Blood Clotting

 The Human Body’s Ability to Repair Wounds

AMONG the numerous mechanisms that make human life possible is the body’s ability to heal wounds and regenerate damaged tissue. The process begins as soon as an injury occurs.

Consider: The healing process is made possible by a cascade of complex cellular functions:

• Platelets adhere to tissues around a wound, forming a blood clot and sealing damaged blood vessels.
• Inflammation protects against infection and removes any “debris” caused by the injury.
• Within days, the body begins to replace injured tissue, make the wound contract, and repair damaged blood vessels.
• Finally, scar tissue remodels and strengthens the damaged area.

Inspired by blood clotting, researchers are developing plastics that can “heal” damage to themselves. Such regenerating materials are equipped with tiny parallel tubes containing two chemicals that “bleed” when any damage occurs. As the two chemicals mix, they form a gel that spreads across the damaged areas, closing cracks and holes. As the gel solidifies, it forms a tough substance that restores the material’s original strength. One researcher admits that this synthetic healing process currently under development is “reminiscent” of what already exists in nature.

What do you think? Did the body’s ability to repair wounds come about by evolution? Or was it designed?

Fascinating lesson in Teamwork

           The Extraordinary Clown Fish       

FEW fish grab our attention the way the clown fish does. Perhaps it wins our hearts with its fancy coloring, which may remind us of a circus clown. Or maybe we are struck by its surprising choice of home—among the stinging tentacles of a sea anemone. Not surprisingly, another name for the clown fish is anemonefish.

Like many Hollywood actors, clown fish are not averse to photographs. Divers and snorkelers can usually expect clown fish to “pose” for pictures, since they rarely stray far from home and are not particularly shy.

But what makes clown fish extraordinary is their seemingly risky lifestyle. Living among poisonous tentacles would seem to be comparable to setting up home in a nest of serpents. Still, clown fish and their anemone of choice are inseparable. What makes this strange partnership possible and successful?

‘I CANNOT LIVE WITHOUT YOU’

           Two-banded clown fish

Like most good partnerships, clown fish and anemones give and take. The relationship is not merely convenient for the 

 

clown fish; it is vital. Marine biologists have confirmed that clown fish cannot live in the wild without a host anemone. They are poor swimmers and would be at the mercy of hungry predators without the anemone’s protection. However, by using the anemone as a home base and as a safe shelter when threatened, the clown fish may reach ten years of age.

The anemone provides a safe nesting site as well as a home. The clown fish deposit their eggs at the base of the host anemone, where both parents keep careful watch over them. Later, the clown fish family can be seen swimming around that same anemone.

What does the anemone get out of this relationship? The clown fish serve as marine bodyguards, driving away butterfly fish that like to feed on anemone tentacles. At least one species of anemone cannot live without resident clown fish. When researchers removed the clown fish, within just 24 hours, the anemones had disappeared completely. Apparently, butterfly fish had consumed them.

It seems that clown fish even provide their host with energy. The ammonium that clown fish excrete helps spur growth in the host anemone. And as the clown fish swim among the tentacles, they help circulate oxygen-rich water to the anemone.

GOING WHERE OTHERS FEAR TO SWIM

             Pink skunk clown fish

In the case of clown fish, protection is skin-deep. They have mucus on their skin that keeps them from being stung. Thanks to this chemical coating, it seems the anemone considers the clown fish one of its own. As one marine biologist put it, the clown fish becomes “a fish in anemone’s clothing.”

Some studies suggest that when selecting a new host, the clown fish has to go through a process of adaptation. It has been observed that when the fish approaches an anemone for the first time, it touches the anemone intermittently for a few hours. Apparently, this on-and-off contact allows the clown fish to modify its protective coating to conform to the new anemone’s particular poison. Possibly the clown fish gets stung a little during this process. But after that, the two get along fine.

The collaboration of such different creatures offers a fascinating lesson in teamwork. In so many human endeavors, people from diverse cultures and backgrounds achieve remarkable results by pooling their resources. Like the clown fish, we may take a little time to adapt to working with others, but the results are well worth it.  Was it evolved or designed?

CuttleFish

The Color-Changing Ability of the Cuttlefish

       CUTTLEFISH can change their color and camouflage themselves, becoming almost invisible to the human eye. According to one report, cuttlefish “are known to have a diverse range of body patterns and they can switch between them almost instantaneously.” How do cuttlefish do it?

Consider: The cuttlefish changes color by using the chromatophore, a special kind of cell found under its skin. Chromatophores contain sacs that are full of colored pigment and that are surrounded by tiny muscles. When the cuttlefish needs to camouflage itself, its brain sends a signal to contract the muscles around the sacs. Then the sacs and the pigment within them expand, and the cuttlefish quickly changes its color and pattern. The cuttlefish may use this skill not only for camouflage but also to impress potential mates and perhaps communicate.

Engineers at the University of Bristol, England, built an artificial cuttlefish skin. They sandwiched disks of black rubber between small devices that function like cuttlefish muscles. When the researchers applied electricity to the skin, the devices flattened and expanded the black disks, darkening and changing the color of the artificial skin.

Research on cuttlefish muscles—“the soft structures that nature is so good at making,” according to engineer Jonathan Rossiter—could lead to clothing that changes color in a fraction of a second. Rossiter says that people might wear cuttlefish-inspired clothes for camouflage—or simply for fashion.

What do you think? Did the ability of cuttlefish to change color come about by evolution? Or was it designed?

Katydid

 The Katydid’s Remarkable Hearing

THE South American bush katydid (Copiphora gorgonensis) has ears less than a millimeter long, yet they work in a way very similar to human ears. The insect can distinguish a wide range of frequencies from long distances. For example, it can tell the difference between the sound of another katydid and the ultrasound of a bat that is hunting.

KATYDID’S EAR

Consider: The katydid’s ears are located on its two front legs. Like the human ear, the ear of the katydid collects sound, converts it, and analyzes the frequency. But scientists have discovered a unique organ inside the ear of this insect—a pressurized fluid-filled cavity that looks like an elongated balloon. This organ, which they named the acoustic vesicle, works like the cochlea of mammals but is much smaller. The acoustic vesicle is responsible for the katydid’s remarkable hearing.

Professor Daniel Robert, of the University of Bristol’s School of Biological Sciences in the United Kingdom, says this discovery will help engineers “develop bio-inspired hearing devices that are smaller and more accurate than ever before.” Researchers believe it will also contribute to the next generation of ultrasonic engineering technology, including imaging systems for hospitals.

What do you think? Did the remarkable hearing of the katydid come about by evolution? Or was it designed?

Honeycomb

THE HONEYCOMB

       HONEYBEES (Apis mellifera) construct their honeycombs with wax secreted from glands found on the underside of their abdomen. The honeycomb is regarded as an engineering marvel. Why?
Consider: For centuries, mathematicians suspected that partitions in the shape of hexagons were better than equilateral triangles or square—or any other shape—for maximizing space with the least amount of building material. But they could not fully explain why. In 1999, Professor Thomas C. Hales provided mathematical proof for the advantage of what he termed “honeycomb conjecture.” He demonstrated that regular hexagons are the best way to divide a space into equal parts with minimal structural support. By using hexagonal cells, bees can make the best use of all the space available to them, produce a light but sturdy honeycomb with a minimum amount of wax, and store the maximum
amount of honey in a given space. Not surprisingly, the honeycomb has been described as “an architectural masterpiece.” Today, scientists mimic the bees’ honeycomb to create structures that are both resilient and space efficient. Aircraft engineers, for example, use panels patterned after the honeycomb to build planes that are stronger and lighter and thus use less fuel. What do you think? Did the superior structure of the honeycomb come about by evolution? Or was it designed?