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Humanity’s impact is monkeying with animals’ evolution
Animals are adapting all the time these days to stay out of our way.
- Evolution is something that happens over time, but animals (humans included) are always mutating and adapting.
- Thanks to human presence and interference, animals are experiencing what has been referred to as "human-guided evolution."
- More animals are becoming night owls. Pollution determines which moths dominate the tree trunks of the U.K. Are these short-term changes, or is humanity doing lasting damage?
We often think of evolution as taking place over extended periods of time as mutations prove themselves advantageous, or not. Mutations, though, are not rare things: They happen all the time. Scientists estimate that there were 37 trillion of them in your own body just over the last 24 hours. (It's amazing more things don't go wrong, right?) The characteristics we see in ourselves and other organisms are merely the latest winners in a wild and woolly mutation free-for-all competition, in which nature, or random chance, tries out many wonderful, bizarre, and ridiculous traits as things settle out over the long term.
Adaptations in response to changing environmental factors occur all the time, too: An attribute that may have been meaningless before may suddenly become very helpful. Here in the Anthropocene, animals are adapting to all sort of habitat changes we've imposed on them. While not yet long-term changes, necessarily, these characteristics suggest we may be having a considerable impact on the ongoing process of evolution in the world's organisms.
Image source: Marek R. Swadzba/Shutterstock
Before the Industrial Revolution got up and running in the U.K., light-colored peppered moths, Biston betularia morpha typica, were a common sight. However, by about 1864, they'd been essentially replaced by a darker peppered-moth cousin, Biston betularia morpha carbonaria. Why?
Pollutants — mostly coal soot —covered the British countryside, darkening its trees. Worse, sulfur dioxide emissions wiped out many of the trees' lichen and moss coverings. Against these darkened backdrops, light-colored peppered moths became far too easy to spot by predators. Better suited were the darker peppered moths, which soon came to dominate the habitat — by 1895, some 95 percent of peppered moths spotted were the darker variety.
Fortunately, the Industrial Revolution days passed, with dirty factories over time being replaced by cleaner alternatives, and today, the light-colored peppered moths are back on top.
The story is a pretty fast-paced and dramatic example of how extreme our impact can be, and also — and there's a hopeful feeling to this — how short-lived it can be if we fix what we've broken.
Urban vs. rural red fox skull measurements
Image source: K.J. Parsons, et al
Researchers published in June a really interesting study regarding a surprising way in which foxes are adapting to life in human-dominated urban environments.
An examination of 111 red fox skulls from London, UK, revealed "urban individuals tending to have shorter and wider muzzles relative to rural individuals." Essentially, the more urban a fox's environment is, the shorter its snout was likely to be. The change may be considered an example of Darwin's "domestication syndrome," as Big Think previously reported.
The study suggests it's all about the biomechanics benefits imparted by such a change:
"Firstly, a shorter snout, as found in urban foxes, should confer a higher mechanical advantage but with reduced closing speed of the jaw. This may be advantageous in an urban habitat where resources are more likely to be accessed as stationary patches of discarded human foods. Furthermore, in some cases, these foods may require a greater force to access them, explaining the expanded sagittal crest in skulls of urban foxes."
If these traits make an individual fox better suited to its city life, it's that much more likely to survive and reproduce than a longer-snouted competitor.
Nighttime on human Earth
Image source: Viktor Grishchenko/Shutterstock
Habitat loss is the single most destructive thing we're doing to animals. It can lead to utter displacement and death, and it can also change the way animals go about doing the things they need to do to survive.
In many cases, animals dealing with fresh human encroachment bend before they break, and some are trying to carry on around us, so to speak. A 2018 study in the journal Science finds, for example, that animals are becoming more nocturnal to get out of the bipeds' way.
The authors of the study analyzed data from 76 other reports to learn how 62 species on six continents were trying to adapt to our intrusive presence. The data was sourced from all sorts of devices such as cameras to GPS trackers, and ran the gamut from 'possums to pachyderms.
What the researchers found was that animals known to split their activities between day and night were overwhelmingly becoming busier after dark. There was a 68 percent increase in nighttime activity among such animals.
If this habitat pressure continues, will we start to see individuals with, for example, better night vision, come to dominate as competitors for scarce resources? It'll be interesting to see.
When people say, "Such and such animal has this trait because it allows them to…" what they're really saying is that "Of all the crazy mutations that nature tried out, individuals with this mutation fared better than others did." Whether it's effective camouflage, the ditching of a trunk, or becoming a night owl — except for owls who already… never mind — temporary adaptations become fixed evolutionary traits when the conditions in which they are beneficial remain in place long enough. In the case of the pressure we're continually imposing on other life forms, it bears saying that only the ones lucky enough to survive humankind's challenging influence in the first place will get that chance to change.
- How About a New Theory of Evolution with Less Natural Selection ... ›
- Researchers Find Evidence That Human Evolution Is Still Actively ... ›
A Harvard professor's study discovers the worst year to be alive.
- Harvard professor Michael McCormick argues the worst year to be alive was 536 AD.
- The year was terrible due to cataclysmic eruptions that blocked out the sun and the spread of the plague.
- 536 ushered in the coldest decade in thousands of years and started a century of economic devastation.
The past year has been nothing but the worst in the lives of many people around the globe. A rampaging pandemic, dangerous political instability, weather catastrophes, and a profound change in lifestyle that most have never experienced or imagined.
But was it the worst year ever?
Nope. Not even close. In the eyes of the historian and archaeologist Michael McCormick, the absolute "worst year to be alive" was 536.
Why was 536 so bad? You could certainly argue that 1918, the last year of World War I when the Spanish Flu killed up to 100 million people around the world, was a terrible year by all accounts. 1349 could also be considered on this morbid list as the year when the Black Death wiped out half of Europe, with up to 20 million dead from the plague. Most of the years of World War II could probably lay claim to the "worst year" title as well. But 536 was in a category of its own, argues the historian.
It all began with an eruption...
According to McCormick, Professor of Medieval History at Harvard University, 536 was the precursor year to one of the worst periods of human history. It featured a volcanic eruption early in the year that took place in Iceland, as established by a study of a Swiss glacier carried out by McCormick and the glaciologist Paul Mayewski from the Climate Change Institute of The University of Maine (UM) in Orono.
The ash spewed out by the volcano likely led to a fog that brought an 18-month-long stretch of daytime darkness across Europe, the Middle East, and portions of Asia. As wrote the Byzantine historian Procopius, "For the sun gave forth its light without brightness, like the moon, during the whole year." He also recounted that it looked like the sun was always in eclipse.
Cassiodorus, a Roman politician of that time, wrote that the sun had a "bluish" color, the moon had no luster, and "seasons seem to be all jumbled up together." What's even creepier, he described, "We marvel to see no shadows of our bodies at noon."
...that led to famine...
The dark days also brought a period of coldness, with summer temperatures falling by 1.5° C. to 2.5° C. This started the coldest decade in the past 2300 years, reports Science, leading to the devastation of crops and worldwide hunger.
...and the fall of an empire
In 541, the bubonic plague added considerably to the world's misery. Spreading from the Roman port of Pelusium in Egypt, the so-called Plague of Justinian caused the deaths of up to one half of the population of the eastern Roman Empire. This, in turn, sped up its eventual collapse, writes McCormick.
Between the environmental cataclysms, with massive volcanic eruptions also in 540 and 547, and the devastation brought on by the plague, Europe was in for an economic downturn for nearly all of the next century, until 640 when silver mining gave it a boost.
Was that the worst time in history?
Of course, the absolute worst time in history depends on who you were and where you lived.
Native Americans can easily point to 1520, when smallpox, brought over by the Spanish, killed millions of indigenous people. By 1600, up to 90 percent of the population of the Americas (about 55 million people) was wiped out by various European pathogens.
Like all things, the grisly title of "worst year ever" comes down to historical perspective.
A new paper reveals that the Voyager 1 spacecraft detected a constant hum coming from outside our Solar System.
Voyager 1, humanity's most faraway spacecraft, has detected an unusual "hum" coming from outside our solar system. Fourteen billion miles away from Earth, the Voyager's instruments picked up a droning sound that may be caused by plasma (ionized gas) in the vast emptiness of interstellar space.
Launched in 1977, the Voyager 1 space probe — along with its twin Voyager 2 — has been traveling farther and farther into space for over 44 years. It has now breached the edge of our solar system, exiting the heliosphere, the bubble-like region of space influenced by the sun. Now, the spacecraft is moving through the "interstellar medium," where it recorded the peculiar sound.
Stella Koch Ocker, a doctoral student in astronomy at Cornell University, discovered the sound in the data from the Voyager's Plasma Wave System (PWS), which measures electron density. Ocker called the drone coming from plasma shock waves "very faint and monotone," likely due to the narrow bandwidth of its frequency.
While they think the persistent background hum may be coming from interstellar gas, the researchers don't yet know what exactly is causing it. It might be produced by "thermally excited plasma oscillations and quasi-thermal noise."
The new paper from Ocker and her colleagues at Cornell University and the University of Iowa, published in Nature Astronomy, also proposes that this is not the last we'll hear of the strange noise. The scientists write that "the emission's persistence suggests that Voyager 1 may be able to continue tracking the interstellar plasma density in the absence of shock-generated plasma oscillation events."
Voyager Captures Sounds of Interstellar Space www.youtube.com
The researchers think the droning sound may hold clues to how interstellar space and the heliopause, which can be thought of as the solar's system border, may be affecting each other. When it first entered interstellar space, the PWS instrument reported disturbances in the gas caused by the sun. But in between such eruptions is where the researchers spotted the steady signature made by the near-vacuum.
Senior author James Cordes, a professor of astronomy at Cornell, compared the interstellar medium to "a quiet or gentle rain," adding that "in the case of a solar outburst, it's like detecting a lightning burst in a thunderstorm and then it's back to a gentle rain."
More data from Voyager over the next few years may hold crucial information to the origins of the hum. The findings are already remarkable considering the space probe is functioning on technology from the mid-1970s. The craft has about 70 kilobytes of computer memory. It also carries a Golden Record created by a committee chaired by the late Carl Sagan, who taught at Cornell University. The 12-inch gold-plated copper disk record is essentially a time capsule, meant to tell the story of Earthlings to extraterrestrials. It contains sounds and images that showcase the diversity of Earth's life and culture.
A team of scientists managed to install onto a smartphone a spectrometer that's capable of identifying specific molecules — with cheap parts you can buy online.
- Spectroscopy provides a non-invasive way to study the chemical composition of matter.
- These techniques analyze the unique ways light interacts with certain materials.
- If spectrometers become a common feature of smartphones, it could someday potentially allow anyone to identify pathogens, detect impurities in food, and verify the authenticity of valuable minerals.
The quality of smartphone cameras has increased exponentially over the past decade. Today's smartphone cameras can not only capture photos that rival those of stand-alone camera systems but also offer practical applications, like heart-rate measurement, foreign-text translation, and augmented reality.
What's the next major functionality of smartphone cameras? It could be the ability to identify chemicals, drugs, and biological molecules, according to a new study published in the Review of Scientific Instruments.
The study describes how a team of scientists at Texas A&M turned a common smartphone into a "pocket-sized" Raman and emission spectral detector by modifying it with just $50 worth of extra equipment. With the added hardware, the smartphone was able to identify chemicals in the field within minutes.
The technology could have a wide range of applications, including diagnosing certain diseases, detecting the presence of pathogens and dangerous chemicals, identifying impurities in food, and verifying the authenticity of valuable artwork and minerals.
Raman and fluorescence spectroscopy
Raman and fluorescence spectroscopies are techniques for discerning the chemical composition of materials. Both strategies exploit the fact that light interacts with certain types of matter in unique ways. But there are some differences between the two techniques.
As the name suggests, fluorescence spectroscopy measures the fluorescence — that is, the light emitted by a substance when it absorbs light or other electromagnetic radiation — of a given material. It works by shining light on a material, which excites the electrons within the molecules of the material. The electrons then emit fluorescent light toward a filter that measures fluorescence.
The particular spectra of fluorescent light that's emitted can help scientists detect small concentrations of particular types of biological molecules within a material. But some biomolecules, such as RNA and DNA, don't emit fluorescent light, or they only do so at extremely low levels. That's where Raman spectroscopy comes into play.
Raman spectroscopy involves shooting a laser at a sample and observing how the light scatters. When light hits molecules, the atoms within the molecules vibrate and photons get scattered. Most of the scattered light is of the same wavelength and color as the original light, so it provides no information. But a tiny fraction of the light gets scattered differently; that is, the wavelength and color are different. Known as Raman scattering, this is extremely useful because it provides highly precise information about the chemical composition of the molecule. In other words, all molecules have a unique Raman "fingerprint."
Creating an affordable, pocket-sized spectrometer
To build the spectrometer, the researchers connected a smartphone to a laser and a series of plastic lenses. The smartphone camera was placed facing a transmission diffraction grating, which splits incoming light into its constituent wavelengths and colors. After a laser is fired into a sample, the scattered light is diffracted through this grating, and the smartphone camera analyzes the light on the other side.
Schematic diagram of the designed system.Credit: Dhankhar et al.
To test the spectrometer, the researchers analyzed a range of sample materials, including carrots and bacteria. The laser used in the spectrometer emits a wavelength that's readily absorbed by the pigments in carrots and bacteria, which is why these materials were chosen.
The results showed that the smartphone spectrometer was able to correctly identify the materials, but it wasn't quite as effective as the best commercially available Raman spectrometers. The researchers noted that their system might be improved by using specific High Dynamic Range (HDR) smartphone camera applications.
Ultimately, the study highlights how improving the fundamentals of a technology, like smartphone cameras, can lead to a surprisingly wide range of useful applications.
"This inexpensive yet accurate recording pocket Raman system has the potential of being an integral part of ubiquitous cell phones that will make it possible to identify chemical impurities and pathogens, in situ within minutes," the researchers concluded.