Stories tagged Life Science

Nov
07
2007

For most people, the scariest part of the hit movie Jurassic Park was when a pack of Velociraptors was hunting down the two little kids in the kitchen. (For me, the most disappointing part of the movie is the fact that the kids got away – they were so annoying, I was rooting for the raptors to eat them for lunch!)

You dare to question the wisdom of Steve?: The omnipotent Spielberg knows all!  All hail, magnificent and mellifluous Steve! Photo by felinebird at Flickr.com
You dare to question the wisdom of Steve?: The omnipotent Spielberg knows all! All hail, magnificent and mellifluous Steve! Photo by felinebird at Flickr.com

Scientists, wet blankets that they are, complained. Velociraptors, they said, were about the size of a turkey. The creatures in the movie were nearly the size of an adult human. Ah, said Spielberg. If you think there were no large raptors, it’s only because you haven’t discovered them yet. Sure enough, almost at the same time the movie was released, paleontologists uncovered a new species, Utahraptor, that fit the movie version to a T.

Suitably cowed, the scientists learned not to question Sir Stephen again. But, over the years, other nagging complaints arose. The movie showed the dinosaurs hunting in packs. But dinosaurs are reptiles, not known for social behavior, and there was no evidence to support this portrayal. Furthermore, each raptor had a huge claw on one toe, and Spielberg showed them walking with the claw held high, not touching the ground. Again, grumblings were heard – there is no evidence to support this hypothesis.

But such is the power of Saint Stephen that he was able to foresee additional paleontological discoveries fourteen years into the future! For now comes word from China of a fossil track way – dinosaur footprints fossilized in stone. The tracks show six Dromeosaurs – another species of raptor – walking side-by-side as a group along a stream bank. Furthermore, the tracks show complete toe prints for two toes on each foot, but only a half-print for the third toe – the toe that held the claw. This indicates that these dinosaurs did walk with their giant claw held erect -- just like the movie said they would!

Scientists have learned their lesson. No longer do they question the word of the Mighty Spielberg. Instead, they are engaged in a mad scramble to find evidence that Dilophosaurus really did have a neck frill and could spit venom.

Wayne Knight is not returning phone calls.

(NOTE: The November Object of the Month at The Science Museum is a set of fossil animal tracks. You can read all about them here. These are much older and much smaller than dinosaur tracks – but no less interesting!)

Nov
02
2007

Nanotechnology sometimes borrows from nature.

Morpho butterfly: Pigments don’t cause these butterflies’ intense colors. Instead, super-small lattice-like structures on the wings reflect only certain wavelengths of light (or color). And the colors shift with your perspective. (Photo courtesy Lionoche, through Flickr)
Morpho butterfly: Pigments don’t cause these butterflies’ intense colors. Instead, super-small lattice-like structures on the wings reflect only certain wavelengths of light (or color). And the colors shift with your perspective. (Photo courtesy Lionoche, through Flickr)

Super-small, light-reflecting structures—instead of pigments—create a morpho butterfly's intense, iridescent wing color. Scientists are developing nanomaterials with similar properties.

Zoom in on a butterfly's wing
Zoom in on a butterfly's wing

If you used a special microscope to look at these butterfly wings, you’d see tiny scales made up of thin layers of transparent wing material with nanoscale gaps between them. Light waves bouncing off the bottom surfaces interfere with waves reflecting from the tops. Most light waves are cancelled and only certain wavelengths—or colors—bounce back to your eyes. The more light in the environment, the brighter the color.

Wing structures: These complicated structures on butterfly wings manipulate light to control the color that we see.
Wing structures: These complicated structures on butterfly wings manipulate light to control the color that we see.

How do transparent thin films create color?: Scientists haven't yet created materials that work exactly like the butterfly wings. But layers and layers of transparent, super-thin films--each with a different index of refraction--can be tuned so that they only reflect specific wavelengths of light (o
How do transparent thin films create color?: Scientists haven't yet created materials that work exactly like the butterfly wings. But layers and layers of transparent, super-thin films--each with a different index of refraction--can be tuned so that they only reflect specific wavelengths of light (o

Scientists are developing all sorts of products that, like the butterfly wings, use layers of transparent materials with nanoscale spacing between them to manipulate light and create color. With them, we can create computer and cell phone displays, fabrics and paints that change color, optical devices that improve telecommunications systems, and films that reflect much more light than glass mirrors. Can you imagine other uses?

Nov
01
2007

The business end of a saber-toothed tiger: Not as dangerous as previously feared, but still, dangerous enough.  Photo by Brendan Atkins from Flickr.com
The business end of a saber-toothed tiger: Not as dangerous as previously feared, but still, dangerous enough. Photo by Brendan Atkins from Flickr.com

Scientists in Australia, using a computer and advanced engineering formulas, have studied the skull of the famous saber-toothed tiger and discovered it wasn’t as fierce as previously thought. Due to weaknesses in the skull, its bite was only one-third as strong as a lion’s of similar size.

Of course, one-third the strength of a lion is still pretty strong.

OTOH, the saber-toothed tiger has a massively powerful body. The researches speculate that, rather than biting its prey on the run as lions do, the big cat first wrestled its prey to the ground and then clamped down on its neck.

No word as to whether these Ice Age creatures will be reintroduced to North America. If so, they would have to compete with these Tigers, the fiercest of all time.

(Other scientists have tried to figure out why the saber-toothed tiger had such big teeth to begin with.)

(And yes, I know it’s not really a tiger, but like my grandmother always used to say, alliteration counts for a lot.)

Oct
30
2007

Plasmodium falciparum, the parasite that causes malaria.: Photo courtesy NIH
Plasmodium falciparum, the parasite that causes malaria.: Photo courtesy NIH

Malaria is one of the most deadly diseases in the world. Spread by mosquitoes, each year it kills more than 1 million people, and makes 300 million seriously ill, mostly children, mostly in Africa.

For years researchers have tried to find a vaccine that will prevent people from contracting the disease. The problem is, the parasite enters the bloodstream at a particular phase in its life cycle. Collecting the parasite at that stage is tricky, because it lives in the salivary glands of the mosquito.

But now a research lab in suburban Maryland has figured out a way to collect the parasites. They breed their own highly infectious mosquitoes, which they keep locked behind five doors so none escape. Once the parasite has reached the proper stage, workers kill the mosquitoes and extract the parasite.

After they collect the parasite, they disable it and render it harmless. It can then be injected into a person. The body recognizes the parasite as a foreign body and produces antibodies to fight it. These antibodies stay in the bloodstream, protecting the person from any real parasites they may later pick up.

Early test indicate the vaccine could be up to 90% effective, and protect against malaria for 10 months or more. Human trials are to begin next year.

You can learn more about malaria in The Science Museum’s on-line exhibit.

Oct
30
2007

As cold as a bucket of clams: A quahog from Iceland claims the title as the world's oldest living animal. Photo by Cool Librarian from Flickr.com
As cold as a bucket of clams: A quahog from Iceland claims the title as the world's oldest living animal. Photo by Cool Librarian from Flickr.com

Clam diggers in Iceland recently pulled up a specimen that proved to be the oldest living animal on Earth. Or, more accurately, had been—the clam is now deceased.

Scientists at Bangor University in Wales counted the age rings on the clam and estimate it to have been up to 410 years old. That’s almost 200 years older than the previous record-holder.

Born in 1607, the clam was a contemporary of Shakespeare, although there is no evidence the two ever met. Researchers nicknamed the clam “Ming,” in honor of the Chinese dynasty that was in power when the clam was born.

Old specimens like this help scientists reconstruct the Earth’s past. Growth rings will be thick or narrow, depending on factors such as water temperature and food supply. Chris Richardson, a professor at the University, compared the growth rings to a tape recorder, faithfully recording environmental conditions.

The clam might also shed light on the science of aging. Scientists theorize that animals that live to extremely old ages have cells that function in ways different from our own. Understanding those differences could help medicine combat the effects of aging in humans.

Oct
26
2007

Bat concerns: The death of a Minnesota man from rabies this fall raises new concerns over the interactions between humans and bats.
Bat concerns: The death of a Minnesota man from rabies this fall raises new concerns over the interactions between humans and bats.Courtesy U.S. Fish and Wildlife Service
It was a Minnesota headline this week that made the nation-wide news…and just in time for Halloween.

A Minnesota man died last week from rabies after being bitten by a bat. It’s led to a lot of discussions about bats, rabies and how they all impact us. Last night during a training session here at the museum, the museum’s resident biologist made a sideline discussion on the topic, pointing out that many more bats than we’d ever imagine have rabies and that the only bats that are studied concerning rabies are those that have encounters with humans.

So let’s set the record straight on bats, rabies and how concerned we need to be on these issues. Here’s information direct from the Center for Disease Control.

In Minnesota, the most common animals to be carrying rabies are bats, skunks and fox. But rabies can be carried by a variety of mammals, including raccoons, coyotes and even dogs. Rabies is a viral disease that impacts our body’s central nervous system. Tens of thousands of people each year are treated for the condition, and usually a few die, primarily for not seeking treatment immediately after having been bitten by a rabid animal.

Now to the bat question. Some common misconceptions about bats: they’re blind, they want to suck your blood and they eat lots of mosquitoes. Bats do have low vision and use a radar-like system to sense objects, but they also can see. Bats are predators, but they prefer insects. But not insects as small as mosquitoes. They prefer bigger bugs like beetles. Think about, there’s not too much meat to munch on from a mosquito.

How do you know if a bat has rabies? The only way to find out is to have it tested in a laboratory. There are some clues that can help you be wary of a rabid bat: if it’s flying during the day, is found in an area you normally don’t find bats (including inside buildings) or is unable to fly. If it’s easy to approach, and therefore handle, there’s a stronger possibility that the bat is rabid.

What do you do if you’re bitten by a bat? After screaming and cursing you should wash the affected area immediately and get prompt medical attention. Bats do have extremely small teeth that may not leave a mark. It’s still best to have the area checked out by medical personnel even if it looks like your skin has not been punctured.

Some other misconceptions: people can’t get rabies from bat guano (feces), blood or urine. And you can’t get rabies from simply touching a bat.

Oct
21
2007

Cleaning up: A ladybug has its eyes on an aphid that it could likely snarf up and eat. A company called Planet Natural is providing ladybugs as a natural alternative to insecticides in getting rid of insect pests. (Flickr photo by teece)
Cleaning up: A ladybug has its eyes on an aphid that it could likely snarf up and eat. A company called Planet Natural is providing ladybugs as a natural alternative to insecticides in getting rid of insect pests. (Flickr photo by teece)
Just yesterday when I arrived home, there were a ton of ladybugs all over the front door. Little did I know they might be hanging around for more than the scenery.

A New York City apartment complex has turned to the little critters to tackle a big clean-up project on the 80-acre complex. It’s shipped in nearly three-quarters of a million ladybugs to eat other bugs that are destroying the ornamental landscaping features of the property.

The bugs come from Montana and have a big hunger for aphids and mites, insects that live and devour plants and flowers. The building complex owner is trying this natural solution to the problem in lieu of using chemical insecticides.

The natural method also helps to keep “the good guys,” other non-destructive bugs, around while chemical applications kill pretty much all of the insects in the area.

The apartment complex purchased the lady bugs from a business called Planet Natural. You can get a box of 2,000 ladybugs for $16.50.

On average, each ladybug can clear an area measuring about 19 inches square, eating about 50 nuisance bugs a day plus any eggs they may have also laid in the area. The commercial cleaners are also a different strain of ladybug than the Asian ladybugs that have become a common, swarming presence in urban areas.

Oct
18
2007

My neighbor's tree dies a slow, agonizing, horrible death: Well, the leaves do, anyway.  Photo by Gene
My neighbor's tree dies a slow, agonizing, horrible death: Well, the leaves do, anyway. Photo by Gene

Oh, sure. Autumn looks pretty, with its big flashy colors and brilliant blue skies. But that’s just a mask it wears to disguise its true, evil intentions. Everything good in the world is dying, all around us, and there’s nothing we can do about it. In fall the nights grow longer, the days colder. Beaches close. Bicycles get packed away for the season. The two most perfect inventions of the mind of man – daylight saving time and baseball – both come to a close. It is the end of life as we have known it. And all we have to look forward to are endless months of icicle winds, lowering skies, and – worst of all – football.

The fiery colors of Autumn are the flames of a funeral pyre, a sign of death and decay. According to Susan Carpenter, native plant gardener at the University of Wisconsin-Madison Arboretum, leaves depend on the chemical auxin to keep open the tubes that supply water, sugar and nutrients. But the cooler temperatures and shorter days of Autumn shut off auxin production. The tubes are cut off, and the leaf strangles and dies. Chlorophyll, the green chemical that gives leaves their summer color, disintegrates, leaving behind two other chemicals: yellow carotene and red anthocyanin. Different tree species contain these chemicals in different amounts, resulting in the various colors we see.

Trees are at their most colorful when a cool, wet summer is followed by a sunny, dry fall. Rainfall promotes tree growth, and moderate temperatures prevent scorching in the summer sun. Extra sunlight in the fall allows trees to continue producing their chemicals right up to the end.

Here in Michigan, we had pretty much the opposite – a summer of drought and searing temperatures, followed by a fairly wet fall. The trees have been pretty brown since mid-September, though a few of them are making a late run at color. Don’t bother, boys. We’re depressed enough as it is.

Oct
15
2007

It doesn't look sad: But, then again, it's not eating.  (Photo by crafterm on flickr.com)
It doesn't look sad: But, then again, it's not eating. (Photo by crafterm on flickr.com)
Crocodile tears. Crocodile tears, crocodile tears, crocodile tears… Where to begin?

Crocodile tears have long been held to be the “holy grail” of animal cruelty advocates worldwide. Practically unique in the animal kingdom, open displays of crocodile emotion have traditionally eluded even the most ardent of professional animal abusers. Whereas fish cry constantly, and most mammals and birds can be made to at least tear up with a threatening glance, crocodiles present an altogether more complicated challenge.

It seems that the legend of crocodile tears began, among Westerners at least, in the 15th century, with the publication of the book “The Voyage and Travel of Sir John Mandeville,” which contained the passage, “In that country be a general plenty of crocodiles …These serpents slay men and they eat them weeping.”

Mandeville’s observations, however, have been nigh on impossible to replicate in the last six hundred years. While most animals succumb to weeping after a smack or two, the bony scutes embedded in crocodile skin make this sort of treatment a waste of time. Indeed, these scutes often allow crocodiles to survive gunshot wounds (scutes, or osteoderms, are what compose the armor of armadillos, as well as that of extinct animals, like anklyosaurs, or the SMM’s glyptodont).

Verbal abuse is no more effective than physical, with “You’re so fat” comments and “Yo mama” jokes barely appearing to even register with most crocodiles. Also, lacking any substantial sort of “psychology” crocodiles and their kin are essentially immune to psychological mistreatment.

Early in the last century, one scientist when so far as to rub onion and salt into a crocodile’s eyes*. While he may have had the beginnings of a mouth-watering recipe for crocodile eyeballs, the experiment yielded no tears, leaving many to believe that the notion of crocodile tears was a myth in the first place.

Not so, says University of Florida zoologist Kent Vliet. Vliet’s recent research seems to indicate that crocodiles do cry, but probably not for the reasons one might expect.

Part of the problem with looking for crocodile tears, as you can probably imagine, is distinguishing the tears from plain old water. With fish, which are emotionally unstable and weak-willed, it’s quite safe to assume that they are crying constantly, constantly surrounded by water as they are. Crocodiles are much more inscrutable.

What Vliet did was to videotape captive caimans and alligators (both close relatives to the crocodile) while they were feeding. These captive animals have been trained to eat on dry land, unlike wild crocodiles, which often feed while at least partially in the water. The tapes showed the crocodilians’ previously dry eyes not only crying, but also sometimes even “frothing and bubbling” as they ate.

There you have it. The precise reason for crocodile tears is still something of a mystery, though. Vliet believes that the tears may be the result of the huffing and hissing that generally accompanies crocodile feeding, with the air being pushed through the sinuses forcing tears from the lacrimal glands.

The main purpose of the crocodile’s lacrimal glands is the same as for our own – to lubricate the eyes. It’s possible that tear production during eating is to help lubricate food, as some of the tears would run through the sinuses and mix with saliva in the mouth. The tears might also help protect the eyes, which recede somewhat into the crocodile’s head as it manipulates its mouth. After all, "there's a lot of drama going on around the head while they are subduing prey," says Vliet.

So next time you’re being cruel to a crocodile, don’t feel bad if it isn’t crying; it’s not your fault. You just have to be more creative. Try feeding it a really disgusting meal, or giving it a little food and then taking it away – there’ll always be a satisfying way to bring a crocodile to tears, for those who are willing to try hard enough.

*This is apparently true – a scientists really did try rubbing onions and salt in a crocodile’s eyes to see if it would cry.

Oct
10
2007

Sign at Hawk Ridge: Photo by Mark Ryan
Sign at Hawk Ridge: Photo by Mark Ryan
Every year, I try to get up to Hawk Ridge in Duluth, Minnesota to watch the hawk migration that takes place every autumn. I’ve written about this event before, so I won’t elaborate too much about it in words. You can check my posting from last year here. And if you want even more information, check out the official Hawk Ridge website.

Kestrel in flight: Lake Superior serves as the backdrop as observers follow a kestrel in flight across the ridge. Photo by Mark Ryan.
Kestrel in flight: Lake Superior serves as the backdrop as observers follow a kestrel in flight across the ridge. Photo by Mark Ryan.

Hawk Ridge birdwatchers: Approaching raptors catch the crowd's attention. Photo by Mark Ryan.
Hawk Ridge birdwatchers: Approaching raptors catch the crowd's attention. Photo by Mark Ryan.
I did want to mention that the day I was there wasn’t an optimal day for seeing a lot of hawks (on some days when the wind is right thousands of them can be seen flying over), but what it lacked in quantity, it made up for in quality – and with gorgeous weather to boot.

Bald eagle soars above Hawk Ridge: Some raptors conserve energy by riding thermals, sun-heated updrafts that flow up the face of the ridge. Photo by Mark Ryan.
Bald eagle soars above Hawk Ridge: Some raptors conserve energy by riding thermals, sun-heated updrafts that flow up the face of the ridge. Photo by Mark Ryan.

Eyes on the skies: Photo by Mark Ryan.
Eyes on the skies: Photo by Mark Ryan.

Raptor identification: A posted display aids observers in identifying hawks in flight. Photo by Mark Ryan
Raptor identification: A posted display aids observers in identifying hawks in flight. Photo by Mark Ryan

Taking count: Throughout the migration official raptor counters are stationed each day at Hawk Ridge (except when rainy and foggy). Photo by Mark Ryan.
Taking count: Throughout the migration official raptor counters are stationed each day at Hawk Ridge (except when rainy and foggy). Photo by Mark Ryan.

Hawk Ridge tote board: The migrating birds are tallied and the count is updated throughout the day. Photo by Mark Ryan.
Hawk Ridge tote board: The migrating birds are tallied and the count is updated throughout the day. Photo by Mark Ryan.

Close up encounter: Hawks are netted and banded and sometimes presented to the crowd before being released again. Photo by Mark Ryan
Close up encounter: Hawks are netted and banded and sometimes presented to the crowd before being released again. Photo by Mark Ryan