Here's Why Evolution Can Be "Survival of the Friendliest"

The state of nature isn't a "war of all against all." Even no-brainer bacteria "know" that sometimes the game is "Survival of the Friendliest"

Illustration by Julia Suits, The New Yorker cartoonist & author of The Extraordinary Catalog of Peculiar Inventions


1. Life’s games are not all “red in tooth and claw” fights. And you need no brain to see that a “war of all against all” might not be the best way. Even single-celled bacteria “know” that.

2. In “Survival of the Friendliest” Kelly Clancy describes the evolutionary logic of relationships beyond rivalry (e.g, “friendships” deep enough to defend common interests, sometimes a “snuggle for survival”). 

3. For instance, ~98% of bacterial species don’t thrive outside mixed-species colonies.

4. "Bacteria are not self-sufficient: They’ve co-evolved to depend on each other." They’ve discovered division of labor, specialization, and cooperation.

5. That specialization is a game-changer. You now need co-workers. If they don’t thrive, you don’t. You’re in a collective extended “survival vehicle” relationship.

6. In a kind of no-brainer biochemical “social contract,” bacterial colonies, like human communities, have to handle the “common good” (suppressing cheating, free-riding, the “tragedy of the commons,” etc).

7. For instance, “helper” species that “provide a common good… may come to be shielded from competition by the species that rely on them, as happens with corals” (not protecting common goods can lower your fitness).

8. Such interdependent survival logic pervades biology (e.g., all “selfish genes,” all trees, all animals).

9. Humans are also deeply “self-deficient” (likely the most common-goods-needing and other-dependent species ever). We dominate because we’re the best cooperators (Yuval Harari).

10. This is a case of what Daniel Dennett calls “free-floating rationales”: logic patterns that are inherent in situations but aren’t contained in (or “known” to) the elements or players involved (they’re free-floating, distributed, relational, systemic).

11. Evolution is itself a free-floating logic pattern (for discovering other, ever more effective logic patterns, and enacting “competence without comprehension"). And it “knows” (has mindlessly discovered) that cooperation can improve productivity (if team-threatening cheating is suppressed).

12. Evolution’s logic is like geometry’s: in both relevant patterns and results arise from the intrinsic logic of the elements involved. In geometry, it’s lines, planes, etc. In evolution it’s kinetic functions like survival, varying replication, and adaptation.

13. Evolution creates code-like “algorithms in motion” (Vikram Chandra). Logic that changes the world.  

14. Unnamed natural laws (free-floating patterns) likely constrain evolution (imposing kinetic logic limits like: negative telos, Turing-inspired universal survivor, cooperation-preserving Golden Punishment Rule, and needism).

daniel-dennett-memes-101

-- 

Illustration by Julia SuitsThe New Yorker cartoonist & author of The Extraordinary Catalog of Peculiar Inventions

Yug, age 7, and Alia, age 10, both entered Let Grow's "Independence Challenge" essay contest.

Photos: Courtesy of Let Grow
Sponsored by Charles Koch Foundation
  • The coronavirus pandemic may have a silver lining: It shows how insanely resourceful kids really are.
  • Let Grow, a non-profit promoting independence as a critical part of childhood, ran an "Independence Challenge" essay contest for kids. Here are a few of the amazing essays that came in.
  • Download Let Grow's free Independence Kit with ideas for kids.
Keep reading Show less

10 Examples of Settled Science that Are 'Controversial'

Many Americans are being misled on serious scientific issues, and science journalists have to spend an inordinate amount of time debunking myths which seemingly never die.

popular

Many Americans are being misled on serious scientific issues, and science journalists have to spend an inordinate amount of time debunking myths which seemingly never die.

Keep reading Show less

Engineers 3D print soft, rubbery brain implants

Technique may enable speedy, on-demand design of softer, safer neural devices.

Dan Kitwood/Getty Images
Surprising Science

The brain is one of our most vulnerable organs, as soft as the softest tofu. Brain implants, on the other hand, are typically made from metal and other rigid materials that over time can cause inflammation and the buildup of scar tissue.

Keep reading Show less

The surprise reason sleep-deprivation kills lies in the gut

New research establishes an unexpected connection.

Reactive oxygen species (ROS) accumulate in the gut of sleep-deprived fruit flies, one (left), seven (center) and ten (right) days without sleep.

Image source: Vaccaro et al, 2020/Harvard Medical School
Surprising Science
  • A study provides further confirmation that a prolonged lack of sleep can result in early mortality.
  • Surprisingly, the direct cause seems to be a buildup of Reactive Oxygen Species in the gut produced by sleeplessness.
  • When the buildup is neutralized, a normal lifespan is restored.

We don't have to tell you what it feels like when you don't get enough sleep. A night or two of that can be miserable; long-term sleeplessness is out-and-out debilitating. Though we know from personal experience that we need sleep — our cognitive, metabolic, cardiovascular, and immune functioning depend on it — a lack of it does more than just make you feel like you want to die. It can actually kill you, according to study of rats published in 1989. But why?

A new study answers that question, and in an unexpected way. It appears that the sleeplessness/death connection has nothing to do with the brain or nervous system as many have assumed — it happens in your gut. Equally amazing, the study's authors were able to reverse the ill effects with antioxidants.

The study, from researchers at Harvard Medical School (HMS), is published in the journal Cell.

An unexpected culprit

The new research examines the mechanisms at play in sleep-deprived fruit flies and in mice — long-term sleep-deprivation experiments with humans are considered ethically iffy.

What the scientists found is that death from sleep deprivation is always preceded by a buildup of Reactive Oxygen Species (ROS) in the gut. These are not, as their name implies, living organisms. ROS are reactive molecules that are part of the immune system's response to invading microbes, and recent research suggests they're paradoxically key players in normal cell signal transduction and cell cycling as well. However, having an excess of ROS leads to oxidative stress, which is linked to "macromolecular damage and is implicated in various disease states such as atherosclerosis, diabetes, cancer, neurodegeneration, and aging." To prevent this, cellular defenses typically maintain a balance between ROS production and removal.

"We took an unbiased approach and searched throughout the body for indicators of damage from sleep deprivation," says senior study author Dragana Rogulja, admitting, "We were surprised to find it was the gut that plays a key role in causing death." The accumulation occurred in both sleep-deprived fruit flies and mice.

"Even more surprising," Rogulja recalls, "we found that premature death could be prevented. Each morning, we would all gather around to look at the flies, with disbelief to be honest. What we saw is that every time we could neutralize ROS in the gut, we could rescue the flies." Fruit flies given any of 11 antioxidant compounds — including melatonin, lipoic acid and NAD — that neutralize ROS buildups remained active and lived a normal length of time in spite of sleep deprivation. (The researchers note that these antioxidants did not extend the lifespans of non-sleep deprived control subjects.)

fly with thought bubble that says "What? I'm awake!"

Image source: Tomasz Klejdysz/Shutterstock/Big Think

The experiments

The study's tests were managed by co-first authors Alexandra Vaccaro and Yosef Kaplan Dor, both research fellows at HMS.

You may wonder how you compel a fruit fly to sleep, or for that matter, how you keep one awake. The researchers ascertained that fruit flies doze off in response to being shaken, and thus were the control subjects induced to snooze in their individual, warmed tubes. Each subject occupied its own 29 °C (84F) tube.

For their sleepless cohort, fruit flies were genetically manipulated to express a heat-sensitive protein in specific neurons. These neurons are known to suppress sleep, and did so — the fruit flies' activity levels, or lack thereof, were tracked using infrared beams.

Starting at Day 10 of sleep deprivation, fruit flies began dying, with all of them dead by Day 20. Control flies lived up to 40 days.

The scientists sought out markers that would indicate cell damage in their sleepless subjects. They saw no difference in brain tissue and elsewhere between the well-rested and sleep-deprived fruit flies, with the exception of one fruit fly.

However, in the guts of sleep-deprived fruit flies was a massive accumulation of ROS, which peaked around Day 10. Says Vaccaro, "We found that sleep-deprived flies were dying at the same pace, every time, and when we looked at markers of cell damage and death, the one tissue that really stood out was the gut." She adds, "I remember when we did the first experiment, you could immediately tell under the microscope that there was a striking difference. That almost never happens in lab research."

The experiments were repeated with mice who were gently kept awake for five days. Again, ROS built up over time in their small and large intestines but nowhere else.

As noted above, the administering of antioxidants alleviated the effect of the ROS buildup. In addition, flies that were modified to overproduce gut antioxidant enzymes were found to be immune to the damaging effects of sleep deprivation.

The research leaves some important questions unanswered. Says Kaplan Dor, "We still don't know why sleep loss causes ROS accumulation in the gut, and why this is lethal." He hypothesizes, "Sleep deprivation could directly affect the gut, but the trigger may also originate in the brain. Similarly, death could be due to damage in the gut or because high levels of ROS have systemic effects, or some combination of these."

The HMS researchers are now investigating the chemical pathways by which sleep-deprivation triggers the ROS buildup, and the means by which the ROS wreak cell havoc.

"We need to understand the biology of how sleep deprivation damages the body so that we can find ways to prevent this harm," says Rogulja.

Referring to the value of this study to humans, she notes,"So many of us are chronically sleep deprived. Even if we know staying up late every night is bad, we still do it. We believe we've identified a central issue that, when eliminated, allows for survival without sleep, at least in fruit flies."

Scroll down to load more…