Science Daily should know better. The title is OK:
Annual Plants May Cope With Global Warming Better Than Long-living Species
But look at the first sentence:
Countering Charles Darwin's view that evolution occurs gradually, UC Irvine scientists have discovered that plants with short life cycles can evolutionally adapt in just a few years to climate change.
Excuse me, but there is nothing there countering Darwin, or countering gradual evolution!
They are mixing two senses of the word "slowly". Under the same strength of selective pressure, all organisms will evolve at the same rate. That does not mean they will evolve over the same time period. Rate is calculated in relation to the number of generations, not in absolute times.
So, humans, tomatoes and bacteria evolve at the same rate (roughly). But, in, let's say 30 years, humans will only have one switch of generations, tomatoes will have thirty, and bacteria will have 10,000 generations. If evolving at the same rate, bacteria will evolve much faster in terms of absolute time than tomatoes which, in turn, will evolve faster than humans in terms of absolute time.
While this distinction is relevant to the problem of a fast-changing climate, organisms differ not in how gradually they can evolve - that is roughly equal - but how many generations they can squeeze into the same absolute time period. So, annuals and perennials evolve at the same rate, but annuals evolve faster.
Comments
In fact, trees will not be able to cope with the rate of Global Warming.
If a tree lives, say 100 years, and supposing it was ideally adapted to its surroundings for the first 20 years of its growth, with increased temperatures, its ideal range may have moved 50 Km northwards during the next 20 years.
The tree cannot move, and cannot even hope to project seeds 50 Km north.
So that tree growth might be blighted, because it is genetically unprepared for a temperature 4 degrees hotter in average. The tree only "strategy" is to make seeds, and hope that a seedling will grow better in the hotter climate, or be carried slightly north.
Annual plants have slightly less trouble than our hapless tree, they can both hope to adapt to a hotter climate at a faster rate (new seeds every year), and that their population might relocate northwards at a faster rate, since a single seed carried by wind or an animal can start a new population in a few generations.
In Quebec, some tall, old trees were saplings during the Little Ice age. Their offspring is already not optimal for current condition, except for a few.
I don't know what is the expected rate of global warming, but a scenario of 1 degree per couple of decades is sufficient to blight whole forrests. The trees will be unable to adapt and evolve at a sufficient rate to cope. Whole groves will die to be replaced by other essences, (a natural outcome in such climatic situation), but, worse, very few specimen will have "migrated" towards their new, proper range, to start new populations.
So it might take as much as a thousand years for the trees to repopulate their range, if, of course, Global Warming stabilises at some point.
The trees cannot outrun the climate changes.
Posted by: _Arthur | January 9, 2007 12:36 AM
That is correct. Trees evolve too slowly to cope with global warming. That may be why dinosaurs died while tiny insectivores did not.
But if they had enough time to go through 10,000 generations, trees would evolve just as much as bacteria, i.e., their rate of evolution is the same as in bacteria while their speed of evolution is slower due to long generation time. They do not differ in rate, just speed. Both exhibit equally 'gradual' evolution, as Darwinian as can be.
Posted by: coturnix | January 9, 2007 12:53 AM
Poor Science Daily. It appears they pretty much cribbed the article from a UC Irvine press release (found on the UCI website) - and the unfortunate opening sentence is there as well.
Another issue with this story is that it's not made clear that the plants in question aren't generating novel anti-global-warming characteristics. Within any plant population there are no doubt alleles that contribute to early and late flowering, and all that's happened here is the early alleles became predominant due to selective pressure from the drought. But the variation already existed in the population. It's not like a species can just get busy mutating, and in a few generations come up with any imaginable useful trait. Yet that's EXACTLY the impression I find many of my students have of evolution, and because of how this story is worded, I can easily see non-scientists reading it in that way.
Posted by: bioephemera | January 9, 2007 2:02 AM
Absolutely right! There is quite a lot of standing variation in seasonality (photoperiodic response etc.) in almost any species of plant and animal studied so far. Alleles are all there to move (or not, or not as much) into the next generation.
Posted by: coturnix | January 9, 2007 2:06 AM
Science Daily is all press releases, all the time. A grain of salt is always good to keep metaphorically handy.
Posted by: CCP | January 9, 2007 8:01 AM
Since Macro evolution does not exists, the posts which address the idea of Darwinian style evolution are simply barking up the wrong tree.
To hint that a bacteria might have 10,000 'changes' in 30 years is preposterous. If they had 'only' a thousand, we would be constantly discovering new bacterial life forms, nearly every time we picked up a microscope. Let's get real folks.
Posted by: James Collins | January 11, 2007 10:12 AM