Wednesday, May 26, 2021

The Descent of Man: How Collaboration Made us What we are




150 years ago, Darwin published "The Descent of Man" -- another great intuition by one of the greatest scientists in history. Today, we understand how humans are what they are because they collaborate with each other -- something that we tend to forget in our current views that emphasize cutthroat competition. Here is how Richerson, Gavrilets, and De Waal comment on this point in their recent article on "Science"

"What makes us different is that our ancestors evolved greatly enhanced abilities for (and reliance on) cooperation, social learning, and cumulative culture—traits emphasized already by Darwin. Cooperation allowed for environmental risk buffering, cost reduction, and the access to new resources and benefits through the “economy of scale.” Learning and cumulative culture allowed for the accumulation and rapid spread of beneficial innovations between individuals and groups. The enhanced abilities to learn from and cooperate with others became a universal tool, removing the need to evolve specific biological organs for specific environmental challenges. These human traits likely evolved as a response to increasing high-frequency climate changes on the millennial and submillennial scales during the Pleistocene. Once the abilities for cumulative culture and extended cooperation were in place, a suite of subsequent evolutionary changes became possible and likely unavoidable."

Tuesday, May 25, 2021

The Secret of Holobionts: How Excessive Efficiency can Kill


Five minutes are enough to take a look at this amazing video. It is extremely well done and it tells you about things that you would never have suspected. How can it be that trees exist? Well, it turns out that their metabolism is truly alien and it exploits physical phenomena that you wouldn't have imagined could be used in that way. But Mother Gaia has many tricks!

One point that has fascinated me most is how this behavior of threes highlights a fundamental characteristic of holobionts: the individual organisms that form the holobiont do not act with a purpose, they do not have "in mind" to benefit the group. But, if it is true that what's good for the hive is good for the bee, also the reverse is often true. And especially in this case. 

Trees pump water by evaporating water, which means they lose most of it. From the video, you'll learn that just about 5% of the pumped water is used by the tree for its needs. The rest evaporates away -- it is the process of evapotranspiration. 

So, trees are highly inefficient pumping machines. But, curiously, this inefficiency is what benefits the forest. This huge evaporation is what puts in motion another pump: the biotic pump. It is a mechanism that generates a depression that, in turn, pulls water from the humid atmosphere near the sea all the way to the inner areas of the forest. Without this mechanism, forests could hardly exist inland. 

If trees were 100% efficient, they would evaporate nothing and the forest would die. I think there is a deep message here, not valid just for forests: too high efficiency can kill. Living is sharing, and if there is no sharing there is no life.





Ugo Bardi is a member of the Club of Rome, faculty member of the University of Florence, and the author of "Extracted" (Chelsea Green 2014), "The Seneca Effect" (Springer 2017), and Before the Collapse (Springer 2019)