grew up in water with atrazine started to behave like females, and even send out chemical signals to attract other males.Laboratory experiments are not the only places where frogs may run into atrazine. The chemical is used as a weed killer, so it can pollute surface water downstream of the crops where it is used. In these rivers and streams, the concentration of atrazine can reach 2.5 parts per billion — the same concentration Hayes tested in his laboratory. This similarity suggests that male frogs may be turning into females in their natural habitats. The Environmental Protection Agency, or EPA, is a government organization responsible for protecting human health and the environment. The EPA defines what concentrations of certain chemicals are allowed in U.S. waterways, and the EPA has determined that up to 3 parts per billion — well above the concentration that turns male frogs into females — of atrazine is safe. If Hayes is right, even the EPA definition of a safe concentration is actually not safe for frogs. Hayes and his team have also showed that it’s not just the frogs’ behavior that changes after exposure to atrazine. Males raised in water containing atrazine had low levels of testosterone and did not try to attract females. But that’s not all: Out of 40 frogs raised in water containing atrazine, four had high levels of estrogen — a female hormone (that’s four out of 40 frogs, or one in 10). Hayes and his team dissected two of the frogs and found female reproductive organs. The other two transgender frogs were introduced to healthy males and mated with those males, producing baby male frogs. Other scientists have looked at Hayes’ work and carried out similar experiments — with similar results. Plus, researchers who study other animals have observed that atrazine affects those animals’ hormones. At least one scientist, Tim Pastoor, says Hayes has made mistakes in his study and that atrazine is safe. Pastoor is a scientist with Syngenta Crop Protection, a company that makes and sells atrazine. In an email to Science News, Pastoor wrote that Hayes’ new experiments don’t lead to the same results as Hayes’ earlier studies. “Either his current study discredits his previous work, or his previous work discredits this study,” Pastoor wrote. It’s important to know how atrazine affects the animal population. Any chemical that can change the reproductive patterns of an animal threatens that species’ survival.

When frog gender flips
When frog gender flips








Designed and Powered by HBJamaica.com™