On Progress: Philosophical Ramblings on the Nature of Evolution

Posted April 10, 2010 by darwinaia
Categories: evolution, history of science

Let us consider, for a moment, the pinnacle of evolution.  This group of organisms builds its own cities, engages in organized labor, builds stratified, complex societies, and even practices agriculture in a sense.  I am referring to ants.  You might argue that my momentary classification of ants as the pinnacle of evolution demonstrates a level of inane stupidity on my part, but please allow me a moment to explain myself.

What would you replace ants with in my model? Most likely, you are thinking “well humans, of course”.  But why?  What justifies the classification of humanity as the ultimate pinnacle of evolution? One might argue that we are currently the “dominant” species on Earth, but “dominant” is a tricky term.  Yes, we shape the environment itself in an extremely tactile and observable manner, but even the humble stromatolite has altered Earth’s atmosphere on a global scale (by releasing oxygen early on in life’s history on Earth).  Yes, we use tools and make war with each other, but chimps do the same thing.  Is it perhaps because we are still alive today? This seems like an even worse reason to assume human superiority than the previous ones.  Given the diversity of life on Earth today, the assumption that humans are somehow the pinnacle of an evolutionary process, while perhaps a nice idea from our perspective, is not a scientifically tenable hypothesis.

Of course, I am not implying that there is nothing special about the human species when Earth’s long history is considered.  Yes, we have technological and intellectual capacities far greater than that of other species here on Earth.  Our species has achieved great things, and this should not be overlooked.  However, on the same note, our connections to the world around us must also not be overlooked.  The human species is clearly a biological phenomenon at some deep and fundamental level; we are part of nature, one with the natural world.  If one reads evolution as a progressive ladder trending inherently towards human excellence, it is far to easy to overlook our connection to the greater world around us.  How does this ideology of progress work?

The ideology of progress is actually quite simple to grasp.  If one reads evolution as a progressive process in the sense we are focusing on, then one accepts that evolution inherently operates as follows:

first, nice simple life

then, more complex life

then, even more complex life

finally, upright, bipedal, conscious organisms with social capabilities.

Of course, the fossil record mirrors this trend to an extent. We start with invertebrates, then fish, amphibians, reptiles, mammals, primates, and ultimately humans as a late arrival on the scene.  However, the ideology of progress attempts to place a directional framework around life’s evolution on Earth.  A Progressivist would argue that life somehow inherently evolves in a directional sense, ultimately tending towards consciousness.  This mindset is reflected in many popular (as opposed to academic) texts dealing with paleontology, as well as in the depiction of evolution as a tree.  First, fish appear, and then disappear as amphibians appear. Then it’s reptiles replacing amphibians. And so on.  Such a mindset is culturally constructed rather than demonstrated by scientific data. In the model of evolution as a tree, humanity is ultimately placed at the top and center of the tree, with other lineages, such as reptilia, as side branches.  The message in such a presentation is clear: humans are the most important species on Earth.  Ernest Haeckel’s own evolutionary tree is perhaps the most beautiful illustration of such an idea. The illustration is public domain, so I’ll upload it in a minute, but here’s the wikipedia page where I borrow the image itself from. Anyway, here’s the image:

Haeckel's tree of life

However, Haeckel’s tree of life is extremely problematic. Species do not stop evolving once a more “advanced” group appears on the scene.   When amphibians first evolved during the Devonian, fish did not disappear, never to be heard from again. Nor did they stop diversifying.  Indeed, evolution still shapes new piscine permutations, even today.  If we were self-aware fishes rather than mammalian in nature, perhaps we would shape our evolutionary ladder in such a way that our fishy heritage would be the defining trunk of the tree of life, with humans off on some side branch of their own. Of course, we are not really fish, we are humans. Therefore, we understandably view our own species as the most important product of evolution (as demonstrated by Haeckel’s tree).  Such an anthropocentric model of evolution, while understandable, is not scientific in nature.

In fact,  Darwin rejected the ideology of progress inherent in Haeckel’s tree.  Darwin preferred the analogy of a coral, rather than a tree.  On p. 25 of the B Notebook (available here), Darwin states that “The tree of life should perhaps be called the coral of life, base of branches dead; so that passages cannot be seen.” Darwin was contemplating  tree-like models, but his tree, or coral, was inherently nonprogressive (image from here):

Darwin's tree, or "coral" of life

Note that in contrast to Haeckel’s tree, Darwin’s own illustration (although superficially tree-like) has no obvious pinnacle. Branches “A”, “B”, “C”, and “D”, each branch off in their own separate direction, with no single branch occupying an obviously central position on top of a well-defined trunk.  Thus, no progress inherent in Darwin’s own illustration of how natural selection works.

But what does this all mean? Is there a reason for my posting of these beautiful yet archaic images?  Trees, branches, corals, and progress…who cares?  This line of inquiry is useful for multiple reasons.  First, Darwin’s coral and Haeckel’s tree offer a wonderfully clear illustration of how one’s own biases can influence one’s science.  While Darwin’s coral suggests natural selection as a wholly non-progressive enterprise, inherent in Haeckel’s tree is his own, and indeed our own, anthropocentrism.  Haeckel’s tree places humans exactly where most of us view ourselves, at the top of the ladder and central to all life on Earth.  In Haeckel’s tree, non-human lifeforms are portrayed as inherently “lower” than humans. In Darwin’s coral, we are relegated to one branch of the larger model, diverging from other lifeforms in a similar manner to that of Haeckel’s tree, but merely away from other lifeforms rather than inherently upward.

So what?  Darwin drew corals to illustrate evolution but Haeckel drew trees. This split, in itself, signifies a far greater split within human society.  Most mainstream Western religious belief systems uphold a view of humanity similar to that presented in Haeckel’s tree.  Humans are presented as beings “Created in God’s image”, at the pinnacle of all life on Earth.  Darwin’s coral, being non-progressive in nature, seems to contradict these belief systems.

However, is such a contradiction between evolution and religious belief really necessary?  While religiously inspired anti-evolution movements see such a contradiction as inherent and deadly to either evolution or religion (choosing, of course, evolution as the ideology to reject), is such a contradiction really there?  Not necessarily.  While some evolutionary biologists, such as Richard Dawkins, are ardent atheists, others, such as Kenneth Miller, are devoutly religious.  As I argue in Gould’s Hopeless Monster, evolutionary theory can, in fact, co-exist with religious belief.  However, the two magisteria DO overlap in some cases, forcing some level of compromise in the zones where this overlap occurs in order to maintain coexistence.

Of course, if one wants to truly accept all implications of modern science, then religious beliefs will often end up shifting to accommodate science in these contested zones.   But this is not to imply that science disproves God.  Indeed, God is a supernatural hypothesis outside the magisteria of science; one cannot scientific prove or disprove the existence of the supernatural.  What science can and must do is to follow the available evidence where it leads in search of natural explanations for natural phenomenon.  So is Darwin’s coral or Haeckel’s tree the correct model for the diversity of life? The fact that the history of life on  Earth has followed a relatively contingent path of development over the past few billion years lends credibility to Darwin’s coral rather than Haeckel’s tree.

But what does this mean for religious belief? Surprisingly, not as much as one might initially think.  While such a model suggests that we are deeply tied to the web of life surrounding us, it does not necessarily exclude the existence of God.  As much as one might argue that a rejection of the ladder of progress somehow “lowers” the significance of human existence, why is such a statement necessary? One could just as easily argue that such a position rather elevates the position of non-human lifeforms, perhaps focusing on the unity of all lifeforms as part of God’s creation, if one wanted to debate the issue in theological terms.  Of course, such a discourse, while influenced by science, is not in itself scientific in any sense, since science cannot, by nature, answer theological questions dealing with the supernatural.

Now, moving away from the question of religion, let’s finally focus on the implications for science as a whole.  The ladder of progress is heavily embedded within the scientific community, even though, as we have seen, it is a non-scientific concept.  In fact, Michael Ruse (1996) has published an entire book, Monad to Man: the Concept of Progress in Evolutionary Biology, focusing on the subject.  If you’re at all interested in the question of progress after reading this post, I strongly suggest checking it out.  Regardless of whether we embrace Darwin’s coral or Haeckel’s tree, our choice has major implications for how we view life as a whole.  If we are to embrace Haeckel’s tree, then consciousness is likely to be the end result of an evolutionary programme, suggesting that self-aware life is likely to be ubiquitous, or at least fairly common throughout the universe.  If we are to rather embrace Darwin’s coral, then consciousness is likely to be far rarer in the universe.  So perhaps ironically, while Darwin’s coral seems to de-emphasize the importance of human life here on Earth, it may prove to be foundational to the importance of human existence in the cosmos as a whole.  If evolution does not necessarily trend towards consciousness, and if it is therefore plausible to argue that we are one of only a few (if not the only) “conscious”, self-aware species in the universe as a whole, then that is an intriguing thought.  If we are indeed organisms of an exceedingly rare nature within the cosmos as a whole, then perhaps such a plausibility is worth contemplating.

News updates

Posted December 11, 2009 by darwinaia
Categories: Uncategorized

First, as a followup on my Ray Comfort post, I somehow failed to adequately highlight the role which the National Center for Science Education played in responding to Comfort’s release.  Not only did they play a role in publicizing Comfort’s “borrowing” of his biography of Darwin (here), but the organization also played a huge role in the organized response to Comfort’s release.  For example, Eugenie Scott did a pretty strong critique of Comfort’s introduction and editing job as part of a US News online debate (here, and here).  It’s also worth noting here that the organization has also developed a website, available here, dedicated to highlighting problems with the text.  These sources are well worth checking out!

Also worth noting is the recent leak of Kent Hovind’s PhD dissertation.  PZ Myers discusses it on his blog Pharyngula, here.  Myers even includes a link where it is possible to download a copy of the thing in pdf form.

Also, if you’re interested in seeing some of the original manuscript pages from Darwin’s On the Origin of Species, you can now, at least digitally!  If you’re interested, check it out here.

Ray Comfort, A Creationist’s worst nightmare

Posted December 5, 2009 by darwinaia
Categories: history of science, Science and Pseudoscience, Science and Religion

Well I’m back in the swing of things after celebrating Thanksgiving with the traditional holiday consumption of everybody’s favorite derived theropod, and I finally got my hands on the Ray Comfort version of Darwin’s Origin of Species. I could hardly wait to read through it!  Comfort added a fifty page Creationist introduction to Darwin’s classic text and handed copies out for free at multiple college campuses in the United States.  I figured I might as well share the wealth, and discuss the introduction on here!

Comfort’s introduction begins with a short biography of Darwin.  This biography is surprisingly good, compared to the rest of the text. Perhaps this is because this segment was “borrowed” (I’ll be nice here and won’t use the term “stolen”) from Stan Guffey.  A story on the NCSE website today described these allegations, which if true, are pretty bad.  Here’s the NCSE story.  Here, we’ll focus on the parts that are definitely (as far as we know for now) written by Comfort.

First, (9-13), Comfort describes alleged “difficulties” for evolutionary theory caused by DNA.  Comfort implies that DNA is so complex that it necessitates the creative actions of a creator.  However, Comfort’s stance assumes that given an extremely unlikely event A, that A, or an event equally as unlikely as A, would never happen.  This is patently false.  If you have 1 in 23521532352535235 odds (randomly selected number) of something happening, this means that one of 23521532352535235 possible outcomes WILL occur.  If you were to claim that probability based arguments rule out the possibility of DNA being formed without Divine intervention, you would be committing a logal fallacy, as demonstrated here. Just because the odds of something happening are extremely low does not mean that it is impossible for said thing to happen.  This line of reasoning also assumes that DNA came into existence in one fell swoop, without steps along the way.  However, we do have models which do not work in this way.  For example, Robert Hazen (among others) has suggested that amino acids could have grown and replicated on a crystalline framework (i.e. on rocks).  The nice thing about this model is it provides a mechanism for explaining the left-handed bias among amino acids in life.  This line of logic also ignores the relatively common nature of amino acids; they pepper comets like candy in a 5-year-old’s bedroom.  Given such models, the odds against DNA coming into existence are far smaller than one would think if one were to argue that DNA came into existence all at one magic moment.

Even if the DNA argument put forth by Comfort (that DNA necessitates a Creator), that does not undermine the validity of Darwinian natural selection.  Darwin’s theory does not seek to explain the origin of life; it can, by nature, work only on already existing lifeforms.  Therefore, the origin of DNA does not seem to be a problem for Darwinian theory, even if one could not offer a plausible scientific explanation.  Therefore, Comfort either misunderstands evolution or is intentionally conflating Darwinian theory with abiogenesis.  Either way, doesn’t bode well for the strength of his introduction!

We’ll move on to something that actually could be problematic for evolution, if Comfort’s allegations were true.  Comfort implies (13-14) that the fossil record does not support evolution, since there are, as he would have usbelieve, no transitional forms present in the fossil record.  He obviously hasn’t gotten the memo on this one:

While I include an image of one of the well known ancestral forms of modern whales (this guy on display at the Smithsonian Natural History Museum), I could have just have easily included one of hundreds of other known “transitional forms”.  However, according to Comfort, we don’t KNOW that whales evolved, so this doesn’t count as a valid transitional  form.  Comfort also heavily emphasizes two fraudulent “transitional forms”, including the classic favorite among antievolutionists, Piltdown Man.  Of course, a few fraudulent finds do not discredit an entire science.  Comfort is building strawmen here, and is apparently hoping that his audience does not do enough further research to catch on.

Comfort also makes the glaring error of calling the recently published fossil Ida “THE” ‘missing link’.  Comfort’s statement implies that scientists are working with only one transitional form, or “missing link”.  It’s an obviously flawed semantic statement, and also an extremely scientifically naive one.  We have hundreds of transitional forms and features.  Why do we absolutely NEED Ida to be “the missing link”?  As it is, there is currently debate going on over the implications and relationships of Ida. However, the semantic problem is not Comfort’s alone.  At least part of the blame can be placed squarely on the shoulders of the press.  However, Comfort should have done his homework on this one first.  For further discussion about Ida, click here.

Next (18-20), Comfort discusses the Cambrian Explosion, claiming (18) that “virtually all the major animal forms appeared suddenly without any trace of less complex ancestors“.  This is utterly and patently wrong.  Many paleontologists today describe the Cambrian “Explosion” as actually occurring relatively slowly.  Even if it was “sudden” in geological terms, by “sudden”, paleontologists mean happening over hundreds of thousands or a few million years.  Comfort’s rhetoric would imply that it happened in a few days.  Comfort therefore misrepresents scientific data on the tempo of the Cambrian “explosion”.  Comfort also ignores, or is not aware of, the presence of “simpler” organisms pre-dating the Cambrian “Explosion”, such as the small shelly fauna. The small shelly fauna DO provide some possible ancestral forms to organisms that Comfort would have us believe arose out of nowhere. Therefore, Comfort once again  drops the ball when trying to discuss science.

Since I’ve demonstrated the lack of scientific validity of Comfort’s claims, I will not waste any more of your time or mine describing  Comfort’s further scientific errors. We’ll move on to his historical ones.  First, p. 31, Comfort implies that Darwin is responsible for “Social Darwinism”, when anyone that knows about the history of scientific racism will immediately tell you that this type of mentality pre-dated Darwin’s work by decades.  Any attempt to blame Darwin for the misuse of his work in this pre-existing racist construct is rediculously flawed.  Once again, Comfort has either failed to do his research, or is attempting to obscure the real story.

Along these lines, Comfort makes a big fuss over Darwin’s views on race.  Apparently, we should be appalled when Comfort tells us of Darwin’s belief that Black people are somehow less intelligent than Whites.  I am appalled, but for the wrong reasons (in Comfort’s eyes).  First, Darwin was a racial moderate for his day (see an earlier post on my blog that essentially debunks any attempt to describe Darwin as a racist).  Second, Darwin actually learned taxidermy from a freed Black slave.  Therefore, it is likely that Darwin viewed Blacks as both intelligent and able.  Comfort then makes a fuss about a statement made by Darwin that implies that women are less intelligent than men.  After quoting (relatively out of context) Darwin’s reasons for marriage, Comfort makes the following statement :

Darwin believed that women were not as competent as men, and less intelligent than men, but they were better than a dog.” (35).

So wait a minute….Comfort is condemning Darwin because he was a British Victorian man?  Of course Darwin is going to seem racist and sexist by today’s standards, especially when selectively quoted.  But Comfort is attempting to judge Darwin by today’s standards, rather than the standards of the Victorian Era.  Darwin lived 200 years ago; even a child should be able to see the underlying problems with Comfort’s approach here.  It both saddens and disappoints me to see such an error made by a grown man, and even worse, get overlooked by editors.

Next (35-37), Comfort attempts to blame Darwin for Hitler’s actions.  There are numerous problems with this approach.   First, even if Hitler did warp Darwinian theory to fit his own agenda, this does not mean that Darwinian theory is inherently genocidal.  Hitler also utilized inherently Christian terminology at times.  Does this mean that Christianity is the real cause of Hitler’s agenda?  Of course not!  So even if Hitler did utilize Darwinian theory, you cannot implicate the theory in Hitler’s crimes.

However, Hitler’s views on evolution were inherently non-Darwinian in many ways.  Hitler sought a biological basis for a Nazi master race, one that pure Darwinian theory could not provide.  Hitler utilized “Social Darwinism”, that old racial pseudoscience that predates Darwinian theory at a far deeper level than he utilized pure Darwinian theory.  If Hitler was so sold on evolutionary theory, then why did the Nazis ban the writings of Ernest Haeckel, the prominent German champion of Darwin? Seems like the Nazis had some issues with pure Darwinian theory.  This thought is confirmed in the article previously linked in this paragraph.  In a quote from a Nazi document on banned books, the following statement is included as a criterion for banning texts: “writings of a philosophical and social nature whose content deals with the false scientific enlightenment of primitive Darwinism” (again, from here).  While it is difficult to grasp what the text means by “primitive Darwinism”, one can assume that it likely includes Darwin himself, being the founder of Darwinism.  It seems that yet again, Comfort has failed to do his homework.

Comfort then tells us that Darwinian theory is embraced by atheists, and implies that it is an inherently athiestic idea (see, for example, pp. 39-41).  However, Comfort fails to tell us about such Christian evolutionists such as Kenneth Miller.  One wonders why…

Finally, we get to the most entertaining part of the introduction.  I have to admit that I never expected to open a copy of the Origin of Species and find a passage warning me about the fires of hell.  Yet this is exactly what one does find near the end of Comfort’s introduction.  However, we are lucky enough to have an explanation from Comfort himself on how to be saved from Hell.  Here’s what he tells us:

To receive the gift of eternal life, you must repent of your sins (turn from them), and put on the Lord Jesus Christ as you would put on a parachute—trusting in Him alone for your salvation. (49)”

Then, to conclude his introduction, Comfort presents the following paragraph:

Please don’t toss this book aside.  If it’s been helpful to you, pass it on to someone you care about—there’s nothing more important than where they will spend eternity.  Thank you for reading this. (49)”

The implications of this statement are clear.  After Comfort devotes nearly 50 pages to telling us why Darwinism is a racist, atheistic, bankrupt science, Comfort is then offering us salvation through his specific interpretation of Christianity.  Comfort is implying, either intentionally or unintentionally, that accepting evolution will likely lead one into the fires of Hell.  One might be tempted to quote Judge John E. Jones III of Kitzmiller v. Dover (“breathtaking inanity”) in reaction to Comfort’s introduction. Comfort has misrepresented both science and history at the most basic level in an attempt to push his own religious views on others.  Worse yet, he has tarnished one of the most important and elegant texts in the history of scientific thought in the process.  While Comfort’s claims do nothing to undermine the strength and validity of Darwin’s work, they do  show an inherent disrespect both for science and for religion.  Comfort forces a wall between evolution and Christianity, which in Comfort’s model, cannot be breached.  However, as I have demonstrated in Gould’s Hopeless Monster, while science and religion may need to make compromises in order to coexist, they ultimately can coexist in some fashion.  Comfort’s model rejects this possibility.  What worries me most is that some people might not research beyond Comfort’s claims, and as a result may actually believe him.  Luckily, the National Center for Science Education has provided protection against Comfort’s patently false claims in the form of a bookmark (available here to print out).  Share one with somebody you care about, especially if they have recieved a copy of the Ray Comfort edition of the Origin of Species.

One Long Argument, one hungry blogger

Posted November 19, 2009 by darwinaia
Categories: evolution

In anticipation of the 150th anniversary of the publication of Darwin’s Origin of Species (November 24th; mark your calendars!), I figured I would address evolutionary theory.  The concept of evolution is one of the simplest in science, yet is often misunderstood.  While searching for a good illustration of how evolution works, I realized that I was hungry.  Heading out to the lobby, I checked the vending machines for something to eat:

 

Noticing the presence of M&Ms in the machine, I had an idea. M&Ms come in different colors; i.e. they have a built-in source of variation.  I opted for the ones with peanuts (E7), put in my dollar, and got a package.  Upon returning to the room, I opened the package of M&Ms, and laid them out to display the degree of variation within said population of M&Ms:

After examining the population, I realized that there was a level of variation such that we have a healthy population, with some traits being rarer than others.  Blue, Green, and Orange were designated as “common”, Brown as “uncommon”, and Red and Yellow as “rare”.  So we have a population with variation.  How does said population evolve?

Certain traits (in this case colors) are advantageous, while others are disadvantageous.  If a predator likes to eat red things, the red M&Ms are in trouble.  There is only one representative of that variety in our population, and this blogger does like red M&Ms.  Therefore, we have a disadvantageous trait, and said variety is removed from the gene pool, i.e. it goes extinct.

While the red variety goes extinct, the blue, green, yellow, and orange varieties go on living happily, and breeding (unfortunately I cannot make M&Ms reproduce…bear with me).  Eventually, some event occurs that alters some portion of our population (be it a behavioral change, mutation, etc).  In this case, we’ll use a reference to 2001 A Space Odyssey.  A monolith pops into the scene.  The blue and orange M&Ms are attracted to it.  The other M&Ms run away:

 

 

If you are not familiar with the scene this is referencing, it is available here.  So the Blue and Orange varieties gain some sort of differential survival advantage (call it “intelligence”) from contact with the monolith.  We’ll say that the monolith is radioactive and caused rapid mutations within the Blue and Orange genomes; we’re not looking at long periods of time here, so I’m taking a leap here and increasing the speed of our demo.  The Blue and Orange varieties chase off the other varieties of M&Ms due to their inherent differences (we’ll say through a mountain pass), and then return to their own region.  A landslide (or in this case a giant screw falling in the middle of the picture) blocks off the pass, separating the blue and orange varieties from the other varieties:

After separation, you have two separate varieties, which compete amongst themselves, and evolve along separate paths.  This is called allopatric speciation:

Eventually, an earthquake or something of the sort removes the geographic barrier, and the populations mix once again:

If the two populations have been separated long enough, and evolved along different enough lines, then they will be able to coexist without competition.  If this is the case, populations will stabilize between the two without much competition:

 

OK, but what has this little thought experiment demonstrated about evolution?  Evolution through natural selection, at its most basic level, requires variation within a population.  When dealing with living organisms, this variation is provided by genetic mutation.  Genetic mutation is pretty much random in nature.  However, certain mutations are favorable for survival, other mutations are unfavorable, and some are neutral.  Darwin’s model of natural selection is based on a competition for resources; certain individuals will just be better able to compete for resources.  These individuals are the ones that will tend to leave the most offspring.  Natural selection works by weeding out unfavorable mutations and increasing the population of organisms with favorable mutations.  Mutation is random.  Natural selection is not.  Natural selection will inherently favor those organisms that have traits which give them an edge for survival.  In our M&M analogy, if predators like to eat red M&Ms, then red M&Ms will likely be rarer (or go extinct quicker) than other varieties.  If some gazelles run faster than others, and the slow ones are the ones that generally get eaten by lions, then natural selection will gradually increase the average speed of the gazelle population as a whole.
Within our M&M analogy, we saw a rapid “Poof”-style evolutionary shift in which some M&Ms drastically changed form after coming into contact with a monolith.  I do not mean to imply some sort of magical evolutionary process in which a bird suddenly hatches from a lizard egg; that’s saltationism, and saltationism is wrong.  However, given the right conditions and environmental pressures, evolution can happen relatively quickly.  When you separate one large population into two smaller ones (our screw-landslide), you decrease the size of the gene pool, and thus enlarge the potential impact of a given mutation.  As such, relatively small populations can often change relatively quickly.  In some cases, once the separated populations come back into contact with each other, they have evolved along separate enough paths that they do not directly compete with each other, allowing for the coexistence of both groups.  In other cases, both groups do still directly compete with each other.  In these cases,  natural selection once again weeds out certain individuals, and allows others to prosper.

As demonstrated, evolution through natural selection is an extremely simple process. Some organisms are better adapted than others, and these well-adapted organisms will tend to reproduce more often, eventually taking over the population. However, as demonstrated through our brief, rough look at allopatric speciation, natural selection is not the only force involved in controlling the evolution of life on Earth.  Environmental factors also can play a major role.  Barriers between populations are also important.  Meteor impacts and other mass extinction events can drastically shift the course of evolution on Earth.  But can evolution explain the diversity of life on Earth?

Given the long period of time for which the Earth has existed (approximately 4.6 billion years), we certainly have had enough time to evolve the diversity of life on Earth.  While some have raised questions (generally pseudoscientific in nature) about the ability of evolution to explain the origin of the eye, or transitions between major groups of animal, for example, these objections are weak.  While we have a working mechanism for evolution, and a huge amount of evidence in support of the idea that life on Earth is the result of a long, drawn-out process of evolution, there is no mechanism given for these arguments against evolution.  No defined laws which would forbid the evolution of the eye.  No tactile reason to believe that one could not evolve a bird from a dinosaurian ancestor, or an amphibian from a fish.  The evidence is clear, and the process is as elegant as it is simple.  Evolution happens.

 

fossil of the week #2

Posted November 12, 2009 by darwinaia
Categories: Uncategorized

glyptodon at AMNH

 

This week’s fossil of the week is Glyptotherium texanum, a large extinct relative of the armadillo.  This particular specimen is on display at the American Museum of Natural History in New York City.  These guys likely went extinct between 10,000 and 11,000 years ago.  Charles Darwin himself actually discovered some glyptodont remains similar to this species while traveling on the Beagle.

In other news, currently working through the newest sequel, this time authored by William Dembski and Jonathan Wells. Released in 2008 , the webpage set up for this book states that its key message is that: “[m]aterialistic science is bankrupt; intelligence acts in nature, and its activity must feature in our scientific understanding of the world“.  As is often the case with the Intelligent Design Movement, there appears to be a key focus on defeating “materialism”.  I haven’t pored very deeply through the online text sample yet (available here), but plan to comment on it in a post once I have. As a text initially intended as a new version of Pandas, I don’t have much hope for it as a strongly convincing read, but I’ll wait until I’ve thoroughly analyzed the sections dealing with material I have a background in before condemning (or if its actually compelling perhaps openly considering) it.

 

fossil of the week

Posted November 1, 2009 by darwinaia
Categories: Uncategorized

Pikaia, on display at the Smithsonian National Museum of Natural History.  One of the oldest known chordates, Pikaia featured prominently in Stephen Jay Gould’s book “Wonderful Life” and can be seen as perhaps an extremely distant uncle to our species.  Picture presented in black and white to highlight the fossil itself (Burgess Shale specimens are notoriously difficult to photograph, and I’m not a professional photographer).

pikaia

T-Rex Soft Tissue and Young Earth Creationists

Posted October 31, 2009 by darwinaia
Categories: Uncategorized

Anyone who’s followed the Young Earth Creationist movement and paleontology lately should know about the 2005 discovery of T-Rex blood vessels by Mary Schweitzer et al.  Young Earth Creationists have jumped on the find (here for example).  Creationists claim that the proteins preserved were far too fragile to have survived for “millions of years” and therefore must be only a few thousand years old.  However, this claim is flawed.
First off, there is the possibility that the Schweitzer soft tissue is the result of replacement (see here for more information on that possibility) of the material by other biological entities (ie bacteria). Other possibilities include that the proteins in question actually are preserved dinosaur remains (recent findings suggest this is a strong possibility).  It is worth noting here that we are looking at proteins, and not full strands of DNA.  Proteins are much more durable than actual DNA strands. Recently, work has been done which suggests that fossils may commonly preserve soft material when trapped in hard sandstone (which blocks oxygen deterioration).

The actual process of extracting the soft material from the bones can lead to a basic misunderstanding of the nature of the find.  The bone that Schweitzer worked with was soaked in acid for analytical purposes (this is a standard practice when working with rocks or fossils).  After being soaked in acid, the remaining “soft material” appeared pliable (see picture on pharyngula here).  However, being soft and pliable after being soaked in acid does not mean that the entire bone appears to be very young.  In fact, the bone looks just like any fossil.  The bone is on display at Montana State University’s Museum of the Rockies, so I’ve been lucky enough to see it up close.  Here are some pictures of it:

T-Rex femur

bone that soft tissue was extracted from

close up of site of extraction

location in bone where soft tissue was extracted from

As you can see, the bone itself does not look like something that just died; in appearance, it is extremely similar to most T-Rex bones one could find.  While the presence of blood vessels and cells being preserved in this bone is a surprise, it is not detrimental to the scientific interpretation of the age of this fossil.  Sure, it’s weird from a paleontology perspective, but unlike “Creation Science”, which forces everything to fit within its preconceived Biblical framework, paleontologists adjusted their position.  They asked the tough questions, and came up with plausible explanations for the existence of this material.  Yet Creationists are quick to jump on the find as proof of a young Earth.  Judging from the fact that the geologic evidence in general supports a very old Earth, and some hypotheses about the preservation of proteins and such have been tested (and shown promise), the Creationists appear to not have as strong a case as one would initially think.  But for Young Earth Creationists, the mantra stays the same:

Don't stop believin'