For decades, researchers have proposed that climate change and human-caused environmental destruction led to demographic collapse on Easter Island. That's probably false, according to new research.
- Easter Island, whose native name is Rapa Nui, is a remote island in the Pacific Ocean about 2,300 miles west of Chile.
- Researchers have proposed that deforestation and climatic changes led to societal collapse on the island, prior to European contact.
- The results of a new study suggest that, despite these factors, the Rapa Nui people managed to adapt and sustain a stable society.
In the popular imagination, the story of Easter Island has long centered on stone. About 900 monolithic statues, or "moai", have been identified on Easter Island, a remote 63-square-mile triangle in the Pacific Ocean whose native name is Rapa Nui. The statues — haunting, hollow-eyed faces — were crafted from massive blocks of volcanic rock by the Rapa Nui people, who settled on the island around 1200 CE.
But for archaeologists and anthropologists, the story of Rapa Nui has often centered on trees, rats, and climate. These are the key factors, some researchers have proposed, that led to ecological catastrophe on the island and, consequently, population collapse.
One popular narrative holds that the growing Rapa Nui population cut down so many of the island's tall palm trees that they depleted their food and logistical resources and inadvertently killed off plant and animal species. Meanwhile, Polynesian rats, which were carried to the island via boat and had multiplied exponentially over generations, contributed to deforestation by eating seeds and plants. Compounding the island's problems were changes in the El Niño Southern Oscillation, which led to drier conditions.
Facing dire circumstances, the natives probably resorted to eating rats. They might have also turned to eating each other, suggested the author Jared Diamond in his book Collapse, in which he states that Rapa Nui is the "clearest example of a society that destroyed itself by overexploiting its own resources."
Busting the Easter Island collapse myth
But the popular narrative about Easter Island could be mostly false. New research suggests that these narratives connecting environmental devastation to population decline aren't accurate. The study, published in Nature Communications, found that while the Rapa Nui people did suffer environmental and climatic changes, they didn't suddenly dwindle in number but rather maintained "stable and sustainable communities on the island" up until the point they encountered Europeans.
To estimate changes in population over time, the researchers tested four demographic models, three of which accounted for variables like climate change or deforestation or both. Their models also incorporated about 200 radiocarbon-dated archaeological samples, which serve as a good "proxy for estimating relative population sizes."
Moai statueskovgabor79 via Adobe Stock
Radiocarbon dating and statistical modeling always come with uncertainties. To minimize analytical uncertainty, the researchers used a form of statistical modeling called Approximate Bayesian Computation. The researchers wrote:
"[Approximate Bayesian Computation] is a flexible and powerful modeling approach originally developed in population genetics, but recently applied in archeology, including paleodemographic research. We demonstrate how ABC can be used to directly integrate independent paleoenvironmental variables into demographic models and perform multi-model comparisons."
The results produced by all four models showed that the Rapa Nui population enjoyed steady growth until the first contact with Europeans in 1722, after which the population seemed to either plateau or decline over subsequent decades. These models suggest that, contrary to previous hypotheses about how the overexploitation of resources led to demographic collapse, deforestation and climatic changes on the island were prolonged processes that didn't have catastrophic effects on the population.
For example, evidence suggests that the Rapa Nui people built productive gardens on deforested land and mulched them with nutrient-rich stone. As for climate change, the researchers pointed to recent studies suggesting that the natives adapted to drier conditions by turning to coastal groundwater sources.
Upending a long-standing narrative
Although the study offers evidence of a robust population prior to European contact, the researchers could not determine which of the four demographic models was most correct, nor did they account for other factors that likely affected the island's population, like warfare. The researchers also did not explore what effect, if any, European contact had on the population.
But overall, the study casts serious doubts on the popular narrative that environmental changes drove down the native population. To be sure, there are dark chapters in the history of Rapa Nui, including civil war, slave raids, and statue destruction; reports suggest that between 1722 and 1774 many of the island's statues were toppled or neglected, likely due to internal conflicts among the natives.
Still, the study suggests that the story of early Rapa Nui is less about environmental destruction than it is about resilience.
The researchers conclude that "despite extreme isolation, marginal ecological conditions, and a series of environmental changes, Rapa Nui people found solutions that enabled them to successfully thrive on the island for at least 500 years prior to the arrival of Europeans."
The size of rabbits and hares has long been evolutionarily constrained by competitors roughly their size.
- Rabbits, hares, and pikas are not as varied in size as other similar animals such as rodents, which can be both far bigger and far smaller.
- Scientists at Kyoto University examined the fossil record to figure out why.
- They found that the smallest hoofed mammals always predict the size of the largest rabbits.
Rabbits are, of course, adorable. We kvell over awww-inducing pictures of the little cuties who look like they couldn't hurt a fly. (Fun fact: Male rabbits are incredibly fierce when they fight each other and will actually fight to the death.)
Rabbits have been around for a long time, and they don't exhibit the same variations in size as for example, rodents. Even a big rabbit is not as big as, say, a capybara that can weigh from 60 to 200 pounds. Likewise, there is no rabbit anywhere near as tiny as a pigmy mouse of sub-Saharan Africa, which can weigh as little as 3 grams or as much as a zaftig 12 grams.
Researchers at Kyoto University's Primate Research Institute wondered why there are no horse-sized — or for that matter, tiny — lagomorphs. The lagomorph order includes rabbits, pikas, and hares.
The curious scientists recently published a paper titled "Why aren't rabbits and hares larger?" in the journal Evolution. It suggests the answer to this question may say something about the factors that most profoundly influence a species' evolution.
Size limited by competition
There are breeds of domestic rabbits that can be somewhat large. Tomiya notes "some breeds of domestic rabbits and other extinct species can weigh up to 8 kg [about 17.63 pounds]. We were surprised by this, and so began to investigate what sort of external forces keep wild lagomorphs across the world from evolving larger body sizes."
After analyzing the available fossil record to explore how lagomorphs have fared through time, the team came to suspect that their size tended to be constrained by competition for food with larger herbivores.
Blame the sheep
As the researchers investigated the ecosystems in which lagomorphs lived, creatures of a different order, ungulates, came to their attention. Ungulates are an order of hoofed mammals including horses, rhinoceroses, and pigs. It also includes cloven-hoofed animals like cows and sheep.
It seems that ungulates were more than mere neighbors of rabbits, hares, and pikas. Similarly sized ungulates probably were their competitors.
The researchers calculated that large lagomorphs would require an excessive amount of energy — food, water and so on — to thrive, considerably more than smaller rabbits and hares. As a result, Tomiya says that when they compared "how much energy is used by populations of lagomorphs and ungulates relative to their body sizes," they found "that lagomorphs weighing more than six kilograms are energetically at a competitive disadvantage to ungulates of the same size."
To confirm their theory, the researchers next looked at the fossil record of North America. They found that the smallest hoofed animals predicted the size of the largest bunnies.
It remains true to this day, he says. "We see this pattern today across numerous eco-regions, suggesting that there is an evolutionary 'ceiling' placed on lagomorphs by their ungulate competitors."
The red queen versus the court jester
Tomiya says the study may help resolve biologists' ongoing "red queen" vs. "court jester" debate over the type of forces that most affect a species' evolution.
The red queen represents biotic forces and the court jester abiotic factors. ("Biotic" refers to other organisms that live in the same ecosystem as a species being studied, while "abiotic" refers to non-living factors such as climate, light, the quality of water, and so on.)
"For some time," says Tomiya, "the court jester model — ascribing diversity to abiotic forces such as the climate — has been dominant, due to the difficulty of studying biological interactions in the fossil record." He says the study's findings show that the red queen shouldn't be counted out when it comes to influencing evolution.
From making their own swabs to staying in constant communication across the board, Northwell Health dove headfirst into uncharted waters to take on the virus and save lives.
- Preparing for a pandemic like COVID-19 was virtually impossible. Northwell Health president and CEO Michael Dowling explains how, as the largest healthcare provider in New York, his team had to continuously organize, innovate, and readjust to dangerous and unpredictable conditions in a way that guaranteed safety for the staff and the best treatment for over 128,000 coronavirus patients.
- From making their own supplies when they ran out, to coordinating with government at every level and making sense of new statistics and protocols, Northwell focused on strengthening internal and external communication to keep the ship from sinking.
- "There was no such thing as putting up the white flag," Dowling says of meeting the pandemic head on and reassuring his front line staff that they would be safe and have all the resources they needed to beat the virus. "It's amazing how innovative you can be in a crisis."
An overfished planet needs a better solution. Fortunately, it's coming.
- Cell-based fish companies are getting funding and making progress in offering a new wave of seafood.
- Overfishing and rising ocean temperatures are destroying entire ecosystems.
- The reality of cell-based fish is likely five to 10 years away.
The world does not have infinite resources. Yet as humans have exploded in population, from 1 billion in 1804 to nearly 8 billion today, we've treated the planet as our perpetual garden, leading to numerous problems, including overfishing. Over one-third of fisheries worldwide are pushed beyond their limits. Tragically, we continue to decimate populations year after year.
If we remain at the current pace, in a few decades all we'll have left to eat is jellyfish—yet another consequence of climate change. Sure, some of the 200 species are edible, though there's a reason you don't see shortages of jellyfish poke. We need to be proactive and limit trawling and other environmentally damaging practices. We also need to innovate, as a few companies are doing.
Enter lab-grown fish.
Some recoil at the mere mention, yet that's what innovation entails. We've gotten ourselves into this problem through technology—giant ships that drudge up entire ecosystems in a matter of hours—and technology might just help keep one of the most nutritious food sources on the planet in our diet. In the last half-century, oceanic "dead zones" have quadrupled due to human intervention. That practice cannot last.
While in countries like America, fish are a healthy option but not a necessity, many other countries rely on seafood as a main staple in their diet—according to the UN, 3.2 billion people. Beyond trawlers, warming ocean temperatures are destroying fish populations. This trend isn't only destroying diets but entire economies as well.
Future of Food: This genetically engineered salmon may hit U.S. markets as early as 2020
While cell-based beef is getting all the press, companies like BlueNalu recently raised $24.5 million in funding. The San Diego-based start-up extracts muscle cells from an anesthetized fish, treats the cells with enzymes in a culture, places the mixture in a nutrient solution in a bioreactor, spins it all around in a centrifuge, and finally 3D-prints the new concoction into the desired shape.
The goal isn't to perfectly replicate a fish that you'd find on ice in your local market. No brain, skin, organs, or even possibility of consciousness are in this creature. In a strange twist, this makes cell-based seafood a potential food source for vegetarians and vegans, since the Adam fish can be returned to the waters unharmed.
One current solution to overfishing—fish farms—comes with it a host of problems, including the proliferation of sea lice, which have a tendency to escape the porous boundaries to infect wild fish. Bonus: with cell-based fish, you won't run into any issues with mercury or microplastics.
What you'll (hopefully) purchase is a good-tasting product, which has thus far been elusive. BlueNalu CEO, Lou Cooperhouse, is confident his company's product will eventually meet standards set by your taste buds.
"Our medallions of yellowtail can be cooked via direct heat, steamed or even fried in oil; can be marinated in an acidified solution for applications like poke, ceviche, and kimchi, or can be prepared in the raw state."
Photo: aleksandr / Shutterstock
There are barriers, of course. As with pluripotent meats, cell-based fish are expensive. A spicy salmon roll produced by the start-up, Wildtype, cost $200 to make. It's going to take a while for the price to drop and consumer demand to rise; estimates are five to ten years.
Another issue is indicative of solar power and wind energy trying to cut in on Big Oil: the seafood industry doesn't want to lose its profit margin. Of course, like oil companies, Big Seafood is betting on a finite resource. The sooner they realize that, the better.
Then there's production, which is where education comes into play. Former BlueNalu Chairman Chris Somogyi tries to demystify the laboratory process.
"We aren't using CRISPR technology. We aren't introducing new molecules into the diet. We're not introducing a new entity that doesn't exist in nature. The approval will be about whether this is safe, clean and are the manufacturing processes reliable and accountable."
If there's an ick factor to cell-based fish, remember that most processed foods are already created in laboratories. There are no Oreo trees or ketchup plants to harvest.
For now, these start-ups and others like them will have to figure out how to create non-energy-intensive and cost-prohibitive solutions for spinning up seafood inside of a petri dish. Novelty alone will create enough demand to get them going, as precedent in the lab-grown meat industry shows.
The reality is that we need to go down this path. There are too many humans and not enough resources. While we can hope (as David Attenborough does in his new Netflix documentary) that national governments will create more no-fish zones, there's no guarantee that will happen. We need science to win this one.
Stay in touch with Derek on Twitter and Facebook. His new book is "Hero's Dose: The Case For Psychedelics in Ritual and Therapy."
The American economy may be locked into an unhealthy cycle that only benefits a select few. Is it too late to fix it?
- What will the economy of the future look like? To answer that we must first consider the current trajectory and the ways in which modern capitalism operates, who it benefits, and if it is sustainable.
- In this video, historians, economists, and authors discuss income and wealth inequality, how the American economy grew into the machine that it is today, the pillars of capitalism and how the concept has changed over time, and ways in which the status quo can, and maybe even should, change.
- "It's not that hierarchy is bad," says John Fullerton, founder of Capital Institute, "it's that hierarchy where the top extracts from below is definitely bad and unsustainable." He says that the modern capitalist system works this way, and that it perpetuates the cycle of growing inequality.