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Wednesday, July 23, 2014

Fully Human

Posted by jlwile on February 27, 2013

The Home Educating Family Association is a wonderful organization that provides all sorts of useful resources to homeschoolers. They publish a magazine called (not surprisingly) Home Educating Family. Recently, they asked me to contribute to their first issue of 2013, which focuses on pro-life topics. I ended up writing two pieces for them. The first one is entitled “My Little Girl,” and it discusses our experience of adopting a teenager (who just turned 34!). It was probably the most difficult piece I have ever written, as it brought up all sorts of (mostly wonderful) memories. I had such a hard time finding the words I needed to convey what I felt, and then I had a hard time proofreading the piece because of my tears! The article is not available on the internet, so if you want to read it, you will need to get the print magazine.

The other article didn’t make it into the print magazine, so it ended up being posted on the Home Educating Family Association blog. It is essentially a composite of two blog posts I wrote previously discussing how a baby in the womb is fully human. It is not emotional, but some might find it interesting. If you care to read the piece, you can find it here.

Why (and How) Your Skin Wrinkles Underwater

Posted by jlwile on February 25, 2013

When immersed in water for a long time, the skin on your hands and feet wrinkles.
(Photo by Brenderous, click for full credit)

Almost everyone has experienced it. When you have been soaking in the bathtub, swimming, or just washing dishes for a long time, the skin on your fingers (and toes) wrinkles. From a scientific point of view, there are at least two questions to consider: (1) How does this happen? and (2) Why does this happen? Most textbooks explain (often incorrectly) the how, but I haven’t found any that explain the why. It seems that over the years, scientists have been studying this, and in the end, they have mostly answered both questions.

Let’s start with the “how.” A lot of textbooks and websites incorrectly explain this part. They say that it is the result of your skin absorbing water and swelling. It turns out that’s not true at all. More than 70 years ago, scientists showed that if certain nerves to the hand are damaged, its skin will not wrinkle, no matter how long it stays underwater.1 Over the years, other scientists have investigated water-induced wrinkling, and it seems to be the result of a process initiated by the nervous system.

Your skin is made of two layers: the epidermis (the layer you see) and the dermis (the layer underneath that contains blood vessels). When your hands and/or feet have been underwater for a long time, your nervous system tells the blood vessels in your dermis to constrict. This reduces the volume of the dermis, which in turn reduces the tension with which the epidermis is stretched. As a result, the epidermis “relaxes,” forming wrinkles.2

This answer is interesting enough, because I have long taught the incorrect explanation for how your skin wrinkles underwater. I am glad that I learned I was wrong on the point, and I will now start teaching the correct explanation. However, the “why” question is also very interesting, and a couple of recent studies have provided a good answer for that question as well.

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Human and Chimp DNA Only 70% Similar, At Least According to This Study

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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Some People’s Beliefs About Climate Change are Blowin’ in the Wind

Posted by jlwile on February 20, 2013

This graph shows the likelihood of New Hampshire residents agreeing with the statement, "Climate change is happening now, caused mainly by human activities" based on party affiliation and the average temperature. The gray fields represent the error associated with the data.
(The graph is from the study being discussed.)

If you have read this blog for any length of time, you probably know that I am skeptical of the idea that human activities are changing climate on a global scale. I don’t think the data support such a notion. Climate is certainly changing, but that’s nothing new. The data strongly indicate that around 1000 AD, the Northern Hemisphere was significantly warmer than usual; this is generally referred to as the “Medieval Warm Period.” About 650 years later, the Northern Hemisphere was significantly cooler than usual, and that period is often called the “Little Ice Age.”1 The important question is whether or not the changes we are seeing today is unusual compared to events such as those. Based on the data I have seen, my answer would be, “No.”

At the same time, I hasten to add that global climate is incredibly complex, and we are not close to fully understanding how it works or even how to measure it in a detailed fashion. Indeed, there are various methods used to determine the “average global temperature” and how it has changed over time, and they each produce different results. So while I think that the data show there is nothing unusual about the way climate is changing right now, I think a lot more study needs to be done.

But what do most people think? When it comes to climate change, their beliefs vary over time. The percentage of Americans who think the earth is warming has been falling since 2007. Interestingly enough, however, there seems have have been a recent rebound, at least when the phrase “climate change” is used. What drives these changes? Are the data changing significantly? Are the proponents of one side “getting their message out” better?

Unfortunately, a recent study has provided insight into why some people change their mind on the climate issue, and the results are rather depressing.

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Even Shark Embryos Detect Electric Fields

Posted by jlwile on February 18, 2013

A bamboo shark embryo in its egg case (Image from the study being discussed)

I have always been fascinated by sharks. In fact, of all the times I have been scuba diving, the dive I remember the most occurred off the coast of South Africa. I went with some marine biologists who had been studying sand tiger sharks (Carcharias taurus). As I initially sunk down into the water, I leveled out just a few feet from the bottom, and as I was checking my gauge to determine my depth, a 2-meter (6-feet) long shark swum right underneath me! We ended up seeing more than a dozen sharks of various sizes on that dive. It was incredible.

One of the things that is fascinating about sharks is the way they hunt. While they use their sense of smell (and to some degree their sense of sight), one of their main hunting techniques involves using their electrical sense. Yes, sharks can sense electrical fields, and they are quite good at it. As a recently published book on sharks says:1

They can detect the minute electrical currents generated by the nervous systems of prey by using electrical sensors called the ampullae of Lorenzini…These sophisticated sensors are very useful in finding prey buried under the sand.

Interestingly enough, these sophisticated sensors often develop while the shark is still an embryo. Is that just to get the shark ready for hunting its prey when it is fully developed, or could there be some use that the embryo has for sensing electrical fields? It doesn’t need to hunt, so for what purpose could it be using its electrical sensors?

Some Australian scientists decided to investigate this issue, and what they found is fascinating!

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Sockeye Salmon Use Geomagnetic Details to Guide Them Home

Posted by jlwile on February 13, 2013

A sockeye salmon jumps a beaver dam to get back to the stream from which it hatched. (Click for credit)

Salmon have an incredible lifecycle. They hatch in freshwater streams, eat and mature a bit, and then they make their way into the ocean. They do most of their growing and maturing in the ocean, and when they are ready to reproduce, they return to the very stream from which they hatched to find a mate and begin the cycle all over again.

A lot of research has been done trying to figure out how the salmon know the way back to the specific stream from which they hatched. Well, each stream has it own mix of soil, rocks, and other environmental elements. As a result, each stream has its own specific mix of chemicals. Most of the data indicate that a salmon remembers the specific chemical makeup of its original stream. Once it gets back to freshwater, then, it starts following a “chemical trail” that will lead it back to the stream from which it hatched.1

While this is rather impressive, it doesn’t really tell us about the most difficult navigational aspect of the journey. The salmon spends a long time in the ocean growing and maturing. As a result, it often ranges far from the place where it entered the ocean. How does it find its way back to the correct freshwater inlet that will lead to the correct stream? It seems hard to believe that it could follow a “chemical trail” that far! Since we know that salmon are equipped with biological machinery that allows them to sense the earth’s magnetic field, it has been thought for some time that salmon use magnetic guidance to get them to the proper freshwater inlet.2

While that’s a reasonable conclusion based on what we know, there hasn’t been a lot of evidence to back it up. However, a recent study published in Current Biology has begun to remedy that situation.

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Cosmos, Bios, Theos

Posted by jlwile on February 11, 2013

Dr. Henry Margenau was the Eugene Higgins Professor Emeritus of Physics and Natural Philosophy at Yale. He died in 1997, but five years before that, he and Roy Varghese, an international journalist, teamed up to edit a book entitled Cosmos, Bios, and Theos: Scientists Reflect on Science, God, and the Origins of the Universe, Life, and Homo sapiens. I came across an old review of the book some time ago, and it sounded intriguing, so I decided to put it on my reading list.

Margenau and Varghese contacted some of the most important scientists of the twentieth century and ask them about their views regarding God and the subject of origins. In the end, they got responses from 60 prominent scientists, 24 of whom had won the Nobel Prize. Most of them responded to six questions that Margenau and Varghese asked:

1. What do you think should be the relationship between religion and science?

2. What is your view on the origin of the universe: both on a scientific level and – if you see the need – on a metaphysical level?

3. What is your view on the origin of life: both on a scientific level and – if you see the need – on a metaphysical level?

4. What is your view on the origin of Homo sapiens?

5. How should science – and the scientist – approach origin questions, specifically the origin of the universe and the origin of life?

6. Many prominent scientists – including Darwin, Einstein, and Planck – have considered the concept of God very seriously. What are your thoughts on the concept of God and the existence of God.

As you might expect when 60 deep thinkers are asked such serious questions, the answers were varied and incredibly interesting. Before I discuss them, however, it is important to make two points. The first one is made in the preface of the book:

Cosmos, Bios, Theos makes no pretension to being a statistically significant survey of the religious beliefs of modern scientists. (p. xiii)

So the reader should not use the responses contained in this book to infer the general attitude among scientists toward the existence of God or the question of origins.

The second point is that not all the scientists responded to those six questions. Instead, some simply wrote a few pages of general thoughts about the topics of God and origins. Others permitted the use of interviews that had already taken place between them and Roy Varghese.

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Hippopotamus “Sweat”

Posted by jlwile on February 8, 2013

This circus poster promoted the myth that hippos sweat blood. (Public domain image)

I am currently in Thailand, speaking at a family education conference. There are a lot of incredibly wonderful families here, and not surprisingly, some of them feel a bit overwhelmed at homeschooling their children in Asia. To all those homeschoolers in the United States: be thankful for all the support that exists where you live. Home education is difficult enough when there are support groups, easy access to curriculum, and homeschooling conferences that showcase multiple speakers and vendors. Imagine trying to homeschool with without such luxuries. That’s what these families do every day.

Because I am one of the few speakers at this conference, I have been giving a lot of talks. However, my favorite thing to do is answer questions. As a result, one of my scheduled times with the parents was simply a question/answer session. It went really well, and I hope I helped these parents with their unique situations. I was also scheduled for two sessions with the teens, and I made one of them a question/answer session as well.

When you offer a one-hour time slot for questions and answers, there is always a risk. What if the attendees have no questions? What if they have a couple of questions, but not nearly enough to last for an hour? I honestly didn’t think this would be an issue for the parents, since they face so many challenges homeschooling where they are. However, I did worry about the teens. While I was sure they had lots of questions, I was afraid they wouldn’t be “brave” enough to ask them in a group setting. To reduce the risk, then, I offered free candy for every question. Not surprisingly, the teens ended up having plenty of questions.

One of the reasons I love answering questions is that I often learn something new in the process, and this conference was no exception. The second question I got from the teens was:

What is the color of hippo sweat?

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Even More Impressive DNA Storage

Posted by jlwile on February 4, 2013

DNA can store incredible amounts of information (montage of public domain images)

A few months ago, I wrote an article about a group of scientists who stored a book that contained words, illustrations, and Java script on DNA. It was an amazing technical achievement, and it demonstrated the incredible storage capabilities of this marvelous biomolecule. Well, another team of scientists has gone even further: they stored words, pictures, and audio on DNA!

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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