In the study, researchers put 16 pigeons in a box with a computer screen (shown above). They were shown microscopic images of breast tissue, some of which indicated the presence of cancer, and some of which did not. There were two “buttons” on the computer screen, one on each side of the image. One button represented the answer “this image shows cancer,” and the other button represented the answer “this image does not show cancer.” Each pigeon was free to choose either button, and if the pigeon was correct, it got a pellet of food.
At first, of course, the pigeons’ answers were random. Over time, however, they learned to look at patterns in the image, and within a matter of hours, they were identifying cancer at a rate that was superior to random guessing. Within a month, they were spotting cancer with about an 80% accuracy rate. The most interesting effect, however, was obtained when several birds were shown an image and their combined answers were used to determine whether or not cancer was present. When that was done, the accuracy of the diagnosis was 99%, which is about as good as a trained person!
The basic process by which proteins are made in a cell. (click for credit)
I am still reading Shadow of Oz by Dr. Wayne Rossiter, and I definitely plan to post a review of it when I am finished. However, I wanted to write a separate blog post about one point that he makes in Chapter 6, which is entitled “Biological Evolution.” He says:
To date, the National Center for Biotechnology Information (NCBI), which houses all published DNA sequences (as well as RNA and protein sequences), currently acknowledges nineteen different coding languages for DNA…
This was a shock to me. As an impressionable young student at the University of Rochester, I was taught quite definitively that there is only one code for DNA, and it is universal*. This, of course, is often cited as evidence for evolution. Consider, for example, this statement from The Biology Encyclopedia:
For almost all organisms tested, including humans, flies, yeast, and bacteria, the same codons are used to code for the same amino acids. Therefore, the genetic code is said to be universal. The universality of the genetic code strongly implies a common evolutionary origin to all organisms, even those in which the small differences have evolved. These include a few bacteria and protozoa that have a few variations, usually involving stop codons.
Dr. Rossiter points out that this isn’t anywhere close to correct, and it presents serious problems for the idea that all life descended from a single, common ancestor.
The box-patterned gecko has an amazing way to stay dry!
(click to see video from which this image was taken)
Studying God’s creation fills me with constant wonder! It is amazing to see how incredibly well-engineered the world and its inhabitants are. Even well-known, well-studied things can surprise us with a new piece of technology that we never imagined. So it is with the gecko. Scientists have marveled at the gecko for years because of the way it can climb almost any surface, and they have studied it so thoroughly that engineers can crudely mimic its climbing ability. The gecko is so well designed that we haven’t completely figured out the details of how it climbs, but we at least have the basics, and they have been known for a while now.
A recent study shows us that at least one species of this amazing group of lizards, the box-patterned gecko, has another marvelous design feature: the ability to repel water in a most ingenious way. The gecko’s skin is covered in microscopic spines called spinules. These spinules force the water to form into droplets, and as the droplets grow in size, they are eventually propelled away from the body! If you click on the picture at the top of this post (and I strongly suggest that you do), you will be able to see a wonderful video of how this happens.
Why would the gecko have such a marvelously-designed system for repelling water? The authors of the study1 suggest that it reduces the ability of bacteria and fungi to grow on the skin, and it may help clean the skin of certain contaminants. Whatever the reason, I love the fact that we are still learning things about this well-studied animal!
REFERENCE
1. Gregory S. Watson, Lin Schwarzkopf, Bronwen W. Cribb, Sverre Myhra, Marty Gellender, and Jolanta A. Watson, “Removal mechanisms of dew via self-propulsion off the gecko skin,” Interface, 11 March 2015, DOI: 10.1098/rsif.2014.1396 Return to Text
This is one way to visualize the meaning of the irrational number “pi.” If a wheel has a diameter of 1, it will travel a distance of pi when it makes one complete revolution. (click for credit)
Was mathematics discovered or invented? That might seem like an odd question, but it is an important one. I haven’t seen any official poll on the matter, but I suspect that most mathematicians, philosophers, and scientists would say that it must have been invented. After all, math is a tool. We use it for accounting, parceling out land, etc. Surely people invented this tool and then improved on it over time. If that’s really true, however, there is a deep mystery that is awfully hard to explain. Nobel laureate Dr. Eugene Wigner (a theoretical physicist and mathematician) put it this way:
The first point is that the enormous usefulness of mathematics in the natural sciences is something bordering on the mysterious and that there is no rational explanation for it.
Think about it. We didn’t invent the natural world. We simply study it. If we invented mathematics, why does it play such an integral role in our understanding of the natural world?
In my opinion, there is no mystery as to why mathematics is so useful in the natural sciences. That’s because I don’t think we invented it; I think we discovered it. Indeed, I think it is the language of creation. As Galileo wrote:
[The universe] cannot be read until we have learnt the language and become familiar with the characters in which it is written. It is written in mathematical language, and the letters are triangles, circles and other geometrical figures, without which means it is humanly impossible to comprehend a single word.
I was reminded of Galileo’s wise words when I read a short paper by two professors from my alma mater, the University of Rochester.
Ozone hole size and worldwide use of ozone depleting substances (click for credit)
A reader sent me this article and asked for my thoughts on it. It discusses the fact that the ozone “hole” over Antarctica grew 22% from 2014 to 2015. It presents the graph shown above, which demonstrates that despite the fact that the worldwide use of chemicals known to destroy ozone has dropped to nearly zero, the size of the ozone hole has not really decreased. It points out two studies that claim the ozone hole will shrink in size by either 2020 or 2040, and it concludes with this sentence:
But the longer the hole persists, the greater the likelihood that the ozone layer is dominated by natural factors, not human CFC emissions.
So what’s the story? By banning the use of CFCs, which we know can destroy ozone in the ozone layer, did we really fix the ozone “hole” problem? Or did we, as this story seems to imply, try to fix something that is probably the result of earth’s natural variability?
The first thing you need to know is that the ozone “hole” isn’t really a hole. It is a reduction in the amount of ozone that exists within the ozone layer, a portion of earth’s atmosphere that is roughly 15-35 kilometers above the surface of the earth. While all portions of the atmosphere have some ozone in them, this portion has the highest levels. Ozone’s molecular structure allows it to absorb some of the ultraviolet light that comes from the sun. That’s good for us, because ultraviolet light is energetic enough to kill living tissue. You can therefore think of the ozone layer as a “shield” that protects us from most of the sun’s ultraviolet light.
The amount of ozone in the ozone layer is measured using Dobson Units (DU). The larger the number of Dobson Units, the more ozone there is in the ozone layer. Globally, the average amount of ozone in the ozone layer is about 300 DU, but in Antarctica, that number fluctuates significantly with the seasons. While there are times the amount of ozone in the ozone layer above Antarctica is 300 DU and higher, there are also times it is significantly lower. The lowest recorded level of ozone in the ozone layer above Antarctica was in September of 1994, when there were only 74 DU of ozone. That reduction of ozone is what scientists refer to as the ozone “hole.”
Coral reefs like this one support a wide diversity of ocean life. (click for credit)
Coral reefs are often called “the rainforests of the sea,” because the are so rich in biodiversity. According to the National Oceanic and Atmospheric Administration, they support more species per unit area than any other marine environment and produce as much as $375 billion each year in economic activity. As an amateur scuba diver, I know the amazing beauty of coral reefs firsthand. That makes the following statistics from the Global Coral Reef Monitoring Network alarming: the oceans have lost 19% of their coral reefs (by area), an additional 15% are seriously threatened in the next 10-20 years, and another 20% are threatened in the next 20-40 years.1
All over the world coral reefs are dying out. Marine pollutants, agricultural run-off and, above all, global warming, are taking a toll on these fragile marvels of nature…Politicians may be able to deny global warming, corals, sadly, don’t have that option.
While it is very fashionable these days to blame nearly any environmental crisis on “global warming,” we have no idea what the key factor in the loss of coral reefs is. Indeed, we don’t even know if there is a key factor. There might be several processes that are working together to produce this global loss of coral, and some of them might be completely unknown. However, an international team of researchers has found one thing that is definitely harming coral, and it certainly wasn’t anything I expected!
The moon during the recent eclipse as seen by a camera (left) and through a telescope (right). [click for a larger image]
If you watched the lunar eclipse on September 27th, you were treated to quite a sight! My wife got some great pictures of it, two of which are shown above. The image on the left is a picture she got with her camera alone, and the one on the right is what she got with her camera looking through my telescope. That was a particularly difficult shot, because the camera wasn’t designed for the telescope. She just pointed her camera at the eyepiece and patiently played with its orientation until she got the best shot she could.
The eclipse was beautiful, but it did produce something unexpected: a dark moon. Now, this eclipse was supposed to be dark, because the moon was at its perigee, which is the closest it gets to the earth. As a result, the earth’s shadow covered it a bit more thoroughly than it would have if the moon had been farther from the earth. Nevertheless, a lunar eclipse doesn’t make the moon go completely dark, because sunlight is bent through the earth’s atmosphere and shines on the moon. The process of sunlight traveling through the atmosphere produces a noticeable effect.
Sunlight is composed of many different wavelengths of light, each of which corresponds to a color that we perceive. The longest wavelengths of sunlight are red, while the shortest wavelengths are blueish. The other colors (orange, yellow, and green) are in between. Because wavelength and energy are inversely proportional, red sunlight is lowest in energy, and blue sunlight is highest in energy. Once again, the other colors are in between. Well, when sunlight passes through the atmosphere, it can bounce off particles and molecules floating in the air. Higher-energy light tends to bounce off more things than lower-energy light, so as sunlight passes through the earth’s atmosphere, the blues and greens tend to bounce around more than the reds, oranges, and yellows.
This is why the sun appears reddish-orange at sunset. When you look at the sun, the light you see is traveling straight from the sun to your eyes. The closer the sun is to the horizon, however, the more atmosphere its light must travel through to reach your eyes. Since the blues and greens tend to bounce off things in the air, they don’t travel as straight as the reds and oranges. As a result, more red and orange light coming from the sun hits your eyes than blue and green light, so the sun appears reddish-orange when it is near the horizon. The same effect causes the moon to appear reddish-orange during a lunar eclipse.
The termite mound behind those zebras makes life better for the plants and animals surrounding it.
In the United States, we think of termites as pests, because they can destroy our homes. However, in Africa, they are anything but pests. Instead, they are “soil engineers” that make their surroundings more hospitable for other organisms. How do they accomplish this? By building their homes, which we call termite mounds. As Dr. Todd Palmer (an ecologist at the University of Florida in Gainesville) puts it:1
These mounds are really the supermarkets of the savanna.
How do termite mounds become “supermarkets of the savanna”? It’s because of the engineering prowess of the termites. If the soil is too sandy to make their mounds, the termites add clay to it. If the soil has so much clay that it is difficult to excavate, the termites add sand to it. Either way, they end up making the soil more ideal for plant growth. In addition, the engineered soil helps the mounds hold onto water more efficiently. Indeed, when an African savanna goes through a dry spell, most of the plants turn brown. However, the plants that grow in and around the mounds remain green.
Not only do termite mounds help retain water, but they also enrich the soil with chemicals that are necessary for good plant health. Studies show that the soil in and around a termite mound has significantly more nitrogen and phosphorus in it than soil that is far from a termite mound. Those nutrients end up producing benefits in plants that grow up to 5 meters away from the mound!2
This is a white-tailed deer. Other members of its species have been caught eating birds!
In order to make sense of the living world, biologists attempt to classify the organisms they find in creation. No classification system is perfect, of course, because creation doesn’t conform itself to the definitions that we invent. A classic example is a slime mold, which I have discussed before (see here, here, and here). These interesting organisms resemble fungi during part of their lifecyle, but they resemble colonies of single-celled organisms (called protists) during other parts of their lifecycle. So, are they fungi, or are they protists? Well, they used to be classified as fungi, but later on, biologists began classifying them with the protists. Either way, however, there are problems, because slime molds simply don’t fit well into either category.
Such problems are to be expected when you are trying to make sense of the incredibly diverse creation that God designed. However, there are some classification schemes you would think should be fairly reliable. For example, animals are generally classified into one of three groups: herbivores, carnivores, and omnivores. What is an herbivore? Here’s how an article from Northwestern University defines it:
A herbivore is an animal that gets its energy from eating plants, and only plants.
The website lists several examples of herbivores, one of which is a white-tailed deer. Montclair State University has a “Whitetail Deer Fact Sheet” that says:
Whitetails, like all ungulates, are strictly herbivores and have teeth that are adapted for chewing.
This, of course, makes perfect sense. After all, the ungulates (a group of animals that includes horses, cattle, sheep, giraffes, camels, deer, and hippopotamuses) have a digestive system that seems optimized for plant matter. No matter how obvious this classification seems, however, it turns out that it’s at least a bit wrong!
The underside of a gecko’s foot as seen through glass (click for credit)
Geckos are lizards that have an uncanny ability to crawl on virtually anything. They effortlessly climb up glass windows without slipping, and they can even crawl on a smooth surface when they are upside down! What gives them this incredible ability? A popular chemistry textbook explains it this way:1
…the gecko uses van der Waals forces to attach itself to surfaces and employs a special technique to disengage from that surface. Van der Waals forces exist between any two surfaces, but they are extremely weak unless relatively large areas of of the two surfaces come quite close together. The toe of a gecko is covered with fine hairs, each hair having over a thousand split ends. As the gecko walks across a surface, it presses these stalks of hairs against the surface. The intimate contact of a billion or so split ends of hairs with the surface results in a large, attractive force that holds the gecko fast. Just as easily, a gecko’s foot comes cleanly away. As the gecko walks, its foot naturally bends so the hairs at the back edge of its toes disengage, row after row, until the toe is free.
I have used this explanation myself when lecturing about van der Waals forces. It sounds like scientists have the gecko’s climbing ability all figured out, doesn’t it? Not surprisingly, however, the gecko’s climbing ability is even more complex than we imagined. As a result, scientists still haven’t completely figured it all out.
The best way to understand what I mean is to look at a bit of history. Back in 1904, German scientist H.R. Schmidt thought that perhaps the gecko employed electrical charges to stick to surfaces. After all, opposite charges attract one another, so if a gecko could induce its feet to develop one charge and the surface to develop the opposite charge, the resulting attractive force could hold the feet to the surface.
About three decades later, another German scientist, Wolfgang-Didrich Dellit, did a simple experiment to test that hypothesis. He shot X-rays at the air surrounding a gecko’s feet while it was on a smooth metal wall. Those X-rays should have ionized the air around the gecko’s feet and neutralized any charge on the wall’s surface. This would have negated any electrical force between the gecko’s feet and the wall, and the gecko should have fallen off the wall. However, after repeated attempts, he couldn’t get a gecko to even slip.2 As a result, scientists ruled out the possibility that electrical charges had anything to do with a gecko’s climbing ability.
Dellit also tested other possible explanations, including that geckos used suction to hold to surfaces, and each was ruled out. Eventually, electron microscopes were used to analyze gecko feet. Once the toe hairs and their “split ends” were seen, the van der Waals forces explanation given by the chemistry text I quoted above was suggested. In the year 2000, a study in Nature confirmed the explanation. It directly measured the force of a single hair from a gecko’s foot, confirming that van der Waals forces were at play.3 As a result, van der Waals forces have been considered the complete explanation for a gecko’s remarkable climbing ability…until now.
![The moon during the recent eclipse as seen by a camera (left) and through a telescope (right). [click for a larger image]](http://www.drwile.com/eclipse.jpg)
