This tiny, transparent roundworm has amazing neurons. (Click for credit)In my high school textbook, I try to emphasize the fact that there is no such thing as a “simple” life form. Even the most basic living organism is a marvel of amazing complexity. Consider, for example, the tiny roundworm, Caenorhabditis elegans, pictured on the left. It is only 1 millimeter long, and because it is transparent, it is very easy to study. In addition, because it’s nervous system is considered “simple,” it has been examined extensively in order to understand how animal nervous systems work.
Why is its nervous system considered “simple?” Well, the functional unit of an animal’s nervous system is the neuron, a sketch of which is given below:
A simplified sketch of a neuron (Image in the public domain)
These individual cells receive signals in their dendrites and transmit them through the cell body and down the axon. Most animal nervous systems are made up of many, many neurons. For example, in the part of the brain known as the cerebral cortex, cats have about 300 million neurons, dogs have about 160 million neurons, and chimpanzees have about 6.2 billion neurons. The animal with the largest number of neurons in the cerebral cortex is probably the African elephant, topping off at about 11 billion neurons, but the false killer whale comes in as a close second, at about 10.5 billion. By comparison, the cerebral cortex of a person contains about 11.5 billion neurons.1
The entire nervous system of C. elegans is a mere 302 neurons. That’s really simple compared to people and animals isn’t it? Well…not exactly.
An artist's rendering of the Mars rover "Curiosity." (NASA image)
A friend of mine told me about a news story he heard on NPR. He said that NASA had some “really exciting” results from the Mars rover named Curiosity, but they were not ready to release the results to the public yet because they wanted to confirm the data. My friend wondered if perhaps NASA had finally found the remains of life on Mars. I found the story on NPR’s website, and it sounds like my friend’s expectation could be right.
According to the story, the principle investigator, Dr. John Grotzinger, says:
This data is gonna be one for the history books. It’s looking really good.
Dr. Grotzinger is waiting to release the results, however, because NASA has been burned a couple of times before. Back in 1996, NASA scientists published a paper that claimed a meteorite from Mars (named ALH84001) held tell-tale signs of bacteria, indicating that there was once life on Mars. As more scientists studied the meteorite, however, several problems with that interpretation were found. As a result, even though some NASA scientists are still saying that the meteorite holds evidence of life on Mars, the data are inconclusive at best.
In addition, NASA scientists published a paper in 2010 claiming to have found a bacterium that could incorporate arsenic into its biochemistry. NASA said that this finding would change the way we think about bacteria and would help us better understand the possibilities for life on other worlds. However, in just a couple of years, two very detailed studies showed that the original NASA claim was incorrect. It’s understandable, then, that NASA scientists are being careful when it comes to the release of any surprising data from the Curiosity rover.
On November 14, there was a solar eclipse that was visible from Australia, New Caledonia, New Zealand, South America, and Antarctica. I would have loved to use it as excuse to visit any of those places, but unfortunately, I couldn’t. However, I was pleased to receive the next best thing. A wonderful home educator who is field-testing my new elementary science curriculum with her family, Marianne Trinham, sent me pictures of the eclipse as seen from Brisbane. I hope you enjoy them!
While the eclipse was total in northern Australia, it was not total in Brisbane. Here is an image of the maximum of the eclipse as seen there:
How did this family get that image? They used binoculars to project it onto a white sheet of paper:
This species of catus worm, Priapulus caudatus, falsified another evolutionary prediction (click for credit)Look at the unassuming worm pictured on the left. It is commonly called a cactus worm, but this particular species is known as Priapulus caudatus. According to evolutionists, cactus worms have been around for at least 500 million years.1, but they just recently falsified yet another prediction made by the hypothesis of evolution. To understand the prediction and why it has failed, you need to learn some background information.
There are many different ways scientists classify animals, but one of the broader ways it is done is by symmetry. Most of the animals with which you are familiar are bilaterally symmetric. This means their bodies can be split into a left half and a right half, and those two halves are roughly mirror images of each other. Cats, dogs, and horses are all bilaterally symmetric, as they all have distinct right and left sides that roughly mirror each other. In addition, cactus worms are bilaterally symmetric. Since there are a lot of animals that have this kind of symmetry, scientists have to find characteristics among the bilaterally symmetric animals that will further classify them.
Well, there are two different ways that bilaterally symmetric animals develop their digestive tract. In all these animals, a puckered indentation forms in the embryo. This indentation, called the blastopore, forms the beginning of a tube that will eventually develop into the digestive tract. However, in some bilaterally symmetric animals, that blastopore ends up becoming the mouth, while in other bilaterally symmetric animals, the blastopore ends up becoming the anus. In other words, some animals start their digestive system with their mouth, while others start their digestive system with their anus. The “mouth first” animals are called protostomes, which is a combination of the Greek word “protos” (which means first) and “stoma” (which means mouth). The “anus first” animals are called deuterostomes, which means “mouth second,” since the Greek word “deuteros” means “second.”
So when a biologist looks at an animal that is bilaterally symmetric, one of the first questions that comes to mind is, “How does the digestive tract develop?” That tells the biologist whether the animal is a protostome or a deuterostome. Well, it turns out that studying the embryonic development of animals is rather time-consuming, so scientists often use other characteristics to infer the group to which an animal belongs. With all that under your belt, you are now ready to learn about the falsified evolutionary prediction.
The La Brea Tar Pits as imagined by Charles R. Knight (public domain image)
Paleontologists have long recognized that the fossil record produces a serious problem for the hypothesis of evolution. Almost thirty years ago, Dr. David Wake and his colleagues stated:1
With natural selection operating in a changing environment as an agent of adaptation, we expect to see changes at the organismal, ultimately physiological and morphological, level. How, though, can we explain the paradoxical situation in which environments change, even dramatically, but organisms do not?
In other words, evolution predicts that in a changing environment, organisms should change in order to adapt. However, when we look at the fossil record, we don’t see such change. Instead, while it is thought that earth’s climate changed dramatically in many different ways throughout the fossil record, the fossils themselves show that the organisms living on earth didn’t change much at all. This has been called the “paradox of stasis,” and while several attempts have been made to resolve the problem2, none of them have been found to be satisfactory.3
In an attempt to understand the paradox of stasis better, Dr. Donald Prothero undertook a series of amazingly detailed studies. With the help of a small army of students, Prothero studied the fossils of all the common birds and mammals that have been preserved in the La Brea tar pits of Los Angeles, California. According to the standard geological view, these tar pits preserved species that lived in the area over a period of time when the region experienced wild climate change. It is thought that 35,000 years ago, the Los Angeles, California area had a very similar climate to what it has today. During the height of the last ice age (20,000 years ago), however, it was significantly colder and significantly wetter. As the ice age waned, the climate returned to what it was 35,000 years ago.
From an evolutionary point of view, one would expect that over the course of this dramatic change in climate, the birds and mammals living in the area would have experienced some amount of evolutionary change in order to adapt to their surroundings. However, that’s not what this series of studies found.
This photo shows four of the eight eyes on a jumping spider. The middle two are the principal eyes, and the other two are the anterior lateral eyes (ALEs). (click for credit)
Most spiders have eight eyes, and their arrangement varies depending on the type of spider. In fact, when studying a spider, scientists often use the number and arrangement of the eyes to help them classify the specimen.1 What does a spider do with all those eyes? Well, in the case of a jumping spider, we know that the two large eyes near the center of the head are the spider’s principal eyes. They can see sharp images, are sensitive to color, and can move to track a target.
The eyes that are right next to the principal eyes are called the anterior lateral eyes (ALEs). They cannot move, do not seem sensitive to color, and as far as we can tell, don’t really allow for the spider to see images. Instead, it has always been thought that these eyes help the spider detect motion.2 But what about the principal eyes? Do they detect motion as well? Three researchers decided to determine the answer to that question by conducting a interesting experiment with some spiders and an iPod touch.
They ended up using removable paint to “blind” specific eyes of jumping spiders from the species Phidippus audax. For 16 of the spiders, they used the paint to “blind” only the principal eyes. They then used the paint to “blind” only the ALEs of 14 other spiders. Finally, they used 16 spiders with none of their eyes “blinded” as a control group. One at a time, they put the spiders in an “arena” that had four walls. Three were foam-core walls, and the fourth wall was the screen of the iPod touch. They allowed each spider to acclimate to the arena and waited for its head to face the screen. When that happened, they remotely started an animation of a black circle either looming towards the spider or retreating from the spider. The results they got were quite interesting.
In my previous article, I discussed a chemical found in both the great orange tip butterfly and the marble cone snail. I made the statement that the researchers were surprised to find that the chemical was identical in both species. A commenter asked a good question: When would the same chemical be different (across species or not)? I thought the best way to answer that question was with a new post.
When most of us think about chemicals, we think about simple molecules like water: H2O. The chemical formula of water tells us that there are two hydrogen atoms linked to one oxygen atom. In a glass of water, there are all sorts of molecules like this, and they are all identical. If we do something to change the chemical formula of the molecule, we come up with a completely different chemical. For example, if I were to add one more oxygen to the molecule, I would get H2O2, which is hydrogen peroxide. It is utterly different from water, so in molecules like these, even a change of one atom makes a world of difference.
However, the biological world isn’t quite the same. The molecules are incredibly complex, often composed of thousands of atoms. Consider, for example, proteins. These are large molecules made by linking smaller molecules, called amino acids, together. When amino acids link up together in a specific way, they tend to make a specific protein. An example would be the protein known as cytochrome c. It is a relatively simple protein found in almost all living organisms. It is simple because, as proteins go, it is rather small. In most living organisms, cytochrome c is composed of “only” about a hundred amino acids.1 That might sound like a lot, but there are proteins in living organisms that are composed of more than 25,000 amino acids!2 So as proteins go, cytochrome c is rather “simple.”
There are many ways to picture a protein, but one way is called a “ribbon diagram.” In this way of picturing a protein, you get a three-dimensional view of the overall backbone of the protein. Here is the ribbon diagram for cytochrome c:
The ribbon diagram of cytochrome c, with the active site pointed out (Click for credit)
The green ribbons represent the structure of the backbone of the protein, and they are composed of many amino acids linked together. The gray bars represent the active site, which is where the protein does most of its work.
The great orange tip butterfly has a toxin in its wings that is identical to the toxin used by the marble cone snail. (Click for credit)
A former student of mine recently alerted me to a study that was published in the Proceedings of the National Academy of Sciences. The authors were studying the proteins found in the wings of a great orange tip butterfly, Hebomoia glaucippe. As they sorted through what they found, they were surprised to find a toxin known as glacontryphan-M.1 The fact that it is a toxin wasn’t surprising to them. After all, Monarch butterflies have cardiac glycosides in their bodies, which are toxic to many birds.2 It is thought that this is a defense mechanism, because birds that eat a monarch butterfly and get sick are unlikely to eat more monarch butterflies.
Here’s what’s surprising: the toxin is also found in a sea snail known as the marble cone snail, Conus marmoreus.3 You can see how it gets its name:
The marble cone snail (Click for credit)
The marble cone snail uses the toxin for hunting. It injects the toxin into its prey, paralyzing it. That makes the prey very easy to eat. Obviously, the researchers were surprised to find the same toxin in two separate species that are supposed to be distantly related in terms of evolution. More importantly, they were surprised at the fact that the two toxins are chemically identical.
One of the biggest problems facing evolutionists is the explanation of how brand new information can be added to a genome. After all, if flagellates eventually evolved into philosophers, an enormous amount of truly original information had to be added to flagellates’ (and their descendents’) genomes. However, genomes are so well-designed and highly-structured, it is difficult to imagine a naturalistic process that could add information to them. Nevertheless, evolutionists have tried their best. One of the more popular notions is gene duplication followed by mutation. We know that genes can be duplicated. It happens quite frequently. The thought is that when a gene is duplicated, one of the copies can continue to produce the protein it is supposed to produce, while the other copy is free to mutate and find some completely new function.
While the thinking behind this idea is logical, experimental evidence to support it has been hard to find. As a result, evolutionists tend to jump on any experimental finding that might suggest the idea is accurate. This is well illustrated by an article that was linked by a commenter on a previous thread. The article claims that researchers have finally shown how a gene can pick up a brand new function, which can then be amplified and modified over time.
Unfortunately, the article’s claim is not accurate. I had already read the scientific paper on which the article was based1, so when I read the article, I understood how incorrect its claims are. However, I am sure the commenter and many other readers of Science Daily do not. As a result, I want to discuss the study’s actual findings. They are very interesting, and they tell us a lot about the genetics of bacterial adaptation. However, they don’t tell us anything about how genes acquire brand new functions or about how information can be added to a genome.
New evidence indicates that proteins and DNA still exist in preserved Tyrannosaurus rex bone cells (Click for credit)In 2005, Dr. Mary Schweitzer stunned the scientific community by publishing data that indicated she had found soft tissue in a Tyrannosaurus rex fossil that is supposed to be more than 65 million years old.1 While many in the scientific community were unconvinced at the time, several lines of evidence now indicate that she was correct. Since that time, other examples of soft tissue in fossils that are supposed to be millions of years old have been found: muscle tissue in a salamander fossil that is supposed to be 18 million years old, retinal tissue in a mosasaur fossil that is supposed to be 70 million years old, and what appear to be bone cells from the same mosasaur fossil. Now, Dr. Schweitzer has come back into the picture with some strong evidence that she has also found bone cells in her Tyrannosaurus rex fossil, as well as one other dinosaur fossil.2
There are three different kinds of bone cells in vertebrates: osteoblasts, osteoclasts, and osteocytes. If you use a microscope, you can tell them apart just by looking at them. Osteoblasts are the cells that build bone, while osteoclasts are the cells that break down bone. Both are important, because your bones adjust to the needs of your body, so there are times that you will need to build more bone, and there are other times you will need to break down some bone. The third group of bone cells, osteocytes, are the most common. They maintain the bone.
The study that found bone cells in a mosasaur fossil found osteocytes, and that’s what Dr. Schweitzer’s team found as well. Now, of course, just because they found microscopic structures that looked like osteocytes isn’t necessarily surprising. After all, the fossilization process could be detailed enough to preserve the shapes of individual cells. If these structures really are just the fossilized shapes of the osteocytes, it is exciting, but not incredibly surprising. However, Schweitzer’s team has done some detailed experiments to show that these aren’t just shapes. Indeed, these osteocyte structures still contain proteins and probably even DNA!
