Buzz
Evolution is often seen as a slow, gradual process, sometimes taking millions of years for the small, incremental changes in organisms to become noticeable. However, there are species today evolving so rapidly that we can actually observe the changes as they happen.
10. Coyotes, Wolves, and Dogs Are Crossing Species Lines
As European settlers traveled through southern Ontario, they hunted wolves on a massive scale, decimating their population to make room for farming. This unintended action also triggered an evolutionary shift, resulting in the creation of a new species: the coywolf.
With wolves now scarce, coyotes from the prairies, no longer threatened by competition, moved into their territory. As the remaining wolves struggled to find mates, they began interbreeding with both the coyotes and the settlers’ domestic dogs.
From this crossbreeding of three species, the first coywolf was born. It was larger and more powerful than its coyote parents, weighing twice as much. Its swift legs, muscular build, and strong jaws combined to make it a superior hunter.
Today, millions of coywolves inhabit the eastern coast of North America. Their distinctive calls can be heard echoing through the woods—starting low like a wolf’s howl, then rising to the high-pitched yelps of a coyote.
9. Swallows Are Developing Shorter Wings
Along the highways of Nebraska, cliff swallows are undergoing a subtle yet impactful evolutionary shift.
Typically, cliff swallows nest on cliff faces. However, these natural locations become perilous during storms, as nests and young birds are often swept away. As a result, the swallows have begun to build their homes on highways, bridges, and overpasses that span busy roads.
Initially, this change proved disastrous. The cliff swallows often became roadkill in their new homes, with thousands of birds found crushed by passing cars. However, unexpectedly, the number of dead swallows started to decrease.
Researchers discovered that the birds have begun to develop shorter wings. The change is only a few millimeters, but it enables the swallows to dart into the air more quickly when a car approaches. This increased speed has significantly reduced the number of bird fatalities.
8. Lizards Are Adapting to Live Higher in Trees
On a series of islands in Florida, a species of lizards known as green anoles have undergone a remarkable transformation in just 15 years.
Their habitat was overtaken by brown anoles from Cuba, making life in their natural environment much more difficult. The two species now compete for food, and the brown anoles have a vicious tendency of preying on the green anoles’ offspring.
To survive, the green anoles began to climb higher into the trees, resulting in noticeable physical changes. Over the past 15 years, their toe pads have expanded, and they have developed more sticky scales on their feet. These substantial changes in such a short period have allowed them to thrive in the treetops.
7. Crustaceans in Dark Caves Are Losing Their Eyesight
Crustaceans living in caves today once had tiny eyes protruding from small stalks on their heads millions of years ago. As they adapted to their dark, damp environments, their eyes became obsolete and gradually vanished from their genetic code.
Although many of these crustaceans still possess small, stumpy eyestalks as a reminder of their previous way of life, the eyestalks are now redundant. These creatures can no longer see, so the eyestalks are gradually disappearing.
Scientists have also monitored how the crustaceans' brains are evolving. While these creatures still retain a section of their brains dedicated to vision, this part of the brain is slowly vanishing due to its increasing irrelevance.
Eventually, the crustaceans are expected to completely lose their eyestalks and the associated portion of their brains, shedding a previously essential body part that has become unnecessary in their dark cave environments.
6. Owls Are Changing Color
The tawny owls of Finland are undergoing a color shift, and it may be due to global warming.
These owls are born with either brown or gray feathers, and they usually pass their color down to their offspring. For a long time, Finland’s population has been dominated by the gray ones, as they are more resilient to the country's harsh winters. As a result, the brown tawny owls typically have shorter lives while the gray ones thrive.
However, with rising temperatures, the winters have become less harsh, allowing the brown tawny owl population to grow. Natural selection is beginning to favor them once more, causing a small evolutionary shift that’s transforming the color of Finland’s forests.
5. Fish in the Hudson River Are Evolving to Coexist with Chemicals
In the Hudson River, a small species of fish called the Atlantic tomcod, which only grows to 25 centimeters (10 inches) long, once flourished for millions of years alongside a diverse ecosystem. However, when industrial waste began contaminating the river, their thriving environment was severely impacted.
One of the most harmful pollutants was a chemical called PCBs, which wiped out much of the aquatic life. The fish’s hearts became smaller and struggled to pump, leading to agonizing deaths.
Despite the devastation, the tomcod adapted and continued to survive in the Hudson. They developed a unique genetic mutation, a feature found in some tomcod populations globally, but nearly universal among those in the Hudson.
The fish are missing six base pairs in one of their genes, and the chemicals struggle to bind to their mutated receptors. This mutation reduces the impact of the harmful chemicals that would typically kill them, allowing the tomcod to thrive where other species have perished.
4. Elephants Are Losing Their Tusks
African elephants are undergoing a significant change, influenced by poaching. Typically, large tusks provide an evolutionary advantage, allowing elephants to fend off rivals and attract mates. Consequently, elephants with larger tusks tend to pass on their genes more successfully.
Poaching, however, has altered this natural balance. Poachers often target elephants with long tusks, seeking to sell their ivory for profit. As a result, these long-tusked elephants are often killed before they can reproduce. With less competition, short-tusked elephants are now more successful in mating, and they are passing down their small tusks to their offspring.
Since the mid-1800s, the average tusk size of African elephants has been halved. In fact, some elephants are born completely tuskless. In the 1930s, this was an uncommon occurrence, with tuskless elephants making up only about 1 percent of the population.
However, in some of the most affected areas, this number has significantly risen. By 1997, 38 percent of the elephants in Luangwa had no tusks.
3. Human Pelvises Are Getting Smaller
Humans, too, are undergoing subtle evolutionary changes. For instance, our pelvises are becoming smaller, a consequence of advancements in modern medicine.
In earlier times, women with birth canals too narrow to safely deliver a child would often not survive childbirth. Thankfully, modern medicine has made it possible for these women to survive, thanks to caesarean sections.
However, in saving these women, we are bypassing some aspects of natural selection. These women tend to give birth to children with similarly narrow pelvises, which contributes to a gradual reduction in the size of human pelvises.
Since the 1960s, there has been almost a 20 percent increase in the number of women with narrow birth canals that require surgical intervention for childbirth. There are signs that this trend may continue, leading to more women needing caesarean sections.
2. Mice Are Becoming Immune To Poison
In Germany, bakers often deal with mice infestations by using traps baited with a potent poison known as warfarin. Mice that consume this poison tend to die shortly afterward, allowing bakers to maintain a mouse-free environment.
However, the mice in Algeria have developed immunity to this poison. As a result, German mice have begun interbreeding with their Algerian counterparts, producing a new hybrid species that carries the immunity of the Algerian mice.
These hybrid mice are now thriving in Germany, immune to the poison meant to eradicate them. They can consume warfarin without any ill effects, allowing them to flourish and continue evolving.
1. A Flower Grew A Perch For Birds
A South African flower known as the rat’s tail has adapted its appearance based on its surroundings. Originally, the flower was deeply rooted in the ground, surrounded by predators that prey on birds. Because of this, birds would avoid the area, leaving the flowers unpollinated and eventually causing them to die off.
In certain areas, however, the rat’s tail flower has evolved a small perch, enticing birds to land. These perches are perfectly sized for sunbirds, allowing them to settle and feed on the flower's nectar, which helps with pollination.
In regions where the flowers don’t rely solely on sunbirds, the rat’s tail doesn’t bother developing such an elaborate perch. So, every time we observe that perch, it's a small yet significant demonstration of evolution at work.
