Animals Parus_major_great_tit_songbird2

Published on February 6th, 2011 | by Michael Ricciardi

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How Climate Change Changes Evolution – One Bird’s Story


As average global temperatures increase, biologists anticipate more negative impacts from this change on a great many species of plants and animals. In most cases, scientists expect climate change to damage ecosystem integrity and ultimately accelerate the extinction of a great many species (as appears to be already happening in many quarters of the globe).

However, in some cases, increasing seasonal temperatures (such as in warmer Springs) may actually help some species adapt to climate change more quickly, and perhaps providing them with an evolutionary advantage. A recent study of a song bird (Parus major, or great tit) population in the Netherlands, by Husby, Visser, and Kruuk, revealed a positive selection mechanism linking Springtime temperature increases, early egg-laying, and greater genetic variance.

This mechanism may help speed up microevolution and may play a vital role in how fast species can adapt to climate changes.

The ‘rate of evolutionary change’ is generally determined by two key variables:

1] The strength of natural selection (a mechanism in Nature that favors the survival of gene-based traits),

and,

2] The amount of variation in genes (and thus the traits they encode) within a given species’ gene pool, that such selection may act upon.

In general, strong, natural selection of a trait results in a greater difference in the expression of that trait showing up between “successful” and “unsuccessful” parents. The greater the heritability of that trait (for example, earlier egg-laying) the greater the evolutionary change across successive generations, that is, the greater occurrence of a trait in a given population.

The researchers examined egg-laying dates, derived from more than 3,800 seasonal breeding records for nearly 2,400 females, and compared these to average daily temperatures derived from national weather service data.

Consistent with previous research, the authors found strong, positive selection on laying date, that is, the earliest breeders showed the highest genetic fitness. As a general rule in evolutionary biology, if an environmental effect (such as warmer spring temps.) strengthens natural selection (of a trait) and/or increases variation of genes (in that breeding population), then the rate of evolutionary change should be accelerated. This all translates, in theory, to a more adaptive breeding population — one that may better survive global climate change.

Indeed, the researchers’ statistical model (gauging genetic variance change versus temperature change) revealed an increase in genetic variance with the warmest temperatures. Also, where selection appeared to be strongest, this was associated with greater genetic variance (in egg-laying dates). All of which should portend for successful adaptation.

Darwin's illustrations of beak variation in the finches of the Galápagos Islands, which hold 13 closely related species that differ most markedly in the shape of their beaks. The beak of each species is suited to its preferred food, suggesting that beak shapes evolved by natural selection.

However, there’s one major problem: the population of this songbird species has declined over the past three and a half decades.

This reality perhaps underlines the sensitive ecological coupling between a species and its food source; it is believed that earlier egg-laying — selected for by warming temperatures — threw the birds out of sinc with the peak, seasonal hatching of caterpillars which are its principal food source. Early egg-layers didn’t get the higher caloric/nutritional intake that later ones did.

It would seem, then, that Nature may have played a cruel trick on the great tit. On the other hand, by increasing genetic variance, this mechanistic coupling may be providing the songbird with a genetic “toolkit”, or reservoir, in preparation for some future evolutionary shift. Alternately, it may be actually slowing the rate of the bird’s decline, as its current state of decline has only been observed since record keeping on them began. Their decline may have been pre-existent and on-going.

Thus, it is unclear if the mechanism revealed in this study can serve the long-term survival needs of birds and other animal species. Evolution does not act equally on all species occupying a niche (it didn’t here change the caterpillars’ behavior in tandem with the birds’). Adaptation is not simply about taking one beneficial trait and spreading it around, but rather, it seems to involve a “mosaic” of mutually supportive traits working within, interacting with, a favorable and diverse environment.

Some content for this article came from Climate Change Could Change Rates of Evolution by Liza Gross (published on PLoS Biology, Feb. 1, 2011). This article was an overview of the research paper Speeding Up Microevolution: The Effects of Increasing Temperature on Selection and Genetic Variance in a Wild Bird Population
by Arild Husby, Marcel E. Visser, Loeske E. B. Kruuk, also published on PLoS Biology, Feb. 1, 2011.

Top image credit: (Parus major, or great tit)) Sławomir Staszczuk.

19th Century Drawing: (Darwin’s finches) John Gould

Less obviously, another benefit of teaching students how the BLAST algorithm works is that it provides an opportunity to illustrate how mathematics functions as a language of biology. For example, given that BLAST has been designed to retrieve homologs, there are several steps in the BLAST program that incorporate molecular evolution concepts to maximize the possibility of finding sequences with a shared evolutionary history. More basically, understanding the steps in the calculation of an E-value provides an opportunity to show the relationship between how the algorithm works and fundamental principles of biochemistry and evolution. Here, we provide an approach to teaching the basics of BLAST to students in order to emphasize how the algorithm translates fundamental biological principles into numerical terms culminating in an E value. Acquiring a feel for the algorithm and exploring genomic sequence data has the potential to inform a student’s grasp of biomedical, biochemical, and biogeochemical concepts, presenting an excellent opportunity for multidisciplinary integration.




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About the Author

Michael Ricciardi is a well-published writer of science/nature/technology articles as well as essays, poetry and short fiction. Michael has interviewed dozen of scientists from many scientific fields, including Brain Greene, Paul Steinhardt, Arthur Shapiro, and Nobel Laureate Ilya Progogine (deceased). Michael was trained as a naturalist and taught ecology and natural science on Cape Cod, Mass. from 1986-1991. His first arts grant was for production of the environmental (video) documentary 'The Jones River - A Natural History', 1987-88 (Kingston, Mass.). Michael is also an award winning, internationally screened video artist. Two of his more recent short videos; 'A Time of Water Bountiful' and 'My Name is HAM' (an "imagined memoir" about the first chimp in space), and several other short videos, can be viewed on his website (http://www.chaosmosis.net).


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  • http://www.chaosmosis.net Michael Ricciardi

    Mr. Blake

    Your comment is full of disinformation.

    The “blame the UN” comment is quite false. It is the IMF/ World Bank that is the primary pusher of carbon trading on the world stage (while it invests 30% or more of its capital in carbon-polluting industries). To the extent that the UN is held captive by the IMF (this is arguable), then its choices are limited. But it is hardly pushing this (the situation is akin to Goldman Sachs selling/pushing mortgage-backed securities while it was also purchasing credit default swaps/insurance against those same securities).

    The UN, thanks to nationalistic “sovereignty” politics (and a divided Security counsel), has little muscle to effect anything — other than issue reports and policy recommendations. You need to study up on the UN Millennium Development goals regarding food/water security for the world’s peoples, as well as various conventions (e.g., Climate Change, Biodiversity) before you start leveling blanket criticisms. It’s more complicated than your comment allows.

    As to “over-population”…this is an old canard. Over-population is not simply a matter of total numbers of people; it is about total per capita consumption of energy and raw materials. by this measure, WE (in the WEST) are over-populated. The average American consumes 32 times the energy/materials that a Sub-Saharan African does. And it is due to this over-consumption that CO2/GHG pollution (and other by-products of over-consumption, such as resource inequality) is such a problem. I suspect that it is a profound social reluctance on our part to change our standard of living, or mode of living, that preserves this false claim.

    Yes, scientists do make some “bad” things — most often this happens when they prostitute their knowledge to big business, the government, and/or the military. Scientists are human; they want fame, status, recognition too. Throw enough money into this mix, and you will get exploitative science/technology for short term gain, power and profit. This is what economics without ethics can do.

    But Mr. Shahan is right: scientists did not create Climate Change. You are “shooting the messenger” here.

    The CO2 issue has not “split” the environmental movement; curbing CO2 emissions is PERFECTLY in keeping with the traditional goals of decreasing industrial pollution (in all its forms)…It is simply now a multi-purpose goal: cleaner air, less harm to ecosystems AND less warming of the atmosphere.

    Sadly, like may well-meaning folks these days, you were sold a bill of goods (propaganda) and you bought it hook, line and sinker. No worries though…there’s still plenty of time to apply the same skepticism to your information sources as you do to climate science.

    Until that day.

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  • http://Web Kerny Blake

    Climate Change has done to news editors, lazy copy and paste journalists, climatologists, progressivism and all of science itself, what nasty priests did for religion. Meanwhile, the UN had allowed carbon trading to trump 3rd world fresh water relief, starvation rescue and 3rd world education for just over 24 years of climate control instead of needed population control. Nice job. Scientists produced cruise missiles, cancer causing chemicals, land mine technology, nuclear weapons, germ warfare, cluster bombs, strip mining technology, Y2K, Y2Kyoto, deep sea drilling technology and now climate change. And how ironic is it that up until 25 years ago, scientists were condemned for producing planet killing chemicals and making environmentalism necessary in the first place? In his State of the Union Address, President Obama, the leader of the free world, didn’t mention the words Climate Change or EPA once. So why are the thousands of consensus scientists not marching in protest? Continued support of the climate change mistake is hurting everyone and the planet as it splits environmental efforts, alienates support for responsible environmentalism and drags well intentioned progressivism and public intellectualism down with it. History is watching. Remove the CO2 mistake and carry on without the needless and thoughtless CO2 death threats to our children.

    • http://www.zacharyshahan.com Zachary Shahan

      Kerny Blake, your continual comments of this sort, which have all been thoroughly debunked, are beyond incorrect. Some of them are so ridiculous, it seems pointless to even show how wrong they are.

      Scientists have not “created” climate change, as I’ve repeated to you many times. They have discovered it throughout the course of decades of thorough research. Just like scientists of the past discovered gravity, heliocentrism, that the world is not flat, etc.

      Thousands of scientists, not only climate scientists have pushed Congress and Obama to take science into consideration more with regards to climate change. And not just climate scientists, but scientists from the leading overarching scientific body in the country.

      Obama not mentioning climate change or global warming was a clear disappointed by many which has been expressed in depth. However, as he has made clear since then, it was no indication of his lack of understanding regarding this issue. It was clearly a political decision to look more centrist, but I and many others would say was a clear failure & horrible choice.

      History is watching, and your children and grandchildren will wonder why some of us (i.e. you) were so slow to catch on and pay attention to the clear science and go forward with the solutions faster.

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