Colleen @ ID 's comment was that there is no correlation between micro-evolution and macro-evolution. Her argument is that micro-evolution does not lead to macro-evolution, so my point regarding Darwin and the human eye was moot.
I am fairly certain that Colleen @ ID will be happy when I admit that she is abosolutely correct. However, it is likely that Colleen @ ID will be dismayed when I explain why she is correct.
First I have to explain what the difference between micro-evolution and macro-evolution.
Micro-evolution involves the gradual evolution of and between species of animals. For those who don't understand, an example of animals who are of different species but are still the same animal type are parrots and parakeets. They are both birds, but they are different species of birds. Micro-evolution is the process by which a new species develops within the animal type.
For instance, scientists have studied the evolution of the sea urchin, Micraster, where they have successfully demonstrated micro-evolution (Arora, & Kania, 2009, p. 202). The scientists were able to track the genetic changes of the mouthparts and other skeletal openings of the species until the original became so different from the later fossils that they could be identified as a new species. Scientists have also been able to use micro-evolution to explain the intermediate forms between two different species (Arora, & Kania, 2009, pp. 202, 203).
Micro-evolution, as described in the book by Arora and Kania (2009, p. 203) is, "a continuous and gradual change in an inter-breeding population. These small variations gradually accumulate to form large differences in structure."
Until some time after the 1970's macro-evolution was known as gradualism (O'Neil, 2011). Macro-evolution has to do with the changing of one animal type into a completely different animal type and does not occur on a regular, systematic basis like micro-evolution. Instead, macro-evolution occurs in irregular fits and bursts and is likely the result of major changes in the environment.
While the exact changes are unknown, likely suspects are predator pressure, meteorite impacts or disease (O'Neil, 2011). The exact cause of the periodic increase is not important for this blog entry, but it would still be fascinating to find out.
Macro-evolution accepts that the only changes that are observed, sometimes for millions of years, only occur within species. Remember that intra- and inter-species evolution is micro-evolution, and not the focus of macro-evolutionists.
Macro-evolutionists have discovered that differences in specific genes, called "regulator genes" produce very dramatic, new variations in body types and are responsible for allowing a drastic enough change in the body type and other characteristics of the animal to allow its offspring to survive in the new environment.
Macro-evolution is not a steady process where evolutionary traits are intereted and an entire line of species continues to improve. The process works more like a saw blade where there are improvements, then mass extinction, then improvements and mass extenction again (O'Neil, 2011).
Why Colleen @ ID is categorically wrong is very simple. Micro-evolution and macro-evolution are two completely different processes. One does not lead to the other because, although similar mechanics are causing both, they are completely different. It is as though Colleen @ ID Colleen @ ID was saying that no one could possibly get to the store because some people walked and others used a pogo stick. Sorry, Colleen @ ID , but both micro-evolution and macro-evolution are both evolution, but of course one does not cause the other. Both happen, sometimes at the same time, but they are different.
Colleen @ ID should learn about evolution before making public statements about it.
ReferencesArora, Mohan P., & Kania, Chander (2009). Organic evolution. Mumbai, India: Himalaya Publishing House.
O'Neil, Dennis (2011). Micro and Macro Evolution. Retrieved 14 September, 2011, from http://anthro.palomar.edu/synthetic/synth_9.htm