SSeveral characteristics of animal bodies have changed and reappeared over the history of the planet. For example, eyes, both simple like those of people and compound like those of various arthropods, have appeared, disappeared, and reappeared.
But species have not.
As far as we know, species do not reappear.
They evolve or die out, but they do not reappear.
They are unique creations of deep time.
A few genetic entrepreneurs are trying to reengineer extinct life forms and bring them back to life, a process known as “de-extinction.” The media sometimes portrays these technological endeavors as positive news stories.
One of these projects involves finding the intact nucleus of a mammoth cell and using it to clone a new mammoth.
It's unlikely that such clones could establish a viable population, even physically, because the lack of genetic diversity in the original samples would make them weak and highly susceptible to disease.
But even if the bodies of those long-extinct species could be recreated from cells, their minds, behaviors, group dynamics, and feeding and reproductive strategies could not. Just like those of human beings, Cro-Magnons, or Neanderthals.
Trying to recreate a human being from genetic material would be monstrous—a Frankenstein project. And yet, somehow, trying to do the same with other animals is considered commendable.
Efforts to reconstruct complex animals from organic matter pieces indicate not just our technical expertise, but also, in some parts of our scientific community, a lack of non-technical wisdom—a deliberate ignorance of our hard-earned departure from the mechanistic views of Descartes. It's a rejection of the understanding that other animals, like us, are not flesh machines, but social and experiential constructs whose whole is much more than their parts.
Each species represents the unique outcome of its past.
That past, with its incredibly long series of events and landscapes and wide variety of other animals, plants, fungi, and bacteria, arranged in a complex and incomprehensible interdependence, can never be replicated.
And it has made all of us who we are.
Among the countless animals that have influenced human behavior are snakes, provoking a deep-rooted terror reaction even when they are not venomous. The fear of snakes is a common phobia—in some cultures, the most common one. We attribute various negative qualities to these reptiles: after all, it was a serpent who lured us out of Eden.
There may be some scientific truth to that, if the tree of knowledge is viewed as a metaphor for the development of our minds.
A concept in anthropology known as “snake detection theory,” proposed by a behavioral ecologist named Lynne Isbell in 2006, suggests that some primates' keen vision, like ours, evolved partly as a response to the presence of poisonous snakes. Primate species that evolved in regions without these snakes do not tend to have such acute vision.
According to Isbell, while some ground-based mammals developed an immunity to snake venom, others like arboreal primates developed sharp vision instead.
Neuroscientists are currently trying to find physical proof to back up her idea.
This implies that snakes, which existed when the first mammals appeared but gained their venomous abilities later, played a crucial role in developing the human brain's capacity.
Some other scientists have proposed that our keen eyesight evolved to help us spot insects on tree branches.
Because we used to enjoy eating insects when we lived in trees.
Environmental economists, one of whom, according to graduate degrees, I am supposed to be, refer to the benefits that other animals and plants provide us, or that we take from them, as their "use value." This is part of a calculation that aims to measure the contributions of other beings to our species in tools such as cost-benefit analysis.
However, the worth of those contributions is immeasurable.
After the K-T asteroid impactApproximately 66 million years ago, there was a significant global cooling and—most likely for one to two years—photosynthesis largely ceased. Three-quarters of plant and animal species suddenly perished, leading to widespread deforestation.
There was a rapid increase in the number of fungi. From the decaying matter of the countless dead, a massive fungal bloom emerged.
Some scientists have suggested that it was this surge of fungi, combined with the cold, that prevented a new evolution of large reptiles like dinosaurs and instead allowed for the rise of mammals.
As cold-blooded creatures, reptiles would have been more vulnerable to fungal infections. Additionally, fungi may have been more appealing to mammals than reptiles.
If those scientists are correct, it would mean that the asteroid that struck Mexico was responsible for our existence.
So far, the average internal temperature of our bodies—98.6 degrees Fahrenheit—has largely prevented fungi from invading them.
However, fungi can adapt to higher temperatures. One such fungus, Candida auris, has been identified by the Centers for Disease Control as an emerging threat to human health.
Our indebtedness to other lifeforms, of course, extends further back in time—even before vascular plants, and even before trees, there were cyanobacteria, also known as blue-green algae. Their appearance around 2 billion years ago generated the free oxygen that led to a breathable atmosphere. This marked the first significant mass extinction we know of, though it’s usually not considered a mass extinction event: It did not wipe out complex, multicellular life. The life forms existing at that time were mostly anaerobic bacteria in the ocean.
Bacteria were poisoned by the oxygen and perished. However, the Great Oxygenation Event allowed for the development of many new creatures.
Including us.
To explain why monkeys no longer live wild in Canada or the United States, an anthropologist named Noel Boaz cites “the ascendancy of the rodents.”
Boaz is interested in historical climate patterns as a factor in human evolution, among other topics. Towards the end of the period known as the Eocene, he has written that climatic cooling in the higher latitudes made fruit trees scarcer and nut trees, which produce fruits with hard shells, more prevalent.
With nuts, primates were at a disadvantage—we still have to crack them open with tools.
But rodents, with their continuously growing front teeth, were fortunate.
Squirrels similar to rodents took the place of the primates that once inhabited this area approximately 45 to 34 million years ago. According to Boaz's theory, the squirrels filled the environmental roles in the trees that the primates previously held.
He suggests that if there were no squirrels, monkeys might still exist here.
In nature, the majority of plants and trees rely on birds, mammals, insects, water, and wind to spread their seeds or pollen and reproduce. They greatly depend on groups of pollinators, which are increasingly at risk of extinction. The United Nations reports that about 40 percent of invertebrate pollinators worldwide are under threat.
Similar to Victorian children, the plants are visible but not audible: they are observed all around converting light into essential resources. Their presence is only noticeable when the wind moves their stems.
Because they cannot move on their own, we often perceive plants as inactive. plants as passive and nearly inert. However, like most forms of distinctiveness, their unfamiliar attributes compensate for their lack of familiar ones.
The green color of plants is a result of their conservative behavior—they appear green to us because they reflect that particular wavelength of solar radiation. Despite this, the majority of the sun's energy comes from rays in the green part of the spectrum. Plants reject those rays during photosynthesis due to the interference and inefficiency they cause in their systems.
Since they are unable to escape from predators, they have adapted to not have essential organs, unlike humans who cannot survive without their hearts or brains.
Many can have up to 90 percent of their physical structure removed without being killed, according to plant scientist Stefano Mancuso.
Along with our loss of their usefulness, the extinction of a species also results in the disappearance of their intelligent contributions.
And we have limited understanding of those potential contributions.
In addition to the
problem of inherent sadness in the end of a life form, one issue is that because we did not create the systems of biological existence, we lack a reliable guide to their functioning—there are no blueprints or manuals. Therefore, when we seek help from experts to rectify an imbalance we have caused in nature, their interventions often go awry.
In numerous instances where we have intentionally or accidentally transported animals or plants while colonizing or traveling, we have caused the destruction of other species and natural systems. This process has accelerated recently due to our global mobility. Despite an increasing awareness of the dangers, there are still situations where deliberate introductions intended to solve a problem end up causing even more issues, leading to a cascade of imbalances and mass extinctions.
The history of this "importation biocontrol," where one non-native species is introduced to control another, is filled with failures.
Mosquitofish, which were brought to various countries to eat the mosquitoes that spread malaria, have greatly increased in places where they don't belong. However, they don't really like to eat mosquito larvae; they prefer fish larvae, which causes native fish to become scarce in those areas.
In northern Australia, Florida, and many islands where sugar is grown, cane toads were brought from the mainland neotropics in the 1930s to control the beetles that were damaging sugar crops. In Australia, they were not very effective against the beetles because they cannot climb well, and the beetles live at the tops of the plants. However, Australia does not have native toads, and the sudden abundance of cane toads led to a series of species declines as the toads outcompeted native lizards, snakes, and crocodiles.
When the populations of predators decreased, the prey species multiplied, causing further damage to local plant communities.
Hawaii in the United States has experienced negative impacts from biocontrol projects and has also seen many species go extinct. Although the islands account for only 0.29 percent of the country's landmass, they are home to over 40 percent of the species now protected under the Endangered Species Act.
The introduction of predaceous snails has caused the native snails to disappear on a large scale; mongooses, brought in to control rats for the sake of sugar crops, have caused great harm to endemic birds and have a strong appetite for sea turtle eggs. They have become widespread on almost all of Hawaii's islands, as well as on other tropical islands like Fiji and Jamaica.
However, the mongooses did not solve the rat problem because they work during the day, while the rats are active at night.
About one-third of biocontrol interventions have led to the establishment of a new natural enemy. Less than one-sixth have successfully controlled the target pest.
The many factors that we have neglected to consider in our biocontrol operations, and which later result in unwelcome surprises, are a warning sign for those who advocate for ambitious “geoengineering” solutions to the climate problem.
These ambitious solutions include proposals to pump ozone-destroying sulfate aerosols into the atmosphere on a large scale to cool it, as well as the dumping of iron dust into the oceans to stimulate algal blooms and the genetic modification of crops to increase their carbon uptake.
There are also plans to block solar radiation through mechanical means, such as deploying large, heavy sunshades or placing 55,000 orbiting wire-mesh mirrors, each 40 square miles wide.
All of these plans come with significant risks of failure. When it comes to making ambitious changes to the foundations of physical life support, our track record is filled with a list of remarkable mistakes.
Several birds, including European starlings, were intentionally brought to the so-called New World by a group called the American Acclimatization Society, which aimed to introduce a selection of favored species from the Old World to improve the New. In hindsight, this mission was misguided.
There are now about 85 million starlings in North America, although not all are descended from the individuals the Society brought in. starlings Starling calls can be loud and accurately imitate sounds from other birds’ calls to car alarms and the human voice. Their mimicry skills are comparable to those of the Australian lyrebird, which has a unique appearance.
To attract a mate, a male lyrebird finds an open patch on the forest floor. There he performs a concert while displaying his lovely feathers with sculptural shaking and fluttering movements.
His performance is a lengthy medley, consisting of perfect imitations of the songs and calls of dozens of other bird species that live in the forest around him, as well as other sounds like the click of a camera shutter and the whir of its small motor. lyrebird The lyrebird even imitates the chainsaws of nearby loggers as they cut down trees.
When animals play dead, from possums to snakes to ducks, biologists don’t usually suggest that they’re doing so because they understand what dead is, as it pertains to themselves. Rather this death-feigning behavior is mostly interpreted as a stress adaptation. However, people can also exhibit tonic immobility during extreme trauma, such as sexual assault and war.
With other animals, tonic immobility comes into play in self-defense, to avoid death by predation. It also shows up in mating, such as when male sharks bite females and the females freeze. Occasionally it appears in ways that seem more like strategy than a response to stress.
Predatory East African fish called sleeper cichlids lie down on their sides on the bottom of Lake Malawi—the only place they live—then go perfectly still, possibly for camouflage or to look as though they’re decomposing. When a scavenger fish approaches, attracted to the apparent corpse, they swiftly flick themselves upright and eat it.
It is worth wondering if the show of blotchiness is a display of genius.
Excerpted from We Loved It All: A Memory of Life by Lydia Millet. Copyright © 2024 by Lydia Millet. Used with permission of the publisher, W. W. Norton & Company, Inc. All rights reserved.
Lead image: studiovin / Shutterstock
When it comes to modifying nature, our résumé is a list of remarkable mistakes.
Excerpted from We Loved It All: A Memory of Life by Lydia Millet. Copyright © 2024 by Lydia Millet. Used with permission of the publisher, W. W. Norton & Company, Inc. All rights reserved.
Lead image: studiovin / Shutterstock
