Evolution gives us a better insight on and understanding of diseases, conditions and other ailments then would be possible without it. This, in turn, furthers our understanding of the cause of many of these ailments and how they might be treated.
For instance, take the disease preeclampsia. It affects about 5% of pregnant women and if left untreated can be fatal. In fact, it kills about 75,000 women worldwide every year.
Unfortunately, once a woman has been diagnosed with preeclampsia, there is not a lot that can be done for her. All that can usually be done is to deliver the baby early. As a result, it is one of the leading causes of premature births in the United States.
What causes it? They discovered that the molecule sFlt-1 causes it. Women with preeclampsia have this molecule at much higher levels than those without it.
But what was this substance? Since healthy women seemed to have it too, it seemed that it might serve some purpose in pregnancy. But it was not made by the woman’s own cells. No, it was released by the placenta, which is genetically speaking, part of the child and not the mother.
The evolutionary biologist David Haig predicted that preeclampsia is caused by a molecule produced by the baby and not the mother. And yes, this was based on his knowledge of evolution.
We will not go into detail here. It will suffice to say that evolution helps explain what this molecule is and what its function might be. You can read more about it here.
So, it may be possible that one day we will come to a better understanding of this ailment. As a result, we may be able to find ways to better treat it or screen for it.
But this would be difficult if we did not understand evolution and its role.
The virulence of diseases can vary widely and quickly. The pathogens that cause diseases can evolve very quickly, causing new strains of diseases or existing diseases with increased virulence.
If we are to develop effective cures or preventative measures against such pathogens, then we should try to understand their evolution. This may allow us to develop measures to mitigate the effects of this evolution.
We also need to understand the evolution of bacteria, which have developed an ever-increasing resistance to antibiotics. If we can understand this evolution then we can develop more effective antibiotics that may overcome bacterial infections. Or possibly help slow down the development of future antibiotic resistance.
It is also useful to know how our own bodies have evolved and are continuing to evolve.
For instance, we know that many European populations are lactose-tolerant where once they were not. But that many Asian populations are largely not lactose-tolerant.
We know that African populations can be more vulnerable to certain viral conditions. This results in an increased vulnerability to autoimmune diseases.
And of course, we can look at how other animals have undergone evolution. This helps us to better understand their medical needs and how they can be tended to.
We know that a certain degree of biodiversity is important in our crops. In fact, a lack of such biodiversity contributed to the famous Irish Potato Famine.
In the 1800s, the Irish planted a lot of the “lumper” variety of potatoes. But they used a lot of clones, which are genetically identical to one another.
This was not a problem as long as the potatoes grew aplenty and were able to provide plentiful crops for the nation. But it became an issue when the rot caused by Phytophthora infestans started spreading throughout the potato crops.
Because they were clones, there was very little genetic variation among the potatoes. Which rendered them with greater vulnerability to Phytophthora infestans. As Ireland was so dependent on the potato, one in eight Irish people died of starvation within three years.
The famine had many causes, not just the low biodiversity of this kind of potato. But the disaster would not have been so bad had more genetically variable potatoes been planted. Some of these more genetically variable potatoes would have likely borne mutations that allowed them to survive the epidemic. And these more resistant varieties could have been planted.
A greater understanding of the evolution of resistant varieties of crops can help crops endure adverse conditions and thus help us avoid agricultural disasters.
It can also be useful to understand the evolutionary history of various types of crops. This can help us identify valuable genetic varieties which may be more suitable to variable or detrimental environmental conditions.
But we need to understand more than the evolution of plants. We need to understand the evolution of the parasites which feed off our crops.
As most people know, parasites can severely damage crops, drastically reducing their yield. We are constantly trying to find ways to use pesticides and other methods to kill or ward off these parasites.
But the parasites frequently evolve defences against pesticides at a rapid rate. This creates an arms race between pesticide development and parasite evolution. Understanding the evolution of these parasites helps us keep ahead in this arms race.
If we understand this evolution, then we can take steps to prevent it by not overusing pesticides. Or we can use different pesticides instead of over-relying on just the one. Or perhaps we can use an array of pesticides since it is less likely that insects will develop a resistance to multiple pesticides at once.