Posted by jlwile on May 9, 2013
Eurasian Jays like this one are monogamous, and the male gets his mate by offering her food (click for credit).
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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Posted by jlwile on April 22, 2013
This nematode's nervous system is perfectly wired for minimum use of materials. (click for credit)
Before that happened, however, Christopher Cherniak did a detailed analysis of the creature’s nervous system. Approximately one-third of the cells in the roundworm’s body are nerve cells, so the nervous system is obviously important to this tiny animal. The system is made of clumps of nerve cells (called ganglia) in the head, tail, and scattered throughout the main nerve cord, which runs along the bottom of the worm’s body. While this system is “simple” compared to the kind of nervous systems you find in many other animals, it has served as a model for helping scientists understand how nervous systems develop and function in general.
Of course, since the nervous system has to process sensory information and control various muscle movements, the ganglia must be connected to one another, to the receptors that sense the outside world, and to the muscles that the nervous system controls. Obviously, then, there is a lot of “wiring” involved. Cherniak wanted to know what determined how this wiring was done in the animal, so he computed all the possible ways that the worm’s nervous system could be wired, given its structure and the number of components it had. His computation indicated that there were 39,916,800 ways the wiring could have been done.
Now that’s a lot of possibilities, but even back in 1994, computers could easily analyze all of them, so he used 11 microcomputers to analyze all 39,916,800 ways the nervous system could be wired. It took them a total of 50 hours to churn through the analysis, but what they found was incredible!
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Posted by jlwile on April 17, 2013
A portrait of Eratosthenes, who lived from 276 BC to 194 BC (public domain image)
Somewhere around 200 BC, a man named Eratosthenes learned that at noon on the Summer Solstice in Syene, a man looking down a deep well would see no light in the well, because his shadow would block all the sunlight. He reasoned that this meant the sun was directly overhead in the city of Syene at that moment. Well, he lived in Alexandria, which was about 500 miles south of Syene. He measured the length of a pole’s shadow in Alexandria at noon on the Summer Solstice and from that determined the angle at which the sun shined on Alexandria when the sun was directly overhead in the city of Syene.
Why would Eratosthenes do this? Well, like all ancient natural philosophers (including the Christian ones who would come a few hundred years later), he understood that the earth is a sphere. If you are under the mistaken impression that most ancient people thought the earth was flat, you need to realize that this is a textbook myth that is repeated over and over again but is nevertheless quite false. Since he knew that the earth is a sphere, he used his measurement to reason that the distance between Syene and Alexandria is about one-fiftieth of the distance around that sphere. He then took the known distance between Syene and Alexandria and multiplied by 50 to get the total distance around the earth. The unit he used to measure distance (the stadium) had different definitions at the time, but assuming he used the one that was typically used for long journeys, his measurement was correct to within 2% of today’s accepted value.1
Does that surprise you? It shouldn’t. In today’s culture, we think of ancient people as ignorant savages, but in fact, many of them were incredibly intelligent. According to at least one geneticist, they were probably more intelligent than we are! In a two-part series published in the journal Trends in Genetics, Dr. Gerald R. Crabtree states:2
I would wager that if an average citizen from Athens of 1000 BC were to appear suddenly among us, he or she would be among the brightest and most intellectually alive of our colleagues and companions, with a good memory, a broad range of ideas, and a clear-sighted view of important issues.
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Posted by jlwile on April 10, 2013
A graph showing Global Climate Model predictions compared to surface temperatures (click for credit).
If you look at the graph above (which is from the article), you will see the GCM predictions most recently cited by Global Warming advocates. The dark cyan areas represent what the GCMs predict with a certainty of 75%, and the lighter areas represent what the GCMs predict with a certainty of 95%. As you can see, the measured surface temperatures (given by the dark line) are not behaving as predicted for the past several years. In fact, they have already strayed out of the 75% certain predictions and are poised to stray out of the 95% certain predictions. This, of course, is discussed in the article. What is not discussed is that the graph is rather misleading.
If you look at the graph from 1950 to the present day, you will see remarkable agreement between the GCM “predictions” and the measured data. However, prior to 2001, none of those “predictions” are actual predictions. They are a retrospective fit to the already-known data. You see, the GCMs are so oversimplified that they contain all sorts of “fudge factors.” Those fudge factors are varied to produce as much agreement as possible between the known data and the GCMs. Since the GCM predictions shown in that graph were produced for the IPCC report issued in 2007, they represent work done after the IPCC report issued in 2001. As a result, the data that appear on the graph prior to 2002 were all known when the work was started on the 2007 report. This means that all agreement between the “predictions” and the data prior to 2002 say nothing about the ability of the GCMs. It only tells you how well the fudge factors could be varied to agree with the known data.
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Posted by jlwile on March 29, 2013
This broad-barred goby is one of the species that responds to a coral's call for help (click for credit)
Anyone who has read this blog for a while knows that I am fascinated by the mutualism that seems to be all over creation. You can seem some of my previous posts about this topic here, here, here, here, and here. I recently came across a study that provides another example of mutualism in one of favorite habitats: a coral reef. As an amateur scuba diver, I spend a lot of time enjoying the wonders of coral reefs, and the more we study their biology, the more amazed I am at the interconnectedness that exists among their inhabitants.
The authors of the study were trying to understand how a very common species of coral, Acropora nasuta, protects itself against the toxic seaweed Chlorodesmis fastigiata. This particular seaweed attempts to take over a coral reef by producing chemicals that harm the coral. The chemicals reduce the coral’s ability to grow and feed, allowing the seaweed to “muscle in” on the coral’s turf. When the seaweed is completely successful, it chokes out the coral, forming a shrubby thicket where the coral once was.
As the authors note, previous studies have already shown that overfished coral reefs are more likely to be taken over by such seaweed, so they wondered if perhaps the fish that live in the coral reefs provide some sort of protection for the coral. They found that certain species of goby (particularly the broad-barred goby, Gobiodon histrio, and the redhead goby, Paragobiodon echinocephalus) do, indeed, protect the coral from the seaweed, but the process by which this happens is rather surprising.
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Posted by jlwile on March 20, 2013
A model of the influenza virus (Public Domain Image)
In his book Genetic Entropy and the Mystery of the Genome, award-wining geneticist and young-earth creationist Dr. John C. Sanford argues that most mutations simply don’t produce a strong enough effect to influence natural selection. As a result, organisms continue to build up deleterious mutations as time goes on. This leads to an erosion of the genome. As he puts it:1
While selection is essential for slowing down degeneration, no form of selection can actually halt it. I do not relish the thought, any more than I relish the thought that all people must die. The extinction of the human genome appears to be just as certain and deterministic as the extinction of stars, the death of organisms, and the heat death of the universe. (emphasis his)
While he quotes a lot of experimental research to support his findings, he has never been able to demonstrate this effect directly…until now. He obviously hasn’t shown that the human genome is deteriorating, but last year he and young-earth creationist Dr. Robert W. Carter published (in a standard, peer-reviewed journal) the results of some of their research, which directly demonstrate that even when natural selection is working hard, it doesn’t seem to do a good job of getting rid of harmful mutations.
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Posted by jlwile on March 11, 2013
This medical image shows the appendix coming from the large intestine. (Click for credit)
BODY PART: 1 (plural appendixes) a small tube-shaped part which is joined to the INTESTINES on the right side of the body and has no use in humans
[emphasis in original]
Of course, anyone who has been reading this blog for a while knows what the scientific evidence actually says: The appendix is not useless in any way. As a recent study tells us:2
Substantial evidence supports the view that the cecal appendix is an immune structure primarily functioning as a safe-house for beneficial bacteria, and comes from a range of disciplines, including medicine, epidemiology, immunology, and microbiology.
In order to salvage what they can, most evolutionists who know about the recent evidence now admit that the appendix has function, but they still insist that it is vestigial. They argue that the appendix evolved this new function once the old function was no longer needed.
At least some evolutionists, however, are more interested in what the data actually say. The authors of the study in reference (2) have looked at the data and have come to the conclusion that the appendix is not vestigial in any way. Instead, it is so important that it has evolved independently at least 32 separate times throughout the course of mammalian evolution!
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Posted by jlwile on February 22, 2013
A chromosome-by-chromosome comparison of chimpanzee and human DNA. The chimp DNA was cut into slices of varying lengths (see legend on the right), and a similar sequence was searched for on the relevant human chromosome, which is shown on the horizontal axis.
(Copyright Answers in Genesis, published at http://www.answersingenesis.org/articles/arj/v6/n1/human-chimp-chromosome in a study by Jeffrey P. Tomkins)
I have written about the similarity between human and chimpanzee DNA three times before (here, here, and here). It’s an important question for creationists, intelligent design advocates, and evolutionists alike, since the chimpanzee is supposed to be the closest living relative to human beings. As a result, a comparison of chimp DNA to human DNA gives us some idea of what the process of evolution would have to accomplish to turn a single apelike ancestor into two remarkably different species like chimpanzees and people.
Early on, it was widely thought that human DNA and chimp DNA were 99% similar. As I discussed in my first post on this subject, that was based on a very limited analysis of only a minute fraction of human and chimp DNA. Now that the entire set of nuclear DNA (collectively called the “genome”) of both humans and chimpanzees have been sequenced, we now know that the 99% number is just plain wrong. Interestingly enough, however, even though both genomes have been fully sequenced with a reasonable amount of accuracy, no one can agree on exactly how similar the two genomes are.
Why is that? Because comparing genomes is a lot harder than you might think. While we know the sequence of the chimp and human genomes really well, we don’t understand the DNA itself. Indeed, there are large sections of DNA that seem to be functional, but we simply have no idea what they do. As a result, comparing the genomes of two different species can be very, very tricky.
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Posted by jlwile on February 4, 2013
DNA can store incredible amounts of information (montage of public domain images)
Yes, the team encoded all 154 of Shakespeare’s sonnets, a photograph of the European Bioinformatics Institute (where the scientists work), and a 26-second audio clip from Martin Luther King’s famous “I have a dream” speech.1 Also, in a very fitting symbolic gesture, they added the famous James Watson and Francis Crick paper that first revealed the structure of DNA.2
This new achievement was noteworthy for more than just the fact that the scientists stored audio on DNA. While the method that the previous team used to store the book worked well, it was difficult for instruments to retrieve the information from the DNA once it was stored there. Thus, the time it took to retrieve the book from DNA storage was fairly long. The scientists who produced this study used a different method to store the information, which made it much easier for instruments to read it back. As a result, not only was everything retrieved from DNA storage with 100% accuracy, the time it took to get it back was significantly reduced.
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Posted by jlwile on January 23, 2013
DNA uses four nucleotide bases taken three at a time to code for an animo acid (click for credit).
How does a gene list the amino acids? As shown in the illustration above, it does so by using the four nucleotide bases known as cytosine (C), guanine (G), thymine (T), and adenine (A). A group of three nucleotide bases codes for a specific amino acid. For example, when a gene has three thymines in a row (TTT), this means “use the amino acid called lysine.” When it has three guanines in a row (GGG), it means “use the amino acid called proline.” So by grouping its four nucleotide bases three at a time, a gene specifies which amino acid should be used in building a protein.
Here’s the catch: There are only 20 amino acids in the standard proteins of life. As a result, there need to be only 20 codes to specify them. However, there are 64 possible ways you can group four nucleotide bases three at a time. Thus, there are 64 different possibilities for how a gene can specify an amino acid, but there are only 20 amino acids the gene needs to specify. As a result, most amino acids are specified by more than one set of three nucleotide bases. As I said above, a sequence of three thymines (TTT) means “use the amino acid called lysine.” However, two thymines followed by a cytosine (TTC) means the same thing. This is why we say the genetic code is degenerate. It has multiple ways it can specify most amino acids.
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