Cedarville Magazine, Spring 2017

HOW DO CHANGES IN ORGANISMS OCCUR? The root source of differences between any two organisms is found in their DNA. SomeDNAmay be the same because the bodies of the organisms must perform similar tasks, but there are many, many differences. DNA is a repository, much like a library, that encodes information for the organism’s proteins that build, grow, and maintain that life-form’s physical body. DNA is composed of four bases: adenine (A), cytosine (C), guanine (G), and thymine (T), arranged in a specific sequence. Changes in the sequence of these bases are known as “mutations” and can come in many forms, including the deletion, addition, or rearrangement of bases. For evolution to be true, many mutations would have had to take place, and the type of mutations would necessitate the organism’s physical form undergoing dramatic change over long periods of time. One of the most popular examples of mutations (and often touted as “evolution in action”) is the development of antibiotic-resistant bacteria. Antibiotics are given to kill bacteria-causing infection and disease. However, bacteria have developed defenses against antibiotics over time, enabling them to survive medicines that would have killed them previously. This is a very serious concern in the health care field as some bacteria have become resistant to multiple antibiotics (e.g., methicillin-resistant Staphylococcus aureus, or MRSA), leaving doctors with no arsenal to treat patients. Bacteria develop resistance through mutations in their DNA. Some scientists have termed these “beneficial” mutations. They aren’t saying that it’s “beneficial” for bacteria to exist that can survive antibiotic treatment; they’re speaking from a scientific mindset. With antibiotic resistance, the mutation is beneficial because it facilitates the organism’s ability to prevail in spite of the effort to eradicate it. I would agree with that conclusion to a certain extent. These mutations are beneficial for bacteria living in an environment where adapting is advantageous, such as a hospital or nursing home where antibiotics are used heavily. However, are these mutations really beneficial for that organism overall? Mutations always come at a cost. In this case, the bacteria gain the ability to resist the antibiotic, but they have done so while losing or altering their ability to do something else. For example, Helicobacter pylori, the bacteria responsible for ulcers, produces a protein (we’ll call it the N protein for short) that is important for the bacteria’s metabolism. One of the antibiotics given for H. pylori infections targets this protein. The N protein converts the antibiotic into a poison, and the bacteria die. Sadly, the overuse and abuse of antibiotics in some countries have led to the development of antibiotic- resistant H. pylori. These H. pylori have a mutation that makes them unable to produce the N protein. When the antibiotic is given to individuals for treatment, the N protein is not present in the bacteria, so they don’t convert the antibiotic into a poison and they survive. The mutation and the subsequent resistance have come at a cost. The bacteria no longer produce the N protein that is needed for normal metabolism. Sometimes other bacterial proteins can perform the missing function, but usually not as well. The resistant bacteria survive well in a health care setting (where there is heavy antibiotic usage) because there is limited competition (fewer bacteria) for the limited nutrients in their environment. Outside of that setting, the resistant bacteria are at a disadvantage because they cannot perform normal functions as well and can be outcompeted by bacteria able to make the N protein. What we learn is that mutations can be beneficial in certain environments but, overall, it’s really a trade- off resulting in no overall benefit or net gain for the bacteria. The point is this: mutations, instead of being the missing piece in the evolutionary puzzle, are typically destructive, or at least not supportive of directional change, as we see with just this one example (and there are many more I could share!). This is true for the vast majority of mutations; they destroy information encoded in the DNA. HOW ARE MUTATIONS A PROBLEM FOR EVOLUTION? Evolutionists believe that numerous mutations, accumulated over long periods of time, have led to the evolution of all life from a single-celled common ancestor. In order for human life to have evolved from this ancestor, mutations would have to change the DNA so the organism would eventually make brains, eyes, and ears (just to name a few!). But mutations are destructive, as we’ve seen with antibiotic-resistant bacteria, and simply cannot make the kinds of changes evolution requires. Let’s look at the popular evolutionary idea that dinosaurs evolved into birds. I once watched an The point is this: mutations, instead of being the missing piece in the evolutionary puzzle, are typically destructive, or at least not supportive of directional change. 14 | Cedarville Magazine