The Irreducible Complexity of Photosynthesis
An Uncommon Descent blog entry entitled 'Is Photosynthesis Irreducibly Complex?' references two articles (one from 'Nature' and another from 'Science Daily') and cites information from them. This is from the blog entry (my reactions in blue):
"After decades of research, biochemists now understand that this critical biological process depends on some very elaborate and rapid chemistry involving a series of enormously large and complex molecules a set of complex molecular systems all working together.
“We know that the process evolved in bacteria, probably before 2.5 billion years ago, but the history of photosynthesis’s development is very hard to trace,” said Blankenship."
Very elaborate chemistry indeed. No wonder the history of photosynthesis development is hard to trace. It's difficult to conceptualize, let alone trace, when explained by a paradigm of purposelessness and mindless direction. One reason for this is the interdependency of different cellular functions. For example, ATP is utilized during photosynthesis. So are by-products of metabolic pathways. If one assumes all related processes (including the Calvin Cycle) evolved prior to photosynthesis, chicken-egg dilemnas arise. They also present themselves if the opposite is assumed. The interdependency of basic universal pathways is strong evidence for design. So too are some points raised in the next comment.
This comment also appeared in that thread:
"There is no question about photosynthesis being IC. But it’s worse than that from an evolutionary perspective. There are 17 enzymes alone involved in the synthesis of chlorophyll. Are we to believe that all intermediates had selective value? Not when some of them form triplet states that have the same effect as free radicals like O2. In addition if chlorophyll evolved before antenna proteins, whose function is to bind chlorophyll, then chlorophyll would be toxic to cells. Yet the binding function explains the selective value of antenana proteins. Why would such proteins evolve prior to chlorophyll and if they did not how would cells survive chlorophyll until they did?"
That comment illustrates another problem for mainstream evolutionists. The evolution of parts can be toxic to the whole. Yet, the selective value of complementary systems is linked to the simultaneous existence of separate and distinct parts. The Darwinian answer is a generous dose of imagination consisting of homologous proteins and speculative "pathways." The purposeful arrangement of parts, suggested by the evidence, is philosophically anethema to mainstreamers.