Many people think that evolution is some magical phenomenon that takes hundreds, even thousands of years to occur. People think of dinosaurs turning into chickens, chimpanzees into people, wolves into chihuahuas and so on. However, what many people don’t realize is that evolution happens every day all around us, just on a much smaller scale.
Omar Tonsi Eldakar is an associate professor at NSU in the department of biology. He offered the example of the recent COVID-19 pandemic as an example of rapid evolution.
“It can occur quite rapidly. You have a great example with COVID-19 where you see these new strains popping up, because we have such a high variation in populations,” Eldakar said.
Things like pesticide resistance in insects or antibacterial resistance in bacteria are further examples of how common – and how quickly – evolution can occur.
Evolution occurs when an inheritable trait that was previously less common becomes more common in a population, often because that trait is better suited to survive in the organism’s environment. Having that variation in populations is important for evolution because without it, nothing would ever change for the better or worse.
However, what people often do not consider is how drastically environments have changed since the rise of urbanization and human industrialization. Native wildlife is now forced to adapt to buildings popping up, to human waste and even harmful direct interactions such as hunting and poaching.
California condors are a critically endangered species, partially due to habitat loss but also due to poison ingestion via their prey. Condors are much like vultures; they feed on carrion, which are dead carcasses of other animals. California condors become poisoned by the lead bullets left in their prey by hunters. The population has dwindled so much since the 1980s that there are less than 30 known individuals left alive.
However, just this year scientists noted the first case of asexual reproduction through a process called parthenogenesis in California condors. While reviewing genetic data in the captive population, scientists noticed that a female condor at the San Diego Zoo produced two male chicks, neither of which had any genetic contribution from any of the male condors in the conservation program.
The male chicks were the result of asexual reproduction, and although neither lived to be fully mature, they lived much longer than other cases of parthenogenesis reported in bird species. Birds like domesticated chickens have reproduced via parthenogenesis before, but the chick usually died before hatching.
Somehow, this California condor had a variation that allowed her to reproduce in a way that had never been recorded before. A possible step towards rebuilding a population that had been eviscerated by human influence.
California condors are not the only animals making changes to survive human influence. According to an article published in the Journal of Hereditary, there has been a rise of tuskless female elephants in Mozambique which scientists believe to be linked to decades of poaching elephants for ivory. Elephant tusks are made from ivory, a compound worth thousands of dollars per pound to humans, while elephants use them for self-defense and foraging.
“They obviously haven’t evolved for nothing. They aren’t just like, ‘oh, we don’t need these and let’s get rid of them.’ They do use them for foraging,” Eldakar explained. “It just simply might be a tradeoff that makes foraging a little more difficult, but at least they’re not being shot and killed.”
However, is it enough to save the species from extinction? Despite these steps that may seem like a way to combat population decline, Eldakar stressed the importance of conservation efforts.
“It’s crucially important that life have the opportunity to evolve in response to their environment, especially when we’re the one hindering it. You will find these unique cases where there might be some variant in the population that has this advantage that allows it to adapt in response to human interference, but that’s not going to be the case for a lot of these other endangered species,” Eldakar said.
Again, the most important aspect of evolution is having variation within a population. If the population is reduced to such a small group of individuals, it’s unlikely that sort of species-saving variation will occur.
“Shrinking an effective population size is shrinking it’s genetic variation, essentially prohibiting that species from being able to evolve in response to its environment. That’s why conservation efforts are important, because they’re really about genetic variation,” Eldakar explained.
