Sticklebacks are small, bony fish that exist in both freshwater and saltwater varieties. While this fish may look unassuming to most people, Evolutionary Biologists consider their story to be one of the greatest examples of Evolution in action.
Saltwater sticklebacks are heavily armored with large spines on their back, along with a pelvic spine. This makes it difficult for large-mouth predators to eat the saltwater form. Freshwater sticklebacks, however, tend to have less armor, and spines that are smaller (and sometimes nonexistent).
Before the 1980’s Loberg Lake was home to a native population of freshwater sticklebacks. Then in 1982 the Alaska Department of Fish and Game poisoned the lake with the intention of killing the native sticklebacks in order to add recreational fish to the lake.
Eight years later, researchers discovered that the lake had been recolonized by heavily armored saltwater sticklebacks.
So far so good. The native sticklebacks in Loberg lake were gone, and a new colony of saltwater sticklebacks had taken their place.
Then something amazing happened. In 1991 researchers discovered that some of the fish in Loberg Lake resembled the native fish that lived in the lake a decade earlier. This reduced armor form began to spread through the lake’s population and by 2001, the fish with reduced armor made up 75% of the population in Loberg Lake.
Genetic analysis revealed a mutation in a small region of DNA that regulated the production of certain proteins. A small region of this DNA had been spontaneously deleted. This deletion mutation resulted in fish with low armor and small spines.
An analogy for this type of mutation might be a book with a missing page.
The fish were adapting to their new environment, and researchers viewed this as an example of “rapid evolution”.
Natural Selection was favoring the fish with reduced armor, and reduced spines, but why? After all, wouldn’t it make sense for the fish to keep this armor to defend themselves from predators?
There were actually several reasons why less armor was actually favorable.
First, unlike the environment that the fish had to face in the ocean, there weren’t any large mouth predators in the lake that the fish had to worry about. This meant that the armor and spines were an unnecessary handicap.
Second, while large mouth predators weren’t an issue, dragonfly larvae were. Dragonfly larvae like to eat small sticklebacks by grabbing onto their pelvic spines and dragging them closer. This made pelvic spines a liability.
The third reason is related to the first two. Heavy armor has obvious advantages, but it also slows the movement of small fish trying to swim away from predators. Less armor meant that it was easier to swim away from dragonfly larvae.
The fourth reason (again, having to do with dragonfly larvae) is that sticklebacks with low armor grow faster, meaning that if you are a baby stickleback, dragonfly larvae have less time to catch you and eat you, before you reach adulthood.
Just so that I am not creating confusion, as you can imagine, there are a number of stickleback species, and even individuals within a species can vary across a range of environments, however for the sake of simplicity in this article I chose to focus on just the basic freshwater form and the basic saltwater form in an around Loberg Lake.
Creation and Intelligent Design
A lot of people have hailed this as a strong example of evidence for Evolution, however there are a number of factors to consider in evaluating this claim.
What we’ve seen here is definitely a good example of mutation followed by natural selection.
So what would critics of Neo-Darwinian Evolution, particularly biologists arguing for Creation and biologists arguing for Intelligent Design have to say?
Creation Biologists and Intelligent Design advocates agree with Evolutionists that living things change. Mutation and Natural Selection are facts of biology. In fact it was a Creationist by the name of Edward Blyth who first proposed the idea of Natural Selection, not Charles Darwin.
Biologists arguing for Creation and those arguing for Intelligent Design disagree, however, with the belief that the origin of everything in biology can be explained by purely natural processes.
Biochemist, and Intelligent Design Advocate, Michael Behe, for example, thinks that the universal tree of life is real, but doesn’t think that natural processes alone are sufficient to explain every adaptation in the history of biology.
Other biologists, especially those arguing for Young Earth Creation, think that the history of life is more akin to an orchard than to a single massive tree.
In other words; biological changes occur, however these changes don’t explain the whole of what we see in life on Earth.
With regards to sticklebacks, what we’ve seen here is a good example of natural selection in action, as well as a good example of a beneficial mutation, however nothing fundamentally new was created.
The genetic basis for this change was the deletion of regulatory information, not the creation of something fundamentally new.
While I will probably receive flak from those who disagree with my view for saying this, when looked at carefully, none of the putative examples of “Evolution in action” ever really show support for the idea of “onward-and-upward” Evolution.
Creation Biologists have put forth the rather abstract argument that none of the random mutations that we’ve seen ever result in an increase in information. Many people reading this will object that we see gene duplications and things along these lines, however even gene duplications are just that — a duplication in existing information, not the creation of fundamentally new information.
There is a lot more that could be said here, however covering every putative example of “Evolution in action” is far beyond the scope of this article. I will have links towards the bottom for more information.
Focusing just on the example of sticklebacks, it is logically fallacious to equate the observed loss of genetic information in a fish with the idea that all of life on Earth arose from a universal common ancestor with no outside intelligence guiding the process.
Textbooks will often define Evolution as simply meaning “change over time”, or change in allele frequency, and leave students with the impression that critics of Evolution deny that species change. These same textbooks will then switch the definition of Evolution without informing the reader, lumping multiple concepts together as if they were one and the same.
On one hand textbooks will define “evolution” to mean change over time, but then they will switch the use of the word Evolution to convey the idea that all of biology can be explained in purely natural processes.
The problem is that this creates a logical fallacy, equating two different ideas as if they were one and the same, and also leaving students with the impression that you can’t have one of these ideas without the other; namely the fact that species change, and the belief that natural causes can explain the origin of everything that we see in biology.
So in summary:
Sticklebacks in Loberg Lake are an example of a loss of genetic information, not the creation of fundamentally new information. Biological changes happen in populations, however when looked at carefully, we do not see the types of changes required for the type of onward-and-upward Evolution that Darwin imagined.
Also, despite the misleading information that you may have heard in a classroom or in your textbooks, biologists on all sides of this debate agree that living things change, but they disagree on what these changes are capable of.
As a biotech major, I once believed that Evolution was good science, however when I took the time to examine the evidence again in light of the arguments of Biologists arguing for Creation, I switched my way of thinking. Despite what you’ve probably been taught in class, there are thousands of biologists arguing for Creation, and thousands more arguing for Intelligent Design.
Unfortunately many people, including most scientists, believe in Evolution because they have only read the arguments of scientists on one side of the debate, and have only heard a misrepresentation of scientists on the other sides of the debate.
I challenge everyone reading this article to look into the arguments for various viewpoints for yourself, and realize that there are well-recognized and well-respected experts (namely geneticists, biochemists, paleontologists, medical doctors and a whole host of other well respected scientists) on all sides of the Creation/ Evolution/ Intelligent Design debate.
Be sure to check out the video that this article was based on!
Thank you for reading!
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