First, I didn’t invent this phrase, I encountered it in a publication some time ago (forgotten where), but I will show why it is true.
Second, a complete demonstration would require far more space than is available, so this will be largely in outline form with a few references.
I would like to begin with a review of the elements of the evolutionary process. This subject can be approached from many directions. I will begin with reproduction as this leads to the essence of the evolutionary process.
Since all multicelled animals (metazoans) have finite life spans, species survival requires that individuals replace, reproduce or copy themselves before they die.
Once the need to reproduce is established, a method must be selected. Single celled animals are the only organisms that are capable of directly making a copy of themselves, since they reproduce by splitting into two parts; however, this is obviously not practical for metazoans. Thus, it is clear that metazoans must somehow employ the same technique as the single celled animals, i.e., begin with a single cell.
But, it’s obviously not that simple. When a single celled animal divides, it merely produces an almost duplicate copy. The evolution of metazoans required a more complex process — the joining of two special cells, an egg and a sperm. Mutations (defined below) within these sex cells allows the creation of an individual, when the egg and a sperm are joined, that is sufficiently different from the parents that the evolution of higher life forms can occur
Of course, for the single fertilized egg cell to become an adult metazoan, the fertilized egg must divide into the billions of cells that comprise the adult metazoan; hence, cell division is an important part of metazoan life. A detailed discussion of embryo genesis is beyond this discussion — it is sufficient for our purposes to recognize that the process exists.
Having established the existence of cells and cell division, I need to digress to a brief review of a few bits of atomic and molecular physics A&M physics. As we all know, electrons, protons and neutrons combine, according to the laws of quantum mechanics, to form atoms. Furthermore, atoms combine to form molecules. Up to a point, molecules can also form according to the laws of quantum mechanics; however, when we consider that branch of A&M physics known as organic chemistry (the A&M physics of carbon atoms), the unaided laws of quantum mechanics alone reach limits.
One of the more important limiting points are the amino acids, organic compound that link together by peptide bonds to form proteins. Now proteins are the well known building blocks of life. BUT amino acids need help to join together to form proteins. The assistant is Deoxyribonucleic Acid, DNA, an extremely long, complex molecule that consists of a chain of four molecules termed bases. Along the chain are found groups of bases termed genes.
The existence of genes were first recognized by Gregor Mendel, but he had no idea what they were. It was not until Microbiologist Oswald Avery (1877-1955) led team that showed that DNA is the unit of inheritance the Journal of Experimental Medicine 1944..One Nobel laureate Joshua Lederberg, has called this discovery "the historical platform of modern DNA research"
Avery’s work inspired James Watson and Francis Crick, and others such as Linus Pauling, to seek DNA's structure. Watson and Crick won the race in April 1953 when they published the structure of DNA.
But, while determining the structure of DNA was important, it was not until gene sequencing specialist Craig Venter, teamed with DNA sequencing machine maker, Applied Biosciences Corp. in 1998 to set up a company named Celera that individual genes were found. Celera would use the shotgun approach to genetic sequencing and scores of AB’s sequencing machines to decipher humanity's entire genetic code. Actually, there is still some question regarding the exact number of genes, see sciencemag.org, 22 August 2003 Gene Counters Struggle to Get the Right Answer
Not surprisingly, DNA is found in all eukaryotes (organisms whose cells have a nucleus), from single celled eukaryotes to human beings.
So, now we have established the central nature of the cell in all life forms, at least those of interest, and the need for DNA to facilitate the production of proteins which make cells possible. But we still haven’t identified the specific aspect of the process which drives it.
To do this, we need to note that cells are not immortal. -- all cells have finite life. Normal cell death is termed apoptosis. Since cells die, they must be replaced and the only replacement mechanism is cell division (the basic reason for current interest is stem cells) thus cell division is necessary for the continuation of life. But, degradation can occur when cells divide basically due to mistakes that are made in the copying of DNA during cell division. A complex machinery exists to repair mistakes, but sometimes DNA repair fails and a cell with new DNA is formed — we call this a mutation.
Mutations can lead to an improved life forms; greater survival ability, etc. or mutations can lead to antibiotic resistant bacteria. This is the driver of evolution and is why Modern biology is unintelligible without an understanding of the evolutionary process
Regarding this premise, one finds many references to elements of the evolutionary process throughout the numerous, biologically related scientific articles. For example the word conserved appears often and refers to the fact that some trait is found in many, apparently unrelated, organisms.
I believe that an excellent illustration of the premise is found in this excerpt from an article in Science Magazine
Common Signaling Themes
Science, Vol 306, Issue 5701, 1505 , 26 November 2004
That signaling mechanisms are shared across distantly related organisms is readily apparent. Alonso and Stepanova (p. 1513) describe signaling by ethylene, a gaseous plant hormone that regulates processes such as seed germination and fruit ripening. Receptors for ethylene are similar to two-component histidine kinases, common signaling machines in bacterial cells. Ethylene signals are also apparently modulated by a mitogen-activated protein kinase (MAPK) cascade, a signaling module present in eukaryotic organisms from yeast to humans.
A comment related to the importance of an understanding of the evolutionary process. Genetic mutation, the driver of ecolution, is the basic cause of cancer and aging. Thus, cures for cancer and the tantalizing possibilty of life span extension, requires the determination of why the mutations occur and then finding a method for either stopping them or preventing them in the first place. I believe this will be accomplished -- we live in exciting times!
A final note: I have not included very many references (sorry, I just don't have the time to look them up). However, entering any of my assertions into Google will generate many supporting links.
Soplar
) I find nothing in your post with which to disagree. I share your motivation to speak out against the encroachment of religion into science. I agree completely with your argument concerning the conflation of the colloquial "theory" and scientific "theory".
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