Stories tagged Life Science

Oct
26
2006

A manatee: Photo courtesy US Geologic Survey
A manatee: Photo courtesy US Geologic Survey

Rescuers from the US Fish and Wildlife Service are trying to capture a manatee that has strayed far from home. These large, gentle creatures normally live in the Gulf of Mexico. But one half-ton hombre swan 700 miles up the Mississippi River and is now inhabiting the harbor at Memphis, Tennessee!

Scientists are concerned for the animal's health. Nearly hairless, manatees need water 68 degrees or warmer. The river is a little bit chillier than that, and biologists worry that the creature’s digestive system could shut down. They are trying to corral it and move it to Sea World Florida, where it can receive medical attention.

Oct
26
2006

Dermestid colony: (Courtesy US FWS)
Dermestid colony: (Courtesy US FWS)

First of all, check out the Museum's dermestid cam. (Dermestid beetles are scavengers—organisms that eat the remains and wastes of other plants and animals.)

If you're at the museum, go to the Science Buzz station in the Mississippi River Gallery on Level 5 to watch a live feed from the dermestid colony. Or, even better, you can look into the colony itself from the queue for the 3D theater, down by the Triceratops on Level 3.

It's a dirty job, but someone has to do it.
Rot happens. And scavengers—like dermestid beetles and turkey vultures—eat rotting things. We associate rot with death, but it also makes life possible. How? As dead plants and animals decay—helped along by scavengers—the nutrients inside their bodies are returned to the soil. That helps new plants grow and starts the food chain over again. Without scavengers and decomposers, we’d be up to our necks in dead stuff. Think of them as the ultimate recyclers!

Bad to the bone
Adult dermestid beetles are small, black, and hairy with patches of white. The brownish-gold larvae have blunt heads and tufts of long brown hair on their rear ends. And they’re hungry—an infestation of dermestid beetles can destroy a museum’s collections. So why does the Museum keep a dermestid colony? The insects eat old, dried out, mummified stuff—leather, fur, feathers, skin, hair, wool, silk, and dried food products. They eat it all, right down to the bone. So they’re valuable for cleaning skeletons.

Many insects lay eggs and develop on dead bodies, eating them as they go. Blow flies—among the first to colonize a body—come and go fairly quickly. Dermestids, on the other hand, can be found around a body as long as there’s anything to eat—from near the time of death to years later. The kinds of insects that a scientist finds with a corpse, and the ages of the larvae and pupae, can be used to estimate when the death occurred. So insect scavengers can also help solve crimes.

Young blowfly maggots on a rat carcass: Photo courtesy Aaron Tarone
Young blowfly maggots on a rat carcass: Photo courtesy Aaron Tarone

Set up a beetle habitat of your own
It’s easy to observe the transformation of complete metamorphosis when you set up your own mealworm colony. Mealworms, the larval form of darkling beetles, are commonly sold in pet stores as food for reptiles and amphibians. These beetles are completely harmless and cannot bite or run very fast. As long as they're well fed, adult beetles won't try to escape their habitat.

Materials

  • A large plastic bin, 2–3” deep
  • A bag of oat or wheat bran
  • Two layers of burlap or cheesecloth, cut to fit inside the bin
  • Light all-purpose household oil to coat the outside edges of the bin when the beetles mature
  • Approximately 50 mealworms, available at pet stores or bait shops

What to do

  1. Lay a square of burlap in the tray.
  2. Pour 1–2” of bran into the tray.
  3. Add the mealworms.
  4. Lay a square of burlap or cheesecloth on top of the bran. (This gives the older larvae a place to pupate.)
  5. Add a fresh slice of apple, potato, or lettuce on top of the bran every week. This will provide all the moisture your mealworms need. Add fresh bran as the level goes down.

Simple experiments
Develop some simple experiments to observe behaviors and record major events in the mealworms’ life cycle:

  1. Measure individual mealworms weekly and record growth rates on a graph.
  2. Place a few “control” mealworms in the refrigerator to see if they develop at the same rate.
  3. Place mealworms in the centers of some Styrofoam meat trays. Cover half of each tray with black construction paper, and hypothesize whether the mealworms will move to the light side or the dark side of the tray.
  4. Record the number of times the mealworm molts, or sheds its exoskeleton, as it grows.
  5. Record the number of weeks until their mealworms pupate, and how long they remain in the pupae.
Oct
12
2006

Stop bleeding fast: photo by crystal via wikimedia
Stop bleeding fast: photo by crystal via wikimedia

Super quick fix for bleeding.

Last June 4th, I reported that MIT researchers used a self-assembling peptide nanofiber scaffold to repair severed brain structures in blind rodents and restore their sight. Those same researchers noticed the material's dramatic ability to stop bleeding in the brain and began testing it on a variety of other organs and tissues.

In a study published online October 10 in Nanomedicine the researchers report that the liquid controlled bleeding in rodents within 15 seconds in seven other wound types, including cuts to the spinal cord, liver [view video here] and femoral artery as well as skin punctures.

Platelets not needed

The liquid does not seem to form a conventional blood clot, the group notes. Electron microscopy turned up no sign of the platelets that would normally gather in a clot. The proteins might instead form tangles that act like hair blocking a drain, Ellis-Behnke suggests.
The gel eventually breaks down into amino acids, the building blocks of proteins, that can be used by surrounding cells for tissue repair.

This discovery has created lots of excitement, especially by surgeons. Still, they caution that extensive clinical trials are needed to make sure the materials work properly and are safe. The MIT researchers hope to see those crucial human trials within three to five years.

Read more at: New Scientist Tech and Scientific American

Oct
12
2006

Wobbly planet Earth: Photo courtesy NASA.
Wobbly planet Earth: Photo courtesy NASA.

The extinction of rodents and other mammals have been linked to variations in the Earth’s tilt and orbit, according to new research published in the journal Nature.

Dutch scientists studying 22 million year old rodent fossils in central Spain found that the rise and fall of the mammal species correlated with cooling periods due to changes in the Earth’s behavior. Rodents offer one of the best fossil mammal records and are excellent indicators of seasonal changes because of their short life spans.

"Extinctions in rodent species occur in pulses which are spaced by intervals controlled by astronomical variations and their effects on climate change," Dr Jan van Dam, of the Utrecht University in the Netherlands, said.

The researchers discovered two cycles associated with changes in climate, habitat and food availability are linked to the disappearance of rodent species. One cycle, which lasts 2.4 million years, is linked to variations in the Earth’s orbit. The other 1.2 million year cycle is related to changes in the tilt of the Earth’s axis. Both cycles would cool the Earth, allowing the expansion of ice sheets and causing species to adapt or die out.

Right now Earth is in a relatively circular orbit and about 700,000 years away from the next period of axis stability.

"The environment is responsible to what happens to species," said Van Dam. "Biological factors are secondary, according to our results."

However, Larry Ciupik, an astronomer at Chicago’s Adler Planetarium says volcanic activities, plate tectonics and the amount of carbon dioxide in the atmosphere also contribute to species turnover.

MORE INFO
New Scientist
LiveScience.com

Oct
05
2006

Skipjack herring: Illustration courtesy Duane Raver and the U.S. Fish and Wildlife Service.
Skipjack herring: Illustration courtesy Duane Raver and the U.S. Fish and Wildlife Service.

I work at the Science Museum and I often learn unusual things during the course of my day. Some things are funny, some I store away to pull out in a Cliff Claven moment, and others make me want to run screaming to my desk to put them into this blog.

This is one of the latter.

Yesterday I learned that herrings may communicate with one another through their anuses by farting. I almost exploded when the person leading the meeting casually mentioned this fact. I ran back to my computer, and sure enough. Researchers at not one, but TWO institutions are studying the phenomena. Both the Institute of Coastal Research at the National Board of Fisheries in Sweden and the University of British Columbia, Vancouver have researchers looking into the matter.

Before this remarkable discovery, it was known that herrings communicated with one another through sounds produced by their swim bladder. Researchers thought that all the sounds they heard coming from the herring were coming from the swim bladder. But, and I am laughing as I type, they noticed that a stream of bubbles would leave the herring’s anus in time with the sounds they were hearing. Sure enough, they are connected, and that sound was soon dubbed by the quick-thinking researchers as a Fast Repetitive Tick (or FRT, if you will).

Researchers note that the unlike the gas we pass, these sounds are not produced by the digestive process, but rather a connection between the swim bladder and the anus. The exact purpose or reason behind the FRTs is not exactly known. One theory is that is a way for the herring to communicate with each other at night. Another is that is an anti-predator tactic. Seriously. Or, it could just be an incidental release of air from the swim bladder as the fish adjusts its buoyancy.

You can hear the herring communicating in this manner here.

Oct
04
2006

The rise of the spread of the deer ticks are back on the road. Over the pass year, 2005, a total of 918 Lymes disease cases were reported at the the Minnesota Department of Health. Deer ticks are also known as black-legged tick. They carry a bacteria that causes the Lyme disease, which is an illness that can cause debilitating arthritis, for example. The deer tick also carry a bacteria that causes human anaplasmosis, which is a serious illness that usually begins with a high fever. So when you are going outdoors remember to wear protective clothings, such as wearing long sleeve shirts and pants, tucking in your pant legs into your socks. Frequently check to see if there are any ticks clinging on to your clothing or skin. Try to stay away from woody areas and bushy places. Or use tick repelling spray.

Oct
03
2006

Pet Cat: This particular cat is not hypoallergenic, but Allerca has made other individuals of the species that are.  Photo Courtesy of A. Bellew.
Pet Cat: This particular cat is not hypoallergenic, but Allerca has made other individuals of the species that are. Photo Courtesy of A. Bellew.

Allergic to cats?

Well, it is now possible to cuddle up with one of the furry critters without battling sneezing fits and itchy eyes. A company called Allerca has developed the first hypoallergenic cat.

How do cat allergies work?

Cat allergy sufferers' antibodies overreact to the Feld1 protein that is secreted by the sebaceous glands on the skin of many cats. This overreaction can cause a wide range of problems including mild symptoms of itchy eyes and runny nose, swelling, breathing problems, hives and even more serious problems such as anaphylactic shock.

The cat allergen has been difficult to deal with because it is extremely small, about 10 times smaller than pollen or dust particles. Also, it is persistent. It can remain in the air for several months.

What did Allerca do?

Allerca began its research by attempting to genetically engineer a low allergy cat. They planned to use a biotechnology technique known as RNA inference. RNA inference makes it possible to silence specific genes. Allerca wanted to figure out how to quiet the Feld1 protein gene.

In the mean time, they ended up unintentionally discovering a naturally occurring hypoallergenic cat. They discovered three cats that produce a slightly different version of the Feld1 protein and this protein had no effect on cat allergy sufferers.

Their research has not yet been published in a scientific journal, but Allerca scientists told Nature that they plan to soon. The company has already begun marketing the cats, so you could purchase your own if you like. Although, it will cost you close to $4000. But if you are a hardcore cat lover who suffers from allergies, it might be worth it to live completely cat allergy free.

Oct
02
2006

Pine Barrens Tree Frog: In this image the tympanum can be seen as the small round disk to the right of the eye.  Image courtesy Bruce Means and the U.S. Fish and Wildlife Service.
Pine Barrens Tree Frog: In this image the tympanum can be seen as the small round disk to the right of the eye. Image courtesy Bruce Means and the U.S. Fish and Wildlife Service.
Do frogs have ears?

Yes, they do, but they are different from the ears we have. Frogs do not have external ears, rather they have something called a tympanum. The tympanum are behind the eyes, and look like round disks. Some tympanum are easier to see than others. They receive sound waves for the frog just like the tympanic membrane (also known as the eardrum) does for us. Frogs not only use the tympanum to hear, but also use their lungs. The lungs help with hearing, and also protect the frog’s eardrums from the very loud noises frogs make by equalizing pressures between the inner and outer surfaces of the tympanum.

What does sublimation mean?

In physics, sublimation is the process by which a solid converts to a gas and bypasses a liquid stage in doing so. Have you ever seen dry ice? At room temperature, dry ice sublimates directly into a gas, skipping the liquid stage.

Where do Komodo Dragons live?

There are about 6,000 Komodo Dragons living in the wild. They live on the Lesser Sunda Islands in Indonesia.

What causes hiccups?

There are a variety of causes for hiccups, including eating too quickly, swallowing too much air, taking a cold drink while eating a hot meal, laughing, coughing, or drinking too much alcohol.

Hiccups are an involuntary spasm of the diaphragm, the large muscle that separates the chest cavity from the abdominal cavity. The sudden intake of air into the lungs is stopped by the glottis, which causes the “hic” sound.

Do you know how fast the Earth spins on its axis?

Well, if you figure the Earth does one full rotation on its axis about every 24 hours (23 hours, 56 minutes, and 04.09 seconds), and the Earth’s circumference is around 25,000 miles (24,901.55 miles), then it spins at roughly 1,040 miles per hour.

Illustration of the life-cycle of the Sun: Illustration courtesy Tablizer.
Illustration of the life-cycle of the Sun: Illustration courtesy Tablizer.Courtesy Tablizer
Will the sun explode?

No, but one day it will be large enough to push the Earth into a new orbit while eradicating the Earth’s atmosphere – but not for a long, long time. Our sun does not have enough mass to “go supernova” and explode. But, in about 5-6 billion years it will start becoming a red giant once it has used up its supply of hydrogen in its core and switched to fusing hydrogen in a shell outside of its core. While this is happening other processes will cause the sun to grow. Much, much later, the red dwarf will become a planetary nebula, and then a white dwarf. This is the standard stellar evolution for a star such as our sun.

Sep
29
2006

Example of ochre cave painting in Kakadu National Park, Northern Australia: Photo courtesy Wikipedia (User: PanBK)
Example of ochre cave painting in Kakadu National Park, Northern Australia: Photo courtesy Wikipedia (User: PanBK)
The use of color symbolism by prehistoric man in Africa may have occurred more than 200,000 years ago, according to a British archeologist whose findings were announced at the annual festival for the British Association for the Advancement of Science.

Lawrence Barham, a researcher from Liverpool University, has been studying ancient human artifacts at a cave site known as Twin Rivers in southern Zambia.

A range of mineral pigments, or ochres, have been found at the site, leading Barham to hypothesize that they may have been used ritualistically by early man, in much the same way some cultures today use color to mark passages of childhood into adulthood or of a warrior becoming an elder.

If his theory is correct, it would mean abstract thinking by early humans would have developed far earlier than previously thought.

"As an archaeologist I am interested to find out where color symbolism first appears because for color symbolism to work it must be attached to language," Barham said.

"Color symbolism is an abstraction and we cannot work this abstraction without language; so this is a proxy for trying to find in the archaeological record real echoes for the emergence of language."

Evidence found at the Twin Rivers site suggests tools were becoming more complex, blades attached to handles rather than just simple handaxes. At the same time ochres of a wide range of colors were being used.

Ochres are derived from scraping rocks and mixing the resulting powder with another substance, such as animal fat, to create paint or dye. The ochres found at the Twins Rivers’ site include red, yellow, brown, pink, black and even purple. The type of humans using them is not known, although a bone fragment points to Homo heidelbergensis, a large-brained ancestor of modern man.

Still, skeptics say the ochres could be merely functional, used for such things as preserving hides, or as glue to fasten stone blades to shafts or handles. But Barham disagrees.

"If you were to argue that these oxides were purely functional and have no symbolic value, you have to explain away the range of colors that are being selected from different places in the landscape. Because if it was just for the iron element, any of them would do - the red, or the yellow. Some are closer to the site than others, so it seems that people were deliberately selecting the material for the color property. That's my argument anyway", Barham said.

Links:

More on ochres
Pigments through the Ages
More about Lawrence Barham’s findings.

Sep
27
2006

You're invited to attend the annual Fall Color Blast on Sunday, October 1, from 1-5pm, at the Warner Nature Center. The event is free and features a professional storyteller, live fiddle music, bird banding demonstrations, canoeing, rides on a solar-powered pontoon, hikes, kids' crafts, free apple pie and ice cream, cider and coffee, and more. (Want more information about programs at the Center?)