Tiny Fish Rapidly Adapted to Cold Water. Was It Evolution?
BY * |
TUESDAY, AUGUST 17, 2010
Researchers have found that tiny fish called sticklebacks can adapt rapidly to a decrease in water temperature. This discovery adds to a long and growing list of animal trait variations that happen quickly. The researchers cited the stickleback adaptation as an example of evolution in action, but the rapidity of this change identifies it as the result of intentional programming--not mindless mutations.
The tiny stickleback seems to have a history of adaptability. A University of British Columbia press release indicated that populations of these fish once lived in the ocean, but then moved to live in freshwater lakes and streams.1 Other marine fish have been found with the ability to thrive in fresh water in only a few generations, like the pompano populations that are bred for freshwater fish farming.2
A team of Canadian and European scientists transplanted sticklebacks from Oyster Lagoon in southwest British Columbia to cold freshwater ponds. In just three years, which corresponds to three generations, stickleback fish "developed tolerance for" water that is 4.5 degrees Fahrenheit colder than the marine population's habitat.1
By the third generation, descendants remained of those "rare individuals" that already had the capacity to tolerate cold before the experiment began.1 The study authors wrote, "This rate of phenotypic evolution is among the most rapid to be observed in a natural population."3
But why were these fish able to adapt so quickly to colder waters? According to the researchers, "Our results suggest that cold tolerance is under strong selection and that marine sticklebacks carry sufficient genetic variation to adapt to changes in temperature over remarkably short time scales."3
But in considering this conclusion, it becomes apparent that the reference to "selection" is superfluous. All that is really needed for these fish to change as they did was for them to have the programmed instructions for "genetic variation" that the authors inferred from the data.3
It was the engineered genetic instructions, not nature's cold temperatures, that directed some offspring to develop slightly different traits in order for them to continue surviving. And engineered instructions are exactly what would be expected from an Architect who equipped His swimming creatures with what they would need to "be fruitful, and multiply, and fill the waters in the seas."4
References
- Tiny fish evolved to tolerate colder temperature in three years: UBC study. The University of British Columbia press release, August 4, 2010.
- Thomas, B. Fish Studies Answer Flood Question. ICR News. Posted on icr.org March 9, 2009, accessed August 11, 2010.
- Barrett, R. D. H. et al. Rapid evolution of cold tolerance in stickleback. Proceedings of the Royal Society B. Published online before print, August 4, 2010.
- Genesis 1:22.
* Mr. Thomas is Science Writer at the Institute for Creation Research.
Article posted on August 17, 2010.
Different genes code for two different forms of stickleback fish.
Click on image for full size
Courtesy of Zina Deretsky, National Science Foundation
Fish Adapting to a Changing World
News story
originally written on October 8, 2008
Scientists have been studying stickleback fish to learn more about how animals cope when their environment changes. Since the Earth is changing quickly because of global warming and other global changes, this research helps us understand how animals will adapt to a changing world. There are two main ways that the stickleback fish cope when their environment changes. First, individual fish can change the way they live their lives. Second, a whole population of animals can adapt over time through the process of microevolution by natural selection.
Some stickleback fish live in the ocean while others live in freshwater. The fish that live in the ocean have bony plates and spines for protection. These plates help the fish survive attacks by birds and other predators. Freshwater stickleback fish usually don�t have the plates, and sometimes the spines, as shown in the illustration at the left.
This change is due to the process of microevolution. For these fish, it can happen very rapidly, sometimes in only dozens of years. That�s fast for evolution. One hypothesis for why the freshwater fish no longer have the protective plates and spines is that they use their energy for growth and reproduction instead of plate production. The freshwater environment is stressful for the fish. Lakes become iced over, limiting the prey items available to stickleback throughout most of the winter, so growth and reproduction are probably better ways to survive.
Of course, it is not up to an individual fish whether it grows plates and spines.� It is coded in a fish�s genes. Scientists have been studying the genes of the stickleback fish to learn which genes allow fish to develop lateral plates. They found the gene that codes for plate development. They called the gene Eda. However more gene mapping showed that in addition to Eda, two other blocks of the same chromosome were also linked to the growth of plates. Fish that had Eda and the other genes grew plates. Fish that had the recessive gene instead of Eda did not grow plates.
Last modified February 6, 2009 by Lisa Gardiner.
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