We're in Venice, California (USA) (near the beach to the west of Los Angeles) awaiting the birth of our grandson. Last night we went trick or treating with granddaughter Zoë. She loved her witch costume and she applied her makeup all by herself.
Halloween is a very big deal in Venice—probably because it's so "bohemian/hippie." There were hundreds of kids in the streets and most houses had elaborate Halloween displays that have been up for days (see And Now for the Spookey Part, and Halloween in the Hood).
More Recent Comments
Thursday, November 01, 2012
Wednesday, October 31, 2012
The Stockbridge 14: What Did They Discover?
Fourteen people have been invited to a special meeting in Stockbridge Massachusetts (USA). They are: Sean Carroll, Jerry Coyne, Richard Dawkins, Terrence Deacon, Simon DeDeo, Dan Dennett, Owen Flanagan, Rebecca Goldstein, Janna Levin, David Poeppel, Alex Rosenberg, Don Ross, Steven Weinberg, and Massimo Pigliucci. On the first day they discussed "naturalism" (morning session) and evolution, complexity and emergence (afternoon session"). Read the summaries in the links to my first post [The Stockbridge 14].
Tuesday, October 30, 2012
What Is Critical Thinking?
We all use the term "critical thinking to describe one of the primary goals of education. What do we mean by "critical thinking"?
As usual, it takes a philosopher to sort out the various meanings and arrive at a reasonable definition. (Philosophers are experts at critical thinking, although they often use it when it's not necessary.) Read what John Wilkins has to say at: What is critical thinking. Contrast his critical thinking about the subject with that illustrated in the Wikipedia article on Critical Thinking.
Here's his bottom line but you really need to see his examples of what is not critical thinking.
Once you've mastered the basic rules of logic, most arguments should be about whether the premises are likely to be true.
As usual, it takes a philosopher to sort out the various meanings and arrive at a reasonable definition. (Philosophers are experts at critical thinking, although they often use it when it's not necessary.) Read what John Wilkins has to say at: What is critical thinking. Contrast his critical thinking about the subject with that illustrated in the Wikipedia article on Critical Thinking.
Here's his bottom line but you really need to see his examples of what is not critical thinking.
Critical thinking is the application of careful analysis and rational reconstruction to arguments, so that the correctness of the reasoning and the truth of the premises can be evaluated and the support for the conclusion determined.I agree with John and this is what Chris DiCarlo and I teach in our course. But, you should read the comments on John's blog.
Rational thinking is the assent of the reasoner to any conclusion that is both correctly reasoned and founded on known to be true, or likely to be true, premises.
In short, a critical and rational thinker is one who accepts the conclusions of good arguments.
Once you've mastered the basic rules of logic, most arguments should be about whether the premises are likely to be true.
Saturday, October 27, 2012
The Stockbridge 14
Fourteen people have been invited to a special meeting in Stockbridge Massachusetts (USA). They are: Sean Carroll, Jerry Coyne, Richard Dawkins, Terrence Deacon, Simon DeDeo, Dan Dennett, Owen Flanagan, Rebecca Goldstein, Janna Levin, David Poeppel, Alex Rosenberg, Don Ross, Steven Weinberg, and Massimo Pigliucci. So far they've discussed the meaning of "naturalism," including the nature of reality (morning session) and evolution, complexity and emergence (afternoon session") [Moving Naturalism Forward].
You can read Jerry Coyne's description at: Interim report: Moving Naturalism Forward Meeting. Massimo Pigliucci has also written about the first day at: From the naturalism workshop, part I.
So far it sounds quite boring. It looks looks like some of the philosophers have tricked the scientists into debating the precise meaning of words that nobody has been able to define precisely in the past one hundred years. Does anyone outside of philosophers actually care whether we have precise definitions of "naturalism" and "supernatural"? We all know what we're talking about when we discuss the existence of god(s).
And what about "emerging properties"? Surely that's a topic that's already been debated to death? What in the world do they expect to learn other than the fact they disagree on the definition of what an enregent property actually means?
As for complexity, it's either so simple that we all recognize it when we see it, or so "complex" that nobody cares. Here's what Coyne says ...
I'm not looking forward to the results of the next two days because they're going to tackle silly topics like the nature of morality, free will, "meaning," and "purpose". I wonder if they're going to debate the difference between methodological naturalism and philosophical naturalism? I wonder when they'll get to the issues of how many angels can dance on the head of a pin?
You can read Jerry Coyne's description at: Interim report: Moving Naturalism Forward Meeting. Massimo Pigliucci has also written about the first day at: From the naturalism workshop, part I.
So far it sounds quite boring. It looks looks like some of the philosophers have tricked the scientists into debating the precise meaning of words that nobody has been able to define precisely in the past one hundred years. Does anyone outside of philosophers actually care whether we have precise definitions of "naturalism" and "supernatural"? We all know what we're talking about when we discuss the existence of god(s).
And what about "emerging properties"? Surely that's a topic that's already been debated to death? What in the world do they expect to learn other than the fact they disagree on the definition of what an enregent property actually means?
As for complexity, it's either so simple that we all recognize it when we see it, or so "complex" that nobody cares. Here's what Coyne says ...
The discussion of complexity, introduced by Simon DeDeo and much discussed by Janna Levin, was way over my head. I found some consolation in the fact that Dennett, too, announced that he didn’t understand what was being said!That doesn't sound very promising.
I'm not looking forward to the results of the next two days because they're going to tackle silly topics like the nature of morality, free will, "meaning," and "purpose". I wonder if they're going to debate the difference between methodological naturalism and philosophical naturalism? I wonder when they'll get to the issues of how many angels can dance on the head of a pin?
[Photo Credit: One Angel Dancing on the Head of a Pin]
Thursday, October 25, 2012
Five Myths (?) About Intelligent Design Creationism
Melissa Travis writes for a blog called Hard-Core Christianity. Her latest post is: Top Five Myths Christians (and Non-Christians) Often Believe About Intelligent Design. It's interesting because it reveals the standard myths that Intelligent Design Creationists believe about themselves.
Here's the list of "myths" along with what Mellisa Travis has to say about them.
There's no "over-arching" scientific theory in sight.
Here's the list of "myths" along with what Mellisa Travis has to say about them.
MYTH #1: Intelligent Design (ID) is just a fancy name for Creationism.FACT: Modern Intelligent Design Creationism evolved from the creationist movement in the 1980s as was proven conclusively in the Dover trial. Intelligent Design Creationism is not a scientific theory. Instead, its a hodgepodge of criticisms of evolution and of scientists and materialism. Just look at the posts on Evolution News & Views (sic) to see what it's all about. Count the number of posts promoting a "scientific" view of Intelligent Design Creationism as opposed to disjointed helter-skelter criticisms of evolution that often contradict each other.
The true story: Intelligent Design theory is not a form of, nor is it synonymous with “creationism.” Rather, it is an over-arching scientific theory that disputes wholly naturalistic/materialistic accounts of the origin of the universe and the origin of life. As such it is an indispensable ally for those who espouse various creation models. ID makes NO CLAIM about the age of the earth.
There's no "over-arching" scientific theory in sight.
Wednesday, October 24, 2012
Is It True?
Is it True? Uncovering the Heart of Each of the World's Religions
The University of Toronto Secular alliance (UTSA), in conjunction with Power 2 Change, Muslim Students Association and the Multifaith Centre is hosting a lecture and discussion series entitled "…is it true?"
This series will feature the following speakers:
Oct. 24: Islam (Amjad Tarsin, Muslim Chaplain, U of T)
Oct. 31: Christianity (Kyle Hackmann, Grace Toronto Church)
Nov. 7: Judaism (Yishaya Rose, Chaplain, Chabad House, U of T)
Nov. 14: Atheism (Professor Larry Moran, U of T, Secular Alliance)
Each speaker will speak on behalf of the philosophical framework to which they subscribe to. Following the lecture, there will be a period of Q and A following by an open discussion amongst attendees.
I encourage you to attend these talks as I suspect a lot of fruitful conversations can emerge. To this end, specifically, we are delighted to have biochemist Dr. Larry Moran, represent our side of the conversation.
University College 5:30pm-7:00pm, rm 52. Light dinner will be served.
Please find event page below:
Hope to see some of you there!
Monday, October 22, 2012
Monday's Molecule #191
Last week's molecule was L-dopa. The winner was Raul A. Félix de Sousa (again, but this time only by four minutes!) [Monday's Molecule #190].
This week's molecule is much more complicated and it's also much more important. You need to identify this complex making sure you distinguish it from other similar complexes. You don't need to name the exact species but you should have some idea of which organisms have this complex and which ones don't. There's not enough room in the comments for the complete IUPAC name!
You'll get special bonus points (and the expensive lunch in the dining room instead of the pub) for explaining how an irreducibly complex structure like this could have evolved.
Post your answer as a comment. I'll hold off releasing any comments for 24 hours. The first one with the correct answer wins. I will only post mostly correct answers to avoid embarrassment. The winner will be treated to a free lunch.
There could be two winners. If the first correct answer isn't from an undergraduate student then I'll select a second winner from those undergraduates who post the correct answer. You will need to identify yourself as an undergraduate in order to win. (Put "undergraduate" at the bottom of your comment.)
This week's molecule is much more complicated and it's also much more important. You need to identify this complex making sure you distinguish it from other similar complexes. You don't need to name the exact species but you should have some idea of which organisms have this complex and which ones don't. There's not enough room in the comments for the complete IUPAC name!
You'll get special bonus points (and the expensive lunch in the dining room instead of the pub) for explaining how an irreducibly complex structure like this could have evolved.
Post your answer as a comment. I'll hold off releasing any comments for 24 hours. The first one with the correct answer wins. I will only post mostly correct answers to avoid embarrassment. The winner will be treated to a free lunch.
There could be two winners. If the first correct answer isn't from an undergraduate student then I'll select a second winner from those undergraduates who post the correct answer. You will need to identify yourself as an undergraduate in order to win. (Put "undergraduate" at the bottom of your comment.)
Stupid American Atheists
American Atheists have decided that it's in their best interests to take sides in the Presidential election. They produced a billboard and mounted it on a truck to drive around Boca Raton, Florida, the site of this evening's third presidential debate [American Atheists Demand Answers on Romney's Religious Loyalty].
This is not only an attack on religion—as opposed to an attack on the existence of god(s)—but it's an attack on a particular religion that just happens to be the religion of one of the candidates. There's no balanced attack on the religion of the other candidate even though his religion is just as bad.
This is really stupid and American Atheists should be ashamed of themselves. It's the sort of thing that rightly fuels the accommodationist objections to the New Atheists.
This is not only an attack on religion—as opposed to an attack on the existence of god(s)—but it's an attack on a particular religion that just happens to be the religion of one of the candidates. There's no balanced attack on the religion of the other candidate even though his religion is just as bad.
This is really stupid and American Atheists should be ashamed of themselves. It's the sort of thing that rightly fuels the accommodationist objections to the New Atheists.
Chris Stedman Defends Accommodationism
Chris Stedman is currently the Assistant Humanist Chaplain1 and the Values in Action Coordinator for the Humanist Community at Harvard [Chris Stedman]. He has a Master's degree in religion and is a former evangelical Christian.
As you might imagine from his position at Harvard, Stedman supports the non-theistic Humanism "religion." His goal is to advance particular social policies and often that goal is shared by theists. Hence, cooperating with theists to achieve common goals, such as social justice, is a major part of his life.
That's noble. Even though I don't share his humanist worldview—and have no intention of becoming a humanist—I can support many of the issues he is passionate about. Like all my atheist friends, I have no problem working with theists of all stripes when it comes to making our society a better place—just as I have no problem working with conservatives, homeopaths, anti-abortionists, people who favor capital punishment, pro-gun lobbyists, and even misogynists and racists if the issue is important enough.
As you might imagine from his position at Harvard, Stedman supports the non-theistic Humanism "religion." His goal is to advance particular social policies and often that goal is shared by theists. Hence, cooperating with theists to achieve common goals, such as social justice, is a major part of his life.
That's noble. Even though I don't share his humanist worldview—and have no intention of becoming a humanist—I can support many of the issues he is passionate about. Like all my atheist friends, I have no problem working with theists of all stripes when it comes to making our society a better place—just as I have no problem working with conservatives, homeopaths, anti-abortionists, people who favor capital punishment, pro-gun lobbyists, and even misogynists and racists if the issue is important enough.
Friday, October 19, 2012
Another Evolutionary Paradox?
The IDiots are remarkably good at uncritical thinking. When you couple this tendency to ignorance of evolution, you come up with some remarkable conclusions.
Take, for example, the well-known fact that rich people tend to have fewer children than poor people. What this means is that poor people are better at passing on their genes (alleles) to the next generation than rich people. If there is a genetic component to richness and poorness then poor people are "more fit" than rich people and, eventually, the poorness alleles will become fixed in the population. That's just a fact and it doesn't matter what you might think about the genetic advantage of being rich.
Of course there may not be any significant difference in the genetic compositions of rich people and poor people in which case the argument becomes moot.
Let's see how an anonymous IDiot deals with this information on their main blog site, Evolution News & Views (sic) ... [Survival of the Poorest: Another Evolutionary Paradox].
The only "puzzle" might be the naive presumption that rich people should have more reproductive success than poor people but we've known that this isn't true for over one hundred years.
Take, for example, the well-known fact that rich people tend to have fewer children than poor people. What this means is that poor people are better at passing on their genes (alleles) to the next generation than rich people. If there is a genetic component to richness and poorness then poor people are "more fit" than rich people and, eventually, the poorness alleles will become fixed in the population. That's just a fact and it doesn't matter what you might think about the genetic advantage of being rich.
Of course there may not be any significant difference in the genetic compositions of rich people and poor people in which case the argument becomes moot.
Let's see how an anonymous IDiot deals with this information on their main blog site, Evolution News & Views (sic) ... [Survival of the Poorest: Another Evolutionary Paradox].
Here's another evolutionary paradox: the "demographic transition." We've alluded to this before, but why not recall the point? Darwin notwithstanding, it seems to support the view that the meek shall inherit the earth."Fitness" is defined in all evolutionary biology textbooks as ...
By all accounts, the rich should be, in Darwinian terms, the fittest. They have the most resources, and the most opportunities for advancement. Yet they leave fewer offspring. That's the finding of a large study of Swedish families that's just been completed.
Nature recently recognized that this has been a known contradiction to evolutionary theory.
The fitness of a genotype is the average lifetime contribution of individuals of that genotype to the population after one or more generations ... A general term for this number is reproductive success, which includes not simply the average number of offspring produced by the reproductive process, but the number that survive, since survival is prerequisite to reproduction.Do the IDiots ever read basic introductory evolution textbooks or do they just pull out "evolutionary paradoxes" from their nether parts? There's no contradiction with evolutionary theory and there's nothing in "Darwinian terms" that defines fitness as anything but reproductive success.
Futuyma, D.J. (2009) Evolution p. 306
The only "puzzle" might be the naive presumption that rich people should have more reproductive success than poor people but we've known that this isn't true for over one hundred years.
[Photo Credit: Ten children of Ethel and Bobby Kennedy (the 11th child was born after Bobby was killed). This is the exception that proves the rule. Prompted by last night's viewing of the remarkable documentary Ethel which also prompts the question, "Why doesn't America have principled politicians like Bobby Kennedy any more?"]
Science Journal Publishes More Gobbledygook
I don't know what's happening at Science these days. It got caught up in the arsenic affair last year and it recently made a fool of itself over the ENCODE publicity fiasco where it was completely duped by Ewan Birney.
Now it has published the following "perspective" in the October 12th issue. It reads like a Sokal hoax but it's perfectly legitimate. That's actually how Stuart Neuman proposes to solve the mystery of the Cambrian explosion.
This story has been promoted by a rogue journalist named Suzan Mazur and she has written a book on the subject. Here's her interview with Stuart Newman, The New Master Of Evolution?. Elizabeth Pennisi, a senior editor at Science, helped publicize the Altenberg 16 back in 2008 by publishing an article in Science [Modernizing the Modern Synthesis]. She has been sympathetic to the bizarre views of some Altenberg 16 members so I suspect she's behind the publication of Stuart Newman's article in Science.
Now it has published the following "perspective" in the October 12th issue. It reads like a Sokal hoax but it's perfectly legitimate. That's actually how Stuart Neuman proposes to solve the mystery of the Cambrian explosion.
Neuman was one of the Alternberg 16, a group of scientists who met in Altenberg, Austria in 2008. Their purpose was to develop a new theory of evolution. The proceedings were collected in a book edited by Massimo Pigliucci and Gerd B. M^uuml;ller, Evolution: The Extended Synthesis.Stuart A. Newman
Physico-Genetic Determinants in the Evolution of Development
Science 338:217-219 [DOI: 10.1126/science.1222003]
Abstract
Animal bodies and the embryos that generate them exhibit an assortment of stereotypic morphological motifs that first appeared more than half a billion years ago. During development, cells arrange themselves into tissues with interior cavities and multiple layers with immiscible boundaries, containing patterned arrangements of cell types. These tissues go on to elongate, fold, segment, and form appendages. Their motifs are similar to the outcomes of physical processes generic to condensed, chemically excitable, viscoelastic materials, although the embryonic mechanisms that generate them are typically much more complex. I propose that the origins of animal development lay in the mobilization of physical organizational effects that resulted when certain gene products of single-celled ancestors came to operate on the spatial scale of multicellular aggregates.
This story has been promoted by a rogue journalist named Suzan Mazur and she has written a book on the subject. Here's her interview with Stuart Newman, The New Master Of Evolution?. Elizabeth Pennisi, a senior editor at Science, helped publicize the Altenberg 16 back in 2008 by publishing an article in Science [Modernizing the Modern Synthesis]. She has been sympathetic to the bizarre views of some Altenberg 16 members so I suspect she's behind the publication of Stuart Newman's article in Science.
Thursday, October 18, 2012
Douglas Axe on Protein Evolution and Magic Numbers
Imagine that I asked you to "prove" evolution by transforming a chimpanzee into a human. Would you recognize the fallacy that I described recently in Why Are Chimps Still Chimps?. Of course you would. Any intelligent person who understands evolution knows that chimps and humans share a common ancestor and both have evolved substantially since the two lineages diverged. In order to change a chimp into a human you would first have to "devolve" it back to the common ancestor and proceed from there. That requires a lot of changes.
Now let's think about two enzymes that are members of the same gene family but have evolved different functions. It's easiest to think of these as two enzymes that are now specific for similar but distinct substrates. Imagine that you were asked to "prove" evolution by changing one of those enzymes into the other? Would you recognize the same fallacy? Would you realize that the most likely evolutionary scenario is that the two different enzyme specificities evolved from an ancestral enzyme that carried out both reactions? [see: The Evolution of Enzymes from Promiscuous Precursors]
Changing one of the modern enzymes into the other would require many changes because in most cases the common ancestor dates back hundreds of millions of years. Many of the changes that have become fixed in the two lineages were not directly involved in selecting one of the substrates over the other (i.e. increasing specificity). They were neutral mutations fixed by random genetic drift after the enzyme became specialized for one or other of the substrates. Many would have to be "reversed" in order to re-create the dual specificity because they would have been detrimental in the ancestral enzyme.
Think about these facts as you watch Douglas Axe explain why his research shows that evolution is impossible [Video: Doug Axe on Protein Evolution's Magic Number (It's Six)].
Now let's think about two enzymes that are members of the same gene family but have evolved different functions. It's easiest to think of these as two enzymes that are now specific for similar but distinct substrates. Imagine that you were asked to "prove" evolution by changing one of those enzymes into the other? Would you recognize the same fallacy? Would you realize that the most likely evolutionary scenario is that the two different enzyme specificities evolved from an ancestral enzyme that carried out both reactions? [see: The Evolution of Enzymes from Promiscuous Precursors]
Changing one of the modern enzymes into the other would require many changes because in most cases the common ancestor dates back hundreds of millions of years. Many of the changes that have become fixed in the two lineages were not directly involved in selecting one of the substrates over the other (i.e. increasing specificity). They were neutral mutations fixed by random genetic drift after the enzyme became specialized for one or other of the substrates. Many would have to be "reversed" in order to re-create the dual specificity because they would have been detrimental in the ancestral enzyme.
Think about these facts as you watch Douglas Axe explain why his research shows that evolution is impossible [Video: Doug Axe on Protein Evolution's Magic Number (It's Six)].
On Attacking the Integrity of Scientists
We are discussing the evolution/creation controversy in my course. One of the issues that comes up frequently is the role of scientific evidence. The importance of science in the 21st century cannot be exaggerated. Everyone wants science to be on their side because if your views conflict directly with scientific evidence then your case is very weak.
So, how do creationists handle this issue? They usually try to present counter-evidence or they cherry-pick the scientific literature looking for papers that lend support to their cause. But that only takes you so far. Creationists are forced to admit that the vast majority of scientists support evolution and that's a real problem for their flock.
The solution is obvious. If you can't attack the science then attack the scientists. By casting doubt on the motives of scientists you can partially neutralize the impact of science.
Here's an excellent example from today's post on Evolution News & Views (sic) [How to Talk About "Evolution"].
So, how do creationists handle this issue? They usually try to present counter-evidence or they cherry-pick the scientific literature looking for papers that lend support to their cause. But that only takes you so far. Creationists are forced to admit that the vast majority of scientists support evolution and that's a real problem for their flock.
The solution is obvious. If you can't attack the science then attack the scientists. By casting doubt on the motives of scientists you can partially neutralize the impact of science.
Here's an excellent example from today's post on Evolution News & Views (sic) [How to Talk About "Evolution"].
Better to think of opinion as sharply divided. The professors, their students and many university-educated people believe one thing (evolution is a fact) and most everyone else is suspicious. They won't believe in evolution if you tell them what the professors believe -- that life in all its complexity assembled itself as a result of a series of lucky hits; that we live in a world of random changes that sometimes "coincide" with the environment (natural selection); and that's how we got here.Of course they don't like it when we refer to them as IDiots or creationists but they have an answer to that one as well.
To believe that, we first have to be blinded by antagonism to the normal, automatic recognition of purpose and design in nature. And for most people, this blindness has to be inculcated; by teachers, by the academy, by the culture.
As to the possibility of our reaching the professor group, the trouble with my correspondent's design versus "accidental mutation/natural selection" formula is not that it is too wordy but that the professoriate have learned to accept that accidental mutation and natural selection can explain everything under the sun.
I have often wondered: What would it take for a biology professor to see some living organism, study it and then clap his hand to his forehead and say: "Wow, natural selection couldn't possibly have done THAT!"
Answer: Nothing. They are locked into a materialist worldview, and they think that anything outside it is unscientific. They have already accepted Lewontin's Law about the necessity of a "prior commitment to materialism." They will look at any strange organism you may show them and say: "Well, it exists doesn't it? How else did it get here, if not by gradual stages, bit by bit, starting with molecules in motion, finally building up to what we see in front of us? What other choice is there?"
In such a dogmatic environment dissenters wisely keep their mouths shut and upholders of the orthodoxy firmly close their minds.
Going beyond that, some of our better-known adversaries indulge in name-calling so mechanically that they may well have ceased to understand the issues. It's as though they become unable to think about what they don't want to think about. Those who resort to slogans like "ID creationism" often show no sign of understanding what the claims of ID are, sufficiently even to be able to restate them.Unfortunatly for the IDiots, I actually understand the issues better than they do! Here's the main tenets of Intelligent Design Creationism.
- Darwin is evil and gave rise to Hilter. Evolutionists are wedded to atheism and materialism. Most scientists are too stupid to interpret evidence correctly. Evolution cannot account for life as we know it.
- Life can only be explained by invoking an Intelligent Designer but we're not going to tell you how or when he/she/it did it.
- The Intelligent Designer is not necessarily a god. We never said that so you can't accuse us of being creationists.
- The general public is being prevented from learning the truth about
creationismanti-evolutionary theory by a vast conspiracy of dogmatic scientists who control higher education (and almost everything else in some secular "foreign" countries like France or Japan).
Does Environmental Change Drive Evolution?
I recently posted an article on the lack of evolution in species that have lived through several ice ages {More Evidence of Short-term Stasis]. This prompted a discussion about whether any serious evolutionary biologists really believe the opening statement in the abstract of the paper, "Conventional neo-Darwinian theory views organisms as infinitely sensitive and responsive to their environments, and considers them able to readily change size or shape when they adapt to selective pressures" (Prothero et al. 2012).
I believe that lots of biologists think like this. Let's discuss a quotation from The Blind Watchmaker (1986, p.178-179) by Richard Dawkins. How many readers agree with him?
I believe that lots of biologists think like this. Let's discuss a quotation from The Blind Watchmaker (1986, p.178-179) by Richard Dawkins. How many readers agree with him?
After many generations of cumulative selection in a particular place, the local animals and plants become well fitted to the conditions, for instance weather conditions, in that place. If it is cold the animals come to have thick coats of hair, or feathers. If it is dry they evolve leathery or waxy waterproof skins to conserve what little water there is. The adaptations to local conditions affect every part of the body, its shape and color, its internal organs, its behavior, and the chemistry of its cells.
If the conditions in which a lineage of animals lives remain constant; say it is dry and hot and has been so without a break for 100 generations, evolution in that lineage is likely to come to a halt, at least as far as adaptations to temperatures and humidity are concerned. The animals will become as well fitted as they can be to local conditions. This doesn't mean that they couldn't be completely redesigned to be even better. It does mean that they can't improve themselves by any small (and therefore likely) evolutionary step: none of their immediate neighbors in the local equivalents of 'biomorph space' would do any better.
Evolution will come to a standstill until something in the conditions changes: the onset of an ice age, a change in the average rainfall of the area, a shift in the prevailing wind. Such changes do happen when we are dealing with a timescale as long as the evolutionary one. As a consequence, evolution normally does not come to a halt, but constantly 'tracks' changing environment. If there is a steady downward drift in the average temperatures in the area, a drift that persists over centuries, successive generations of animals will be propelled by a steady selection 'pressure' in the direction, say, of growing longer coats of hair. If, after a few thousand years of reduced temperature the trend reverses and average temperatures creep up again, the animals will come under the influence of the new selection pressure, and will be pushed towards growing shorter coats again.
Prothero, D.R., Syverson, V.J., Raymond, K.R., Madan, M., Molina, M., Fragomeni, A., DeSantis, S., Sutyagina, A., and Gage, G.L. (2012) Size and shape stasis in late Pleistocene mammals and birds from Rancho La Brea during the Last Glacial–Interglacial cycle. Quaternary Science Reviews 56:1–10. [doi: 10.1016/j.quascirev.2012.08.015]
Tuesday, October 16, 2012
More Evidence of Short-term Stasis
A group of paleontologists recently documented stasis in birds and mammals from 35,000 years ago to today (Prothero et al., 2012).
Intelligent Design Creationists such as Douglas Axe are surprised by this result [Tar Pit Study Shows Complete Absence of Evolutionary Change]. So, apparently, are the authors even though they are evolutionary biologists and they have published this observation before.
How many Sandwalk readers are surprised by this paper?
Intelligent Design Creationists such as Douglas Axe are surprised by this result [Tar Pit Study Shows Complete Absence of Evolutionary Change]. So, apparently, are the authors even though they are evolutionary biologists and they have published this observation before.
How many Sandwalk readers are surprised by this paper?
Subscribe to:
Posts
(
Atom
)