AMAZING SCIENCE

[1] THE BLUBBER OF MARINE MAMMALS For decades, scientists could not understand how dolphins could swim at the speed of nearly 40 kilometers an hour. The animals simply did not have enough muscle, the scientists thought. But dolphins have a secret, part of which lies in their blubber, a complex substance also found under the skin of porpoises, whales, and other marine animals. Blubber is a thick, dense layer of highly organized connective tissue with a lot of fat cells. It covers practically the whole creature, and it is strongly attached to the musculature and skeleton by highly organized, fan-shaped networks of tendons and ligament. These networks, in turns, are composed of elastic fibers and collagen, a protein that is also found in skin and bones. Blubber, therefore, is much more than a layer of insulating fat. It is a highly sophisticated combination of various living tissues. How, though, does blubber help dolphins and porpoises to swim so fast –Dall’s porpoises at speeds of up to 56 kilometers an hour? For one thing, blubber gives the animals a more streamlined shape. For another, the blubber between their tail flukes and dorsal fin is crosshatched with an especially dense array of collagen and elastic fibers –a design that gives the tail elasticity and stores mechanical energy. Hence, when muscles move the tail in one direction, the blubber, like a spring, helps to pull it back, thus both adding thrust and conserving energy. Blubber also aids buoyancy and provides thermal insulation. Its fat content stores energy for lean times. Understandably, this versatile composite has attracted the interest of those who are trying to improve the efficiency of marine craft and their means of propulsion. [2] THE SQUID’S BEAK The beak of the squid baffles scientists. They wonder: How can something that is so hard be attached to a body that has no bones? Should not the combination of materials cause abrasion and hurt the squid. The tip of the squid’s beak is hard, whereas the base of the beak is soft. The composition of the beak –which is made up of chitin, water, and protein –changes in density so gradually from soft to hard that the squid can use its beak without causing any harmful abrasion. Professor Frank Zok, at the University of California, says that studying the squid’s beak could revolutionize the way engineers think about attaching materials together in all sorts of applications. One potential application is in the making of prosthetic limbs. Ali Miserez, a researcher at the same University, imagines creating a full prosthesis that mimics the chemistry of the beak, so that it matches the elasticity of cartilage on one side and, on the other side, is made of a material which is very stiff and abrasion resistant. [3] THE GLOWIMG BEETLE On a quiet evening in rural Brazil, a tiny train emerges from beneath the forest litter. Two red headlights light its path, and 11 pairs of yellow-green lanterns illuminate its sides. To be sure, this is no ordinary train. Rather, it is a 70-millimeter-long larva of the Phengodidae family of beetles, found in North and South America. Because females, which retain their larval form, resemble internally illuminated railway cars, they are often called railroad worms. Brazilian country folk call them little trains. During the day the dull-brown larva is hard to spot. But at night it advertises its presence with its amazing array of lights. These are energized by the organic substance luciferin, which, aided by enzyme luciferase, oxidizes to produce cold light. Colors of the light include red, orange, yellow, and green. The red headlights glows almost constantly –but the yellow-green lateral lights. Research suggests that the headlights help the larva to find millipedes, its favorite prey, whereas the sidelights seem to discourage predators, such as ants, frogs, and spiders. In effect, the glow says “I am unpalatable. Go away. Accordingly, the sidelamps luminescence when the larva senses a potential predator. They also shine when its attacks millipedes and when the female is curled around her eggs. Under normal circumstances, the sidelights build up to peak intensity and then darken –all within a few seconds –repeating the cycle as often as necessary. [4] YOUR SENSE OF TASTE Bite into your favorite food, and immediately your sense of taste is activated. But just how does this amazing process work? Your tongue –as well as other parts of your mouth and throat –includes clusters of skin cells called taste buds. Many are located within papillae on the surface of the tongue. A taste bud contains up to a hundred receptor cells, each of which can detect one of four types of taste –sour, salty, sweet, or bitter. Spicy is in a different category altogether. Spices stimulate pain receptors –not taste buds. In any event, taste-receptor cells are connected to sensory nerves that, when stimulated by chemicals in food, instantly transmit signals to the lower brain stem. Taste, however, involves more than your mouth. The five million odor receptors in your nose –which allow you to detect some 10,000 unique odors –play a vital role in the tasting process. It has been estimated that about 75 percent of what we call taste is actually the result of what we smell. Scientists have developed an electrochemical nose that uses chemicals gas sensors as an artificial olfaction device. Nevertheless, neurophysiologist John Kauer, quoted in Research/Penn State, notes: Any artificial device is going to be extremely simplistic in comparison to the biology, which is wonderfully elegant and sophisticated. No one would deny that the sense of taste adds pleasure to a meal. Researchers are still baffled, though, by what causes people to favor one type of taste over another. Science may have many of the basics of the human body down, “says Science Daily, “but our sense of taste and smell are still somewhat of a misery. [5] YOUR SENSE OF HEARING In 1973, Dr Martin Copper was the first to demonstrate a hand-held cellular telephone. It had a battery, a radio and a micro-processor [a minicomputer]. New Yorkers gaped in amazement when they saw cooper making a phone cell on the street. But the invention was possible only because back in 1800 Alessandro Volta had invented a reliable battery. In addition, the telephone had been developed by 1876, the radio by 1895, and the computer 1946. Finally, the invention of the microprocessor in 1971 made cell phones possible. Nevertheless, we might ask, was communication with sophisticated devices really new? A communication device often taken for granted is the human voice. Over half the billion of neurons in the motor cortex of your brain are involved in controlling your speech organs, and about 100 muscles operate the complex mechanism of your tongue, lips, jaw, throat, and chest. Although some animals can hear sound frequencies beyond the range of human hearing, the combination of a human’s ears and brain is a formidable one, say audio experts. Our hearing enables us to determine loudness, pitch, and tone and to approximate the direction and distance of a sound source. The frequency range of a healthy human ear is roughly 20 to 20,000 hertz, or cycles of sound oscillation per second. The most sensitive region is in the 1,000 to 5,000 hertz range. Moreover, we may be able to detect a change of just one hertz from, say, 440 hertz to 441 hertz. Indeed, a healthy ear is so sensitive that it can detect sounds when the vibration, or to-and-fro movement, of the air at the eardrum is less than the diameter of an atom! According to a university course on hearing, “the human hearing system is close to the theoretical physical limits of sensitivity… There would be little point in being much more sensitive to sound, as all would hear would be a ‘hiss,’” the result of the random movement of the atoms and molecules that make up the air. Eardrum vibrations are amplified mechanically by lever action and are transferred to the inner ear by means of the OSSICLES –tiny bones known as the hammer, the anvil, and the stapes. But what if your ears are suddenly struck by a deafening sound? In that event, they have built-in protective mechanism in the form of muscle action that adjusts the OSSICLES to reduce the force of the sound. However, the ears are not equipped to deal with prolonged loud noise. Such exposure can permanently damage the hearing. Your auditory system also helps you to detect a sound source. The secret lies in a number of factors, including the shell-like shape of the outer ears, its grooves, the separation of the two ears, and some computational brilliance on the part of your brain. Thus, if the intensity of a sound fades just slightly from ear to ear or if the sound reaches one ear just 30 millionths of a second before it reaches the other, your brain will promptly point your eyes toward the sound source. OUR 6TH SENSE In primitive species, the only function of the limbic system is the regulation of the sense of smell. As the brain becomes more complex, the limbic system diversifies to regulate aspects of behavior, such as emotional expression, while retaining its tie to the olfactory system. It is interesting to note that ANUBIS- the jackalheaded god of Egypt, the guardian of the threshold, and symbol for the limbic system –had a particular acute sense of smell The limbic system’s ability to determine “this is it –this is truth,” is vital to creation of our mental realities. As “guardian at the inner threshold” it opens the heart to new understanding and facilitates the process of recollection and learning. In the human mind, perceptions presented by the FIVE SENSES are compared to memory perceptions. Through its instrument, the limbic system, the faculty of imagination harmonizes inner and outer perceptions. The images created by imagination then become material for the intellect. Thus, imagination is the intermediary between perception, memory, and thought. Indeed, thought and learning are made possible by the image making part of the soul. Scientists have long sought the physical instrument wherein resides the capacity for imagination, memory, and learning. Many believe that these faculties are located in the outer brain, or the two cerebral lobes. In one famous experiment the American psychologist, Karl Lashley, searched for the elusive site of memory storage. He found that rats did not suffer significant deterioration of their ability to thread their way through a learned maze even though they were missing up to 90 percent of their cerebral lobes. From this and other experiments one may theorize that each specific memory is distributed over the brain as a whole. Perhaps the images of imagination and memory are developed in the brain in a manner analogous to a hologram. What is apparent from the study of much neural structure is that the brain relies on patterns of increasing refinement, simplicity, elegance, and wholeness. If the images of memory are experienced over the entire surface of the outer brain and perhaps even throughout the brainstem as well, how are we able to evoke those memories which are important to us? What physical structures participate in our ability to recall images by processes of order and association? To investigate this question, we must search more deeply into the inner mysteries of the brain. Deep within the temporal lobes of the outer brain we must seek out those structures comprising the limbic system. The portion of the limbic system which appears to be especially concerned with facilitating memory and learning is called the HIPPOCAMPUS, or sea horse. The hippocampus is a rather large structure reaching a peak size in man. The internal architecture of the hippocampus is curious, resembling a series of leaves like the pages of a book. Viewed a great number of circuit-boards arranged in stacks. The input lines from the sense organs run through the stack of leaves and make contact with the neurons [brain cells] in each leaf. The output lines connect with forebrain, other portions of the limbic system, mammillary bodies, thalamic and hypothalamic nuclei –all structures participating in the facilitation of memory and learning.