New research shows that in the span of just fifty years songbirds have become slightly smaller, probably as a consequence of global warming. This is no big surprise as it has long been understood that size is inversely correlated with temperature. The Darwin contemporary Christian Bergmann first observed this trend, in terms of a correlation with latitude, and the trend became known as Bergmann's Rule. But how did the change come about?The new research, which accounts for more than 100 species and almost half a million birds, shows a rapid reduction in size as the earth warmed in recent decades. The change is slight, but the statistics in the massive study are undeniable.
Perhaps the change is a consequence of natural selection shifting the populations to slightly smaller sizes, as the smaller individuals have greater reproductive success. Or perhaps the change is a result of built-in biological responses to the temperature change.
However the changes arose, the process involved complex structures and mechanisms--structures and mechanisms that must have evolved if the theory of evolution is true. Under evolution, we must believe that not only have the world's species evolved, but their various response mechanisms have as well.
Evolutionists explain that evolution happened to construct such response mechanisms. When needed those mechanisms were helpful, and so were selected for.
Cornelius,
ReplyDelete"Even if only a single mutation was responsible, the short time span makes the evolution narrative highly unlikely." what makes you think it was a mutation? there is almost always variation in size in a population (look at humans for an example), and changes in climate can select for those with smaller size. do you think a mutation is responsible for the changes in beak size with shifting food availability in Geospiza fortis?
Evolutionists have always explained their bizarre and unlikely theory as a consequence of astronomically long time periods.
ReplyDeleteI think it is truer to say that evolutionary theory is change plus time. More changes require more time. Small changes less time. It's just more or less of the same thing. Is there another explanation that fits the evidence and observations better, Dr. Hunter?
Hunter's point with this post seems to be "evolution was observed, therefore evolution is wrong." Keep knockin' 'em dead, CH!
ReplyDeleteYup. Fast changes in phenotype that has nothing to do with selection or even mutation.
ReplyDeleteIt should be obvious that the environment affects development of an organism, and thus major characteristics of the organims.
Selection and mutation are not the proper paradigms to describe the population changes but rather developmental plasticity.
Evolutionary theory gets it wrong, developmental plasticity gets it right!
Mary Jane West-Eberhard in Proceeding of the National Academy of Sciences:
"Contrary to common belief, environmentally initiated novelties may have greater evolutionary potential than mutationally induced ones."
She unfotunately has to give credit to Darwinian mechanisms creating the capacity for developmental plasticity. That is pure speculation. What is in evidence from direct empirical observation is developmental plasticity is a better paradigm to describe certain population changes than mutation and selection!!!!!
Maybe even Darwin's finches are examples of developmental plasticity than Darwinian evolution!
nanobot,
ReplyDeleteYou might want to brush up on developmental plasticity versus mutational mechanism.
Sal
nano:
ReplyDelete"what makes you think it was a mutation?"
I don't.
"there is almost always variation in size in a population (look at humans for an example),"
Agreed.
"and changes in climate can select for those with smaller size."
So the evolution in this case would be brought about by structures and processes (genes, interactions between different genes, meiosis, etc) that evolution created. Correct?
Serendipity is a wonderful thing, Sal. Thanks!
ReplyDeleteFrom Mary Jane West-Eberhard's paper I picked up on two-legged goats which led me here So, Jerry Coyne doesn't think "versus"at all.
Wow. Bad even by your standards.
ReplyDeleteThe entire premise of this post is that evolution is some slow hulking process that could never account for rapid phenotypic change (while some design can?, and that the authors have disproved evolution by observing recent change.
1) The actual evolutionary argument (which nanobot has already made) would be that the population is diverse-that is, it has alleles of genes that allow for a distribution in size. These have been accumulated over long, long times. The authors find bird size (like humans) does follow a distribution. When there is selective pressure against large birds (global warming), the alleles favoring small birds are selected. NO ONE is saying that 'small' mutations have cropped up in all species over the last 100 years.
2) Note the authors (in the actual paper, not the silly press release) don't argue the point you've slimed them with:
"there is debate over the degree to which populations can meet the challenges of climate change with evolutionary or phenotypic responses in life history and morphology"
OR-key word
"This confirms that phenotypic responses to climate change are currently underway in entire avian assemblages."
In phenotype-not genotype!
"Although our data cannot demonstrate that body size is evolving under climate change, they do show that the response is correlated with natural selection and may therefore be adaptive."
Again, they are charting the selective pressure and phenotypic changes, which would be a prerequisite for evolution, but freely admit the point:
"A definitive answer requires quantitative genetic analyses or long-term studies of marked individuals"
Which hopefully, they will now do.....
3) The observed change in phenotype could be epigentic. Imprinting affecting offspring size is commonly observed. I know ID loves epigenetics, but there is no compelling argument why it is not a natural, evolved natural process.
4) I see Dr. Hunter believes in global warming. Thanks for being part of the consensus. As many times as the contrary has been posted by your compatriots, I find this refreshing.
Pop quiz! Here is a quotation:
ReplyDelete"In X a number of biologists have advocated what may be called Y views of evolution, especially the conception that in certain cases rapid evolution can occur."
The questions are:
a) What is the value of Y?
b) Where is the quotation from?
Too-facile use of search is forbidden; I've made some trivial changes to discourage this. I'll provide the full original quote and source with the answers, of course.
The DarwinDefenders' scornful response on display in this thread (it's their normal response) is simply a reflection of their equivocal use of the word "evolution" (which they mis-use even when they're not equivocating).
ReplyDeleteRobert:
ReplyDelete"4) I see Dr. Hunter believes in global warming. Thanks for being part of the consensus. As many times as the contrary has been posted by your compatriots, I find this refreshing."
I didn't know that. Can you give an example, or did you mean they doubt AGW?
Robert:
ReplyDelete"1) The actual evolutionary argument (which nanobot has already made) would be that the population is diverse-that is, it has alleles of genes that allow for a distribution in size."
So evolution created evolution?
> But more recent ideas suggest that animals might actually be responding instead to something else that correlates with temperature, such as the availability of food, or metabolic rate.
ReplyDeleteIf reduced availability of food really does account for the reduced average size, then isn't there likely no surprise in this case? Individuals on restricted diets (as distict from say their offspring) growing less big is a completely uncontroversial form of adaptive variation, right?
"I didn't know that. Can you give an example, or did you mean they doubt AGW?"
ReplyDeleteNo, a large part of the debate seems to focus on the validity of the climate record, and the interpretation of warming trends.
http://www.uncommondescent.com/category/global-warming/
10/5, 10/10, 12/8, 12/16, for examples
So evolution created evolution?
Genetic changes, accumulated over time, created allelic diversity for natural selection to act on.
Does fire create fire?
I haven't been paying close attention to Dr Hunter's blog until recently, but there seems to be a pattern to the posts along the lines of "this new study is a problem for evolutionary theory" but that is as far as anything goes. Does Dr. Hunter propose some better explanation? Maybe he has and I've missed it. If anyone could provide a link I'd be grateful.
ReplyDeleteThanks in advance.
I guess you would argue for the evolution of evolvabilty along the line you assert the anthropic principle.
ReplyDeleteThere is another example of a temperature dependency in nature. The sex ration in the eggs of the American alligator depends on the temperature in the nest. In other animals one could specuate about a relatively simple mechanism where growth factor proteins degenerate more with increasing temperature and thus lead to smaller sizes. But since the mechanism has not been discovered yet the situation is probably more complicated.
I think that Mr. Hunter is hinting that a "front-loading" explanation is better. Or that animals are designed to have a natural elasticity but one that is not enough to result in speciation. But I'm not sure if that is what he is getting at or not.
ReplyDeleteSal,
ReplyDeleteI missed your first post, but I do wish you would stop taking such liberties in your liberal re-interpretation of other scientist's careers.
Mary Jane West-Eberhard has published on the evolution of social behavior in wasps, sexual selection, and phenotypic plasticity.
She credits Darwin for his focus on social competition for mates.
One of her major books is titled "Developmental Plasticity and Evolution," which yes, looks at developmental plasticity, as she says:
"alternative phenotypes—alternative pathways and decision points during development, and their significance for evolution, especially for higher levels of organization, for speciation, and for macroevolutionary change without speciation."
"This line of thinking culminated with the publication of a fat book, Developmental Plasticity and Evolution (Oxford University Press, 2003), which tries to relate the condition sensitivity of development to the genetic theory of evolution that I learned as a graduate student, a body of thought that is still fundamentally sound and easily accommodates attention to development."
You go to far in making it sound like phenotypic plasticity is a mechanism that competes with evolutionary understandings of biology, and that she is somehow on your team.
Ref for quotes:
ReplyDeletehttp://www3.interscience.wiley.com/cgi-bin/fulltext/121641681/HTMLSTART
Your posting, dear Cornelius, is interesting, especially in regard with the discovery that speciation doesn't come about gradually via natural selection but suddenly. Please have a look at today's newscientist (http://www.newscientist.com/article/mg20527511.400-accidental-origins-where-species-come-from.html?DCMP=OTC-rss&nsref=life).
ReplyDeleteRegards,
kyrilluk
I think that Mr. Hunter is hinting that a "front-loading" explanation is better. Or that animals are designed to have a natural elasticity but one that is not enough to result in speciation.
ReplyDeleteIs Collin on the right track, Dr. Hunter? Do you subscribe to "front loading" as a better explanation of observed reality than the ToE?
If anyone is not aware that there is also discussion at Uncommon Descent on the same topic (here let me warmly compliment Dr. Hunter on his open comment policy) can I recommend, in particular Allen MacNeill's comment responding to Sal Cordova and his "interpretation" of the Grant's heroic work on Galapogos finches.
ReplyDeleteGalapagos, sorry!
ReplyDeleteThis comment has been removed by the author.
ReplyDeleteEven in this Pennsylvanian passerine study, although they don't have genetic data, and even though size can certainly be ecophenotypically labile, reading the abstract (which is all I can see for free; http://www3.interscience.wiley.com/journal/123306738/abstract?CRETRY=1&SRETRY=0), it does not look like this trend is due to phenotypic plasticity.
ReplyDelete1. Masses were calculated fat free. Given extra nutriment, passerine birds (especially migraters) would tend to turn it into fat to get them through the lean times.
2. There is no correlation between size and habitat quality.
3. The major negative correlation cited is between size and temperatures of the previous winter. If this were ecophenotypy (the result of plastic development), the correlation should be with the growing season. Instead it looks like cold winters kill off runts, but otherwise small birds enjoy advantages (not surprising, as passerines are generally small birds).
Alan Fox:
ReplyDelete========
I think that Mr. Hunter is hinting that a "front-loading" explanation is better. Or that animals are designed to have a natural elasticity but one that is not enough to result in speciation.
Is Collin on the right track, Dr. Hunter? Do you subscribe to "front loading" as a better explanation of observed reality than the ToE?
========
I feign no hypothesis.
kyrilluk:
ReplyDelete===
especially in regard with the discovery that speciation doesn't come about gradually via natural selection but suddenly. Please have a look at today's newscientist (http://www.newscientist.com/article/mg20527511.400-accidental-origins-where-species-come-from.html?DCMP=OTC-rss&nsref=life).
=====
I think that one is here:
http://darwins-god.blogspot.com/2010/03/speciation-is-about-happy-accidents.html