Early Eyes in Evolution

Posted on November 25, 2008 by Michael

I’ve already blogged about eyes and evolution, so I won’t go on about further research. But I will post an interesting article from sciencedaily.com.

ScienceDaily (Nov. 23, 2008) — Researchers unravel how the very first eyes in evolution might have worked and how they guide the swimming of marine plankton towards light.

Larvae of marine invertebrates – worms, sponges, jellyfish – have the simplest eyes that exist. They consist of no more than two cells: a photoreceptor cell and a pigment cell. These minimal eyes, called eyespots, resemble the ‘proto-eyes’ suggested by Charles Darwin as the first eyes to appear in animal evolution. They cannot form images but allow the animal to sense the direction of light. This ability is crucial for phototaxis – the swimming towards light exhibited by many zooplankton larvae. Myriads of planktonic animals travel guided by light every day. Their movements drive the biggest transport of biomass on earth.

“For a long time nobody knew how the animals do phototaxis with their simple eyes and nervous system,” explains Detlev Arendt, whose team carried out the research at EMBL. “We assume that the first eyes in the animal kingdom evolved for exactly this purpose. Understanding phototaxis thus unravels the first steps of eye evolution.”

Studying the larvae of the marine ragworm Platynereis dumerilii, the scientists found that a nerve connects the photoreceptor cell of the eyespot and the cells that bring about the swimming motion of the larvae. The photoreceptor detects light and converts it into an electrical signal that travels down its neural projection, which makes a connection with a band of cells endowed with cilia. These cilia – thin, hair-like projections – beat to displace water and bring about movement.

Shining light selectively on one eyespot changes the beating of the adjacent cilia. The resulting local changes in water flow are sufficient to alter the direction of swimming, computer simulations of larval swimming show.

The second eyespot cell, the pigment cell, confers the directional sensitivity to light. It absorbs light and casts a shadow over the photoreceptor. The shape of this shadow varies according to the position of the light source and is communicated to the cilia through the signal of the photoreceptor.

“Platynereis can be considered a living fossil,” says Gáspár Jékely, former member of Arendt’s lab who now heads a group at the MPI for Developmental Biology, “it still lives in the same environment as its ancestors millions of years ago and has preserved many ancestral features. Studying the eyespots of its larva is probably the closest we can get to figuring out what eyes looked like when they first evolved.”

It is likely that the close coupling of light sensor to cilia marks an important, early landmark in the evolution of animal eyes. Many contemporary marine invertebrates still employ the strategy for phototaxis.

Can you feel the beauty?

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Darwin Wasn't Right

Posted on November 22, 2008 by Michael

Darwin Was Right About How Evolution Can Affect Whole Group

Evolutionary biologists at McGill University have discovered molecular signals that can maintain social harmony in ants by putting constraints on their fertility. Dr. Ehab Abouheif, of McGill’s Department of Biology, and post-doctoral researcher, Dr. Abderrahman Khila, have discovered how evolution has tinkered with the genes of colonizing insects like ants to keep them from fighting amongst themselves over who gets to reproduce.

“We’ve discovered a really elegant developmental mechanism, which we call ‘reproductive constraint,’ that challenges the classic paradigm that behaviour, such as policing, is the only way to enforce harmony and squash selfish behaviour in ant societies,” said Abouheif, McGill’s Canada Research Chair in Evolutionary Developmental Biology.

It’s unfortunate that group selectionism is gaining some traction once again. It almost never makes any sense and simply acts as a way of taking the easy explanation over the difficult answer.

This study found that evolution has changed the genetic make-up of ants to the point where social harmony is achieved through “reproductive constraint”. In other words, some worker ants have less or no fertility level relative to others because of particular gene regulations. Big deal. This doesn’t point to any group selectionism.

What makes far more sense is that ants which promote social harmony are more successful on average. Instead of looking toward the goal-oriented ideas of group selectionism, it’s more reasonably to view this as individual genes promoting their own fitness. That is, most ants in a colony, if not all, are going to share a high degree of genes. It isn’t that the vehicle for these genes – the organism, in this case, the ant – is important. The survival of the gene itself is important. With more harmony comes, perhaps, more reproduction and more success. And what’s being reproduced are a high number of shared genes.

Think of it this way. My brother and I share 50% of our genes. If I help him to reproduce, I have roughly 25% of my genes surviving to the next generation. Of course, if I simply reproduce on my own, that’s 50% of my genes that will be passed on. But if I’m fighting with my brother over the same woman, we decrease our reproduction odds. It may just benefit me on the level of the gene to help him reproduce at my own expense. Having assistance will help his odds (even if this assistance is passive, as in not fighting him). This will give 25% of my genes a better chance of surviving than the 50% of genes I ‘own’ have when there is conflict.

Rather than showing the notion of group selectionism to be valid (though it remains plausible), this research offers some interesting evidence which favors natural selection occurring at the level of the gene

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Darwin Wasn’t Right

Posted on November 22, 2008 by Michael

Darwin Was Right About How Evolution Can Affect Whole Group

Evolutionary biologists at McGill University have discovered molecular signals that can maintain social harmony in ants by putting constraints on their fertility. Dr. Ehab Abouheif, of McGill’s Department of Biology, and post-doctoral researcher, Dr. Abderrahman Khila, have discovered how evolution has tinkered with the genes of colonizing insects like ants to keep them from fighting amongst themselves over who gets to reproduce.

“We’ve discovered a really elegant developmental mechanism, which we call ‘reproductive constraint,’ that challenges the classic paradigm that behaviour, such as policing, is the only way to enforce harmony and squash selfish behaviour in ant societies,” said Abouheif, McGill’s Canada Research Chair in Evolutionary Developmental Biology.

It’s unfortunate that group selectionism is gaining some traction once again. It almost never makes any sense and simply acts as a way of taking the easy explanation over the difficult answer.

This study found that evolution has changed the genetic make-up of ants to the point where social harmony is achieved through “reproductive constraint”. In other words, some worker ants have less or no fertility level relative to others because of particular gene regulations. Big deal. This doesn’t point to any group selectionism.

What makes far more sense is that ants which promote social harmony are more successful on average. Instead of looking toward the goal-oriented ideas of group selectionism, it’s more reasonably to view this as individual genes promoting their own fitness. That is, most ants in a colony, if not all, are going to share a high degree of genes. It isn’t that the vehicle for these genes – the organism, in this case, the ant – is important. The survival of the gene itself is important. With more harmony comes, perhaps, more reproduction and more success. And what’s being reproduced are a high number of shared genes.

Think of it this way. My brother and I share 50% of our genes. If I help him to reproduce, I have roughly 25% of my genes surviving to the next generation. Of course, if I simply reproduce on my own, that’s 50% of my genes that will be passed on. But if I’m fighting with my brother over the same woman, we decrease our reproduction odds. It may just benefit me on the level of the gene to help him reproduce at my own expense. Having assistance will help his odds (even if this assistance is passive, as in not fighting him). This will give 25% of my genes a better chance of surviving than the 50% of genes I ‘own’ have when there is conflict.

Rather than showing the notion of group selectionism to be valid (though it remains plausible), this research offers some interesting evidence which favors natural selection occurring at the level of the gene

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Karl W. Giberson

Posted on November 21, 2008 by Michael

Every once in awhile, a scientist will come out and say science and religion can co-exist. There will be some press coverage because of the obvious tensions between evidence-based thought and willy-nilly faith. So it comes as no surprise that physicist Karl Giberson is receiving some attention for his recent claim and book that says evolution and God can co-exist. (I presume the man has a longer history in the creationism-evolution issue than what LiveScience seems to suggest, but he evidently has yet to make a big splash.)

Obviously, he thinks one can be a Christian and accept evolution, but these two sets of knowledge “don’t make as much contact with each other as people think,” he said. Many fundamentalists “elevate Genesis beyond what is appropriate.”

Fundamentalists’ spin on the creation story in Genesis “robs it of everything that is interesting,” he said. Instead, readers should recall that the Bible repeats the refrain that God found what he made “good” and looks at the world as good.

It is true that bastardizing such a great piece of literature to literally mean something which is utterly absurd is a crying shame, but that doesn’t suddenly make evolution and religion, especially Christianity, compatible in any meaningful way. At best, perhaps the particular Christian god fully guided the process of evolution, making it mimic precisely what would be expected without any sort of foolish guidance, but that’s a rather superfluous compatibility. What’s more, that can comply to most any concept of a god that humans have had in the past 10,000 or more years. It’s a very non-cromulent way of thinking.

“It makes the world so much more interesting,” Giberson said. “The mystery of God’s existence is a more satisfying mystery than the mystery of how can all this arise out of a particle.”

Despite being a rather subjective claim, it seems difficult to fathom how anyone can honestly believe such a thing. First of all, it’s unclear how a mystery can be “satisfying”. It can be interesting and exciting and all that. Most of the good ones are. But satisfying? It’s when we solve the mystery or at least a piece of it that satisfaction becomes present. And, of course, the only way we can do that for most of the big questions is through the best way of knowing – science.

But what is your evidence, Shermer said, for belief in God?

“I was raised believing in God, so for me, the onus would be on someone to stop me from believing,” Giberson said, adding that “there is a certain momentum that is already there.”

This reminds me quite a bit of the silliness of George Smith. Apparently, an objective look at two sides is out of the question. It is the job of the non-believer to dismantle the long-term indoctrination of the believer. I almost don’t want to explicate on why this is so damn wrong. But I will.

Blind, stupid faith offers nothing of worth to a discussion. Once that argument is presented, any debate falls to shreds because faith is specifically belief without – or even despite the lack of – evidence. Perhaps an argument as to why faith is a bad way of knowing (indeed, it seeks to avoid a knowledge of anything) can be presented, but then one is simply dealing with a stubborn child. Perhaps it is that the onus is to lower one’s self to explaining why faith informs us of nothing.

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I am Darwin

Posted on November 18, 2008 by Michael

There is a campaign being put on by i-am-darwin.org where users are encouraged to submit videos to YouTube where they describe how Darwin has influenced their lives. It shouldn’t be terribly difficult since the man made one of the most significant scientific discoveries yet known to man.

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Novel Information

Posted on November 11, 2008 by Michael

One of the more “sophisticated” creationists misconceptions about evolution/natural selection (they often conflate the two) is that new information can never be created. This actually has no sophistication in it at all, but it sounds fancy and for that reason it helps to trick a good number of people. It’s especially a shame when it confounds those who want to learn some actual science. So here’s a simple example of “novel information” being added to a genome.

Scientists Decode Cancer Patients’ DNA

ST. LOUIS, Nov. 10 (UPI) — Scientists in St. Louis say they have decoded the complete DNA of a cancer patient and traced her disease — acute myelogenous leukemia — to its genetic roots.

The research team at the Genome Sequencing Center and the Siteman Cancer Center at Washington University School of Medicine in St. Louis said the first-of-its-kind achievement involved sequencing the genome of the patient — a woman in her 50s who ultimately died of her disease — and the genome of her leukemia cells, to identify genetic changes unique to her cancer.

“Our work demonstrates the power of sequencing entire genomes to discover novel cancer-related mutations,” said senior author Richard Wilson, director of Washington University’s Genome Sequencing Center. “A genome-wide understanding of cancer, which is now possible with faster, less expensive DNA sequencing technology, is the foundation for developing more effective ways to diagnose and treat cancer.”

The study appears in the journal Nature.

When a cancer occurs, it is the usually the result of the loss of cell cycle control. Instead of the cell being told to die, it continues to replicate; it may lose its contact inhibition, meaning when an area gets too crowded, cells continue to replicate – this should not happen. There are other ways cancers occur, but they aren’t important for my purposes. What is important is the fact that a change in information in a genome is what caused the cancer in this woman in question. Let’s be clear from the get-go: this is not evolution. Individuals do not evolve. But what this does show is that novel changes occur to genomes all the time.

Recently, Steve Jones said evolution in humans is coming to an end. I haven’t heard his entire presentation, so I’m guessing he thinks it’s actually just slowing down, not ending. But either way, he’s wrong. But I bring him up because the reason why he’s wrong is interesting. He says that the fewer mutations present in reproducing males are contributing to less diversity in offspring. He says this because younger men are reproducing more than older men and older men, especially 35 and older, have more mutations in their DNA. (He later refutes his point by saying survival rates are up, inherently suggesting mutation rate must be up).

So why is this important? It’s important because mutations equal “novel information”. That’s what happens when cancers occur. That’s why the research team sequenced the genome of the woman plus the genome of her cancer cells. There are differences and those differences result in markedly different things. In this case, it’s unfortunate that cancer occurred. In other cases, it’s genetic diversity.

This is a bit of a roundabout way of explaining this, but I hope the point comes across. Cancer is a change in information. It’s obviously a bad one and it doesn’t get passed on in somatic cells, but let’s focus purely on the point: it is a change in information. It is a creation of new information. Although it is bad, it is new and it results in genotypic and phenotypic changes.

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Survey: 1 in 3 British teachers think creationism should be taught

Posted on November 8, 2008 by Michael

One in three.

One in three Brit teachers believes creationism should be at par with evolution

London, Nov 7 : One in three Brit teachers believes that the theories of creationism and intelligent design should be given the same status as evolution in the classroom, according to a new survey.

According to the survey of 1,200 teachers, 53 per cent thought that creationism should not be taught in science lessons, while 29 per cent thought it should, reports Timesonline.

However, 88 per cent said that if students raised the issue in a science lesson, they should be allowed to discuss it.

Creationism is based on a literal interpretation of scripture as an explanation for the origins of life.

Intelligent design is a more modern version, which says that life is so complex it cannot be explained solely by evolution.

According to National curriculum guidelines, creationism has no place in science lessons.

Last year, Professor Michael Reiss, a biologist and Royal Society director of education, provoked a furore by calling for creationism to be treated in science lessons as a legitimate ‘world-view’.

It’s nice to see a news article which calls intelligent design what it is – a “modern version” of creationism – but it’s still unfortunate to hear such a silly thing be called a “theory”. Maybe it’s stupid statements like this that have played into the awful science education of so many British teachers.

It should be of note that while creationism is rampant all over the world, including Britain, this was a survey of all teachers, not just science or biology teachers. Regardless, however, of one’s particular field, there’s little excuse for thinking magic is at all a legitimate world view.

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How Natural Selection is Cumulative

Posted on November 8, 2008 by Michael

Tale Of Two Snails Reveals Secrets About The Biochemistry Of Evolution

In the new study, Emilio Rolán-Alvarez and colleagues note that scientists long have known that animals of the same species can have different physical characteristics enabling them to survive in different habitats. One famous example is the different beak sizes and shapes that evolved in Darwin’s finches, enabling the birds to live on different foods in different habitats on the Galapagos Islands. Until now, however, scientists knew little about the invisible biochemical changes behind such adaptations.

To help fill those gaps, the scientists studied two populations of marine snails that live only a few feet apart on the Spanish coast. One group lives on the lower shore, typically submerged in water and protected from large changes in temperature. The other group lives on the upper shore exposed to daily changes in temperature, humidity and other environmental conditions. Tests with mass spectrometry showed major differences in about 12 percent of the proteins in the snail, a subset of proteins that apparently enables the snails to survive in different environmental conditions.

This is a wonderful example of the how natural selection works in a cumulative way. Rather than the misconception that entire organs and bodily systems come into existence in one fell swoop, this study of snails offers a taste of reality.

Notice that these snails have the same set of proteins. However, between the two groups, there are differences within the proteins. Essentially, the proteins are expressed differently. At least part of the reason has to do with differing levels of ATP, or energy. That is, these proteins are regulated slightly differently, but differently enough to allow for this species of snail to live in two distinct environments. This can be important in explaining the cumulative effects of natural selection – this is still one species of snail, but they have minute differences in just 21 proteins which allow for slightly different living conditions. If the snails continue to diverge and actually fully speciate (they are in a state of sympatric incomplete speciation now) – i.e., they cannot or simply do not produce fertile offspring – then it is highly likely that such an event would be contigent upon this first deviation in protein regulation.

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Japanese Researchers Begin to Pull Ahead

Posted on November 6, 2008 by Michael

Thanks to the tireless efforts of the soon-to-thankfully-end Bush administration, the United States is beginning to fall behind in science and technology. One example to this effect is the recent advancements made by the well-funded research of Japanese scientists.

TOKYO (AFP) – Japanese researchers said Thursday they had created functioning human brain tissues from stem cells, a world first that has raised new hopes for the treatment of disease.

Stem cells taken from human embryos have been used to form tissues of the cerebral cortex, the supreme control tower of the brain, according to researchers at the government-backed research institute Riken.

The tissues self-organised into four distinct zones very similar to the structure seen in human foetuses, and conducted neuro-activity such as transmitting electrical signals, the institute said.

Research on stem cells is seen as having the potential to save lives by helping to find cures for diseases such as cancer and diabetes or to replace damaged cells, tissues and organs.

The team’s previous studies showed stem cells differentiated into distinct cells but until now they had never organised into functioning tissues.

Let’s hope an Obama administration can finally give the scientific community the true support it has been needing for the past 8 anti-science years.

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Solid Argument

Posted on November 4, 2008 by Michael

This is from a bigoted article by Gerald Christian Nordskog, with Dr. Ted Baehr and Dr. Tom Snyder. The bigotry isn’t particular important (or well constructed). The interesting piece is when these mooks try to venture beyond their expertise of hate-mongering.

Most homosexuals seem to have adopted an irrational, unscientific view of the now defunct evolutionary model. They fail to realize, however, that, if evolution were really true (which it isn’t), there actually wouldn’t be any human homosexuals in the world. Why? Because, according to evolutionary theory, nature would have “selected out” over time, by the so-called “natural selection” evolution process, any truly genetic homosexual tendency because homosexual people do not procreate, or create any descendents. Thus, their deviant tendencies would have been eliminated from the gene pool by the untenable methodology of evolution.

No biologist is going to claim there is a gene which determines sexual preference. That isn’t how genetics work. Although studies have been conducted which have found that the genetic marker Xq28 conveys a tendency toward homosexuality, there is nothing that says homosexuality is deterministic. In fact, that study is far from solid but if it were true, it still wouldn’t say homosexuality is deterministic. This is essentially the problem encountered (unwittingly) by these bigots.

I may have a gene which gives me a predisposition to strong muscles around my shoulders. That doesn’t mean I’m going to be a great pitcher for the 2013 Boston Red Sox. It doesn’t even mean I would necessarily even have a chance at making it into an Independent League. Most genes have some degree – often a high one – of interaction with environmental conditions. This is why there is no “gay” gene(s) – and just the same, this is why there is no “straight” gene(s).

But just to be antagonistic toward these bigots, one possible way a gene which gives a predispotion (though not determinism!) toward homosexuality can be maintained in a gene pool is through sexually antagonistic selection.

The results of this model show the interaction of male homosexuality with increased female fecundity within human populations, in a complex dynamic, resulting in the maintenance of male homosexuality at stable and relatively low frequencies, and highlighting the effects of heredity through the maternal line.

These findings provide new insights into male homosexuality in humans. In particular, they promote a focus shift in which homosexuality should not be viewed as a detrimental trait (due to the reduced male fecundity it entails), but, rather, should be considered within the wider evolutionary framework of a characteristic with gender-specific benefits, and which promotes female fecundity. This may well be the evolutionary origin of this genetic trait in human beings.

Bigotry never wins.

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