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Holobionts: a new Paradigm to Understand the Role of Humankind in the Ecosystem

You are a holobiont, I am a holobiont, we are all holobionts. "Holobiont" means, literally, "whole living creature." It ...

Showing posts with label Symbiosis. Show all posts
Showing posts with label Symbiosis. Show all posts

Saturday, August 26, 2023

Lichens and Lichen Lovers. Holobionts Everywhere

 

Irene, a young biologist from Abbadia San Salvatore, embraces a beech tree growing on the slope of the Amiata Mountain in Tuscany, Italy. Note the white lichens growing on the surface. In addition to being a tree lover, Irene is also a lichen lover. And a holobiont, too. 


"Life did not take over the globe by combat, but by networking" -- Lynn Margulis, 1996


It is not so easy to find fellow lichen lovers. Lichens are so common and yet so misunderstood and ignored, despite being the quintessential example of a holobiont. They are creatures formed of two completely different species, a fungus and an alga (or a cyanobacterium, not the same thing as an alga, but functioning in a similar way). Algae and cyanobacteria are photosynthetic organisms that provide food for the fungus. The fungus, in turn, digs up mineral nutrients from the substrate and provides them to the algae/cyanobacteria. A perfect example of symbiosis, lichens have existed for hundreds of millions of years, possibly billions of years, and they probably were the first organisms to colonize the land in very ancient times. 

Once you discover lichens, you can't avoid being fascinated by their incredible variety of shapes and colors. They can have tiny, leafless branches (fruticose), flat leaf-like structures (foliose); they may form  a crust that adheres to the substrate, (crustose), have a powder-like appearance (leprose); and more. They give you some ideas of the overall health conditions of the biome in which they appear, especially if they appear in the foliose state. Some of them are edible and they have been appreciated as food by many traditional culture and also by reindeer. Below, a print shows Japanese lichen collectors


In our culture, lichen lovers are a little rare, but they do exist, and when they find each other they may engage in lyrical appreciations of the lichens they observe, as I did when I met Irene, in the woods of the Amiata mountains. There is a facebook site on lichens (unfortunately it has not been updated during the past three years), an active "società lichenologica italiana", a "British Lichen Society,"  and you can surely find many more sites on the subject by searching the Web. But the mere fact of seeing these little creatures for what they are is a source of endless wonder. You don't need to be in the wild. You can find plenty of lichens anywhere in urbanized areas. 

Here are some white lichens growing on the nearly forgotten tomb of Vernon Lee (1856- 1935) British writer and poet who lived most of her life in Tuscany. Poetry is a form of virtual holobiont growing in the mind. 



h/t Irene Mazza, Cinzia Mammolotti, and Miguel Martinez



 

Tuesday, January 26, 2021

The Holobiont Explained. What it is, how it functions, how it came to exist

 


 

In this clip, I do my best to explain the concept of "Holobiont," popularized first by Lynn Margulis in 1999 with her book "Symbiotic Planet." It is a powerful concept to explain how we relate with our surroundings: the whole ecosystem and our fellow human beings. If we ever arrive to assimilate this idea into the general way of thinking, we have hope to stop the aggression on everything not human (or considered not human enough) and live in peace on this planet.



Saturday, December 19, 2020

The Secret of Holobionts

 


"Braiding Sweetgrass" is a wonderful book, the kind that's best digested a few pages at a time. (h/t Erik Assadourian). In it, the author, Robin Wall Kimmerer, happily moves back and forth from the uses of her Native American ancestors and her knowledge as biologist. She never uses the concept of "holobiont," but the book teems of holobionts on almost every page.
 
I am about halfway through it, and the book remains full of surprises. Here is what I read this morning, while drinking my coffee. It is about how the ancient Native Americans had found a way to optimize their plots of land by planting together three different seeds: corn, beans, and squash, poetically referred to as the "Three Sisters." Kimmerer goes on describing the details of exquisitely intricate ways in which these three species collaborate with each other, maximizing the supplying of nutrients to all three. She says.
 
"It’s tempting to imagine that these three are deliberate in working together, and perhaps they are. But the beauty of the partnership is that each plant does what it does in order to increase its own growth. But as it happens, when the individuals flourish, so does the whole. In reciprocity, we fill our spirits as well as our bellies."
 
And that's the true secret of holobionts.