The Wonders of Creation Archives : Page 9 of 17 : Proslogion

An Insect with Gears

The video above shows you the jumping prowess of a juvenile Issus coleoptratus, a species of plant hopper. As its name implies, this insect hops from plant to plant, eating sugar directly from the veins of the plant’s leaves. Believe it or not, jumping is a rather difficult way to travel, because once you are in the air, you don’t have a lot of control over your body’s movement. As a result, the jump itself is very important. Not only must it be aimed correctly, it must happen so that the body stays upright throughout the time it is in the air.

That latter task can be a bit difficult. Imagine, for example, if an insect pushes off really hard with one leg, but not very hard with the other leg. This imbalance would cause the body to start spinning in the air, which would make for horrible aerodynamics and a very difficult landing! The same thing would happen if the pushes were not timed very well between the legs. If one leg started pushing sooner than the other, the insect would once again go spinning out of control. Most jumping insects are designed to deal with this by having their jumping legs arranged on either side of the body. This gives them a larger margin of error when it comes to both the timing and the force of each leg. This is convenient, but it also inherently limits how high and far the insects can jump.

For species of insects that must jump really high and far, the legs must be right under the body. This maximizes the amount of force that goes into the jumping motion, but it also allows for only a tiny margin of error in terms of the timing and relative force of each leg. As a result, these species must coordinate their jumping legs very, very precisely.

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Relationships in Nature Go Deep – Really Deep!

It has long been known that the species of jewel wasp pictured above (Nasonia vitripennis) can mate with another species of jewel wasp (N. giraulti), but the male offspring die in their larval stage. This, of course, keeps the species separate. Scientists have always assumed that the death of the male larvae must have something to do with an incompatibility between the two species at the genetic level. However, a recent study indicates that’s not true. The real reason the males die off is because their bacteria are incompatible with them.

Each species has bacteria living in its gut, helping it digest food, fight off infection, etc. However, the actual mix of bacterial species is different in each wasp species. When male larvae that came from the interbreeding of the two species were given antibiotics to kill off those bacteria, the larvae were able to survive. They weren’t incredibly healthy, but they were as healthy as purebred wasps that also had no bacteria living inside them. However, when bacteria from either species were introduced back into the larvae that came from interbreeding, they died! In the end, then, the males don’t die because of genetic incompatibilities. They die because of bacterial incompatibilities. As ant taxonomist Dr. Corrie Moreau commented:¹

I would never have predicted that…We were blown away.

So in some way that we don’t currently understand, the bacteria that live in the gut of these two species of jewel wasps so fundamentally affect their development that the wasps cannot survive unless they are compatible with a specific mix of bacteria. Interestingly enough, this isn’t the only case of bacteria affecting the development of an animal.

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The Atomic Bomb and the Brain

One of the features of the mammalian brain is a structure called the hippocampus. Since the brain is split in half, every mammal has two hippocampi, one on each side, as illustrated in the drawings of the human brain above. These structures are very important for the formation of memories as well as spatial navigation. The reason I am telling you all this is because an incredibly interesting study was just published in the journal Cell, and it uses the aftereffects of the atomic bombs (both their use and testing) to pin down the specifics of how many new brain cells people make in their hippocampi throughout their adult life.

At one time, it was considered a rather strong scientific fact that adult mammals do not produce new neurons (the cells that make up the basic building blocks of the nervous system). For example, An Introduction to Neural Networks (a textbook published in 1995) puts it this way:¹

In mammals, although not in many other vertebrates, central nervous system neurons have an important peculiarity; they do not divide after a time roughly coinciding with birth. When a neuron dies, it is not replaced.

Prentice-Hall’s textbook, Exploring Life Science (published in 1997), tells us what this means for people:²

All the neurons you will ever have were formed by the time you were six months old.

We now know that such statements are incorrect. In a variety of mammals that have been studied, adults produce new neurons in the olfactory bulb (a part of the brain used in the sense of smell) and the hippocampus.³ This new study uses a technique that shows adult humans produce a significant number of new neurons in their hippocampi, but they probably don’t produce new neurons in their olfactory bulbs.

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People Weren’t The First to Develop an Internet!

mycorrhizae1 — This microscope image shows an arbuscular mycorrhizal fungus in a clover plant's roots.
(Click for credit.)

The microscope picture above shows you a clover root (the mostly transparent material in the picture) whose cells have been “infected” with a fungus (the thick, dark material in the picture). At first glance, you might think the fungus is a parasite that takes nutrients from the plant, but that’s not really true. While the fungus does take nutrients from the clover, it also supplies the plant with critical nitrogen- and phosphorus-based chemicals that the plant has a hard time extracting from the soil. This is a mutually-beneficial relationship, which is often called a mutualistic relationship.

As anyone who has read this blog for a while knows, I am fascinated by such relationships. I have blogged about them many, many times before (see here, here, here, here, here, and here, for example). In fact, I have blogged about this specific kind of mutualistic relastionship before. It is called a mycorrhiza, and it is very, very common in nature.

About 95% of all vascular plants develop mycorrhizae,¹ and these relationships come in many different forms. For example, in the relationship shown above, the fungus forms a highly-branched structure called an arbuscule, which comes from the Latin word arbusculum, which means for “little tree.” This arbuscule is formed inside the walls of the root’s cells, and the fungus is called an arbuscular mycorrhizal (AM) fungus. Such fungi cannot exist by themselves. They can only exist as a part of a mycorrhizal relationship. There are other forms of mycorrhizae as well, but the study I want to discuss is specifically about AM fungi.

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Want to Lose Weight? Ask Your Bacteria for Help.

Gastric bypass surgery has been done on many people who are thought to have a medical need to lose weight but cannot do it on their own. The most common technique is called “Roux-en-Y,” and it involves using a small part of the stomach to make a “stomach pouch” that is about the size of an egg. That pouch is then connected to the jejunum, which is the middle section of the small intestine.¹ This means the food eaten by the patient bypasses most of stomach and the first section of the small intestine. Studies that have followed patients for 2-12 years show that the surgery does help them lose weight and keep it off.²

While most experts think this kind of gastric bypass surgery works because it forces people to change their eating habits, recent evidence suggests that at least one other factor is involved. As Science News reports:³

Previous studies of people and rats have found that the natural mix of microbes in the intestines changes after gastric bypass, with some groups growing more prominent and others diminishing. No one knew whether the altered microbial composition was merely a side effect of the surgery, or if shifting bacterial populations could help generate weight loss.

Well, a recent study was published that indicates at least some of the weight loss experienced by gastric bypass patients is attributable to the microbes.

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“Ancient” Bacteria Use Quantum Mechanics!

lh2_pb — The light-harvesting antenna complex of purple bacteria (Click for credit.)

The quantum world is a strange one. In a process called “quantum tunneling,” particles can pass through barriers as if they aren’t there at all. As a result of a process called “perturbation,” empty space can give rise to virtual particles that “blip” into and out of existence. Because of a phenomenon known as “quantum coherence,” a particle can be in several different places at once. These ideas defy common sense, but they have been experimentally verified in many different ways.

It turns out that photosynthesis (the process by which some organisms convert the energy in sunlight into energy that they can use) exploits quantum coherence in an incredible way. When light strikes a photosynthetic organism, its energy must be captured so that it can be used in an amazingly complex process that will convert it from radiant energy into chemical energy. It has long been known that photosynthesis is about 95% efficient when it comes to the first step of capturing light’s energy.¹ Until now, however, scientists have not understood how photosynthesis could be that efficient.

After all, harvesting light in a biological environment is difficult. Even though photosynthetic organisms have a well-designed “antenna” system for capturing that light (an example is given above), a living organism is usually in motion. Its environment is also constantly stimulating it in different ways. As a result, even though the antenna system is well designed, it will be distorted and deformed as the organism moves and responds to its environment. This means there should be times when the antenna system is well-aligned, producing very efficient transfer of energy, but there should also be times where it is misaligned, reducing its efficiency. Nevertheless, photosynthesis stays very efficient, regardless of how the antenna complex is distorted.

How does the antenna complex stay efficient? The answer is incredible.

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CAPTCHA – Why We Can Read It and Robots Can’t

We’ve all seen it. Whether it’s there to keep automated spammers away from your blog comments or to make sure you are a real person who is registering for an account, at some point we’ve all had to deal with a graphic like the one above. It’s called CAPTCHA, which stands for Completely Automated Public Turing test to tell Computers and Humans Apart. While there is some controversy over who invented it, the process was first patented in 1998 by Mark D. Lillibridge, Martin Abadi, Krishna Bharat, and Andrei Z. Broder at AltaVista.

Why is CAPTCHA so effective? Because even though it is relatively simple for you and me to read the obscured and distorted words in a graphic, so far no one has been able to program an automated system to do the same thing. Computers can be programmed to scan a picture of a page of printed text and read the words in the picture. However, when the words are obscured or distorted too much, the program doesn’t recognize them anymore. A human looking at the same picture can read the words, even when the most sophisticated automated system cannot.

A team of scientists at the Salk Institute for Biological Studies is starting to reveal the amazing complexity behind our ability to interpret such images.

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Optics Is Starting to Catch Up to the Arthropods

dig_eye — This is one of the digital cameras inspired by the design of arthropod eyes (Click for credit.)

There are two basic designs for animal eyes: “simple” eyes and compound eyes. Your eyes are called “simple” eyes, because each has only one lens. The lens focuses light that enters your eye onto a layer of tissue called the retina, which has light-sensitive cells. Those cells detect the light and send electrical impulses to your brain, which then produces an image of what the eye is seeing. In contrast, many arthropods (a broad class of animals including insects, crustaceans, spiders, etc.) have compound eyes. Each compound eye has many lenses, and each lens focuses light onto its own set of light-sensitive cells. The brain then collects the information from each of these optical units (called ommatidia) and produces a composite image.

Each eye design has its own strengths and its own weaknesses. A simple eye produces a very sharp image of whatever the lens is focused on. However, the farther anything is from the center of a simple eye’s vision, the more distorted it becomes. In addition, a simple eye has a narrow depth of field. When it focuses on an object, other things in the field of view are blurry if their distance from the eye is much different from the object being focused on. The compound eye, on the other hand, does not produce very sharp images. However, because its lenses are so small, there is very little distortion of objects that are away from the center of the eye’s view. In addition, the small lenses have a nearly infinite depth of field – objects stay in focus whether they are near or far from the eye.

The practical upshot is that compound eyes tend to be very valuable if you want a wide, panoramic view. In addition, they are very sensitive to motion. If you’ve ever tried to swat a fly, you understand that. The fly seems to see your hand no matter how slowly you move it or where you are relative to the fly. Simple eyes, on the other hand, are more valuable if you want very a very sharp, clear image of what you are focused on. So far, the cameras produced by human science and technology have been modeled after simple eyes. They give sharp, clear images of what the camera focuses on, but the view is not panoramic and the depth of field is narrow.

Now that has changed.

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Tides at the Bay of Fundy

fundy_tides — Low tide (left) and high tide (right) at Hopewell Cape in the Bay of Fundy.
(Copyright Kathleen J. Wile, all rights reserved)

As I mentioned in my previous post, my wife and I are in Canada, seeing some of the sights. Since I had read about them, I wanted to see the tides at the Bay of Fundy, which are the largest in the world. When I mentioned this to one of the organizers of the Canadian convention at which I spoke, she suggested that we go to Hopewell Cape, which has rocks that erosion has carved into some interesting shapes. She said it would be a great way to see the tides, and she was right!

On the left side of the picture above, you see some of those rocks as they appear at low tide. Notice there are several people walking around the rocks. In fact, if you look very closely, you will see a spot of red in front of the biggest rock formation. It has a white blotch above it. That’s me in my red jacket and gray hair. On the right, you see the same rock formations at high tide. There’s a big difference, isn’t there?

The Bay of Fundy experiences the largest difference between high and low tide of any place in the world. On most coastlines, the difference between high and low tide is noticeable, but not dramatic. In the Gulf of Mexico, for example, it is about 0.5 meters. On the coast of Southern Africa, it is about 1.6 meters.¹ However, the difference between high tide and low tide in the Bay of Fundy can be more than 15 meters!² That’s why the pictures above are so interesting, at least to nerds like me.

But why does the Bay of Fundy experience such incredible tides? I am glad you asked!

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Give Her What She Wants!

An old proverb says, “The way to a man’s heart is through his stomach.” Some birds, like Eurasian Jays (Garrulus glandarius), have their own take on that proverb. These birds are monogamous,¹ and they have an elaborate courtship ritual. Part of that ritual involves the male offering food to the female. For these birds, then, the way to the female’s heart is through her stomach. Obviously, the male wants to offer the female something appealing, but how does he know what she wants?

It has been generally assumed that the male simply offers the female food that he likes. After all, the ability to consider another individual’s feelings is rather advanced. There is some evidence that great apes are able to consider the feelings of human beings,² but in general, it has been thought that most animals don’t have the intellectual ability to realize that a different individual might have different feelings or preferences. A recent experiment involving Eurasian Jays indicates that might not be correct.

In the experiment, a male was separated from a female by a wire fence. The male could watch the female as she ate large meals of either moth larvae or mealworm larvae. The male was then given a single mealworm larva and a single moth larva. Consistently, the male would pick up the food that was not in the female’s meal and offer it to her through the wire fence. The researchers concluded that this was because the male realized the female would be tired of what she had eaten in her large meal, and therefore the other food would be more appealing to her. This, of course, would mean that the male realized the female might have a different preference than he did, and he took that into account when deciding what to offer her.³

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