Human Errors: A Panorama of Our Glitches, from Pointless Bones to Broken Genes

by Nathan H. Lents

away. The rate of myopia increases to more than 70 percent of the population in Asian countries.

eyes. Some birds literally see the Earth’s magnetic field. Many birds also have an additional translucent eyelid that allows them to look directly into the sun at length without damaging their retinas.

sensitive are cats’ eyes that they can detect a single photon of light in a completely dark environment.

Air comes in and out like ocean tides through all those branches, hence humans are termed tidal breathers.

This is horribly inefficient because there is a great deal of stale air left in the lungs when fresh air is brought in. These mix, diluting the oxygen content of the air that actually reaches the lungs.

This burden of stale air in the lungs limits oxygen delivery, and so we must overcome this by breathing deeper, particularly during m...

Nearly five thousand Americans choked to death in 2014, the majority of them choking on food. If we had separate openings for air and food, this would never happen.

Nature is replete with animals that have bones they don’t need, joints that don’t flex, structures that aren’t attached to anything, and appendages that cause more problems than they’re worth.

arrangement. No robot arm will ever be designed to imitate our nonsensical bone structure.

for eating. Humans have more dietary requirements than almost any other animal in the world.

apart. Scurvy is a dystopian novel written by the human body.

Animals are the exact opposite of self-sufficient. They must constantly eat other living things in order to survive.

Further, chickpeas, also called garbanzo beans, contain large quantities of all nine essential amino acids all by themselves, as do quinoa and a few other so-called superfoods.

During a famine, it’s not the lack of calories that is the ultimate cause of death; it’s the lack of proteins and the essential amino acids they provide.

poor. Calcium insufficiency is one of the most frustrating dietary problems from a design standpoint because lack of calcium stems from our species’ poor ability to absorb it rather than from not having enough of it in our food.

The WHO estimates that 50 percent of pregnant women and 40 percent of preschool children are anemic due to iron deficiency.

plants. Foods such as legumes, nuts, and berries—which we’re told to eat plenty of—contain polyphenols, which can reduce our ability to extract and absorb iron.

efforts. It’s not enough to eat the right foods to meet our exacting dietary needs; we must eat those foods in the correct combinations. It’s no wonder so many of us opt for a multivitamin instead.

that most wild animals are teetering on the edge of starvation pretty much all the time.

good. Intense exercise leads to intense hunger, which in turn leads to poor diet choices and chips away at the mental resolve to lose weight.

You expend a few dietary calories every single day just to copy your largely useless DNA.

If the first mutation doesn’t kill or harm the bearer, future mutations won’t either. These mutations will not be eliminated by natural selection.

Scientists estimate that the human genome contains the intact remnants of nearly twenty thousand pseudogenes. That’s almost as many broken genes as functional ones.

Were it not for this broken gene, the AIDS crisis might never have happened, or at least it might not have been so widespread and so deadly.

mutation, natural selection can protect the species only if the lethal effects are felt immediately.

The reason the SCD mutations were not eliminated is that the carriers of SCD—the individuals who have only one copy of the code and are thus not afflicted with the symptoms—are more resistant to malaria than noncarriers.

Other single-gene genetic disorders include cystic fibrosis, various forms of hemophilia, Tay-Sachs disease, phenylketonuria, Duchenne muscular dystrophy, and hundreds more.

conditions are often inherited from a parent, but even when the mutation occurs spontaneously in an individual with no family history of it (which actually happens quite often), the resulting disease will be passed on to 50 percent of that person’s offspring.

Because of its late onset, Huntington’s can be passed on with natural selection having little to say about it.

systems. Instead, recent therapies that have had great success in treating HIV are targeted at simply keeping the virus in the dormant phase for the rest of the patient’s life.

Around 8 percent of the DNA inside every single cell of your body consists of remnants of past viral infections, nearly a hundred thousand viral carcasses in all.

This forced the scientific community to take another look at McClintock’s work and admit that she was right. In 1983, she was awarded the scientific community’s highest honor—the Nobel Prize.

them. Disruptions by Alu or other TEs have also created genetic susceptibilities to type 2 diabetes, neurofibromatosis, Alzheimer’s disease, and cancer of the breast, colon, lung, and bone.

genome. Nearly half of human DNA is made of autonomously replicating, highly repetitive, dangerously jumping, pure genetic nonsense that the body dutifully copies and maintains in each one of its billions of cells.

ways. We have to take a very long view to appreciate this, but rare beneficial mutations provide the raw material with which natural selection produces new adaptations.

most studies report that somewhere between 7 to 12 percent of couples trying to conceive have faced persistent difficulties.

impressive, sperm swim at around 1.4 millimeters per second, which would be like a human running twenty-five miles per hour—a

to 85 percent of all miscarriages are due to chromosomal abnormalities, meaning that the new embryo has extra, missing, or badly broken chromosomes.

when a human sperm and a human egg fuse, the resulting embryo ends up with the proper number of intact chromosomes only around two-thirds of the time.

know.) Some couples experiencing infertility with no known cause may actually be conceiving zygotes just fine; the embryos may simply be failing to take root in the womb.

words, our species’ poor overall reproductive rate may be nature’s way of keeping parental attention on the helpless infant until he or she can stand on his or her own two feet

experience. It is no exaggeration to say that, for most of the time our species has existed, being born was the leading cause of death. For women, giving birth was the next biggest threat.

The difficulties we associate with childbirth are uniquely human, the product of the rapid evolution of a large cranium together with the failure of evolution to keep up with those changes.

limitation. Once again, science has provided solutions to a problem caused by nature. But in the process, science has effectively short-circuited evolution, consigning humans to the faulty reproductive systems that nature gave us.

decades. There is even a report of a woman in Chile who carried a nearly five-pound stone baby in her abdomen for fifty years. She gave birth to five children naturally during that

While it is true that the average lifespan in the medieval, classical, and even prehistoric periods was just twenty or thirty years, the average age of death was low because so many died as infants or as children.

up. The precise mechanism of menopause seems to be a timed, age-related decrease in the expression of DNA-repair enzymes in the cells surrounding the egg within each follicle.

So the question is, does a grandmother’s contribution to her grandchildren bring so much selective advantage that it is worth the cost of a lower reproductive rate?

sons. Adult male orcas spend much more of their time hunting and foraging with their mothers than with any other whales, including their fathers.