Mother bats expert at saving energy

Source: http://www.biologynews.net/archives/2010/02/11/mother_bats_expert_at_saving_energy.html
In order to regulate their body temperature as efficiently as possible, wild female bats switch between two strategies depending on both the ambient temperature and their reproductive status. During pregnancy and lactation, they profit energetically from clustering when temperatures drop. Once they have finished lactating, they use torpor* to a greater extent, to slow their metabolic rate and drop their body temperature right down so that they expend as little energy as possible. These findings by Iris Pretzlaff, from the University of Hamburg in Germany, and colleagues, were just published online in Springer's journal Naturwissenschaften – The Science of Nature.

When energy demands are high, such as during pregnancy and lactation, female bats need to efficiently regulate their body temperature to minimize energy expenditure. In bats, energy expenditure is influenced by environmental conditions, such as ambient temperature, as well as by social thermoregulation – clustering to minimize heat and energy loss. Torpor, another common temperature regulation strategy, has disadvantages for reproductive females, such as delayed offspring development and compromised milk production.
Pretzlaff and team investigated, for the first time in the wild, the thermoregulation strategies used by communally roosting Bechstein's bats during different periods of their reproductive cycle – pre-lactation, lactation, and post-lactation. They collected data from two maternity colonies roosting in deciduous forests near Würzburg in Germany, predominantly in bat boxes. The authors measured ambient temperature over those three periods as well as the bats' metabolic rate by using respirometry (measuring the rate of oxygen consumption).

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The Beautiful Moth

ONE pleasant evening a moth flew into a plush restaurant. As it fluttered by her table, a lady dining there frantically shooed the moth away as if she were being attacked by a disease-laden mosquito! The moth proceeded to another table, finally alighting on a man's lapel. This man and his wife had an entirely different reaction—they admired the moth, reflecting on the beauty and harmlessness of this delicate creature.

"Moths are about as harmless as a creature can get," explains John Himmelman, cofounder of the Connecticut Butterfly Association. "They have no biting mouth parts, and some adults, such as the well-known luna moth, don't eat at all. They don't carry rabies or any other diseases, they don't sting . . . In fact, most people don't realize that butterflies are actually day-flying moths."

Everyone admires butterflies, but few stop to admire the beauty and variety of moths. 'Beauty?' you may say, skeptically. Some think of the moth as merely a lackluster cousin of the beautiful butterfly, yet both are given the same scientific classification—Lepidoptera, meaning "scaly wings." The wide variety observable among these lovely creatures is astounding. The Encyclopedia of Insects states that there are 150,000 to 200,000 known species of Lepidoptera. But of these, only 10 percent are butterflies—the rest are moths!

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How Crops Survive Drought

Breakthrough research done earlier this year by a plant cell biologist at the University of California, Riverside has greatly accelerated scientists' knowledge on how plants and crops can survive difficult environmental conditions such as drought.
Working on abscisic acid (ABA), a stress hormone produced naturally by plants, Sean Cutler's laboratory showed in April 2009 how ABA helps plants survive by inhibiting their growth in times when water is unavailable -- research that has important agricultural implications.
The Cutler lab, with contributions from a team of international leaders in the field, showed that in drought conditions certain receptor proteins in plants perceive ABA, causing them to inhibit an enzyme called a phosphatase. The receptor protein is at the top of a signaling pathway in plants, functioning like a boss relaying orders to the team below that then executes particular decisions in the cell.
Now recent published studies show how those orders are relayed at the molecular level. ABA first binds to the receptor proteins. Like a series of standing dominoes that begins to knock over, this then alters signaling enzymes that, in turn, activate other proteins resulting, eventually, in the halting of plant growth and activation of other protective mechanisms.
"I believe Sean's discovery is the most significant finding in plant biology this year and will have profound effects on agriculture worldwide," said Natasha Raikhel, the director of UC Riverside's Center for Plant Cell Biology, of which Cutler is a member.

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The Eye of the Peacock Mantis Shrip

The peacock mantis shrimp, found on

Australia’s Great Barrier Reef, is equipped

with the most complex eyesight in the animal

kingdom. “It really is exceptional,”

says Dr. Nicholas Roberts, “outperforming

anything we humans have so far been

able to create.”

Consider: The peacock mantis shrimp

can perceive polarized light and process it

in ways that humans cannot do. Polarized

light waves may travel along a straight

line or rotate in a corkscrew motion. Unlike

other creatures, this mantis shrimp

not only sees polarized light in both its

straight-line and corkscrew forms but is

also able to convert the light from the one

form to the other. This gives the shrimp

enhanced vision.

DVD players work in a similar way. To

process information, the DVD player must

convert polarized light aimed at a disc

into a corkscrew motion and then change

it back into a straight-line format. But the

peacock mantis shrimp goes a step further.

While a standard DVD player only

converts red light—or in higher-resolution

players, blue light—the shrimp’s eye can

convert light in all colors of the visible

spectrum.

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WAS IT DESIGNED?

Biology of Sharks and Rays

Like other sharks, the Great White is a biological "swimming machine", sculpted by evolution to utilize the properties of water with elegant efficiency. Everything about the White Shark's body shape is stripped-down and fine-tuned to optimize its swimming efficiency in a way that is appropriate for its active lifestyle.

Swimming style and body form are intimately linked. The White Shark combines a solidly-built, torpedo-shaped body, a narrow tail stalk supported by lateral keels, and a crescent moon-shaped caudal fin. This body form — shared by the Great White and its lamnid relatives, the makos and porbeagles — is noticeably different from that of a so-called 'typical' shark and, not surprisingly, these sharks employ a distinctly different swimming style. Unlike the graceful, nearly whole-bodied swimming stroke used by a typical whaler shark (family Carcharhinidae), the lamnids swim in a relatively stiff-bodied, almost 'militaristic' fashion. Each swim stroke involves arching the body laterally into a shallow curve, with the amplitude increasing from very small — at the head and anterior two-thirds of the body — to large — at the posterior edge of the caudal fin. By oscillating the body from side-to-side in this fashion, tremendous swimming speeds can be achieved with remarkable energy economy. This stiff-bodied swimming style is simply the most energy-efficient for a fish with the same general build as a White Shark. Thus, jacks, tunas, billfishes, swordfish, and lamnid sharks have independently evolved a similar body form and swimming style. But this high-speed swimming style comes with a hefty price: significant loss of maneuverability.

Comparison of Red Muscle in Lamna, Isurus, and Carcharodon. Note that the extent of Red muscle is inversely proportional to the 'stiffness' of the shark's propulsive stroke. A diagram for my field / laboratory notebook, 1987.

Not all lamnid sharks employ stiff-bodied swimming in precisely the same way. Among lamnids, the very stout-bodied Porbeagle (Lamna nasus) and Salmon Shark (Lamna ditropis) swim the most stiffly, flexing little more than the tail back-and-forth in a rather clunky manner, resembling the motion of a mechanical toy that had been wound up and let go. The sleek Shortfin Mako (Isurus oxyrinchus) swims rather less stiffly, flexing most of the posterior half of its body to generate propulsive strokes. Employing the posterior two-thirds of its body in each propulsive stroke, the moderately stocky White Shark is by far the most graceful swimmer among lamnids. Since the Porbeagle and Salmon Sharks each have a length-to-width ratio closer to 4.5 than any other lamnoid, it is not surprising that they swim in the stiff-bodied style that is close to ideal for their shape. But, if body shape were the only factor that mattered, on the basis of its form, we would predict that the Shortfin Mako — not the White Shark — would employ a swimming stroke that is least stiff-bodied.

Like other sharks, the Great White's swimming muscles are primarily of the type known as "white muscle". But, as with its lamnid relatives and a few other sharks, the White Shark also possess a band of dark "red muscle" that runs along the flanks just under the skin. Red muscle has substantially greater stamina than white. From opportunistic dissections of Porbeagle, Salmon, Shortfin Mako, and White Sharks, I have noted that the length of this band of dark muscle varies considerably among the various genera. Porbeagle and Salmon Sharks (genus Lamna) typically have a very short band of red muscle along their flanks, the Shortfin Mako's (Isurus) are somewhat longer, and those of the White Shark (Carcharodon) longest of all. Given red muscles' stamina, the White Shark's less stiff-bodied swimming style compared with other lamnids may be due to the fact that it has the most extensive band of red muscle along its flanks.

This marriage between muscle form and swimming function may result in significant advantages to the White Shark. If the benefits of stiff-bodied swimming comes at the cost of reduced maneuverability, the development of a more sinuous propulsive stroke may partially off-set that loss. As such, the White Shark may be more maneuverable than its lamnid cousins. This ability, in turn, may lead to predatory advantages when pursuing such swift and agile prey as seals and sea lions. If this is true, the Great White has struck a highly beneficial compromise between the limitations of its body form and the adaptability of its red muscle band.

[As appeared in the magazine Awake!, November 2010]

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WAS IT DESIGNED?

The Milk Bypass

If you have ever watched a sheep, a goat, or a cow giving birth, you have probably marveled at how quickly the newborn gets to its feet and finds its way to the udder for mil. All mammals feed their young on milk. But in the case of young ruminants, such as lambs, kids, and calves, there is another, unseen marvel.
Consider: Cows have a four-chambered stomach for the multiple processes needed to digest grass and forage. But newborns feed only on milk, which does not need all those processes for digestion. So when the newborn suckles, a special bypass tunnel opens to all the milk to go directly to the last chamber.
If milk were to find its way into the first chamber, called the rumen, the calf would suffer because the rumen is where hard-to-digest food is broken down by bacterial fermentation. Fermenting milk produces gas that newborns cannot eliminate. However, when young ruminants drink mil, whether from a nipple or a bucket, a reflex action snaps shut the entryway to the rumen.
Remarkably, something different happens when a newborn drinks water. It needs plenty of water in it rumen so that bacteria and microbes there can multiply, ready for when the youngster begins to live on forage. Although milk goes directly to the stomach’s final chamber, plain water enters the rumen. The call’s amazing bypass is for milk only!
     What do you think? Did the milk bypass come about by chance? Or is it the work of an intelligent Creator?
Milk bypasses the first three chambers of the calf’s stomach

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Fast Food FOR INSECTS

Insects readily feast of quick, high-calorie food. A convenient source is a flower head. Like fast-food chains, flowers advertise their presence with bright colors. Finding the flowers attractive, insects alight on the flowers, where they can munch on pollen or sip nectar.
Being particularly sluggish after a cool night, these cold-blooded creatures need the sun’s energy to get going. Many flowers offer the insects a complete package-nutritious food and a place to bask in the sun. Let’s take a look at a familiar example.
The oxeye daisy is a common flower that grows throughout much of Europe and North America. It may not seem special, but if you take the time to inspect it, you will see a lot of activity. This daisy offers an ideal place for insects to start the day. The white petals reflect the sun’s warmth, and the yellow center offers a good resting place where insects can soak up solar energy.
To make the visit even more appetizing, the center of the daisy is replete with pollen and nectar, nutritious foods that many insects thrive on. What better place could an insect find for having a good breakfast and enjoying the sun?
Thus, a whole parade of insects alights on oxeye daisies during the course of the day. You many spot beetles, colorful butterflies, shield bugs, crickets, and flies of every sort. Of course, if you are not observant, you may never notice these fascinating insect “fast-food chains.”
Therefore, the next time you are in the country-side, why not make an effort to examine some of these inconspicuous daisy ecosystems? If you do, the experience is likely to enhance your appreciation for the Creator who designed them all.

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Nature Had It First

“Ask, please,…the winged creatures of the heavens, and they will tell you…. The hand of Jehovah itself has done this.” –Job 12:7-9

Everything about birds appears to be designed for flight. For example, the shafts of wing feathers must support a bird’s entire weight during flight. How can the wings be so light yet so strong? If you cut through the shaft of a feather, you may see why. It resembles what engineers call a foam-sandwich beam. It has a pithy interior and a rough exterior. Engineers have studied feather shafts, and foam-sandwich beams are used in aircraft.
The bones of birds are also amazingly designed. Most are hollow, and some may be strengthened by internal struts in a form engineers call the Warren girder. Interestingly, a similar design was used in the wings of the space shuttle.
Pilots balance modern aircraft by adjusting a few flaps on the wings and tail. But a bird uses some 48 muscles in its wing and shoulder to change the configuration and motion of its wings and individual feathers, doing so several times a second. No wonder that avian aerobatic ability is the envy of aircraft designers!
Flight, especially takeoff, consumes a lot of energy. So birds need a powerful, fast-burning “engine.” A bird’s heart beats faster than that of a similar-size mammal and is usually larger and more powerful. Also, a bird’s lungs have a different, one-way-flow design that is more efficient than a mammal’s.
How efficient is a bird’s “engine”? A measure of an aircraft’s efficiency s whether it can take off carrying sufficient fuel. When a Boeing 747 takes off for a ten-hour flight, roughly a third of its weight is fuel. Similarly, a migrating thrush may lose almost half of its body weight on a ten-hour flight. But when a bar-tailed godwit takes off from Alaska heading for New Zealand, over half its body weight is fat. Astonishingly, it flies for about 190 hours (eight days) nonstop. No commercial aircraft can do that.

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WAS IT DESIGNED?

The Kingfisher’s Beak
Traveling at speeds of nearly 300 kilometers an hour, the Japanese bullet train is one of the fastest in the world. In part, it owes its success to a small bird-the kingfisher. Why?
Consider: In pursuit of a tasty meal, the kingfisher can dive into water with very little splash. That fact intrigued Eiji Nakatsu, an engineer who directed test runs of the bullet train. He wondered how the kingfisher adapts so quickly from low-resistance air to high-resistance water. Finding the answer was key to solving a peculiar problem with the bullet rain. “When a train rushes into a narrow tunnel at high speed,” Nakatsu explains, “this generates atmospheric pressure waves that gradually grow into waves like tidal waves. These reach the tunnel exit at the speed of sound, generating low-frequency waves that produce a large boom and aerodynamic vibration so intense that residents 400 meters away have registered complaints.”
The decision was made to pattern the front end of the bullet train after the kingfisher’s beak. The result? The bullet train now travels 10 percent faster and consumes 15 percent less energy. In addition, the air pressure produced by the train has been reduced by 30 percent. Thus, there s no large boom as the train passes through a tunnel.
What do you think? Did the kingfisher’s beak come about by chance? Or was it designed?

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Powered Flight

For centuries, men dreamed of flying. But a man does not have muscles powerful enough to lift his own weight into the air. In 1781, James Watt invented a steam engine that produced rotary power, and in 1876, Nikolaus Otto furthered the idea and built an internal-combustion engine. Now man had an engine that could power a flying machine. But who could build one?
The brothers Wilbur and Orville Wright had wanted to fly ever since they learned to fly kites as boys. Later, they learned engineering skills by building bicycles. They realized that the key challenge of flight was to design a craft that could be controlled. A plane that cannot be balanced in the air is as useless as a bicycle that cannot be steered. Wilbur watched pigeons in flight and noticed that they bank into a turn, as a cyclist does. He concluded that birds turn and keep balance by twisting their wing tips. He hit upon the idea of building a wing that would twist.
In 1900, Wilbur and Orville built an aircraft with twistable wings. They flew it first as a kite and then as a piloted glider. They discovered that it needed three basic controls to adjust pitch, roll, and side-to-side movement. However, they were disappointed that the wings did not produce enough lift, so they built a wind tunnel and experimented with hundreds of wing shapes until they found the ideal shape, size, and angle. In 1902, with a new aircraft, they mastered the art of balancing the craft on the wind. Could they mount an engine on it now?
First, they had to build their own engine. With knowledge gained from the wind tunnel, they solved the complex problem of designing a propeller. Finally, on December 17, 1903, they started the engine, the propellers whirred, and the craft lifted off into an icy wind. “We had accomplished the ambition that stirred us as boys,” said Orville. “We had learned to fly.” The brothers became international celebrities. But how did they manage to power themselves into the air? Yes, nature played a part.

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Hummingbirds-‘Faster Than Fighter Jets’

In terms of body lengths per second, a diving hummingbird flies faster than a fighter jet, says researcher from the University of California, Berkeley, U.S.A. Christopher Clark filmed the courtship rituals of male Anna’s hummingbirds and calculated that when swooping to impress females, “the feathered acrobats reached speeds of almost 400 body lengths per second.” Such a speed is comparatively “greater than [that] of a fighter jet” at full throttle, says Clack. When pulling up at the end of its dive, the bird is subject to a force ten times the pull of gravity-more than fighter pilots can stand without losing consciousness.

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The human eye contains a retina-a membrane with approximately 120 million cells called photoreceptors, which absorb light rays and convert them into electric signals. Your brain interprets these signals as visual images. Evolutionists have contended that where the retina is placed in the eyes of vertebrates, creatures with a backbone, proves that the eye had no designer.
Consider: The retina of vertebrates is inverted, placing the photoreceptors at the back of the retina. To reach them, light must pass through several layers of cells. According to evolutionary biologist Kenneth Miller, “this arrangement scatters the light, making our vision less detailed than it might be.”
Evolutionists thus claim that the inverted retina is evidence of poor design-really, no design. One scientist even described it as a “functionally stupid upside-down orientation.” However, further research reveals that the photoreceptors of the inverted retina are ideally place next to the pigment epithelium-a cell layer that provides oxygen and nutrients vital to keen sight. “If the pigment epithelium tissue were place in front of the retina, sight would be seriously compromised,” wrote biologist Jerry Bergman and ophthalmologist Joseph Calkins.
The inverted retina is especially advantageous for vertebrates with small eyes. Says Professor Ronald Kroger, of the University of Lund, Sweden: “Between the lens of the eye and the photoreceptors, there must be a certain distance to get a sharp image. Having this space filled with nerve cells means as important saving of space for the vertebrates.”
Additionally, with the nerve cells of the retina tightly packed and close to the photoreceptors, analysis of visual information is fast and reliable.
What do you think? Is the inverted retina an inferior structure, a product of mere chance? Or was it designed?

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WAS IT DESIGNED?

The Cold Light of the Firefly

In tropical and temperate regions, the firefly is recognized by the flashing light it uses to attract a mate, Interestingly, the firefly's light is superior to the incandescent and fluorescent light produced by man. In fact, the next time you look at your electric bill, think of what this small insect can do.
Consider: An incandescent lightbulb emits only 10 percent of its energy as light; the rest is basically wasted, discharged as heat. A fluorescent bulb performs much better, emitting 90 percent of its energy as light. But neither of these is a match for the firefly. With very few ultraviolet or infrared rays, the light emitted by this insect is nearly 100 percent energy efficient!
The firefly's secret lies in the chemical reactions of the substance luciferin, the enzyme luciferase, and oxygen. Special cells called photocytes use luciferase to trigger this process, with oxygen as fuel. The result is cold light-so named because it produces virtually no heat. Horticultural and environmental educator Sandra Mason aptly remarked that lightbulb inventor Thomas Edison "must have neen envious of fireflies."
What do you think? Did the cold light of the firefly come about by chance? Or was ti designed?

Firefly on leaf: @E.R. Degginger/Photo Researchers, Inc.; Firefly in flight: @Darwin Dale/Photo Researchers, Inc.

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