Thursday, December 12, 2013

Convergent Evolution: Sounds Scientific?

What is convergent evolution? According to Wikipedia:

  • Convergent evolution describes the independent evolution of similar features in species of different lineages. Convergent evolution creates analogous structures that have similar form or function, but were not present in the last common ancestor of those groups. The wing is a classic example of convergent evolution in action…The recurrent evolution of flight is a classic example of convergent evolution. Flying insects, birds, and bats have all evolved the capacity of flight independently. They have "converged" on this useful trait.

Never mind that the capacity for flight requires massive changes in the shape of the body, muscles, respiratory and circulatory systems! However, some evolutionists, like Simon Conway Morris, believe that the forces of unguided evolution are so fertile that it was inevitable that the best body structures would inevitably evolve:  

  • Convergence is a dominant force in evolution, and given that the same environmental and physical constraints are at work, life will inevitably evolve toward an "optimum" body plan, and at some point, evolution is bound to stumble upon intelligence, a trait presently identified with at least primates, corvids, and cetaceans. (Wikipedia)

But could evolution reinvent the same brain structures over and over again? In this regards, neuroscientist and evolutionist Paul Patton made an interesting revelation:

  • “One of the most common misconceptions about brain evolution is that it represents a linear process culminating in amazing cognitive powers of humans, with brains of other modern species representing previous stages…However research in comparative neuron-anatomy clearly has shown that complex brains—and sophisticated cognition—have evolved from simpler brains multiple times independently in separate lineages.” (Scientific America Mind, “One World, Many Minds,” Dec 2008/Jan 2009, 72-73)

Patton acknowledged that what had been promoted as the evolutionary pathway of the brain (from simplicity to complexity), is not so. Previously, it had been taught that our brains derived from four sequential evolutionary steps in which the fish brain was overlaid by a reptilian complex and later repackaged in over-lying paleo- and then neo-mammalian brain additions:

  • “A ‘neural chassis” corresponding to the brains of fish and amphibians; a reptilian complex, consisting of the basal ganglia, which were held to dominate the brains of reptiles and birds; a paleomammalian component, consisting of the brains limbic system, which supposedly emerged with the origin of mammals and which was responsible for emotional behavior; and finally a neomammalian component, consisting of the neocortex, the site of higher cognitive function.” (75)

What does this say about the “common brain structures” that had confidently cast fish as our ancestors?

  • “In recent decades scientists have cast aside a linear, sequential view of brain evolution in which the human brain incorporated components resembling the brains of modern fish, amphibians, reptiles and birds.” (79)

How then do evolutionists explain not only the similarity in brain function but also the similarity in structure? Convergent evolution comes to the rescue – the inevitableness that these analogous structures would independently evolve! However, the evidence is lacking.

But is natural selection and random mutation (or any other naturalistic explanation) so generative? Evidently not! If life evolved, it only happened once, as evidenced by the universality of the features common to all life.

Besides, the sheer numbers of analogous organs – the so-called products of “convergent evolution” - strain credulity. In the case of bioluminescence, the ability to produce light, we are asked to believe that this ability has independently evolved on at least 40 separate occasions! Malone and Vett explain this:

  • From single-celled organisms called dinoflagellates to glow worms found in caves; from deep-sea fish to googly-eyed glass squids; there is a vast array of creatures with an ability to mix varying forms of luciferin and luciferase to produce light at will. It turns out that each of these creatures uses a slightly different variation of the key chemicals to produce light. One would think that closely-related organisms should have similar luciferns and liciferases, while creatures further apart on the evolutionary sequence would have much different versions of such chemicals. NO SUCH PATTERN EXISTS. Thus according to those who have extensively studied this subject, “bioluminescence is estimated to have evolved independently at least 40 times.” (Inspired Evidence 
It is difficult enough to believe that this ability to produce light – with its many necessary structures and complex chemicals – could have evolved at all. However, evolutionists are forced to insist that this same ability magically evolved “independently 40 different times.” It is wildly improbable that any collection of chance mutations could have accounted for these common features.

There’s another interesting feature about bioluminescence. Malone and Vett observe,

  • A firefly’s luminescence is 88% efficient while the light produced by the best luminescence reaction developed by mankind is a mere 23% efficient.
Not bad for a collection of genetic abnormalities – random mutations!

Whatever we might think about this improbability, these observations, and many others like them, demonstrate that common structures do not prove common descent. The evolutionist can’t logically have it both ways. Either commonalities do prove common descent or they do not prove common descent, which they admittedly don’t! However, evolutionists have construed it so that “heads I win; tails you loose.” They’ve even made up a term for when common features fail to reflect common descent – “convergent evolution.” Sounds scientific, doesn’t it!

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