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7 myths you learned in biology class that you probably still believe
You’ll be surprised how many commonly known science “facts” are actually total misconceptions.
Science classes are supposed to give students not only the most up-to-date knowledge and information but also a belief in the scientific method and perhaps imbue them with the logic and reasoning skills associated with it. Trouble is, there are a lot of myths out there that sabotage these lofty goals. In fact, many of them originate in science classes themselves, taught over and over by teachers too lazy to look them up. Despite already being debunked, they persist. Here are 7 commonly held myths from biology class you probably still believe.
1. Humans sit atop the food chain
Food web. Credit: Socratic.
Sometimes you’ll hear the carnivorous among us exclaim, “I didn’t fight my way to the top of the food chain to eat a salad.” Though we may understand their meaning, the concept behind it is dead wrong. That’s because the food chain metaphor itself is too simplistic. It’s more like a food web, which more accurately portrays how energy is passed among organisms in a certain ecosystem.
Food webs are made up of food chains, which are when energy is transferred up in a linear fashion. The trouble with the food chain is, there are usually multiple organisms who are both predator and prey. Many organisms can eat multiple things and conversely be consumed by multiple predators. The food chain model also often ignores the producers at the bottom. As such, a food web, although still imperfect, is a far more precise model.
2. Respiration is synonymous with breathing
Cellular respiration. Credit: Sheri Amsel, Exploring Nature.
Most people think respiration and breathing are the same thing. That is, sadly, nowhere near true. While we’ve got a good handle on what breathing is, respiration is when muscles release glucose during physical activity, like exercise. Glucose is the body’s fuel. We use it for energy. This misconception may be due to the fact that study of the respiratory system focuses mainly on breathing. And therein lies the confusion.
3. Cats and dogs are colorblind
Credit: Stocksnap, Pixababy.
The reason for the pervasiveness of this myth might be due to the fact that vision in these species works much differently than ours. Shockingly, recent research finds both dogs and cats can see the colors green and blue. But not quite like us. The color in a dog's vision is 1/7th less vivid than ours due to the fact they have fewer cone cells.
They do, however, have more rod cells in their eyes than humans. These cells sense light. This means dogs have better night vision than we have. With cats, colors look completely different. Purple, for instance, may look more blue to them, while red and pink appear as different shades of green.
4. Sugar is as addictive as cocaine
Credit: Getty Images.
This comes from the bestselling book by Dr. Robert Lustig, Fat Chance. First published in 2009, it claimed that sugar stimulates the brain’s reward system in much the same way as drugs do, such as cocaine, heroin, and alcohol. One problem though, although sugar may, in fact, trigger dopamine, no scientific studies using neuroimaging have ever backed up this claim. While it may be proven to be accurate in the near future, there’s no way currently to substantiate this statement.
5. Daughters inherit traits from their mothers and sons from their fathers
Autosomal recessive inheritance. Credit: Cburnett, Wikipedia Commons.
Genetics is fun, isn’t it? It can also be a tad confusing. Most people carry this misconception from when they learned how we inherit traits. It’s true that an offspring inherits an allele from each parent.
But the characteristic that is taken by the organism happens to be the dominant one, regardless of which parent it came from or the sex of the offspring. Another common misconception is that we get half of our characteristics from each parent. The truth, all that matters is which alleles are dominant.
6. Sharks can smell one drop of blood in the water from a mile away
A great white shark. Credit: Skeeze, Pixababy.
It’s a scary thought, but does the claim stand up under scientific scrutiny? Just know that no shark is darting for your swim trunks from miles away. Sharks have highly developed brain regions for sensing odors. They can pick up 1 part of blood per 10 billion parts of water. But while this might conjure up the image of a shark honing in from miles away, it's useful to know what 1 in 10 billion parts of water actually is. A good way to visualize this is the ball of a ball-point pen in an Olympic swimming pool (still impressive nevertheless). Molecules, of course, scatter and drift in the water and there are loads of them in the ocean. The best a shark could do is pick up blood from a couple of football fields away if the currents and other conditions are just right.
7. Humans evolved from chimps
A chimpanzee in the Leipzig Zoo. Credit: Thomas Lersch, Wikipedia Commons.
While the chimpanzee may be our closest living relative (homo sapiens are equidistant from them and bonobos), we didn’t evolve from them per se. Rather, chimps, gorillas, and humans share a common ancestor that walked the Earth some 6-10 million years ago. A recently unearthed fossil from Kenya’s Rift Valley may be the common thread. This has tentatively been identified as the Nakali ape (Nakalipithecus nakayamai). So how closely related are we to chimps? We share 98.8% of the same genes.
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 simple trick allowed marine biologists to prove a long-held suspicion.
- It's long been suspected that sharks navigate the oceans using Earth's magnetic field.
- Sharks are, however, difficult to experiment with.
- Using magnetism, marine biologists figured out a clever way to fool sharks into thinking they're somewhere that they're not.
For some time, scientists have suspected that sharks belong among the growing number of animals known to navigate using Earth's magnetic field. Testing anything with a shark, though, requires some care.
The key was selecting the right candidate. Keller and his colleagues chose the bonnethead shark, Sphyrna tiburo, a small critter that summers at Turkey Point Shoal off the coast of the Florida State University Coastal and Marine Laboratory with which Keller is affiliated.
Bonnetheads elsewhere have been known to complete 620-mile roundtrip migrations. As the lab's Dean Grubbs puts it, "That's not bad for a shark that is only two to three feet long. The question is how do they find their way back to that same estuary year after year." There's a report of a great white shark migrating between two locations, one in South Africa and another in Australia, year after year.
The research is published in Current Biology.
Keller and his team rounded up 20 local juvenile bonnetheads and transported them into a holding tank at the marine lab. For the tests, the researchers simulated three real-world magnetic fields. As the various magnetic fields were activated, the sharks' movements were captured by GoPro cameras and their average swimming orientations calculated by software.
The first simulation, serving as a control, mimicked the magnetic field of the nearby shoal from which the sharks had been captured. When this field was activated, the sharks essentially acted like they were "home," just swimming around as they do.
A second field was the magnetic equivalent of a location 600 kilometers south of the lab within the Gulf of Mexico. When this field was activated, the sharks, apparently mistaking themselves for being far south in the Gulf, began swimming northward toward the shoal.
The opposite occurred with a field standing in for a location in continental North America 600 km north of their home shoal — the sharks began swimming southward.
"For 50 years," says Keller, "scientists have hypothesized that sharks use the magnetic field as a navigational aid. This theory has been so popular because sharks, skates, and rays have been shown to be very sensitive to magnetic fields. They have also been trained to react to unique geomagnetic signatures, so we know they are capable of detecting and reacting to variation in the magnetic field."
His team's experiments confirm what's long been suspected, Keller says: "Sharks use map-like information from the geomagnetic field as a navigational aid. This ability is useful for navigation and possibly maintaining population structure."
A machine learning system lets visitors at a Kandinsky exhibition hear the artwork.
Have you ever heard colors?
As part of a new exhibition, the worlds of culture and technology collide, bringing sound to the colors of abstract art pioneer Wassily Kandinsky.
Kandinsky had synesthesia, where looking at colors and shapes causes some with the condition to hear associated sounds. With the help of machine learning, virtual visitors to the Sounds Like Kandinsky exhibition, a partnership project by Centre Pompidou in Paris and Google Arts & Culture, can have an aural experience of his art.
An eye for music
Kandinsky's synesthesia is thought to have heavily influenced his painting. Seeing yellow summoned up trumpets, evoking emotions like cheekiness; reds produced violins portraying restlessness; while organs representing heavenliness he associated with blues, according to the exhibition notes.
Virtual visitors are invited to take part in an experiment called Play a Kandinsky, which allows them to see and hear the world through the artist's eyes.
Kandinsky's synesthesia is thought to have heavily influenced his 1925 painting Yellow, Red, Blue.Image: Guillaume Piolle/Wikimedia Commons
In 1925, the artist's masterpiece, "Yellow, Red, Blue", broke new ground in the world of abstract art, guiding the viewer from left to right with shifting shapes and shades. Almost a century after it was painted, Google's interactive tool lets visitors click different parts of the artwork to journey through the artist's description of the colors, associated sounds and moods that inspired the work.
But Google's new toy is not the only tool developed to enhance the artistic experience.
Artist Neil Harbisson has developed an artificial way to emulate Kandinsky by turning colors into sounds. He has a rare form of color blindness and sees the world in greyscale. But a smart antenna attached to his head translates dominant colors into musical notes, creating a real-world soundtrack of what's in front of him. The invention could open up a new world for people who are color blind.
A new study suggests that private prisons hold prisoners for a longer period of time, wasting the cost savings that private prisons are supposed to provide over public ones.