When I was a master’s student in the Entomology department at Penn State, there was one professor who, at the end of every research talk given by a seminar speaker or job candidate, would ask “So what? Why should I care?” He had a deep booming voice, and we all squirmed in our seats while we waited for the speaker to come up with an answer that would explain the broader significance of the research topic they had just finished talking about. I have to say, though, that Dr. Cameron’s question has stuck with me through my research career. I try to keep an answer in mind as I propose new research projects or present my latest results at scientific conferences. I don’t want to be caught squirming for an answer in the event that there is another Dr. Cameron in the audience. This question is one I’ve tried to keep in mind while I wrote the Three Chromosomes in a Trench Coat series, and in this last installment I will attempt to answer the question, “So what? Why should the reader care?”
I discussed this a bit in the first installment. I find the phenotypic plasticity, adaptation, and fitness landscapes fascinating. God not only created all the animals and plants on the Earth, but they were created in such a way that they can often, but not always, self-adjust when the need arises. It gives me joy to study the nitty-gritty mechanics behind that. To paraphrase Eric Liddell in the Chariots of Fire movie, “I believe that God made me for a purpose. But He also made me to study science, and when I science, I feel His pleasure.” Learning about living things is one way that I worship God.
So, that is why I care, but it doesn’t answer the question about why I want you, the reader, to care. Partly, I want you to care because I want you to share my joy, but I know that insects and molecular biology aren’t everyone’s cup of tea. Mostly, though, I want you to care because it is important to understand how human actions impact the rest of creation and how that should inform how we “reign over the fish in the sea.”
Andy has nicely shown with his most recent Quandary Den simulation it is advantageous for organisms to be phenotypically plastic because the phenotype is the ultimate target of natural selection, and flexibility increases the fitness (the number of offspring contributed to the next generation) of a population, and in some cases, the ultimate success of a species. The Asian tiger mosquito, Aedes albopictus, is a great example of phenotypic plasticity increasing the success of a species. This mosquito is medically important because it can transmit viruses that infect humans including yellow fever, dengue fever, and Chikungunya. They can also spread parasitic worms. Unlike many types of mosquitoes that are only active in the evening, A. albopictus is especially aggressive and is active (and bites) during the day.
These mosquitoes are native to tropical regions, and especially to Southeast Asia. Now they are found all over the world and are listed among the top 100 most invasive species. They were first introduced into the United States around 1985 when they arrived in Texas in a shipment of used tires from Japan. Since then, they have continued to invade the U.S. and are now found in 40 states. One thing that has made them so successful, other than our failure as a society to deal with used tires, is their ability to quickly adapt. In the more temperate regions of their range, they have acquired the ability to enter diapause in response to shortening daylengths and to spend the winter in suspended animation. This is not something they typically do in the southern, tropical parts of their range. How they are able to enter diapause is an active area of research, but it involves changes in gene expression that help them preserve fat stores and make them more resistant to desiccation.
On the flip side, many organisms do not have the same sort of phenotypic plasticity and they are not able to adapt to extreme changes in climate. Many are not able to survive a broad range of temperatures. Others are extreme specialists in terms of their diet. Monarch butterflies (Danaus plexippus) only feed on milkweed plants, and habitat loss that includes a reduction in milkweed plants will lead to reduced numbers of these familiar butterflies. The same is true of many types of fish, frogs, and birds, and bees. Some of the animals and plants that are threatened may not seem immediately valuable. But honestly, we don’t yet understand how they all interact with each other. Removing one part may have impacts that we will only discover once they are gone. This makes studying all types of animals and plants, and not just the ones that we are fond of or see the immediate value for, important. It is also important to study how flexible phenotypes are, so we can accurately predict the impact of changes in temperature, oxygen availability, and/or the amount of light in the environment.
Ultimately, I want you to care about gene expression, epigenetics, and phenotypic plasticity because there is more to the discussion of evolution than the age of the earth or the origin of mankind. It is a process that is ongoing, and our actions are influencing it. People who consider themselves Christians should be part of conversations about placing limits on fossil fuel use, restricting CO2 production, gene editing therapies, GMOs, and requiring vaccines. It is necessary to have some understanding of how these things work in order to make a relevant contribution to the discussion.