Oh yeah? So there!

January 20, 2011

Oh, what the hell. I really shouldn’t be doing this as I have actual work to do. CL Taylor (@cltaylor463) claimed to have disproven evolution several times. So I called him on it. He says

@BipedalTetrapod I just refuted your ignorant evolution-Athestic ideas in the past seven tweets

Okay then. Let’s have a look-see at the refutation, in reverse chronological order:

I have once again picked apart evolution!

Ya, ya, you said that. Butlet’s have a look

Adaptive radiation is a pipe dream develped by evolutions to justify a faulty assumption of evolution.

Um, no. Adaptive radiation is observable in the fossil record. Sorry, but “I say so” isn’t refutation.

All creatures are not perfect. Imperfections mean nothing evolution is flawed.

No. Evolution never EVER claimed creatures are perfect. Quite the opposite. Creationists do, however, so that’s a point for me.

Homology means that we have common traits with other animals but nothing more evolution is flawed

You share the same number of arms and legs and hands and feet with your siblings and cousins, yes? Are these genetic? Did you inherit those traits from a common grandparent? Or is it just chance that your whole family has the same number of fingers and toes? If these characteristics are genetic traits that are inherited from a common ancestor, then ALL organisms that share those traits inherited them from a common ancestor.

98% is not 100%.A chimp is not a human.Our DNA is so complex that we do not share a common ancestor.

Duh. If a chimp were human it wouldn’t be a chimp. DNA isn’t actually complex. It is very simple. Paired nucleotides strung together. It’s just that there are a shitload of pairs.

Life does not have a family tree evolutionist.We did not come from bacteria.

“because I say so” isn’t an argument. So, wrong.

It is impossible both mathematically&observingly for evolution to exist.

Whatever that means. Evolution is observable and has been observed (see http://www.talkorigins.org/faqs/faq-misconceptions.html#observe, http://www.talkorigins.org/faqs/faq-speciation.html) and mathematics is used all the time in evolution.

Since radioactive dating is inaccurate,Evolution is based on unscientific&undocumented assumptions.

Radioactive dating is quite accurate. http://www.talkorigins.org/faqs/faq-age-of-earth.html. Evolution is based on science, and always has been, whether you like it or not.

Evolutionist,still believe in the principle of superposition?

That recent strata are deposited on older strata? Duh.

Evolutionist-Calculations based on invalid assumptions always=invalid results

But calculations made repeatedly on assumptions that have been validated by umpteen different analyses from all walks of science tend to be valid. I would say, however, that Intelligent Design calculations, which are based on invalid assumptions, do lead to invalid results. So thanks for pointing that out.

There is no way for scientist to know the original amount of radioactivity in rocks when made.

Yes, there is, by looking at the quantity of the products of radioactive decay.

The earth’s rotation was stopped twice in Joshua10:13-14;II Kings20:9-11.

Gee, you got me there. Why, I must give up my atheistic evolutionist ways! No. Just kidding. Sorry, but it really wasn’t.

Only God could have designed cell differentiation so well. Random chance could not have done such.

Evolution is NOT about random chance. It is about iteration under selective pressure.

Evolution flaws-the uniqueness of DNA is so complex that it proves complex organism were made seperate&along side simple living things.

See the Chimp comment earlier. To which I will add that “It’s too complicated for me to understand so it must be false” is not a valid argument. I count 14, not 7 tweets. But anyway, let’s take a couple more:

@kaimatai It is not observable to believe in Evolution, b/c it denies the existance of God. God is the law and order in life.

So, what you are saying is, your faith is so shaky that it is threatened by actual observations of real events?

@kaimatai I find it very hypocritical that your lack of stable morality is lecturing me on your Postmodernism. Really? You are a fraud also

You want lack of stable morality? Research shows that the faithful have a wandering moral compass.


The Disingenuous “Thermodynamics” Argument

January 20, 2011

You know, I still keep seeing the second law of thermodynamics being used as an argument against evolution, despite multiple thorough rebuttals. So let me add a few words of my own in an effort to stem the flow of stupid.

The argument, loosely summarized, goes like this:

  1. The Second Law of Thermodynamics says that entropy must increase in any closed system.
  2. Since life from non-life requires complex molecules to form from simple molecules, life could not arise by chance, because this would violate the 2nd Law.
  3. Since mammals and birds and fish are all more complex than single-cell organisms, they could not have evolved, as a system cannot become more complex over time.

The rebuttals for this are, quite simply:

  1. The Earth is not a closed system. We receive about 1.3 kJ of solar energy per square metre per second, every second, always.  The second law of thermodynamics does not apply.
  2. Life from non-life is abiogenesis, not evolution. But abiogenesis is thought to have been driven by heat and chemosynthesis, so again there is an input of energy.
  3. Lastly, and most ironically, the very people who claim that single celled organisms couldn’t possibly become complex, multicellular organisms, themselves grew from a single cell. So it’s good enough for them, but not any other organism. And secondly, the argument using thermodynamics against evolution proposes, instead, the sudden appearance of all living things. Like that doesn’t violate the laws of thermodynamics. Sheesh.

But wait, there’s more. You see, the argument that evolution is impossible because of the second law was widely promoted by the likes of Drs. Henry Morris and Duane Gish of the Institute for Creation Research. Please note that these gentlemen, at the time they made these claims, had doctorates in Engineering and Biochemistry respectively. Which means they understood the laws of thermodynamics, and would have known that the argument was wrong. Which means they were blatantly lying.

The fact that this argument is still being presented as evidence against evolution is appalling, and shows just how ill-informed the anti-evolution movement really is.  Feel free to send anyone you find using this argument to this page, or for a more torough thrashing, to the Talk Origins Thermodynamics FAQ.


Quality, not quantity, leads to speciation

October 7, 2010

In 1859, Charles Darwin published a book that changed how biologists understand the living world. Although his book was titled “On the Origin of Species by Means of Natural Selection”, it never actually explained the process of speciation. Although an elegant and thorough explanation of the mechanisms underlying evolution, he extrapolates this to say “species have changed, and are still slowly changing by the preservation and accumulation of successive slight favorable variations”. In other words, natural selection produces change, and the accumulation of enough changes produces a new species. A century and a half later, this is still accepted wisdom.

For most Biologists (and scientists in general), accepted wisdom is not enough. Ernst Mayr put forth the notion of allopatric speciation – that physical isolation can allow genetic change to occur separately in two populations, eventually leading to reproductive isolation and thus to speciation. Steven Gould and Niles Eldridge produced the idea of punctuated equilibrium – that the history of life consists of long periods of stasis (ie species remain relatively unchanged) punctuated by rapid bursts of species diversification.

Although many viewed speciation and macroevolution as the rapid accumulation of many individual variations, effectively speeding up the process, others (Goldschmidt, Gould) proposed that these events occurred through single (or a small number of) events that produced significant morphological or physiological change. The technical term for this is saltation (meaning a jump), though Goldschmidt’s term “hopeful monster” is also used – not always kindly.

In the early 80’s, Homeobox genes were discovered. These are genes that regulate body pattern, and it was discovered that the duplication, relocation, and modification of these genes is responsible for significant changes in body plan. Suddenly there were genes that could produce “hopeful monsters” without significant genetic change. And yet, the gradualistic model of speciation through accumulation of many small changes has persisted, primarily because there has been no evidence that a single or small number of changes can produce enough change to create a new species.

Recently, Dr. Mark Pagel at the University of Reading decided to put to the test. He reasoned that if speciation is dependent on the accumulation of a number of genetic changes, that would show up statistically as a normal distribution in a survey of the number of genetic differences between species in the family trees of different groups.

What he found was that the distribution did not follow a normal curve, but an exponential (poisson) distribution instead. This is the distribution one finds with truly random distributions, such as the frequency of lightning strikes. The differences between these two random distributions are subtle but significant. The most important difference is that a normal distribution has a mode – a peak value around which the values are distributed. A poisson (exponential) distribution does not – any value is equally likely.

The implication for evolution is that there is no typical, usual, or expected number of mutations required for a population to become a separate species from its parent population. In other words, We can’t say that a new species arises after about 20 (or 60 or 2000) mutations. It may take any number of mutations to form a new species – 50, 100, 1000. Or just one.

At first this seems to fly in the face of the “accepted wisdom” that there is some sort of threshold for speciation. But given that mutation is random, any number of mutations could occur that produce little or no effect, or that do produce an effect but in genes that are unimportant. For speciation to occur, a change must arise that leads to a reproductive barrier. What this study tells us is that a sufficiently significant change is as likely to occur from a single mutation as from 10, 30, or 100.

So while the accepted wisdom – or at least the default assumption – is that speciation arises as the result of an accumulation of minor changes, it now looks more like a single significant change is responsible for a speciation event. The implication being that the quality of mutation, not quantity, is the deciding factor for speciation.

Although in retrospect this makes perfect sense, it does provide additional context for models of evolutionary change – such as punctuated equilibrium and Goldschmidt’s “hopeful monsters” – that were ridiculed when first proposed. Which just goes to show that Hamlet was right: There are more things in heaven and earth, Horatio, Than are dreamt of in your philosophy.

http://www.nature.com/nature/journal/v463/n7279/full/nature08630.html

http://www.newscientist.com/article/mg20527511.400-accidental-origins-where-species-come-from.html?full=true


The Triceratops that Never Wasn’t

August 11, 2010

 

I recently returned from a holiday abroad to find headlines proclaiming that Triceratops Never Existed! My first thought was of course, WTF? And my second thought was, just how stupid are they? And then the little pessimistic third thought was that the way this story is being waved about, it will be used as “ammunition” by antievolutionists, one more little item with which to further wrap themselves in ignorance.

So here is the story.

Ceratopsian dinosaurs were (mostly) large, quadrupedal herbivoves with a frill behind the skull, and many bore horns from the nose and/or the top of the skull over the eyes. There is substantial diversity in the group in the shape and size of the frill and horns, leading to the definition of many different genera and species. But there is also variation within each species, blurring the boundaries between the different classifications. Because of this, the group as a whole has undergone taxonomic revision several times. The recent work by John Scanella and Jack Horner continues this trend by further clarifying the taxonomy of this intriguing group.

Scanella and Horner surveyed known specimens of the ceratopsian classified as Torosaurus, and concluded that the developmental and morphological evidence suggests they are not members of a separate genus, but in fact “fully grown” members of Triceratops. This is bolstered by the fact that there are no known juvenile Torosaurus remains – though the discovery of such remains would, of course, reverse this change in classification. Since the name Triceratops was coined first, it remains while Torosaurus becomes obsolete (pending further study and corroboration by other researchers). This sort of thing happens all the time, partly because defining “species” for organisms that have been dead for 70 million years with only a limited dataset is tricky business, and partly because we learn more. Science progresses.

So, in fact, the story headlines should have read “Torosaurus reclassified as adult Triceratops“. But a) that requires understanding what is being written, and b) wouldn’t sell papers. It really ticks me off just how wrong the statement “Triceratops never existed” really is. Animals classified as Triceratops and Torosaurus did exist, which is why we have their fossils. The classification of one of these groups may be in error, but it would be Torosaurus that ceases to be as a genus.


Biology in Avatar

January 24, 2010

I recently saw the film Avatar. Despite the rehashed plot (think Dances with Wolves), I enjoyed the film immensely for its visual impact, effects, action, and of course way-cool 3D. I also liked much of the biology in the film. I thougt the creatures and plant life of Pandora were very plausible and creative. The idea of an ecology based on interconnected neural networks is an interesting one, and is conceivable if electrochemical signalling evolved early in the evolution of life on Pandora.

But there is one thing that bugged me a little.

The designers put a lot of effort into the consistency of the biology. The animals seem to share the hexapedal body plan, paired neural appendage, and clavicular respiratory organs openings. Also, many have a smaller, second eye on each side. The Na’vi people, however, do not. The neural appendage clearly indicates they evolved on Pandora, which means they share common ancestry with the other animals. And yet they have only four limbs, no second pair of eyes, and they have a nose.

Okay, I get that from a concept standpoint the humanoid appearance makes them a) easier to relate to from an audience standpoint, and b) has that added “just ’cause they look human don’t mean they are human” kick. I may be quibbling, but to go through the degree of design that they did and not even give the Na’vi anatomical vestiges – a second bump on the shoulder, depressions beside the eye and beside the collar bone, something to indicate common ancestry, seems to me like a significant oversight in an otherwise stunning production.


A Wandering Moral Compass

December 3, 2009

One of the main arguments by young-earth creationists against evolution actually has nothing to do with either creation or evolution.  The argumant goes like this:

  • With evolution there is no need for a god.
  • The study of evolution therefore leads to atheism.
  • Since God is the arbiter of right and wrong, disbelief in God removes any perceived need for a moral filter a person might have.
  • Therefore, evolution is wrong because it leads to amorality.

While this is just so wrong on so many levels – akin to “Your research is completely false because I dislike your sweater” – there is something even more. It turns out that it is belief in god that leads to a wandering moral compass.

A recent study, described in New Scientist, shows that people map their own beliefs on what they think God believes. In other words, people presume God’s beliefs based on their own, rather than the other way around. Thus, as people’s beliefs change, so does their presumption of God’s beliefs.

 This means that there is no absolute and permanent recognition of what God believes, and thus there is no definitive moral compass imposed by the Almighty. Even worse, it says that whatever a person believes, if they are a believer, they will tend to think that their personal beliefs are shared by God, and therefore just.

As an argument, this does not, of course, demonstrate the validity of evolution (there is plenty of that elsewhere) any more than the original argument refutes it. It does, however, suggest that creationists should not throw stones. Or, to take it a step further, maybe it suggests that evolution should be taught because it removes the wandering moral compass, leading to greater morality. 

I’m just sayin’.


Newly discovered mutation protects against prion disease

November 19, 2009

A recent article in New Scientist is a perfect illustration of how mutations can be beneficial, how beneficial genes can spread rapidly, and how humans are still evolving.

The mutation is a single amino acid change that appears to provide complete resistance to kuru, a prion disease similar to CJD or mad cow disease. Kuru was passed on through ritual cannibalism in Papua New Guinea, when family members ate the brain of the dead out of respect. Of course, once the disease began to spread, more funerals would lead to more cannibalism, which lead to more disease.

The protective gene is thought to have arisen within the last 200 years, and spread rapidly due to the selective pressure of kuru on the community.