Random Selection
Some maintain that there is no other explanation for variability than random natural selection influenced by environment.
Beyond my real comprehension are two explanations contributed by Chris Lindsey of Mallorn.com in an email exchange we had on this subject:
"You might want to look up the subject of cellular automata -- it covers what you're looking for. Granted, they haven't come to any conclusions yet, but I think some folks have hit on it.Fractals also play a key role in nature -- complex systems can be described by a single mathematical function. When you take this into account, it suddenly becomes clear how tiny bits of information in DNA can produce such a complex organism, and how tweaking the 'formula' slightly can make changes."
Those of you more mathematically inclined than I may make the connections and understand cellular automata and fractals.
My more ordinary mind, wanting reasons for leaf shape to which I can relate, grasps that evolution, climate, environment, genetic adaptations, cell function and variations that provide some survival advantage to a plant all play a part in the shape of a plant's leaves. Exactly how these relate to the leaf shape of each species of plant is not fully understood because not every species has been subjected to scientific study.
I still do not know exactly why my oak leaves, who started this quest, assume the specific shape variations on a single plant that they do; I am not certain that anybody today can pinpoint one shape and say with certainty that it was formed for a specific purpose. Perhaps that answer lies in the future - maybe you will be the one to discover it.
See ya' later!
More Information
- If you are at all interested in the evolution of plants, Dr. Karl Niklas' online 'talk' Plant Evolution: Adaptation or Historical Accident? is a 'must read'. Dr. Niklas is a Professor of Plant Biology, Cornell University. This 'talk' is part of a series of lectures, presented by California Academy of Sciences, hosted on the BioForum site, in which scientists share their research results with high school biology teachers.
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