Biology is the study of the many varieties of life. Source: Wikimedia Commons.
This century is often called the age or the century of biology. Why?
Pigliucci: Largely, I suspect, because of discoveries in genetics and molecular biology, even though it is true that biology throughout the early 21st century has been an exploding science in a variety of areas, ecology and evolutionary biology, for example. But largely I would think the genetics in the first and molecular and evolutionary biology especially in the second half of the 20th century clearly demonstrate that biology is very much relevant to everyday life. We now understand the basics of how human beings are put together. We are even getting to the point of being able to change how you are put together through genetic engineering, so that has definitely marked the century as the century of biology, even though it started out as the century of physics. We marveled at quantum mechanics and the general theory of relativity, but it turns out that once in a while biology won in this century.
How can evolution play a role in both the conservation and management of the environment?
Pigliucci: Evolutionary biology is important in conservation because conservation is a particular example of the general problem evolutionary biologists are interested in—dealing with how species expand or contract the environment they occupy. Some species are very successful and they occupy lots of different environments. They spread very rapidly. Some species, on the other hand, are dwindling down to extinction. These two processes are essentially evolutionary processes.
There are changes in populations, demographics, and genetics over time, and so evolutionary biologists spend a lot of time studying what is called biogeography, that is, the study of the distribution of living organisms and what mechanisms determine the biogeography of species. These mechanisms are the same mechanisms that evolutionary biologists have been interested in ever since Darwin. These include
- natural selection
- migration patterns of different species
- the origin of new mutations
- perhaps the change in the DNA that allows certain species to be more successful in a new environment
So evolutionary biology is relevant to conservation biology because conservation biology essentially represents the same sort of basic questions and problems that evolutionary biologists are dealing with.
What about evolution’s role in agriculture?
Pigliucci: Well, agriculture is an interesting problem because it represents essentially applied evolution in the sense of human beings using evolutionary processes to improve their crops or their animals. This was noted by Darwin since the 19th century. The main analogy, the reason why we call natural selection natural selection, is because Darwin made the analogy of artificial selection done by plant and animal breeders.
Now in the case of other cultures where the interest in evolutionary biology is not just in the fact that humans are mimicking a natural process, which is in itself very interesting, but also that humans are changing the environment by doing agriculture and by changing the environment, they are posing new challenges to the evolution of species that surround them. When we plant a particular crop in a particular area, for example, all of a sudden that environment has changed, from an ecological perspective, and all the animals and plants that live in that area are now faced with a new environment. A new environment poses an evolutionary challenge. There will be natural selection on insects, for instance, feeding on the new plants to adapt to the new environment. So in some sense agriculture is both an example of how human beings can use evolutionary processes to their advantage but also, in so doing, how people change their environment and cause new natural evolution as a response to the changes.
How does evolution contribute to the understanding of human disease and medicine?
Pigliucci: There is an entire field that has been developed over the last 20 years called evolutionary medicine. The idea of evolutionary medicine is that human beings are animals like any other species. We are not outside of nature. As such we are subject to the same sort of natural phenomena, including natural selection and other types of evolutionary mechanisms. So evolutionary medicine tries to understand the origin of disease, why we have certain kinds of disease, and how we can fight them using evolutionary principles. Here are two examples:
One of the typical examples is the idea that is essentially evolutionary when we use antibiotics for our ailments. We should use antibiotics in an intelligent way. For example, we should be using multiple antibiotics in a careful regimen. If we use single antibiotics and we don’t use them carefully enough, what we do is cause natural selection in the pathogen to select for resistance. The origin of resistance in antibiotics is an imminently evolutionary mechanism, and if we understand how evolution works, then we can avoid it or at least we can slow it down.
The same situation goes for the most successful approaches to complex diseases such as HIV/AIDS. One of the best approaches to fight that kind of battle is, in fact, to bombard the population of viruses with a variety of responses, not just with one. For the same reason as multiple antibiotics. The virus evolves very rapidly to respond with resistance to individual medical solutions or medications. When we use multiple ones, what we are doing is using the basic principle of evolution—living organisms simply cannot evolve resistance to complex environments because they cannot count on multiple divisions happening at the same time. That is an important principle that comes out of evolution.
Biotechnology holds great promise; how does evolutionary biology fit in?
Pigliucci: It interacts in a variety of ways, one of which is that a lot of biotechnology does not start from scratch. Biotechnology research companies may design things from scratch, but they look at nature as a starting point and examine what nature has done up to a certain point, depending on the researchers’ particular interest. Then they try to improve on nature in a direction that is favorable for humans. In a sense they are doing pretty much the same things that plant breeders and animal breeders have been doing for a long time. You start with something that is already there in nature and has a certain degree of usefulness, and then you improve it by technological means, by artificial selection.
Now, biotechnology, of course, has progressed to creating things that do not exist in nature. However, even these advances have some connection with evolutionary biology. One of my favorite examples is the one of the most profuse tools in biotechnology—using enzymes to splice pieces of DNA at particular locations. These are the basis for what has been made possible through molecular evolution through the second half of the century. Well, it turns out that these enzymes that we use to splice DNA for our own purposes actually evolved in bacteria to protect them from attacks by viruses. So splicing enzymes—enzymes that cut DNA in particular places—are formidable weapons that natural selection evolved in bacteria to protect them from viral attacks. And they work very nicely because those enzymes can recognize the viral host DNA as distinct from bacterial DNA. We, as molecular biologists, have discovered this nice little class of enzymes, and now we are using them for all sorts of interesting things, but in fact we have to thank natural selection for these enzymes.
How does evolution help us understand ourselves?
Pigliucci: Excellent question. It depends, of course, on what one means by “understanding ourselves.” I do have an interest in philosophy, for example, and philosophy is that classical area where you go when you want to understand yourself. “Know thyself!” However, today, most philosophers would agree that the understanding of human nature does begin with understanding biology in the sense that one can now possibly grasp what a human being really is. We must also understand the limitations and the characteristics of the human beings that come from our evolutionary history, from our past.
Let me give you an example. As many human beings on this planet, I have had my bouts struggling with overeating. Where does overeating come from? There is a cultural component like having too easy availability of food in Western society. Well, why would ease of availability of food create a problem? It creates a problem because of our evolutionary history. Imagine when we were a species of primates in the open savannah. There were no McDonald’s around. And there were no other fast foods, no ease of availability of foods. So we evolved, by natural selection, a tendency to eat whatever contained proteins or sugars that happened to be available as much as possible. That instinct is still with us. The only problem now is that we don’t live in the savannah anymore. We live in cities where there are in fact junk food places that are open 24 hours a day. Nowadays the problem has both medical and psychological implications. It costs us hundreds of millions of dollars from the medical perspective. Also many individuals have a problem psychologically with weight, the way they see themselves, and the way they think of themselves. All of this is the result of natural selection, which worked in the past at its best in a particular environment. We have changed our environment, but we have not changed ourselves from a biological perspective, so we are in trouble.
How is evolution important to disciplines other than biology?
Pigliucci: The best example at this point, I guess, would be software engineering. Because of the computer revolution we are now using software that is increasingly sophisticated. The most interesting software that we use is the result, essentially, of the evolution of computer programs that are made to compete against each other. In other words, to make them do whatever human beings want to make them do. A lot are very complex pieces of software. For example, the kind of software that runs the larger operations in airports is just too complicated for a human mind to write. Software engineers use what they refer to as genetic algorithms. It is the idea of writing simpler pieces that engineers then put into competitions against each other. They then evolve by mutating themselves, that is, by essentially inserting random changes into the code and then going through a second round of selection. And this works very nicely! Software engineers have borrowed this process from evolutionary biologists.
Human blood smear. Interpreting and analyzing DNA evidence in forensic cases depends on principles of evolution. Source: Jagiellonian University Medical College.
Forensics is another example. The ways you interpret and analyze DNA evidence in forensic cases depends on principles of evolution. To be able to say that a DNA match for a suspect is significant to a case, you have to know something about the distribution of that particular kind of DNA in a human population and the frequencies of DNA involved in that population. So you have to know something about how human populations themselves evolve in order to make a more meaningful comparison between the simple suspect data you are analyzing. Forensics would be another example of evolutionary medicine, about how biotechnological and medical research are now able to use exquisite evolutionary principles.
Of course there are the classical areas—agriculture, management of territory, conservation biology, and others. Some of my students who have a Ph.D. in evolutionary biology, instead of becoming college professors, have gone on instead to work for US Fish and Wildlife and the USDA in helping the organizations learn more about managing systems. Well, their knowledge comes from an understanding of evolutionary biology that is the basis of their work. Yes, understanding evolution can help you get a great job!
© 2005, American Institute of Biological Sciences. Educators have permission to reprint articles for classroom use; other users, please contact firstname.lastname@example.org for reprint permission. See reprint policy.