Humans Continue to Evolve
Modern day human evolution is a contentious topic in the scientific and broader community.
While many people conceptualize evolution to be a gradual process, with natural selection blindly tinkering away at genetic and phenotypic diversity across generations, dramatic changes in a species, under certain circumstances, can accelerate rapidly.
Recent studies suggest that Homo sapiens are not exempt from the process and may still be evolving.
Nicholas Wade, an author of two books on recent human evolution and a writer for the Science section of the New York Times, reported yesterday on the most recent known instance of human evolution in response to natural selection.
Using a complete set of data on birth, marriages, and death records on the island of Île aux Coudres, researchers from the University of Quebec at Montreal extracted the histories of women born on the island between 1799 and 1940. The scientists determined in their study that the age at which a woman had her first child decreased on average from 26 to 22 years, resulting in four more children in a lifetime.
Though biologists cannot rely on genetic sequences to discover recent instances of human evolution, they can infer such findings from the health histories and morphology of individuals.
Researchers from the University of Yale examined the vital statistics of over 2,000 postmenopausal women participating in the Framingham Heart Study. Investigators searched for correlations between women’s physical characteristics and the number of offspring they produced. They determined that slightly overweight women tended to produce more children and that these characteristics were in fact passed on genetically.
Drawing upon other examples of recent human evolution, such as defenses against malaria and tolerance to lactose, studies have also shown that hundreds of genes in our genome have changed in the past millennia and the brain may even be shrinking.
Still, countless questions remain: Do you think these studies sufficiently suggest that humans are still evolving? If so, what does the future hold in store for our species?