Stories tagged Life Science

Feb
13
2006

Snowy owl: The snowy owl's white feathers make it less visible to its prey.
Snowy owl: The snowy owl's white feathers make it less visible to its prey.

In the Winter 2006 "Change in the Weather" post, museum biologist Dick Oehlenschlager said that, if you were lucky, you might see a snowy owl or two out near the Minneapolis-St. Paul International airport.

Last weekend, I saw what HAD to be a snowy owl in the wildlife reserve off I-494 near the airport.

Oehlenschlager says that snowy owls are here in larger numbers than usual this winter. Normally, they nest in the Arctic tundra in northern Canada and Alaska, and come south some winters to hunt voles, mice, and other small mammals. Some scientists think their visits to Minnesota are periodic, coinciding with the population lows of Arctic lemmings—a favorite prey.

Pretty cool.

Feb
11
2006

It's a pretty amazing world we live in. Dozens of new species are discovered within days of more nearing extinction. I've heard it many times, and it seems almost corny to repeat it, but it has to be true that species have become extinct due habitat destruction, invasive species and who knows what else that we didn't even know existed.


Female mountain yellow-legged frog: Image courtesy U.S. Fish and Wildlife Service.

An example of one "what else" is the story of what's happening to the mountain yellow-legged frog. This little fellow would seem to be quite the survivor, living up to nine months under snow and ice in the Sierra Nevada range. The populations of these frogs were at one time so great that they were practically a tripping hazard. However this frog is headed towards extinction, fast.

But interestingly, it's not entirely our fault. Introducing trout to the lakes that the frogs had called home for sport fishing and forcing them into smaller more isolated lakes has not helped matters, nor has agricultural pollutants transported to the area by prevailing winds, but it turns out the biggest culprit is a fungus.

The chytrid fungus has caused frog extinctions in other countries, and grows on the skin of the frog, making it hard for them to properly use their pores to control their water intake — they die of thirst while they are living in water. And it is not just the mountain yellow-legged frog that is dying from this fungus, the boreal toad population in Rocky Mountain National Park is also being decimated by this fungus.

And because it is a fungus, not people that are pushing the frogs to extinction, the U.S. Fish and Wildlife Service is struggling to declare the frog an endangered species. Since the fungus is natural and not the by-product of agricultural waste or pollution, it is hard to secure funding to save a frog afflicted with it. Why save a frog that is dying through no fault of ours?

What do you think? Should funding be set aside to save species from extinction if they are becoming extinct through natural causes? Or should we focus our resources on trying to save species that are facing extinction as a direct result of our actions?

Feb
10
2006

I saw a bald eagle yesterday as I was driving along the Mississippi near downtown St. Paul. Something about those birds makes me want to stop what I am doing and just watch them soar. Hard to do when you're driving.


Eagle: Image courtesy U.S. Fish and Wildlife Service.

Anyway, that got me thinking that I've seen more bald eagles in the past 12 months from or near the Science Museum than I have ever before. I wonder what is making them more prevalent. Is it the fact that the temperatures are more moderate? Or that the river is not iced over?

It turns out that the Mississippi River is a popular location for bald eagles to over winter and even to live year round and it's the open water they like, because it makes hunting easier. Hard to catch a fish that's protected by a layer of ice, I guess.

Liza wrote a great blog on eagles about a year ago. Check it out for more information as well as a bunch of great eagle resources.

Feb
03
2006

You heard me.

Pigeons!: pigeons pigeons pigeons  Merwedekanaal, Utrecht.  Photo Courtesy Eti.
Pigeons!: pigeons pigeons pigeons Merwedekanaal, Utrecht. Photo Courtesy Eti.

Later this year researchers and students at the University of California, Irvine, will start a pigeon blog. 20 pigeon bloggers will be released over San Jose equipped with a prototype kit that contains a small GPS receiver, pollution sensors, cameras, and a home made cell phone. The sensors will measure the level of pollution in the air and then will send the information to the cell phone that will then text the information to a blog in real time. All this fits in a small package that the pigeons carry on their back.

The pigeons are set to be released at the Inter-Society for Electronic Arts' annual symposium in San Jose on August 5, 2006. The data they text to the blog will be displayed in the form of an interactive map.

So contribute your comments and ideas to Science Buzz now before blogging goes to the birds!

Feb
02
2006

Professor Stephen Fuller and some colleagues at Oxford University's Wellcome Trust Centre for Human Genetics have created a map of the 3-D structure of the virus (HIV) that causes AIDS.

They used a technique called cryo-electron tomography to see the virus. The technique has been used to look at the virus before, but its unusual variability in size and shape makes it hard to map. The Oxford scientists used a computer program to combine 100 images of 70 individual viruses. They looked for similarities to create a never-before-seen image of the virus' structure. (Read the original paper, published in the journal Structure.)

[IMAGE: To come]
[Caption: HIV, 60 times smaller than a red blood cell, is way too small to be seen with an ordinary microscope. Electron microscopes and x-rays can "see" it, but the images usually aren't great because the virus varies in size and shape. The variation is one of the unique features of HIV; most viruses are much more uniform.]

The shape of a killer

HIV particles, like other viruses, aren't cells but strands of genetic material wrapped in proteins. Viruses hijack living cells by replacing the cell's genetic code with their own, and then reproducing quickly. (Read about the life cycle of HIV and see an animation of how it all works.)

Scientists think that the size and shape variability that makes HIV hard to image is key to the virus' success, and they wondered how HIV, unlike other viruses, is so varied without losing its crucial structure. The new image provides some insight: the cone-shaped core of the virus spans the width of the viral membrane. Usually, the internal structure of a virus defines its size. But HIV's membrane determines its size instead, and limits the way it can assemble.

Understanding how the virus grows and assembles will help researchers develop new therapies for people infected with HIV.

Make it at the museum

A virus uses one protein over and over again to build a shape that encloses its RNA. HIV makes a geometric shape called an icosahedron—it has 20 identical triangular sides. HIV is an unusual virus—its internal structure is asymmetrical.

On Saturday, February 4, the Make It team will be on hand to help you make a virus model of your own to take home!

Jan
26
2006

The peregrine falcon "Athena" was spotted at the High Bridge power plant next box on January 25th.

Athena nested at the High Bridge plant last year with the former resident male, "Smoke." An unidentified rival male killed Smoke early last May, and last year's nest didn't produce any young.

We have not seen a male with Athena yet this year.

Read more about Saint Paul's falcons and last year's drama.

Check back often for updates.

Jan
26
2006

Preble's meadow jumping mouse: Preble's meadow jumping mouse.  Photo courtesy U.S. Fish and Wildlife Service.
Preble's meadow jumping mouse: Preble's meadow jumping mouse. Photo courtesy U.S. Fish and Wildlife Service.

This little fellow, the Preble's meadow jumping mouse (Zapus hudsonius preblei) is causing quite a stir. Almost a year ago, Interior Secretary Gale Norton suggested removing the bouncing rodent from the endangered species list. She based her suggestion on a study done by a biologist hired by Norton's department that showed there was no genetic difference between the Preble's meadow jumping mouse and the much more common Bear Lodge meadow jumping mouse. However, in a recent United States Geological Survey report geneticists found that the mouse was, in fact, a distinct subspecies.

The Fish and Wildlife Service said the new study results raise significant questions about the previous study, and that it will convene a panel and study the mouse for at least six months before deciding on its status.

If the mouse were removed from the endangered species list a large section of Colorado and Wyoming, which is identified as critical habitat to be conserved for the recovery of the mouse, would be available for new development.

The Preble's meadow jumping mouse is capable of jumping 18 inches into the air and can change direction in mid jump. It can leap distances up to three feet, and also can swim. The mice are hibernating now, but when they wake up I'm sure this will be a huge relief.

Jan
25
2006

Girls Laughing: Photo by spanishgirl_in_oxford
Girls Laughing: Photo by spanishgirl_in_oxford

Researchers at the University of Maryland conducted an experiment to see what impact laughter has on the heart. The researchers showed clips from comedies and from dramas to 20 volunteers. They then compared measurements of blood flow before viewing the clips, and a minute after viewing the clips. After gathering 160 measurements of blood flow from the brachial artery the researchers found that when comparing the amused or stressful states brought on by film clips, more than 50 percent more blood flowed when laughing. They concluded that increased blood flow from laughter compared favorably to increased blood flow from light exercise or cholesterol lowering drugs. The researchers published their findings in the journal Heart. Gene referenced a similar study in his blog this past April.

Meanwhile, researchers at Westfield State College and McMaster University conducted two studies that examined the long held stereotype that guys like women who laugh at their jokes, and women like men they think are funny. In the first experiment 200 volunteers were given photos of persons of the opposite sex. The photos had either humorous or dull quotes beneath them. Women ranked photos with humorous quotes beneath the photos as better potential partners than those with dull quotes. The men's ranking of the women's photos was not influenced by the quotes underneath them.

In a second study, 130 volunteers were asked to imagine two people of the opposite sex - one who was funny themselves, and one who appreciated other people's humor. When asked which person they would choose for a relationship, women usually chose the imaginary funny guy, while men chose the women who appreciated their sense of humor. While the findings are from a relatively small sample from a limited area, there is some thought that the reason women prefer men they think are funny is because their humor is a sign that they have a healthy and active brain - and therefore have a better chance of having healthy offspring.

Personally, I don't know how much I buy into this - I don't picture our distant relatives pulling a Seinfield-like routine ("What's the deal with fire anyway?"), but I guess I could see them being good at physical comedy...but I am not sure that would be endearing. Perhaps this trait is just cultural or regional? What do you think? If you're interested in learning more about romance related science check out the Café Scientifique on Valentine's Day from 6-8pm at the Varsity Theater in Dinkytown.

We've heard that laughter is the best medicine - and it looks like that's being found true for your heart - in more ways than one.

Jan
20
2006

What are the genetic and environmental factors that impact human health and disease? Researchers in the United Kingdom are trying to find out, in an ethical way, through a long-term research project they hope will improve the health of future generations.


DNA: Space-filling model of a section of DNA molecule. Courtesy United States Department of Justice.

Unprecedented research project
Biobank, as the project is called, will ask 500,000 volunteers to fill out a lifestyle questionnaire and donate blood and urine samples. Over the next 20 to 30 years, the information will be tracked against medical records so that researchers can study the connection between the participants' genes, lifestyles, and the diseases and conditions they may develop.

Potential benefits versus ethical concerns
Scientists hope to use the information to learn how our genes and environment interact over the years to cause illness, and to develop new methods to prevent, diagnose, and treat disease.

But a project like this raises significant privacy concerns. To protect the participants, Biobank will encrypt the data it collects and make it anonymous so that it can't be traced back to the donor. In addition, only researchers approved by Biobank's ethics board will be able to use the information.

Dec
29
2005

The journal Science has named a few studies that followed evolution in action--in influenza viruses, chimpanzees, and stickleback fish--"Breakthroughs of the Year."

Science Blog explains the significance of these studies, and the rest of the "top ten" science achivements of the year.