Medical and technological advances have allowed more of us to survive and to live longer, healthier lives. Does this make evolution irrelevant?
In the most basic sense, evolution refers to the process of genetic change in a population over time. It occurs because gene variants are more likely to survive and prosper if they offer the organism an advantage over others, in turn making it more likely they will survive and reproduce – thus passing on their traits to future generations.
This process has been instrumental to our survival as a species. Through evolution, our human ancestors developed a whole host of traits that made them better suited to their environment, whether that is the ability to recover faster from disease, fend off hungry predators or acquire more succulent berries than their neighbors.
A famous example includes the (literally) breath-taking ability of members of the Bajau Laut tribe, who are able to hold their breath for minutes at a time. This incredible feat enables them to reach levels more than 70 meters (230 feet) underwater sans diving equipment when collecting seafood. Other genetic variants have provided protections to those with the mutations to diseases such as malaria, tuberculosis and leprosy.
However, with the advent of technologies and medicines that enable us to live longer, healthier lives, many have questioned what role evolution in the traditional sense will play in our development as a species. Even biologist, broadcaster and British national treasure, Sir David Attenborough, has expressed doubts.
“We stopped natural selection as soon as we started being able to rear 90-95% of our babies that are born. We are the only species to have put a halt to natural selection, of its own free will, as it were,” he told the Radio Times, media at the time reported.
So, will we continue to evolve when the selection pressures that impacted our ancestors cease to be a life and death situation? According to recent studies, the answer is yes.
One of the factors driving evolution today is culture, which can impact sexual selection. This refers to preferences that influence who we find attractive and who we choose to reproduce with, and can have an effect within relatively a short time frame.
“If a genetically based trait, like hair color, becomes more common or less common from one generation to the next then that is considered evolutionary change,” Scott Solomon, an evolutionary biologist at Rice University, previously told IFLScience.
“That’s often different from what your average person on the street might think about evolutionary change. It doesn’t necessarily mean new traits coming into existence, it could just mean existing traits are more common or less common.”
One example of this is highlighted by a study published in 2015, which found that sexual selection in the Netherlands in recent decades favored tall men. Dutch men today are among the tallest in the world but this was not the case in the eighteenth century, when the average height of Dutch soldiers was 165 centimeters – below that of men in the United States and many other European populations. In just 150 years, or a few generations, Dutch men have added approximately 20 centimeters to their height as a consequence of natural selection, overtaking men in the US and much of the world.
Another recent example of natural selection was spurred by the rise of a new deadly virus, HIV. According to YourGenome, rates of genetic variants that offer a protective advantage against the virus are increasing in regions most affected, such as South Africa. It is thought that mothers with the adaptation are more likely to survive an infection and are, therefore, able to pass it on to their children.
So while what causes the process of evolution may change over time, it does not appear to be stopping any time soon.
Source Link: How Do We Know Evolution Is Still Happening Today?
