Stories tagged Life Science

Dec
27
2005

Imagine that you are on a glacier and all around you thousands of black worms rise up out of the ice. It sounds like a scene from a science fiction movie, but it isn't. The worms are ice worms, and they're real.

Ice worms are extremophiles, animals that thrive in conditions that most creatures would not be able to survive, such as volcanos, glaciers and deep in the ocean. Ice worms live in glacial ice. They average around 1 cm long and 1 mm wide, and eat snow algae. Ice worms are the opposite of worms like earthworms, in that instead of becoming less active as temperature decreases, ice worms become more active with cooler temperatures. And there are a lot of them. One glacier can have an ice worm density of 2600 worms per square meter.

The ideal temperature for an ice worm is zero degrees Celsius, or 32 degrees Fahrenheit. This ability of ice worms to thrive in such extreme temperatures is the focus of a three year $214,206 NASA grant. Researchers hope ice worms can help unlock the secrets of how life might survive on distant ice worlds such as Europa.

Ice worms actually disintegrate through the process of autolysis when they are exposed to temperatures greater than 5 degrees Celsius. (Autolysis in cell biology refers to the destruction of a cell by its own digestive enzymes.) With the glaciers that are the only habitat for these organisms slowly melting due to global warming, ice worms are losing their habitat. If you consider that there are over 7 billion worms in one glacier, their impact on ecologies that are influenced by the glaciers must be significant, both in terms of biomass and in terms of nutrient processing. There is a lot more to learn about these organisms, and the role they play in the ecosystem.

For a time ice worms were believed to be mythical creatures — there is even an amusing poem that features the ice worm. I never knew these things existed — pretty amazing worm, I think.

Dec
14
2005

Whales and dolphins occasionally run aground on beaches around the world. In Cape Cod, near Boston, animal rescue workers deal with some 200 incidents a year.

But something unusual happened on Friday, December 9. A powerful storm, combined with low tides, trapped large numbers of whales and dolphins. Altogether, 39 animals died.

Mass strandings occur when groups of these social creatures get caught in shallow areas when the tide is heading out. The December event was unusual not only for the large number of animals involved, but that two different species were beached in two different locations.

Dec
09
2005


Tasha the boxer: Tasha, the boxer whose DNA was sequenced. Photo courtsey of the National Institute of Health

A few days ago scientists from MIT and Harvard released the genomic sequence for the dog.

Previously, genomic sequences for mice, rats, bees, cows, mosquitos, fruit flies, sea urchins, humans, and chimpanzees, as well as several viruses and bacteria have been completed.

Studying genome sequences helps scientists understand how genes work together to direct the growth and health of an organism. Considering the cost and time involved - the dog sequencing took over two years and over $30 million to complete - making the right choices about what species to sequence is an important question. Researchers at the EMBL-European Bioinformatics Institute are proposing a system to determine what organisms should be sequenced next.

Nov
15
2005


Singing Mouse Photo

Researchers at Washington University in St. Louis have discovered that mice sing.

Scientists already knew that mice make ultrasonic sounds-squeaks that are too high-pitched for us to hear without special equipment. But these scientists used microphones and computer software to study the squeaks of 45 male mice.

What's in a song?

The researchers separated the squeaks into types of syllables based on how quickly the pitch rose or fell. The mice "sang" about 10 syllables per second. And almost all of the mice repeated sequences of syllables in clear patterns. None of the mice are Marvin Gaye, exactly, but their noises meet the scientific definition of song. (People, birds, whales, and some insects do the same thing.)

Why sing?

Researchers still have to figure out WHY the mice sing. Because the mice sang in response to pheremones-chemicals that transmit messages between animals of the same species-one guess is that male mice sing to impress females.

Hear the mice singing.

Nov
14
2005

I'm allergic to cats. I like cats just fine, in fact, I think they're great, they just turn me into a sneezing and sniffling wreck. And now researchers are finding that just like some people are allergic to cats, some cats may be allergic to people!


PJ the Cat

Feline asthma is a common condition in cats - one of every 200 has the disease. Researchers are exploring how the lifestyles of the people who live with cats are possibly causing asthma attacks. Cats who live exclusively indoors are more likely to develop feline asthma as their exposure to household dust, dust or other chemical vapors from their kitty litter, cigarette smoke (if they live with a smoker), human dandruff and pollen from household plants is much higher.

Research in the study of human asthma has suggested a link between bacterial Mycoplasma infection and a worsening of asthmatic symptoms. Studies conducted in the United States and Australia report finding Mycoplasma in a fifth of all lung fluid samples from cats with asthma.

If you have a cat that suffers from asthma, researchers suggest that you remove possible triggers from your home, and switch from a granule based litter to a newspaper based product. Personally, I'm looking forward to the day when hypoallergenic cats are inexpensive and generally available.

Nov
09
2005

It's deer hunting season in Minnesota. Deer hunting is a major industry in this state, generating $236 million in retail sales in 2001, 4,825 jobs and $122 million in wages. The sale of hunting licenses for deer brought in $19.7 million to the DNR in 2004. The revenue from these licenses account for 29% of the DNR's Game and Fish Fund, which help buy and manage wildlife management areas and fund research on forest animals.

As important as all this is, deer hunting plays an even more critical role in managing the state's deer population. There are more than a million whitetail deer in Minnesota, and due to recent mild winters the population is nearing record numbers.

The record number of deer is having an impact in many parts of the state. Deer grazing is threatening some plant species, such as trillium, wild lily of the valley, and rose twistedstalk. Reforestation of Eastern white pines and white cedar trees is difficult due to deer grazing. Deer related traffic accidents are also a concern, with an estimated 20,000 deer-vehicle crashes annually.

Deer management through hunting is tricky, especially since the DNR cannot predict what the winter weather will be like. Seven of the last eight winters have been milder than average, leading to increased deer numbers despite more liberal hunting policies meant to control the population. Severe winters result in "winterkills" that can reduce the population significantly, but without being able to predict them, the DNR has to make some educated guesses. Another factor that worries the DNR is that while the number of hunters is increasing, it is not increasing at a rate that can control the high population of deer.

As a result, the DNR is loosening restrictions on hunting anterless deer. Hunters used to have to enter a lottery to obtain an anterless permit. Now any hunter can buy them over the counter.

What do you think? What would you suggest to help control the deer population? What do you think about hunting? Do you think it is an effective deer population management strategy? If not, what would you suggest as an alternative?

Oct
25
2005

The Minnesota Department of Health has confirmed five cases of polio in Amish children in Minnesota. All five cases have been from the same Amish community near Clarissa, Minnesota. The last significant outbreak of polio was in 1979 and occurred primarily in Amish communities in Pennsylvania.


Polio Virus: Illustration of polio virus. Courtsey of CDC/Barbara Rice.

Polio, or Poliomyelitis, is a highly contagious disease caused by a virus. Polio mainly infects children, especially those under the age of three. At the peak of the polio epidemic in 1952, nearly 60,000 cases, resulting in 3,000 deaths, were reported in the United States. There are four forms of polio.

  • 95% of polio infections are asymptomatic, meaning they produce no symptoms at all.

The remaining 5% of polio cases result in physical symptoms.

  • Abortive polio is similar to the flu.
  • Nonparalyic polio causes sensitivity to light and sore muscles.
  • Paralytic polio, the most severe form, causes permanent muscle paralysis.

None of the five reported victims are showing symptoms of paralytic polio.

Polio was virtually eliminated from the Western hemisphere in the late 20th century after the polio vaccine became widely available, but the disease continues to cause illness in other parts of the world.


Polio Vaccination Poster: This 1964 poster featured what at that time, was CDC's national symbol of public health, the "Wellbee", who here was reminding the public to get a booster vaccination. Image courtsey of the CDC/ Mary Hilpertshauser.

Most everyone nowadays is vaccinated for Polio. But vaccinations are not common in the Amish community. Still, Amish are not the only group that do not get vaccinations: in Minnesota, about 2% of parents opt out of vaccination programs for school age children. Doctors across the country are using this outbreak to encourage members of the Amish community, and those outside of the Amish community who have opted out of the vaccination programs, to reconsider their decisions and get vaccinated.

Oct
18
2005


Whooping cranes and an ultralight: Because of Operation Migration, now in its fifth year, 40 adult birds in the flock now make the migratory flights south in the fall and north in the spring on their own. Photo © Operation Migration


Whooping crane: An adult whooping crane (Photo courtesy USGS)

On Friday, a group of endangered whooping cranes took to the skies, migrating from Necedah, Wisconsin, to their winter habitat in Florida—1,200 miles away.

The 20 cranes, which were hatched and raised in captivity, have to be taught to migrate. (Whooping cranes learned their migration route by following their parents, but the knowledge was lost when the population dwindled and no wild birds used the flyway.) So Operation Migration's pilots in ultralight planes lead the birds south.

The birds' route takes them from the Necedah National Wildlife Refuge, in Wisconsin, to the Chassahowitzka National Wildlife Refuge in Florida. Read the Operation Migration field journal to see where the flock is today and what's been happening to them.

(The Patuxent Wildlife Research Center, which also helps to raise endangered whooping cranes, has links to lots more resources.)

Oct
13
2005


Gorilla: A gorilla chewing some food.

Biologists working in the rainforest of Africa have documented gorillas using simple tools, such as using a branch to dig for food.

For a long time, scientists thought only humans used tools. In 1960, Jane Goodall observed chimpanzees using tools in the wild—the first non-human species known to use tools. In 1993, Caral van Schaik of Duke University found tool use among orangutans on Borneo. Now, we can add gorillas to the list of tool-using primates.

Humans and gorillas last shared a common ancestor some 5 to 8 million years ago. Apparently, tool-use evolved sometime before then, and has been inherited by both species. Researchers say this discovery will help us understand the evolution of the human species, and the human brain.

Oct
13
2005

Scientists at Rutgers University in New Jersey have discovered that the amount of oxygen in the Earth's atmosphere has more than doubled over the last 205 million years.

By studying samples of seafloor material going back millions of years, they determined that the atmosphere was only 10% oxygen during the time of the dinosaurs. It rose as high as 23% by 40 million years ago. (The air is 21% oxygen today.) That's about the time that really large mammals, like elephants and rhinos, started to emerge.

Oxygen levels may have affected the evolution of mammals. These warm-blooded creatures need three to six times as much oxygen as a reptile of the same size. The lack of oxygen may have prevented them from growing very large. But as oxygen levels increased, mammals could start getting bigger.