Opening description of Virology from Wikipedia (As of 3/2/14):
“Virology is the study of viruses – submicroscopic, parasitic particles of genetic material contained in a protein coat – and virus-like agents. It focuses on the following aspects of viruses: their structure, classification and evolution, their ways to infect and exploit host cells for reproduction, their interaction with host organism physiology and immunity, the diseases they cause, the techniques to isolate and culture them, and their use in research and therapy. Virology is considered to be a subfield of microbiology or of medicine. ”
Note the inclusion of evolution in the list of primary aspects of the study of viruses.
If you’ve ever needed solid, undeniable proof that Darwinian evolution occurs, virology is pretty damned well the nail in the coffin of doubt, assuming you’re capable of accepting observable facts as part of reality.
Over the last several decades, virologists have watched as viruses continue to observably evolve by natural selection in order to survive the barrage of anti-viral medicines and vaccines that we create to combat them.
Virology is a sub-field of microbiology, which, as a larger field, has also documented the observable evolution – again, through natural selection – of bacteria to survive the antibiotics we create to kill them.
Everyone knows that this is what happens. The news media has been talking about “superbugs” for over 20 years – viruses and bacteria that have developed a strong resistance or outright immunity to the treatments that used to kill them, and more often than not became stronger and more deadly in the process. THAT is Darwinian evolution in action: The most resilient genetic strains of a virus or bacteria survive the onslaught of modern medicine to procreate as their less resilient counterparts die off.
This is not something that takes millions of years. It takes only decades. In some cases it has taken less than a decade. Virologists can and have directly observed HIV and AIDS evolving as a single genetic strain spreads out in a chain from a patient 0. It’s not a huge evolutionary shift from one person to the next, but when you get a few hundred people down the chain of infection, the virus can start looking very different.
There are many diseases today (both bacterial and viral) for which active, observable evolution that has occurred in our lifetime is the only reason 1) they exist in the first place and/or 2) they have not been completely wiped out by modern medicine.
Evolution is also the reason we (or at least some of us) have the mental capacity necessary to create medicines that will combat these illnesses, and many others, until the day we do, finally, overcome them.
Evolution: Not “just a theory.” A theory backed by evidence. You just have to look for it.