The Mystery of Cat and Fly Species


Within On the Origin of Species by Means of Natural Selection, or the Preservation of the Favoured Races in the Struggle for Life are actually two titles—separated by “or”.

In the text of the book, “species” is the most commonly word used from the title—1,926 times. From the words in the title, the next most commonly used word from the title is “natural”, appearing just 764 times.

Therefore, in the 3,878 sentences of first edition, nearly 50% of the sentences include the term “species.” The concept of “species” is central. Ironically, however, Charles Darwin never defines the term “species”. In fact, Darwin explains that “species” defies definition:

No certain criterion can possibly be given by which variable forms, local forms, sub species, and representative species can be recognized.

After 150 years of unprecedented research, the concept of species continues to defy definition. Technological advances in the mid-twentieth century were expected to discover the molecular basis of species. However, rather than solving the mystery, technology has only re-enforced the mystery.

“If we want to solve the problem underlying every origin of species in molecular terms,” Italian geneticist Giuseppe Sermonti explains in his book entitled Why a Horse is Not a Fly, “we have to admit that for the moment the answer is not forthcoming. And there is no answer.”

A natural explanation for the mystery of species continues to elude a scientific explanation. What we know is what we have always known. A cub is born a cub because its mother was a she-cat that mated with a tom. The fly emerged as a fly larva from a fly egg. Kind follows kind. Who knows why?

Through decades of studying tens of thousands amino acids, nucleic acids, proteins, DNA, RNA, and genetic codes, the deciphering any molecular hieroglyphic evidence to define a species continues to elude scientists. This issue is what is called the “species problem.”

While a genetic difference explains why some peas have red flowers and some have white flowers, and why some fruit flies have red eyes and some have white eyes, there is no evidence that a “cat gene” and a “fly gene” exists. A gene does not determine the species: cat or fly. In fact, any molecular basis to distinguish between species simply does not exist.

As with genes, the phenomena continues true with proteins. “Strikingly enough, bacteria, animals and plants have 80% of their enzymes in common,” according to Sermonti.

Cytochrome C, one of the first proteins systematically studied across the animal kingdom, demonstrates stability throughout the animal kingdom rather than the “slight, successive” changes as theorized by Darwin. For Australian molecular biologist Michael Denton, “this must be considered one of the most astonishing findings of modern science.”

Twentieth century research was driven to unveil a molecular basis for the difference between species. The search, however, has been a failure. “The cytochrome C from all species—man, fly, spinach,” according to Sermonti, “was functionally identical and the mutations that were thought to have accounted for the molecular differences were termed ‘neutral’ [of no effect]. Spinach cytochrome C did its job just as well as human cytochrome C.”

“[T]he more one approaches the molecular level,” according to UCLA molecular biologist Richard E. Dickerson, “the more similar they appear, and the less important the differences between, for instance, a clam, and a horse become.”

On the bottom line, species are not differentiated by differences at the molecular level. French evolution biologist François Jacob concluded: “Biochemical changes do not seem to be the main driving force in the diversity of living organisms.”

There is not a single cohesive Tree of Life to demonstrate the “successive, slight” changes in the sequence of a single molecule between the species as expected from Darwin’s theory of natural selection.

Darwin was torn between the two titles. The second title, Preservation of the Favoured Races in the Struggle for Life, the evidence aligns with the theory, while On the Origin of Species by Means of Natural Selection is not supported by the scientific evidence for the term “species”.

Perhaps, Darwin should have heeded his intuitive observation: “No one definition has satisfied all naturalists; yet every naturalist knows vaguely what he means when he speaks of a species. Generally the term includes the unknown element of a distinct act of creation.”

What makes a cat a cat and a fly a fly—the “kind after kind” principle.

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Darwin, Then and Now is a journey through the most amazing story in the history of science - the history of evolution. The book encapsulates who Darwin was, what he said, and what scientists have discovered since the publication of The Origin of Species in 1859.

With over 1,000 references, Darwin Then and Now is a historical chronicle of the rise and fall of the once popular theory of biological evolution.