Bedbugs are becoming a new species of nightmare insects.
Wikimedia Commons
While you might be familiar (a little too familiar, you might say), with bedbugs, they didn’t
always used to be the terrifying critters we know today.
Thousands of years ago, our cave-dwelling ancestors got along perfectly fine with bedbugs
— mainly because they were nearly an entirely different species back then. Unfortunately,
as humans migrated out of caves and into cities over thousands of years, they brought
bedbugs along for the ride. The insects with traits that made them better able to survive
their new urban lifestyle — such as being more active at night, when humans sleep, and
having longer, thinner legs for hopping away from us quickly — outlived their less-evolved
bedbug friends.
In just the last few decades, these city-dwelling insects have become almost an entirely
separate species from their cave-dwelling cousins. In addition to their new penchant for
the nightlife, today’s urban bedbugs have also evolved resistance to pesticides: They have
thicker, waxier exoskeletons (to shield them from toxins) and faster metabolisms (to beef-up
their natural chemical defenses).
Humans have used artificial selection to create crazy specific dog breeds.
There’s nothing “natural” about the silky-smooth fur, distinctive coloring, or even the friendly
personality we’ve come to associate with man’s best friend.
Over the past 150 years or so, humans have been specifically mating dogs that look a
certain way to create the animals we now keep as pets via a process known as
breeding. This is artificial selection, where one species (humans) directs the traits
that get passed down to future generations of another species (dogs).
It's important to keep in mind, though, that all our selective pressures still haven't resulted in
any new dog species (cocker spaniels and poodles can still interbreed, for example) but
merely a bunch of breeds. Nevertheless, our actions can be seen in the doggie genome, the
collection of all of its genes. At least 155 different regions show evidence of strong recent
selection favoring traits from skin wrinkling (like that seen in the Shar-Pei) to coat and size.
Plus, these changes are still happening, as breeders mix and match breeds to create pets
like labradoodles (labrador retriever and poodle mixes), and cockapoos, (cocker spaniel and
poodle mixes).
Stray dogs that have left human care are evolving more wolf-life traits.
Although dogs separated from their wolf ancestor around 18,000 years ago, several new
groups of pups that are more genetically similar to wolves have begun to show up around
the world sometime within the past 150 years.
This is a good example of what happens when a strong evolutionary pressure, like humans'
intensive practice of breeding dogs for favorable traits, is suddenly removed.
Stray dogs in Moscow, for example, who've been living largely separate from humans
for the past several hundred years, have evolved to be expert beggars. Because the
survival rate in the wild for these animals is so low, their evolution has happened at a
superfast pace: the strays who have the traits that help them survive (they're unfriendly
toward humans, feeding only on their trash, they have superior navigation skills, etc.) pass
those traits onto their pups.
Moths living around dirty humans evolved darker wings to blend into their sooty
surroundings.
The peppered moth can most easily be spotted on a dark surface: its distinctive off-white
wings, speckled with tiny dark spots, make it stand out.
During the industrial revolution in Britain and the US, when humans started pumping their
air full of pollutants, that dark soot fell on trees, darkening their bark and endangering the
moth, who’d easily be picked out by predators on a shadowy tree. Over several
generations, as the lightest moths were eaten and the darker moths tended to
survive, the majority of moths in the region became dark via a process called natural
selection.
But when pollution control laws in both countries started to scale back the amount of soot in
the air in the 1970s, dark moths again became more prone to getting eaten. Today, most
moths have returned to their original light color.
Humans created a new top predator that is taking over the Northeast.
And you thought coyotes were terrifying.
A new hybrid of the coyote and the wolf, or coywolf, that first emerged in the last few
decades is now coming out in droves in the Northeastern US. About 2/3 of the
coywolves’ DNA is from wolves, while another 1/4 is from coyotes. The remainder is
from domesticated dogs.
But nothing about these animals is domestic. They’re even bigger than either their wolf or
coyote ancestors, weighing in at as much as 140 pounds. They’re also social, like wolves,
meaning they tend to hunt in packs.
Coyotes and wolves would likely have never come together in the first place if not for
human farming and hunting practices, which drove the wolf north and coyotes east. But
they’re definitely here to stay — the coywolf’s unique genetic makeup appears to be
particularly appropriate for its northern habitat — moreso, even, than either of its parent
species, meaning the hybrid genes will likely keep getting passed down to future
generations. While the DNA from the wolf appears to allow the coywolf to hunt larger prey,
the coyote DNA helps it adapt rapidly to urban areas.
Bacteria have evolved to outsmart our antibiotics — and we’re on the cusp of an
“apocalyptic scenario."
Doctors commonly treat bacterial infections with antibiotics. When one drug doesn't work,
they try another. But now, physicians are finding that some of our infections are resistant to
even our strongest drugs. The bacteria have, genetically speaking, outsmarted
us. Those with traits that allow them to survive in antibiotic-rich environments pass them
onto future generations, making each successive strain more resistant to our drugs than the
last.
Last year, 23,000 Americans died from bacterial infections that didn't respond to antibiotics.
Certain strains of "nightmare bacteria" kill up to half of the patients they infect, and cases
are becoming increasingly common across 42 states.
The problem isn't exclusive to the US, though. Because of our global overuse of these
drugs — and our increasing reliance on them — antibiotic-resistant bacteria could kill up to
10 million people worldwide each year by 2050, according to a recent report from the
Healthcare Infection Society.
A special fish managed to beat the toxic pollution of New York City’s dirtiest river.
When New Yorkers started dumping PCBs (a type of industrial toxin) in the Hudson River in
1929, they wiped out a large majority of its wildlife.
But at least one species survived — and thrived. Over the span of a few decades (PCBs
were banned in 1979) a fish called the tomcod evolved to resist the poison via natural
selection.
Fish with a special set of genes that make a key poison-shielding protein were the
only critters to survive the toxic onslaught. They, in turn, passed their protective genes
onto their offspring.
Happy fishing!
A pest that thrives on one of our favorite foods is developing immunity to the
toxins we use to keep it at bay.
Corn is one of the staples of American cuisine. Its derivatives are in everything from
candy and soda to hamburger patties and fast-food taco meat. To soothe our corn
sweet tooth, we've begun growing the crop in massive quantities, making powerful
pesticides necessary to kill of pests that feed on the increasingly vulnerable plant.
Unfortunately, our overuse of pesticides have, in turn, spurned genetically
stronger pests.
When the western corn rootworm, for example, developed a resistance to the chief
pesticide in Monsanto's GMO corn (a gene designed to produce a special protein to
destroy the worm's digestive tract), the company responded by switching up the
pesticide in its corn to another type of protein. The worms evolved to resist it that as
well.