AP Biology class blog for discussing current research in Biology

Author: rosaparks

Fruit Fly Fight Club

Everybody knows that males tend to be more aggressive than females.  But why is that the case?


In a recent New York Times article, a study on fly aggression by neuroscientists from the California Institute of Technology revealed that male flies, just like humans, tend to be more aggressive than female flies.  And their findings may provide an insight as to why male humans are more aggressive than female humans.

Doctor David J. Anderson set up a fight club for flies and found out that a tiny cluster of neurons only found in the brain of male fruit flies control aggression.  These neurons, active only when the males were fighting each other, released tachykinin, a neuropeptide linked to aggression                                                                                                                                                                                 .

Humans have a different kind of tachykinin, called substance P, which is associated with inflammatory processes and pain.

The few neurons that caused an increase in aggression in the flies were only found in males.  They found that the levels of aggression in flies is directly associated with the amount of tachyninin produced by the neurons.  From these studies, it appears that humans and flies have more in common than we think.  And the flies can teach us about the neurology of own aggression.




Largest Mass Poisoning of a Population in History

Picture this familiar scene: waking up in the middle of the night, too lazy to go to kitchen, and quenching your parched mouth with water from the bathroom sink. To people in America, this is a safe undertaking. But to people in Bangladesh, it could be deadly.

Arsenic is a naturally occurring element on Earth’s crust, which can enter drinking water from natural deposits. Its effects on the human body have been known to cause respiratory, circulatory and heart problems. Recently, however, researchers have had the chance to study itseffects on humans more closely in Bangladesh because of its unusually high percentage of arsenic in its water supply. And what researchers found was eye opening.

Researchers at the University of Chicago studied more than 11,000 Bangladesh men and women. After 6.6 years, they found that residents exposed to arsenic at 19 parts per billion or less showed signs of reduced lung function. While people who were exposed to 20 parts per billion or higher had the lung capacity similar to that of a long-term smoker.

The researchers recorded 407 deaths, 198 from circulatory diseases. 35-77 million people are exposed to arsenic in Bangladesh alone.  The World Health Organization deemed the country’s arsenic contamination as “the largest mass poisoning of a population in history.”

Why should we be worried (other than the obvious ethical issues)? A group of Dartmouth researchers found that 2.3 million people in New England use wells as their main source of drinking water. This makes up approximately 40 percent of the population in Maine and New Hampshire. Although wells in the United States generally contain small amounts of arsenic, the researchers found that overtime, small doses of arsenic can lead to skin, bladder and lung cancer. So maybe next time it’s worth the trip to the kitchen.

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