Micro-learning
June 18, 2009
They may not be salivating to the sound of a bell, but apparently two classically simple organisms, Escherichia coli and Saccharomyces cerevisiae, do anticipate changes in their environments and respond accordingly, according to a new study published online yesterday in Nature. E. coli consistently experience to maltose shortly after lactose in their journey down the digestive tract. When the scientists exposed E. coli to lactose, the genetic pathway of maltose digestion was partially activated, indicating that the bacteria were, somehow, preparing for what was coming. Even more impressively, S. cerevisiae was able to anticipate the stages of fermentation, in which sugar and acidity levels change, alcohol content rises, and the temperature is amped up. When the yeast felt the heat, genes for dealing with the stressors of the next stage of the process were activated.
The researchers were further able to show that these responses were indeed adaptive as the organism’s fitness was enhanced by this anticipation. And just like Pavlov’s dogs, E. coli strains that were repeatedly exposed to lactose but not maltose for 500 generations stopped activating the maltose genes. Thus, the authors say, “the natural temporal order of stimuli is embedded in the wiring of the regulatory network.” Could that be the case? Is the evolution of gene networks over evolutionary time really analogous to the evolution of the neural networks in our brains over the course of our lives? And could this “environmental anticipation…be ubiquitous in biology” as the authors suggest?
A paternal presence pre-birth
June 15, 2009
The dramatic size dichotomy between male and female gametes (known as anisogamy) is a testament to the initial difference in parental investment between the sexes. Indeed, it has long been assumed that any non-genetic factors influencing our development came packaged in the spacious cytoplasm of the egg. With the sperm’s insatiable need for speed, evolution has shed all unnecessary bulk from the gametes’ data-filled head, leaving only the barebones DNA helix that makes you your father’s child.
But a recent study published yesterday in the online edition of Nature challenges this long-standing belief that sperm are nothing more than packets of genetic code. Scientists at Huntsman Cancer Institute at the University of Utah School of Medicine found that mature, human sperm have extensive epigenetic markings, particularly at loci that are important in development.
Maybe we have a little more than we realized to be thanking our fathers for this Father’s Day.
Blissfully ignorant?
June 10, 2009
“My experience is what I agree to attend to.” ~William James (1842-1910)
Can we really pick and choose what we experience? Can we ever really ignore the bad and focus on the good? Behavioral science writer Winifred Gallagher argues just that in her new book, Rapt: Attention and the Focused Life. Robert Desimone, a neuroscientist at MIT, studies the concepts raised in Rapt. Through his work on macaque monkeys and humans, Desimone has found that it is indeed possible for controlled, top-down processing to win the battle over the brain’s attention. A noisy environment can hinder one’s ability to ignore strong signals, but eventually it may be possible to hone one’s concentration skills, Desimone told the New York Times.
This obviously has its benefits, such as dealing with tragedy or hardship. But if no one recognizes the bad in this world, who will there be to attend to it? What would happen if we all suddenly become blissfully unaware?
Women can do math, too
June 5, 2009
The gender differences in mathematical ability aren’t due to some innate shortcoming of the analytical minds of women, but simple sexism. According to a new study published in PNAS, the disparity in the performance of men and women on mathematical tasks can be attributed to sociocultural factors.
The data compiled in this study revealed that in the US, girls’ math have caught up to boys’ in terms of standardized testing scores at the grade school level. And while males are more likely than females to score in the highest percentiles, suggesting potential gender differences among the mathematically talented, these differences are not ubiquitous across cultures. In fact, the greatest discrepancies in performance between the sexes correlated with measures of gender inequality, suggesting that it is simply the result of sociocultural factors.
But things are looking up for women in math. Women now comprise 30% of math PhDs in the US, up from only 5% in the 1950s. Watch out, boys!
Scaring bedbugs to death
June 4, 2009
A new study in this month’s Journal of Medical Entomology discovered that by combining bedbug alarm pheromones with a desiccant dust used to kill them, exterminators may be able to trick the pests into moving around and through the deadly dust, resulting in a much more efficient execution.
Bedbugs are a growing problem in the United States, as many populations have begun to develop a resistance to the typical pyrethroid insecticides used to kill them. Just to throw out a few stats I learned last year while researching another article, bedbug incidents increased about 70 percent between 2000 and 2005, according to the National Pest Management Association, and New York City recorded a 1,900 percent increase in bedbug complaints since 2004.
This new study suggests that an old insect control agent with a new twist could be the solution. While it may seem a bit sadistic to use the bedbugs’ own pheromones against them, this could be the beginning of a whole new strategy in pest control. What other insect chemicals can we exploit for the purpose of protecting ourselves, our homes, and our gardens?
Mass migration exodus?
June 2, 2009
According to a recent review in Endangered Species Research, many of the world’s large, migratory ungulates are traveling shorter distances or no longer migrating at all. A second review to be published in next month’s in Endangered Species Research discusses how certain features characteristic of migratory species may make them particularly vulnerable to the changes associated with the changing climate. For example, migrants often travel to high latitude habitats, which are extremely sensitive to climate change. In addition, a presentation I attended last year at Indiana University’s National Teach-In on global warming mentioned the dwindling wetland areas that many shorebird species use as stopover points during their annual migrations. Thus, it seems both terrestrial and aerial migratory animals may be more affected by the global climate change than sedentary species. This begs the question, are additional conservation efforts needed for these species? Do we need to think about protecting migration routes, as opposed to simply having wildlife preserves at either end?
Top 10 new species
May 26, 2009
With so much attention given to the dwindling species of the world, the new ones often get overlooked. In a much more uplifting report than the endangered and threatened species list, the International Institute for Species Exploration at Arizona State University and an international committee of taxonomists announce the top 10 new species described in 2008. Among the winners are the oldest known viviparous vertebrate and, my personal favorite, a tiny seahorse that’s just a half an inch tall.
Every organism has something new to teach us — something innovative about the way it thrives in its environment that can deepen our understanding of survival and evolution — and the rate at which new species are being discovered is testament to the diversity of life on Earth. What new species will we discover this year, and what will we learn from them? Be sure to vote for your favorites to make next year’s top 10.
Mockingbirds recognize humans?!
May 20, 2009
According to a new study in PNAS, mockingbirds were not only able to tell people apart, they were also able to remember who had threatened them previously and accurately assess their threat level based on those previous experiences. That’s like us recognizing and remembering which bird pooped on our car last week so we could be sure to park in the garage next time we see it on our block.
This is the first time a wild population of animals has been shown to recognize individuals of another species. The fact that this ability was found in a species of such modest cognitive capabilities suggests to me that perhaps it is not so uncommon. In light of my ‘Sharing my backyard’ series, I thought this research was particularly thought provoking. What other creatures living in our backyards are studying us and our habits and adjusting their behavior accordingly? Despite our big brains and focused animal research, do the neighborhood fauna know us better than we know them?
Sharing my backyard: Canada geese, friend and foe
May 17, 2009
I’ve recently moved to Philadelphia, my dog Barley in tow, so it’s time for another edition of ‘Sharing my backyard.’ Last weekend, we were on a hike in a park not too far from my new house in Mt. Airy when we stumbled upon a goose sitting awkwardly on the edge of a cliff overlooking the Schuylkill River. Unaware, Barley trotted by, a little too close for comfort for the nesting goose. It (she?) flew off, honking incessantly, and revealed four stark white eggs huddled together in the depths of her nest. She flew down to the water’s edge where a second goose (presumably her mate) joined in the honking. Not the best defense really, I thought. But I ushered Barley along the trail to leave the noisy family in peace.
Anyway, it got me thinking about Canada geese. I remember reading once that they are considered a nuisance in some areas, but stumbling upon this quaint nest on the cliff’s edge overlooking the peaceful river, I found that hard to believe. But sure enough, a quick search on the world wide web and I was able to confirm the rumor: while they were once nearly extinct, Canada geese are now so numerous that the DNR of many states has listed them as an official nuisance.
Take Michigan, for example. In 1970, an estimated 9,000 geese called the Great Lakes state home. By 2007, those numbers had risen to over 300,000. The U.S. Fish and Wildlife Service estimated the national good population at 4.5 million in 2006, with an average annual growth rate of 10%. At that rate, the total population could grow to nearly 8 million by 2012.
So that’s a lot of geese, but what’s the problem? Well, in a word, poop. An adult goose can drop up to two pounds of fecal matter daily. In addition to being just plain gross, goose droppings can increase the risk of bacterial infections by fecal coliforms, a gram-negative bacteria found in feces. This issue is especially potent in public swimming areas, which may have to be closed down until public health agencies are able to test the water to confirm that it is safe for swimming.
There are many measures that could be taken to reduce the expanding geese populations, but the one that’s most advocated is to put an end to geese feeding. In addition to supporting their growing numbers, feeding the geese can cause them to become unnaturally comfortable around humans, which has been known to turn into erratic behavior and even aggression.
But despite all this bad news I learned about Canada geese, they are still an awesome animal, especially when they fly in those massive Vs on their annual migrations. And believe me, I still plan to go back and check on that nest Barley and I found in the woods that day.
Strong Soy
May 13, 2009
Life on Earth is resilient. If it weren’t, we wouldn’t be here to write about it. Ice ages, droughts, meteor collisions – the evolutionary history of our planet is littered with potential disasters for the organisms that call it home, but through it all, life has persisted, progressed, and even prospered. Now, as the environment is undergoing rapid change at the hands of humans, this resilience is maybe more important than ever. Here’s a great example:
Soybeans lived through the Chernobyl disaster, the worse nuclear power station accident in history. It’s been more than 20 years now, and the soy plants are still thriving. And earlier this year, scientists at the Slovak Academy of Sciences began to figure out how. Compared to unexposed plants, the Chernobyl soy had different amounts and different types of proteins in their seeds, including a significant increase in a protein called betaine aldehyde dehydrogenase, which is known to help protect human blood from radiation damage. They published their findings online in the Journal of Proteome Research on March 25, 2009.
So, despite a serious environmental disaster, the soy are surviving and teaching us a thing or two about dealing with hostile environments in the process. What else do we have to learn from the enduring organisms of Earth and will it help us find a new home once this planet is no longer hospitable to our relatively fragile species?
