There are more than 640 species of cone snails. The shells of these snails range in size from just a few centimeters to more than 20 centimeters in length. Most cone snails live in the tropical waters of coral reefs, primarily in the western Indo-Pacific region. Some cone snails are also found in temperate waters around South Africa and in cooler waters near southern California.

The geographic cone snail shown here is the most venomous of the 500 known species of cone snails. (Photo credit: Jeff Rotman / Alamy)

These stealthy snails bury themselves beneath the sand and lie in wait for their prey. They use their siphon, a tube-like organ, to sense chemicals emitted by other aquatic animals, and their eye stalks to detect changes in light. When a suitable species happens by, the cone snail loads a hollow tooth-like “harpoon” into its proboscis. It fills the harpoon with venom and shoots it into its prey. The venom contains a mixture of chemicals that acts as a neurotoxin. The toxin quickly affects the victim’s nervous system, paralyzing it and ultimately leading to its death. Soon after, the snail uses its proboscis to engulf its victim, and suck it into its shell where it is digested. Each harpoon is used only once, as the snail produces additional ones in an internal tooth sac.

Each cone snail species has on average 100 different toxins. This means that there are more than 50,000 different toxins expressed across the more than 600 species of cone snails. Scientists are interested in learning how each toxin affects the victim of a cone snail sting. Results from experiments with cone snail toxins, or conotoxins, are helping scientists understand how cells, particularly those cells found in the nervous system, interact and communicate. This information is highly valuable to those in the biomedical research field, as these toxins could prove to be important for the development of medicines and treatments for human ailments. Conotoxin research has already led to the development of a pain medication for those suffering from cancer. This new pain treatment offers the same pain relief as morphine but lacks the addictive side effects of many traditional painkillers. Biomedical researchers also think conotoxins may have a role to play in the development of treatments for epilepsy, Alzheimer’s, and Parkinson’s.

However, like many species that inhabit tropical reefs, cone snails are vulnerable to habitat loss and human actions. These snails, though dangerous to handle, are attractive to shell collectors and the shells of rare species can fetch up to $5,000. Some scientists worry that the snails’ importance to biomedical research may also harm populations living in the wild. Some biomedical researchers are using new techniques that allow them to “milk” captive snails for their venom, rather than dissecting the venom sacs from dead snails. In addition, scientists are currently studying cone snail populations around the world to determine which species are vulnerable or are already under threat of extinction. Scientists hope that putting proactive conservation measures into place now will help protect populations in the wild and prevent cases of overharvesting for either recreational or scientific pursuits.

More to Explore

• The Cone Snail
• The Geographic Cone Snail (Conus geographus)
• How A Venomous Cone Snail Catches and Kills Fish
• Venomous Snails: One Slip, and You're Dead...
• Toxic Snail Venoms Yielding New Painkillers, Drugs
• The Venom Cure
• Killer Cone Snails [video]

Before we delve too far into the topic, let’s discuss some terminology. An introduced species, also called an alien or non-native species, is any organism that was brought to an ecosystem as the result of human actions. In some cases, the introduced species may die out or is able to coexist with native species. In other cases, the introduced species may pose a threat to the stability of an ecosystem by preying on or outcompeting native species for resources. Additionally, introduced species may cause economic damage, particularly in terms of lost revenue resulting from the damage to agricultural crops. When an introduced species causes ecosystem instability or economic harm, it is referred to as an invasive species.

Though the introduction of non-native species to some ecosystems was not intentional, that is not always the case. For example, starlings and house sparrows were first introduced into the United States in the 1890s after an eccentric drug manufacturer named Eugene Scheiffelin from the Bronx decided that all of the songbirds mentioned in Shakespeare’s plays should be imported from England into New York. In the case of the starlings, what initially began as a population of 100 birds released into Central Park has since turned into a population of over 200 million, which can be found across the entire continent of North America, and even up into Alaska. Other species of plants and animals have been intentionally introduced for a variety of reasons including uses for agricultural, recreational, and ornamental purposes.

Though many decry the spread of colony-collapse disorder that is affecting honeybee colonies across North America, and researchers are rushing to find its cause and cure, nobody talks about the fact that honeybees are in fact a non-native species to North America. English settlers introduced honeybees to the New World in the 1600s. Since that time, additional colonies of bees have been introduced from Europe, Asia, and Africa. However, no one argues that since their introduction, honeybees have taken on a significant role as pollinators to a variety of plants, including many important crop species. The loss of honeybees at this point could have a devastating effect on crop production that depends on them, such as the Californian almond industry.

Clearly, not all non-native species are perceived of as being “bad.” But when should a non-native species be considered to be good, and when should it be considered to be bad? Can such a distinction be made? Three scientists recently published a review article in the journal Conservation Biology that calls into question the practice of thinking that non-native species are inherently bad. The article, written by Martin Schlaepfer (State University of New York-Syracuse), Dov Sax (Brown University), and Julian Olden (University of Washington), suggests that non-native species can, and do, contribute to conservation objectives. These contributions include:

• providing habitat or food resources to rare or endangered species,
• serving as functional substitutes for extinct species, and
• providing desirable ecosystem functions.

According to the authors, “Non-native species might contribute to achieving conservation goals in the future because they may be more likely than native species to persist and provide ecosystem services in areas where climate and land use are changing rapidly and because they may evolve into new and endemic taxa.”

Conservation biologists are not so sure non-native species, such as the tamarisk plants shown here, are as bad as they were once considered to be. (Credit: James Steinberg / Photo Researchers, Inc.)

One example of an often-maligned non-native (and invasive) species that is providing ecosystem services is the tamarisk, or saltcedar, tree. This tree is of particular concern in the southwestern United States, where it is commonly found alongside rivers. Concerns about this species include its ability to outcompete local plant species and its ability to draw a significant amount of water from the water table. Conservation biologists worry that if left unchecked, the tamarisk tree could replace native species, thus affecting those species that depend on native plants as sources of food or shelter. However, recent research suggests that the plant’s ability to draw down the water table have been exaggerated. In addition, these trees now serve as habitat for the southwestern willow flycatcher. Eradicating tamarisk trees now would result in reduced habitat available for this endangered bird species.

Research conducted by scientists at Princeton University found that in some cases, non-native species take over the roles once held by native species. The scientists compared the health of plant populations on New Zealand’s North Island, where most native vertebrate pollinators have gone extinct, and the health of plant populations on the remote Little Barrier Island, just off the coast of New Zealand, where native species thrive. In their study, published in the journal Proceedings of the Royal Society B, the scientists found that on the North Island, non-native species, such as rats, have taken on the role as pollinators once held by the now-extinct native species. These results indicate that just removing the non-native species could cause significant harm to the North Island plant population. Instead, in such cases, conservation biologists need to take into consideration the role that non-native species have in an ecosystem before taking action to eradicate them.

According to David Wilcove, co-author of the New Zealand study, “…our findings show that eliminating an invasive species for the benefit of native species could actually harm an ecosystem, a surprising dynamic that could frustrate ecosystem restoration efforts.”

Clearly, non-native species are not always the evil-doers that they are often portrayed to be. In fact, the longer a non-native species is in an ecosystem, the more it may become entangled in the ecosystem’s functions. Over time, a non-native species may even prove to be a benefit to the ecosystem in which it was once reviled.

According to the authors of the Conservation Biology article, “We predict the proportion of non-native species that are viewed as benign or even desirable will slowly increase over time as their potential contributions to society and to achieving conservation objectives become well recognized and realized.”

More to Explore

• Harm not those strangers that pollinate, study warns
• Rethinking the War on Invasive Species
• The Potential Conservation Value of Non-Native Species [pdf]
• Alien Species Reconsidered: Finding a Value in Non-Natives

Northern leopard frogs leap with the help of a catapult-like mechanism in their tendons. (Photo credit: Oxford Scientific)

Many species of frogs are excellent jumpers. Members of the order Anura are known for their particularly powerful jumps. In fact, jumps made by members of this amphibian order are an example one of the most powerful accelerations in vertebrate movement. However, the acceleration of a frog’s jump requires more energy than its muscles are capable of producing. Scientists have hypothesized that these animals use a catapult-like mechanism to store and quickly let go of energy to produce powerful leaps that far exceed the capacity of their leg muscles. Researchers at Brown University recently conducted an experiment to determine if such a mechanism was behind the frog’s incredible ability to jump.

The research was conducted by Brown University scientists Henry Astley, a doctoral student studying biomechanics, and Thomas Roberts, an associate professor of ecology and evolutionary biology. In their experiment, the scientists implanted metal beads into the shin bone, ankle bone, and leg muscle of four northern leopard frogs (Rana pipiens). The researchers then used three-dimensional X-ray video technology to track the movements of each frog before, during, and after a jump. The film was recorded at 500 frames per second, which allowed the scientists to view the jumps 17 times slower than normal.

In viewing the resulting videos, the scientists determined that the catapult-like mechanism hypothesis was correct. The video footage showed that as the frog prepares to jump, its calf muscle shortens. Once 100 milliseconds has passed, the calf muscle stops moving. This indicates that the stretched tendon, which is wrapped around the ankle bone, is fully loaded with energy. When the frog leaps, the tendon lets the stored energy go, which causes a quick extension of the ankle joint, thrusting the frog forward. In real time, the frog jump takes about a fifth of a second.

"Our research offers the first complete picture of the muscle-tendon-joint system during jumping," Astley said in email correspondence. "Prior work led us to this, but was never able to definitively prove the existence of the catapult mechanism."

The scientists believe that this research has implications beyond just understanding the mechanism that powers jumping in frogs. "The biggest implication is that these catapult mechanisms may be much more common than previously thought," Astley said. "[It] may exist in many more animal species than presently known."

The results of this research were reported on November 16, 2011 in an online edition of the journal Biology Letters. The National Science Foundation funded this research.

More to Explore

• Evidence for a vertebrate catapult: elastic energy storage in the plantaris tendon during frog jumping [abstract]
• Frogs’ amazing leaps due to springy tendons
• Fluoroscopic View of Frog Jumping [video]
• Frog’s Leap A Marvel of Muscle Mechanics [video]
• The Anuran Life Cycle
• Northern Leopard Frog

Yellow stripes are just one example of the body patterns found on members of the poison dart frog species Ranitomeya imitator. (Photo credit: Dennis Flaherty/ Photo Researchers, Inc.)

An interesting aspect of Ranitomeya imitator is that the species has 10 different body patterns, or morphs. Marcel Chouteau, an evolutionary biologist at the University of Montreal, was interested in finding out why there were so many different body patterns within the same species.

To conduct his experiment, Chouteau enlisted the help of his girlfriend to help him make 3600 frog models out of modeling clay. Each model was life size and measured 18 millimeters in length. One-third of the clay models were painted to resemble frogs with a yellow stripe pattern on its back; another third were painted to resemble frogs with green patches on its back; and a final third were used as a control for weight selection and were painted brown to resemble the coloring of non-poisonous frogs in the area.

Three hundred of each model type (striped, patchy, and control), for a total of 900 models, were placed at two sites within the Amazon rain forest. One site was located in the lowland plains. The second site was located 10 kilometers away at a mountainous location. After the models were placed, Chouteau returned to check on them every 24-hours over a span of three days. Chouteau repeated his three-day experiment on three different occasions.

Due to the malleable nature of the model’s clay bodies, predation marks from bites were clearly visible. Chouteau found that at each site, the frogs that looked least like the local frog had the most bite marks. Accordingly, when predators see targets of a different species, they attack. However, he also found that the predators learn quickly to avoid the novel prey. After the first 24 hours of the study, the number of bite marks significantly decreased for the non-typical frogs.

The results of this research indicate that predators play an important role in the selection of multiple body patterns within the same species of poison dart frog. It appears that avian predators are just as geographically-specific as are their frog prey. The unrecognized frog phenotypes are more easily detected by predators, and hence do not last long in a new territory. In other words, predators keep each pattern going by selecting against any frogs that do not match the skin pattern they have learned to avoid. These results support the idea that natural selection plays an important role in the development of the many different skin patterns found among members of Ranitomeya imitator.

The results of this research were published in the December 2011 issue of the journal The American Naturalist.

More to Explore

• Predators drive the evolution of poison dart frogs' skin patterns
• The Role of Predators in Maintaining the Geographic Organization of Aposematic Signals [abstract]
• One Species, Ten Patterns? Why Poison Dart Frogs Dress Differently
• Ranitomeya imitator

Research indicates rising global temperatures may result in smaller plant and animal species. (Photo credit: Evgeny Dubinchuk/Fotolia)

Plants and animals are already beginning to change their behavior due to a warmer climate. Animals are beginning to migrate earlier, plants have changed their flowering periods, and many plants and animals have shifted their distribution away from the equator and closer to the cooler north and south poles. Recent research indicates that these modified behaviors are not the only change that species will undergo if the climate continues to warm as expected. These studies show that plant and animals may actually shrink in size as the climate continues to change.

Jennifer Sheridan, a professor of conservation biology at the University of Alabama, and David Bickford, a professor of environmental science at the National University of Singapore collaborated together on an article published in the journal Nature Climate Change. In the article, the scientists evaluated data from the fossil record, as well as modern-day studies to hypothesize what might happen if plant and animal sizes shrink due to a warming climate.

Their studies of the fossil record indicate that animals such as beetles, spiders, and pocket gophers significantly shrank in size during the Paleocene-Eocene Thermal Maximum, which occurred around 55.8 million years ago. Modern-day observations indicate that over the last 100 years, a variety of plant and animal species have decreased in size as average global temperatures have increased.

In addition to synthesizing data from the fossil record and current literature, the scientists also conducted two experiments. In one experiment, the scientists exposed ocean-dwelling creatures such as scallops, oysters, and scallops to conditions mimicking ocean water with increasing levels of acidity. As the acidity of the water increased, the marine animals’ ability to form their shells decreased, leading to an overall decrease in size. In a second experiment in which plants were grown under controlled climate conditions, the scientists found that for every 2 degrees that the temperature was increased, fruit size decreased by 3 to 17 percent. Similarly, when a variety of animals, including fish, beetles, marine invertebrates, and salamanders were exposed to increasing temperatures, they decreased in size, too. Fish, in particular, decreased between 6 and 22 percent in size.

Some species of salamanders are decreasing in size due to increased temperatures. (Photo credit: Carsten Meyer/Fotolia)

Research published in the journal The American Naturalist corroborates this data. This study focused on ectotherms, also known as cold-blooded animals, and how increased temperatures affect their growth rate and development. Experiments conducted with copepods, which are tiny aquatic crustaceans, showed that when exposed to warmer temperatures, the copepods go through their life stages at a quicker pace, meaning they reach adulthood at a smaller size than normal. This observation held true for a range of copepod species.

Why are species shrinking? Scientists point to a few explanations. Smaller plant size is linked to warmer and drier conditions and scarce water supplies. In addition, drought conditions often lead to forest fires, which diminish the amount of nitrogen, a nutrient necessary for plant growth, in the soil. These smaller plants in turn provide less of a satisfying meal for the herbivores that eat them. If the herbivores are unable to eat enough of their plant food source, or cannot find a replacement plant to eat, they will likely be unable to grow to their full size. Smaller herbivores in turn require predators to find more prey to eat to maintain their body size, or they too, will shrink in size.

Though not much is yet known about how worldwide food webs will be affected by a potential decrease in size across species, scientists hypothesize that changes in one species could have a ripple-effect on other species within their food web. They also foresee some species not feeling any affects due to a changing climate, which could also lead to imbalances within a food web, as some species thrive while others decline. Though computer models can help to show how shrinking species’ size may affect ecosystems in the future, only time will tell the actual impact these changes. As described above, current research indicates that shrinking species size could have a significant impact, though more research is necessary.

More to Explore

• Shrinking Body Size as an Ecological Response to Climate Change [abstract]
• Growth and Development Rates Have Different Thermal Responses [abstract]
• Climate Change Is Shrinking Species, Study Warns
• How Climate Change May Shrink Species

Turkey is a common sight on Thanksgiving. (Photo credit: Photodisc/Getty Images)

The centerpiece of many Thanksgiving dinners in the United States is a roasted turkey. According to the United States Department of Agriculture (USDA), it is expected that over 248 million broad-breasted white turkeys—the standard turkey found in your local supermarket—will be raised in the United States. This Thanksgiving alone, according to the National Turkey Federation, it is estimated that Americans will consume 46 million turkeys. However, a growing number of small-scale poultry producers across the United States are eschewing modern industrial farming practices and instead are raising unique and rare breeds of turkeys that have been around since the very first Thanksgiving feast in 1621.

An Introduction to Heritage Turkeys

According to the Heritage Turkey Foundation, heritage turkeys were originally bred for fine flavor, beauty, and thriftyness, a quality that referred to the amount of meat produced from the quantity of food fed to the turkey. Turkeys are a quintessential American food—all domesticated turkeys in the United States are descendants of wild turkeys native to North and South America.

There are three criteria a turkey must meet to qualify as a heritage turkey, according to the American Livestock Breeds Conservancy (ALBC). These qualities include the following:

This male turkey (commonly called a 'tom') is an example of the Bourbon Red heritage breed. (Photo credit: Keith J Smith/Alamy)

• The turkeys must reproduce naturally by mating. In order to qualify as a heritage turkey, the turkey must be the result of naturally mating pairs of both grandparent and parent stock.
• The turkeys must have a long productive outdoor lifespan. Breeding hens most be productive for five to seven years. Breeding toms must be productive for three to five years. It is imperative that the turkeys have the genetic ability to withstand the rigors of living outdoors.
• The turkeys must have a slow, natural growth rate. The birds should reach marketable weight in about 28 weeks. This long period of growth lets the birds develop strong skeletal structures and healthy organs prior to putting on muscle mass.

There are a number of different breeds of heritage turkeys. Many of the turkeys were originally bred for qualities such as productivity or specific color patterns. Among the breeds that are named by the American Poultry Association as standard breeds are Black, Bronze, Narragansett, White Holland, Slate, Bourbon Red, Beltsville Small White, and Royal Palm. Two other popular varieties of heritage turkeys include the Jersey Buff and White Midget. Over the past ten years, populations of heritage breeds of turkeys have been on the rise. According to Marjorie Bender, ALBC research and technical program director, in 1997 there were 1328 breeder birds; just four years ago, that number had grown to 10,404 breeder birds. Though most heritage turkey breeds are still endangered, there populations are much more secure than they were ten years ago.

Comparing Heritage Turkeys to Standard Turkeys

Over 99 percent of the turkeys raised in the United States are of the broad-breasted white variety. (Photo credit: INSADCO Photography/Alamy)

What makes heritage turkeys different from the standard turkeys you might find in your local supermarket? The standard turkey you most often find in the supermarket is a breed called the broad-breasted white turkey. These turkeys have been bred to provide a large amount of breast meat. Because of their abnormally large breast-size, the turkeys are unable to reproduce naturally. Instead, artificial insemination is necessary. Without human intervention, these turkeys would go extinct after just one generation.

In addition, while heritage turkeys must be free to roam, most broad-breasted white turkeys are raised in confined conditions. Due to these confined conditions, the turkeys are given antibiotics and other supplements to prevent the spread of disease. Heritage turkeys are certified antibiotic-free. The diets of both types of birds are also different. Since heritage turkeys are allowed to roam freely in the outdoors, they feed on a natural diet of insects, seeds, and grasses. Industrial turkeys are fed a steady diet of grains. According to research conducted by the USDA Sustainable Agriculture and Research Education Program, meat from turkeys that spent some portion of their lifetime outside had 21 percent less total fat, 30 percent less saturated fat, 28 percent fewer calories, 50 percent more vitamin A and 100 percent more omega-3 fatty acids.

One of the biggest differences between a standard turkey and a heritage turkey is the length of time it takes for each to reach maturity. Standard turkeys reach an average weight of 32 pounds over a period of 18 weeks. This length of time to maturity is 10 weeks earlier than it takes for heritage turkeys to reach maturity. To put this value into perspective, a market-ready standard turkey is the equivalent of an 11-year-old child weighing 300 pounds.

Drawbacks and a Look to the Future

One of the benefits of industrially-raised turkeys is their low cost in the marketplace. Raising a large amount of turkeys in a small space under standardized conditions lets producers sell them at the supermarket for a lower price. Because heritage turkeys require more space and take longer to grow to maturity, they are more expensive to raise. This added expense is passed on to the consumer. Compared to a standard supermarket turkey, heritage turkeys are often exponentially more expensive.

Because most heritage turkeys are produced by small-scale farms, they are often fairly difficult to procure. Most heritage turkeys are accounted for long before the Thanksgiving holiday. Although the production of heritage turkeys remains a niche industry, a growing interest in organic and sustainably-produced food products is helping to bring the breeds to the forefront. Without the farmers' intervention, many of the breeds of heritage turkeys would go extinct. By continuing to raise these rare and unique breeds of turkeys, poultry farmers help to maintain the genetic diversity of turkey species.

"Endangered breeds are a significant part of biological diversity in agriculture," Ms. Bender said. "These breeds are important to conserve because they provide options for the future. Agriculture will change, [and] the animals will be able to meet the new demands only if we assure their survival."

More to Explore

• Definition of a Heritage Turkey
• American Livestock Breeds Conservancy
• Heritage Turkey Foundation
• National Turkey Federation
• Thanksgiving Day Facts

Research indicates that yawning helps to cool down your brain. (Photo credit: Will & Deni McIntyre/Photo Researchers, Inc.)

These results support the thermoregulatory theory of yawning, which suggests that yawning is caused by brain temperature increases. The act of yawning is therefore used to cool the brain down. Scientists think that this cooling effect occurs due to an increase in blood flow to the brain caused by the stretching of the jaw as well as the countercurrent heat exchange that is associated with the deep inhalation of a yawn.

Andrew Gallup, a post-doctoral research associate at Princeton University, collaborated with Omar Eldakar, a post-doctoral fellow at the University of Arizona, on this research study, which was published in the September 2011 issue of the online journal Frontiers in Evolutionary Neuroscience. Their field-observational experiment involved measuring the incidence of yawning among a group of 160 randomly-chosen young adults in Arizona. Eighty of the participants were tested during the summer months and the remaining 80 participants were tested in the winter months. In their study, the scientists showed each participant an image of someone yawning (since yawning is “contagious”— perhaps looking at the photo that accompanies this article made you
yawn?) and measured the number of times each participant yawned.

Results from their research show that there is a higher incidence of yawning when ambient air temperatures were lower than human body temperature. They found that study participants yawned less frequently (around 25 percent of the time) during the summer months, when air temperatures often exceeded human body temperature and humidity was lower. During the winter months, when air temperature was mild (around 71 degrees Fahrenheit) and humidity was slightly higher, participants yawned more frequently (nearly 50 percent of the time). Their results also indicate that yawning is related to the amount of time a person spends outside exposed to the elements. The scientists found that though nearly 40 percent of the participants yawned within the first five minutes of being outside, in the summer months, this number drastically reduced as time outside increased. During the winter months, yawning occurred at a slightly higher frequency after more than five minutes outdoors had passed.

The results of this research support previous non-human animal studies. For example, a study involving rats found that the rats' brain temperatures decreased immediately after a yawn. A second study using rats found that the incidence of yawning increased as air temperature increased. However, when the air temperature became too warm, the frequency of yawning decreased. Similar results occurred in a study involving parakeets. In one such study, parakeets were exposed to three different conditions: moderate air temperature, high air temperature, and increasing air temperature. Though yawning did not increase in the first two situations, the birds yawned at a significantly greater frequency when the air temperature increased over time.

So why do you yawn you are tired? Research indicates that both exhaustion and sleep deprivation are both associated with higher brain temperatures. These increased brain temperatures in turn trigger yawning to help the brain to cool down. Additionally, brain research also shows that yawning helps with the transition from sleeping to waking states, and vice versa.

The results from these studies have many practical implications. For example, studying the mechanism behind yawning could help researchers improve their knowledge about neurological diseases such as multiple sclerosis and epilepsy, both of which are associated with frequent yawning. The occurrence of excessive yawning could also be used as a diagnostic tool for thermoregulatory impairments.

More to Explore

• Contagious Yawning and Seasonal Climate Variation
• More Than A Sign of Sleepiness, Yawning May Cool the Brain
• Why We Yawn
• Yawn

Research indicates that aerobic activity promotes brain health. (Photo credit: Rubberball/Getty Images)

You probably know that physical activity is an important part of obtaining and maintaining a healthy body weight. But, research shows that a consistent aerobic exercise regimen has a number of other positive effects on your health, too. These positive effects include a decreased risk for type II diabetes, cardiovascular-related disease, osteoporosis, and mental disorders. Recent research also indicates that physical fitness is also important when it comes to brain health and development.

Connecting Exercise to Brain Health in Children and Teens

Studies show that only 50 percent of children and only 8 percent of teens are physically active for the government-recommended 60 minutes per day. If 60 minutes of exercise sounds like a lot to you, consider that the average 8 to 17 year old spends 7.5 hours doing passive activities such as watching TV, using a computer, playing video games, or texting on their phone.

Childhood and adolescent years are associated with rapid development of the brain. During this time period, structural and functional circuitry necessary for higher-level thinking, form in the brain. This circuitry allows for the brain’s executive functions, such as the ability to regulate behavior, multi-task, and avoid distraction. Several studies have shown that physical activity is particularly important during early childhood. For example, one study found that an aerobic exercise regimen followed for three months improved the executive function abilities of overweight children. The results of another study linked inactivity during childhood to poorer academic performance and lower performance on standard neuropsychological tests.

Connecting Exercise to Brain Health in Older Adults

Unlike in the childhood and teenage years, during young adulthood, not much change occurs in the brain. Instead, the years between the ages of 19 and 35 are associated with stability in brain structure and function, as well as peak cognitive performance. Researchers have found mixed results in studies relating physical activity to brain health in this age group. However, once older adulthood is reached, exercise once again becomes important for brain health and function.

Aerobic exercise helps to prevent cognitive impairment in older adults. (Photo credit: Keith Brofsky/Photodisc/Getty Images)

During old age, the hippocampus normally shrinks 1 to 2 percent in size every year. The loss of hippocampus volume is associated with an increased risk for the development of cognitive impairment, such as dementia or Alzheimer’s disease. Multiple studies have shown that adding a consistent aerobic exercise program increases hippocampus volume. Studies show that aerobic training results in the generation of new neurons in the hippocampus, and these new neurons are connected with an improvement in hippocampus function.

Research also indicates that weight-training is also important for maintaining or enhancing brain function in older adults. One six-month study found that a three-time weekly program of moderate- to high-intensity resistance training led to improved memory performance and verbal concept formation. Another study that focused on older women found that those who lifted weights performed better on cognitive tests than those women who just did toning exercises.

Connecting Exercise with Improved Brain Function

In addition to strengthening the heart, aerobic exercise also results in a significant increase in the movement of blood to the brain. Researchers think this rapid influx of blood to the brain is required for the growth of new neurons. Research using mice as the test subject corroborate this hypothesis. Several studies using mice as a test subject indicate that aerobic exercise increases the growth of new blood vessels as well as new neurons in the brain, actions that are both associated with improved learning and memory.

Adding Exercise to Your Day

How can you get in the recommended amount of exercise every day? It may not be as hard as you might think. First, the 60 minutes of exercise do not have to be continuous—just try to incorporate at least 60 minutes worth of physical activity throughout your day. The important thing is to integrate aerobic, muscle-strengthening, and bone-strengthening exercises to your daily routine. Examples of aerobic exercise include dancing, running, bike riding, martial arts practice, and playing sports. Muscle-strengthening exercises include push-ups, sit-ups, and lifting weights. Bone-strengthening exercises include activities that apply force to your joints, such as jumping rope, running, and gymnastics.

As the research shows, exercise is not just important for maintaining a healthy body. Adding physical exercise to your daily routine is also quite important for maintaining a healthy and well-functioning brain. It seems that Thomas Jefferson was right when he said that “A strong body makes the mind strong.”

More to Explore

• Physical Activity for Everyone
• Let's Move!
• Exercise Helps Overweight Children Think Better, Do Better in Math
• Exercise May Help Prevent Brain Damage Caused by Alzheimer's Disease
• Moderate to Intense Exercise May Protect the Brain
• Exercise Has Numerous Beneficial Effects On Brain Health and Cognition, Review Suggests

There are more than 350 species of mantis shrimp. (Photo credit: SuperStock/Alamy)

There are two main types of mantis shrimps. The two types are distinguished by the appearance of their raptorial appendages, or raps. “Spearers” have sharp barbs on the tip of their rap, which they use to spear soft-bodied prey, such as shrimp or fish. “Smashers” have a club-like modification on their raptorial appendage, which lets them smash their shelled prey, such as clams and snails. Perhaps what makes the smasher’s club-like weapon most formidable is the speed at which it can be deployed. Scientists using super-high speed video cameras were able to calculate the speed at which a smasher mantis shrimp strikes its prey. So how fast is a mantis shrimp’s punch? At a speed of nearly 80 kilometers per hour (50 mph), a strike from a mantis shrimp counts as one of the fastest limb movements in the entire animal kingdom.

But their raptorial appendage weaponry is not the only strange thing about mantis shrimp. Mantis shrimp eyesight is also quite unusual. To begin with, their eyes are able to distinguish between 100,000 different colors—that is 10 times the amount that human eyes perceive. Why might mantis shrimp have the ability to perceive such a wide range of wavelengths? It turns out that a number of mantis shrimp species have fluorescent yellow markings on the scales of their antennae and carapace. Research published in January 2004 in the journal Science indicates that the fluorescent markings are part of a threat display directed toward males of the same species as well as potential predators.

A mantis shrimp's eyes can perceive 10 times as many colors as a human. (Photo credit: Michael Patrick O'Neill/Photo Researchers, Inc.)

The ability to perceive such a wide range of light wavelengths isn’t the only thing that makes a mantis shrimp’s eyes interesting. A mantis shrimp’s eyes are also able to perceive circular polarized light, or CPL, something no other animal can do. Though humans cannot perceive this type of light, we use CPL filters in items such as camera lenses and 3D glasses.

According to research published in March 2008 in the journal Current Biology, one benefit of circular polarization vision is that it enhances contrast in murky conditions, such as the turbid waters that mantis shrimp inhabit, which lets the shrimp see better in their surroundings. In addition, research indicates that the males of some species of mantis shrimp have a patch on their bodies that reflects circular polarized light. Scientists hypothesize that these reflective patches may be used as a part of a sex-specific “secret communication channel” between mantis shrimp, since other marine animals cannot perceive CPL.

Recent research published in August 2011 in the journal Aquatic Biology indicates that mantis shrimp also communicate by “rumbling.” Vibrations within the mantis shrimps’ muscles are responsible for these low-frequency noises. Recordings made near the animals’ muddy underwater burrows indicate that the mantis shrimp use these noises as a way to establish and maintain territories. Since only males were observed making these noises, scientists think that the rumbling may also be used to attract female mates.

Though these strange underwater creatures have been around for 400 million years, much remains unknown about them, particularly since they spend most of their time in their undersea burrows. Many mantis shrimp species are also nocturnal, which makes tracking their behavior that much more difficult. However, from the data and observations that researchers have been able to gather thus far about mantis shrimp behavior and body composition, it seems these strange marine crustaceans are definitely worth the extra effort required to study them.

More to Explore

• Secrets of the Stomatopod
• Chesapeake Bay Field Guide: Mantis Shrimp
• TEDTalks: Sheila Patek Clocks the Fastest Animals [video]
• The Mantis Shrimp Has the World’s Fastest Punch
• Mantis Shrimp versus Clam [video]
• New Form of Vision Discovered
• Shrimp Eyes May Hold Key to Better Communications
• Fluorescent Enhancement of Signaling in a Mantis Shrimp
• A Shrimp’s Eye View
• Circular Polarization Vision in a Stomatopod Crustacean [pdf]
• Mantis Shrimp: Ocean Floor Critters Communicate in Synchronized Rumbles
• Rumbling in the Benthos: Acoustic Ecology of the California Mantis Shrimp Hemisquilla californiensis [pdf]

Stable isotope analysis can tell scientists whether this wedge of cheese was made in Parma, Italy, or Hoboken, New Jersey. (Photo credit: Sue Wilson/Alamy)

What is a stable isotope?

You may know that radioactive carbon isotopes are used to determine the age of objects such as fossils and other materials of organic origin. But not all isotopes are radioactive. Stable isotopes are isotopes that do not decay over time like radioactive isotopes do. Analysis of these naturally-occurring isotopes can be used for a variety of purposes, such as authenticating that a cheese labeled as Parmesan was truly produced in Parma, Italy.

Four stable isotopes commonly used to authenticate a biological product, such as a type of food, include hydrogen, oxygen, carbon, and nitrogen. Hydrogen exists as the isotopes ¹H and ²H. Oxygen exists as ¹⁶O, ¹⁷O, and ¹⁸O. Carbon exists as ¹²C and ¹³C. (¹⁴C is a radioactive isotope.) Nitrogen exists as ¹⁴N and ¹⁵N.

Stable isotope analysis can be used to determine if the water really came from a spring in France. (Photo credit: Simon Belcher/Alamy)

Stable isotopes can be used to identify the geographic origins of water and test whether the bottled water you're drinking is actually from Fiji, a spring in France, or from the local municipal water supply. How is this possible? How is this possible? Oceans only show small variations in isotopic abundance, and thus ocean water is typically used as a standard, where both the H and O isotope rations are deemed to be 0 percent. However, as water evaporates from the ocean and condenses into clouds, the isotopic ratios differ significantly, dependent on cloud temperature and the amount of leftover moisture in the cloud mass. Bodies of water, such as lakes and rivers, reflect these isotopic ratios from the input of precipitation. These isotopic abundances can further change as evaporation occurs over these bodies of water. Through the water and oxygen cycles, plants and animals incorporate hydrogen and oxygen isotopes from local water sources into their bodies. The isotopic analysis of water samples collected from locations all across the United States, as well as from locations around the world, has allowed scientists to create a map that indicates the expected isotopic ratios in a substance from a given area. Thus, when testing a bottled water sample, scientists can determine if water’s source is correctly labeled.

Stable isotopes can also be used to determine if beverages or other foods have been contaminated. For example, stable isotope analysis can be used to determine if a product marked “100 percent pure clover honey” has actually been spiked with corn syrup or another form of unlabeled sugar. Carbon isotopes can be used to determine the diet of livestock. For example, stable isotope analysis can find out whether ground beef marked as “grass-fed” was actually made from cattle that were primarily fed a grain-based diet. Nitrogen isotopes can be used to trace nitrogen sources for plants and food sources for animals and humans, which can in turn be used to determine the origins of products derived from these sources.

Measuring Stable Isotopes

To determine the stable isotope ratio in a sample, whether it is a drop of water or a piece of meat, it is placed into a machine called a mass spectrometer. The sample is incinerated to become a gaseous form, and then bombarded with ions to scatter the sample's atoms. A strong magnet is used to pull the sample's atoms through a flight tube. Since the different isotopes vary in mass (for example, ¹⁸O is heavier than ¹⁶O), it takes longer for the heavier atoms to travel through the flight tube, thereby separating the different isotopes in flight. A detector at the end of the flight tube counts the number of atoms for each specific atomic mass. The counts of each isotope are added and calculated as a ratio. It is the ratios of heavy to light isotopes that convey the important information to scientists.

The downside of using a dedicated mass spectrometer is that it can take up a lot of room, is relatively high-maintenance, and can typically range in cost from $300,000 to $1,000,000. In recent years, a new family of isotope analyzers that use optical technology has been developed that solves many of these problems. These new analyzers are compact (similar in size to a briefcase), portable (meaning samples don't need to be taken, or sent, to a dedicated lab), and significantly less expensive than mass spectrometers. In addition, the use of the new analyzers does not require special training or major manipulation of the samples before testing. Though mass spectrometers will likely remain necessary for when extremely precise measurements are required, the new machines provide a more convenient and affordable way to conduct stable isotope analysis.

Other Uses of Stable Isotopes

Stable isotope analysis has a role in a number of other applications outside of food identification and authentication. For example, oxygen isotope ratios in the keratin protein found in a hair or fingernail sample can be used to determine where a person has traveled over a period of time. This information has implications for forensics, as such data could be used to retrace a person’s geographic location during the duration of their hair or fingernail growth.

Stable isotopes are also used from ice cores, tree rings, or ocean sediments as a proxy for past climate conditions. We now know the temperature of the air and ocean water, as well as atmospheric CO₂ concentrations for the past 900,000 years due to information gathered from stable isotope analysis.

Scientists are now creating synthetic isotopes that are being used for medical uses as well as new sources of energy. Given these innovations, while isotopes have been a useful tool for ecological and forensic scientists, it is thought that we have only scratched the surface of using stable isotopes in scientific research.

More to Explore

• Determining Geographic Origins of Foods Using Stable Isotope Ratios
• The Isotope Waggle Dance: How the Honeybee Communicates with the Chemist
• Stable Isotopes Determination in Food Authentication: A Review [pdf]

Venus flytraps are native to coastal North and South Carolina. (Photo credit: Jupiterimages/Getty Images)

This plant, commonly called Venus’ fly-trap, from the rapidity and force of its movements, is one of the most wonderful in the world. –Charles Darwin

Like most plants, carnivorous species such as Venus flytraps and pitcher plants, use photosynthesis to make the food that is needed to for survival. However, unlike other types of plants, carnivorous plant species also supplement their diets by catching and digesting small animals such as insects, spiders, and slugs. Why is carnivory necessary for some species of plants and not others? Research indicates that carnivory evolved in plant species that live in soil that lack the macronutrients necessary for plant growth and survival. Most carnivorous plants live in bogs, fens, and other habitats where light and moisture are abundant, but soil nutrients such as nitrogen, phosphorus, and potassium are significantly limited.

Charles Darwin was actually the first scientist to make a detailed description of several genera of carnivorous plants. His experiments indicated that these plants use enzymes similar to those found in the human stomach to digest the captured animals. Experiments conducted by Darwin’s son Francis showed that increased plant growth was a direct effect of capturing and digesting prey.

Approximately 600 species of carnivorous plants can be found around the world. Interestingly, the majority of carnivorous plants live in North America. Among the plants found in North America is the Venus flytrap, which is restricted to a 700-mile region along the coast of North and South Carolina. These coastal areas are characterized by warm, humid, and sunny conditions. The soil is acidic and lacks the minerals and nutrients necessary for the survival of most plants.

The Venus flytrap attracts potential prey by secreting from its leaves a nectar with a sweet aroma. Located on each lobe-shaped leaf are three to six sensitive trigger hairs. When the same or more than two hairs are touched, cells on the outer surface of the leaf expands rapidly, and the trap snaps shut. At less than 100 milliseconds, this movement is among the fastest movements in the plant kingdom. The two leaves do not completely shut at first. Scientists hypothesize that this incomplete closure allows smaller insects to escape, as it would cost the plant more metabolically to digest the insect than it would benefit from the nutrients found within the prey. Secretions, such as uric acid, by the trapped insect cause the trap to close its leaves together even tighter, forming an airtight seal.

Digesting insects such as flies helps a Venus flytrap get the nutrients it needs to grow. (Photo credit: James H. Robinson/Photo Researchers, Inc.)

Once closed, digestive glands found within the leaves secrete enzymes similar to pepsin and other proteases, which digest the soft tissues of the captured insect. The flytrap also secretes an antiseptic fluid, which kills off any bacteria or fungi and prevents the insect from decaying while being digested over a period of five to 12 days. Factors that determine how long it takes the leaves to reopen include the ambient air temperature, the size of the caught prey item, the age of the flytrap, and the number of times the leaves have trapped a prey item. After the insect is digested, all that remains is its exoskeleton. When the flytrap reopens, the exoskeleton blows away in the wind, or is washed away by rain. If a non-food item, such as a pebble or twig triggers the leaves to close, the trap will reopen after a period of 12 hours, and the undigested item will be ejected.

A leaf on a Venus flytrap does not endlessly capture insects. In fact, after only 10 to 12 partial or complete closures, the leaves remain spread open. Over the next two to three months, the leaves will continue to conduct photosynthesis, until they drop off the plant for good.

Though scientists have been studying the Venus flytrap since Darwin’s time, some mysteries remain. Among the questions yet to be answered include how exactly the leaves close. A leading hypothesis suggests that an electrical current running through each leaf lobe results in a change in fluid pressure that causes the leaves to snap shut. Further research will be required to fully understand this intriguing and unique carnivorous plant.

More to Explore

• How Venus Flytraps Work
• Chomp! Meat-Eating Plants
• The Mysterious Venus Flytrap
• No Such Thing as a Free Lunch for Venus Flytraps

Research indicates fluency in more than one language helps protect the brain. (Credit: Blend Images/Alamy)

Though conjugating verbs and translating prose may seem like a pain, scientists have found a compelling reason why studying a foreign language is important. New evidence suggests that those who speak two or more languages are more likely to delay the onset of brain disorders such as Alzheimer’s disease (AD) than those who only speak one language.

Research has shown that bilingual children and adults perform better on tasks that are run by the brain’s executive control system. New research published in the fall of 2010 in the journal Neurology indicates that another advantage of bilingualism is that it helps multi-language speakers maintain brain function as they age.

Dr. Ellen Bialystok, a psychologist at York University in Toronto, Canada, studied a population of Alzheimer’s patients that included both bilingual and monolingual individuals. Patients that spoke two or more languages were on average diagnosed with Alzheimer’s four years later than single-language speakers. Interestingly, the physical effects of the disease on the brains of bilingual patients were more advanced than that of the monolingual patients, though both populations had the same mental abilities. Bialystok’s research indicates that bilingual patients are better able to cope with the cognitive effects of the disease. Brain research shows that the effort required to speak two languages causes the brain to work harder. When the brain works harder, the result is a brain with more cognitive reserves and more resources that lets it function at a higher level even when damage or impairment occurs due to a disease such as Alzheimer’s.

“We’ve been able to show that people who spend most of their lives actively using two languages are able to postpone symptoms of Alzheimer’s disease by four or five years beyond what we see in comparable monolingual patients,” Dr. Bialystok said in an interview about her research with the media outlet Voice of America.

“It’s possible that the bilingual mind is just better connected and better able to cope when there’s a disease like Alzheimer’s because it has a more robust set of mental activities,” she said.

According to Amy Weinberg, a linguist at the University of Maryland-College Park, individuals who speak two or more languages are better at cognitive control. The term cognitive control refers to a person’s ability to focus their attention to solve a problem. Those who speak more than one language are constantly using cognitive control to focus on speaking and comprehending one language at a time.

Bilingualism also contributes to cognitive reserve. According to Dr. Yaakov Stern, a clinical neuropsychologist at Columbia University, cognitive reserve refers to “the ability to optimize or maximize performance through differential recruitment of brain networks.” In an article published by Stern in the journal Alzheimer Disease and Associated Disorders, he noted that “[t]he idea of reserve against brain damage stems from the repeated observation that there does not seem to be a direct relationship between the degree of brain pathology or brain damage and the clinical manifestation of that damage.” Studies indicate that individuals with higher levels of intelligence and education have brains that are better equipped to deal with brain damage. Those individuals that participate in brain-stimulating activities, such as playing word games or solving logic puzzles, are also better-protected from brain impairment as they age. The cognitive reserve hypothesis suggests that the brains of these individuals process tasks in a way that helps to limit the effects of brain damage, should it occur.

So, the next time you’re in a foreign language class, pay attention! Not only are you becoming a more well-rounded citizen by gaining fluency in a second language, you’re also doing a world of good for your brain—and your mental health far in the future.

More to Explore

• To Stave Off Alzheimer's, Learn a Language?
• Being Bilingual a Good Brain Work-Out, Experts Say
• Being Bilingual May Delay Alzheimer's and Boost Brain Power
• Delaying the Onset of Alzheimer Disease
• What is Cognitive Reserve? Theory and Research Application of the Reserve Concept [pdf]
• Cognitive Reserve and Alzheimer Disease [pdf]
• The Bilingual Advantage

Though they lack eyes, cavefish have other adaptations that help them to survive in their dark habitats. (Photo credit: Martin Shields / Photo Researchers, Inc.)

The fish species Astyanax mexicanus is interesting in that it includes both cave-dwelling and surface-dwelling populations. In Mexico there are 30 separate populations of cavefish. Many of these populations evolved in isolation, which means each population evolved independently of the others. The populations that live in caves lack eyes and body pigment, while the populations that live aboveground have large eyes and are pigmented. Due to these obvious phenotypic differences within the same species, cavefish are a popular subject for evolutionary biologists.

Though in early stages of development cavefish have eyes that begin to grow, at a certain stage programmed cell death, or apoptosis, occurs in the lens and the eyes stop growing. The surrounding skin tissues around the eyes continue to grow, covering over the space where eyes would typically be found. The remains of the undeveloped eye can be found buried within the eye’s orbital socket.

However, even without eyes, cavefish still retain the ability to detect changes in light due to the functions of the pineal gland. If a shadow occurs above the fish, they will swim upward to investigate, as it may be a source of food, and without predators in the cave system, they do not fear being eaten. (In direct contrast, surface-dwelling fish typically seek shelter in the presence of a shadow.)

Compared to surface-dwelling fish, cavefish have a larger mouth and jaws and a greater number of tastebuds. Cavefish also have larger and more neuromasts than surface-dwelling fish. Neuromasts are specialized nerve cells that are a part of a fish’s lateral line. In cavefish, these cells are more densely distributed on the fish’s head, particularly in the area where its eyes would be. Cavefish use these sensory organs to detect movement and vibration in their watery environment. The response to vibrations in the water, called vibration attraction behavior, or VAB, is an adaptive behavior. Vibration detection helps cavefish find sources of food in the water, which, without eyes, they would not be able to see. Recent cavefish research conducted by evolutionary biologists indicated that VAB and neuromast abundance coevolved to make up for the loss of vision in cavefish and help the blind fish find food in darkness.

More to Explore

• Cavefish: Evolution in the Dark [video]
• SEED Magazine: How the Cavefish Lost Its Eyes
• Emerging Model Systems in Evo-Devo: Cavefish and Microevolution of Development

Organic household wastes such as egg shells and non-meat food leftovers can be composted. (Credit: Andrew Walters/Alamy)

What is Composting?

Composting refers to the process of controlled decomposition of organic materials. In composting, organic material decomposes into a nutrient-rich material called humus. The resulting humus can be added to soils to improve its nutrient and moisture content.

Using a compost bins also keeps organic materials out of landfills, where they take up unnecessary space. In addition, when organic materials decompose in landfills, they produce methane gas and acidic leachate. If not dealt with correctly, the production of methane gas can lead to explosions and leachate can pollute the local water supply.

On a large scale, composting is used in landscaping to stifle pest and weed growth, prevent the need for chemical fertilizers, and promote crop yield. In addition, compost has been used to help remediate polluted soils by aiding in the removal of heavy metals, pesticides, and both chlorinated and nonchlorinated hydrocarbons. On a smaller scale, compost can be used as potting soil for houseplants and as a soil enhancer for home gardens.

Building An Indoor Compost Bin

To make a compost bin for indoor use, initially you will need a plastic storage bin with a iid, shredded newspaper, and red worms. You can purchase red worms from many garden centers or from online retailers. The rule of thumb is to use two pounds of worms for one every pound of waste you plan to compost.

Your storage bin will ideally be longer than it is deep. It is more important to have more surface area than depth. An ideal bin size is 2' x 3' x 1'. After procuring your container, poke holes in the lid and along the sides of the bin, about 1 to 2 inches from the top.

Next, gather some black-and-white newsprint and shed it into 2 inch-width pieces. Wet the paper in the sink and wring out the excess water. Place the moistened paper along the bottom of the container until the container is about half-full. Add your worms onto the newspaper layer and cover them with another two inches of moistened newspaper. Place the lid on top of your container.

Let your worms acclimate to their new home for about a week before adding scraps (see the lists below) to the bin. Before adding the scraps, chop them into small piece if necessary. Bury the scraps within the bedding layer; don't just pile the scraps on top. Don't overload the bin with too much food at one time as this can lead to spoilage. After about three months, move the compost over to one side and add food and newspaper to the other side. After about two weeks, all the worms should have moved over to the new bedding area. You can now remove the compost and use it in your gardening projects.

Building an Outdoor Compost Bin

Some composting bins are kept outside. (Credit: Cultura/Alamy)

If you have the space outside, you can make an outdoor compost bin. Bins suitable for composting can be bought at garden centers (such as the one shown here), or you can build one yourself. See the resources below for instructions on how to make your own outdoor compost bin. Place a layer of wood chips, saw dust, or straw in the bottom of the bin to absorb any excess moisture. Similar to your indoor compost bin, you can place food scraps into your outdoor bin. In addition, the larger-sized outdoor bin is an ideal location for yard clippings (such as cut grass or raked leaves). To help with oxygenation, use a shovel to turn over the contents in your compost bin every week or so.

What Can and Can't Be Composted

Not everything can be put into your compost bin. The following items can be composted:

• black-ink newsprint
• cardboard rolls
• coffee grounds and filters
• eggshells (washed clean of egg residue
• nut shells
• vegetable and fruit peels
• tea bags

These items should not be put in your compost bin:

• dairy products
• fats, grease, lard, or oils
• meat, fishbones, or scaps
• pet waste
• colored paper or newsprint with color ink

Troubleshooting Your Compost Bin

Your compost bin should not smell. There are several reasons why your compost may develop an odor. First, make sure that you are burying your food scraps underneath the bedding. If there is too much moisture in your bin, add more newspaper scraps to soak up the excess. Some food items are naturally stinky when they decompose—you may want to avoid composting broccoli and onion scraps, and never compost dairy, meat, fat, or oil products. If you notice that your compost is too moist, add more dry bedding (newspaper scraps). If fruit flies seem to be gathering around your bin, make sure that you are properly burying the food. Also, wash off vegetable or fruit peels before you add the scraps to your bin to remove any fruit fly eggs that may be present.

A Perfect Earth Day Activity

As you have learned, starting your own compost bin is a fairly easy process. Composting is a fun way to make use of much of the organic waste that you produce each day that would otherwise take up space in a landfill. Building your own compost bin is just one way that you can live a greener life. You may even want to consider making a compost bin to help celebrate Earth Day on April 22! Are you doing anything special to celebrate Earth Day? Leave a comment below about any special activities you or your classmates are doing in celebration of Earth Day.

More to Explore

• The Care and Keeping of Worms (PDF)
• Constructing a Garbage Can Compost Bin
• Worm Man Composting Worms
• Worm Composting
• US EPA: Composting
• Composting 101

Tiny polysaccharide fibers in sea squirts are similar in composition to the cellulose found in plants. (Photo credit: Andrew J. Martinez/Photo Researchers, Inc.)

Researchers at the University of Manchester in northwestern England have found that cellulose taken from tunicates can be used to influence the growth of skeletal muscle cells in the laboratory. Tunicates, also called sea squirts, are simple marine mammals. Though they float freely in the water as larvae, once they mature into adults, most tunicates attach themselves to the ocean floor and live the reminder of their lifetime without moving.

Celllulose is a polysaccharide, or complex carbohydrate, that is most typically thought of as the substance that makes up the cell walls of plants. The cellulose that makes up a tunicate’s body structure is similar to that produced by plants. In their experiment, the scientists extracted the cellulose from the tunicates as cellulose nanowhiskers (CNWs). At just tens of nanometers wide—much thinner than a strand of human hair—these nanowhiskers are tiny in size.

When applied to a layer of precursor muscle cells, the nanowhiskers caused the muscle cells to quickly align and fuse together. Proper alignment is important to muscle tissue because similarly-aligned fibers help provide a muscle’s strength and stiffness. Both of these characteristics are important for movement.

Dr. Stephen Eichhorn, a scientist who contributed to the study, believes these results could have a profound effect on medical research.

“Cellulose is being looked at very closely around the world because of its unique properties, and because it is a renewable resource, but this is the first time that it has been used for skeletal muscle tissue engineering applications,” Dr. Eichhorn said in a press release about the research.
”There is potential for muscle precision engineering, but also for other architecturally aligned structures such as ligaments and nerves.”

Other scientists who contributed to the research included lead author James Dugan, a Ph.D. student, and Dr. Julie Gough. The results of their research were published in the journal Biomacromolecules.

More to Explore

• Nanoscale Whiskers from Sea Creatures Could Grow Human Muscle Tissue
• Directing the Morphology and Differentiation of Skeletal Muscle Cells Using Oriented Cellulose Nanowhiskers [abstract]