I had an opinion piece published in the Shreveport Times on Dec. 7, which can be viewed here.
On Dec. 9, Mr. Ryan Gatti responded to it. He tried to attack evolution by asking me a bunch of questions.
I asked Ken Miller, an eminent scientist, and the author of the Pearson textbook to help me make sure I answered all the questions satisfactorily. I’m going to provide a shortened version of Mr. Gatti’s questions and Ken Miller’s answers.
1) What came first, bone marrow or bones?
“The bone marrow contains lymphoid cells, which are associated with blood-formation and the immune system. In many invertebrates, lymphoid tissue is found associated with the gut (digestive system). Teleost fishes, the first organisms to possess true bones, do not have bone marrow, but do have organs such as the spleen and thymus, which contain true lymphoid tissue. The first land vertebrates appeared during the Devonian period, as extensively documented by an increasingly rich fossil record. These organisms contained the first bones large and strong enough to support the weight of such an animal on land. The increased diameter of these bones made it possible for the delicate lymphoid tissue to be sequestered inside them, producing the first appearance of recognizable bone marrow in organisms that today we would classify as amphibians. So, the answer is that the historical record indicates that lymphoid tissue appeared before bones.”
2) What evolved first, the millions of photo receptors in the rear of the mammalian eyeball, the optic nerve or the mammalian cornea?
“The vertebrate eye evolved hundreds of millions of years before the first mammals, as Mr. Gatti should know, so the issue is not when the “mammalian eyeball” first appeared. Primitive photoreceptor cells are found in literally thousands of different organisms which possess neither a corner nor a true optic nerve. While it is certainly true that we cannot compress millions of years of evolution into a rapid-fire lab experiment that could produce neurons from scratch in an afternoon, we can nonetheless study the genetics and morphology of light-sensing systems in organisms today. It is a fact that light-sensing cells are involved in a wide variety of optical systems that lack lenses, corneas, or optic nerves, so the answer is that the photoreceptor cells (which are themselves modified ciliary cells) came first. It is also a fact that the development of eyes in organisms as diverse as mammals and insects are controlled by a single gene family, indicating the common evolutionary origin of visual organs.”
3) What came first, the Fallopian tube’s cilia or the mammalian egg?
“The cilia evolved first, no question about it. In fact, all animals today belong to the same group as a class of single-celled organisms known as choanoflagellates. These organisms are defined by a distinctive collar around their flagella. The cells of mammals (and other vertebrates) possess cilia and flagella very similar to these, so it is clear that vertebrate cells possessed such structures well before the evolution of the reproductive systems of placental mammals. These structures didn’t evolve from a “disorganized biological soup.” Rather, they evolved from cellular proteins such a tubulin, nexin, and dynein that serve multiple purposes within the cell.”
4) What evolved first, the code within DNA or the code breaker ribosome?
“Mr. Gatti would do well to brush up on the last 20 years of research in molecular biology, including work for which the Nobel Prize in Chemistry was awarded last year (2009). Although the ribosome consists of both RNA and protein, this work shows that RNA itself reads the DNA code and does the ribosome’s most important work, which is the protein synthesis. Since certain RNA molecules are able to catalyze chemical reactions, join amino acids, and even catalyze their own replication, it is clear that RNA molecules carrying out the work of the ribosome appeared first. The more stable DNA molecule evolved later, most likely as a backup molecule for information originally contained in RNA sequences.”
I would also like to establish that every single creationist argument has been refuted over and over again, and their attempts to poke holes in the theory of evolution have been answered. I could ask Ken Miller to refute any additional questions that are asked, but rather than waste his time, I would suggest critics go meet with a biologist at a university near them. I know they can answer those questions.