Tuesday, July 18, 2017


A while back I was on a discussion list and people were talking about biological symbiosis as a metaphor for people communicating and collaborating. As a former biologist, I felt a responsibility to respond, so I wrote a sort of quick guide to sociality in the non-human world. Several people later thanked me for the essay, so I thought I might as well post it here, in case it's helpful to anyone else.

There are quite a few biological terms that describe points along the spectrum from cooperation to shared identity.

Within the same species:

- Kin selection describes how organisms "altruistically" help other individuals that are related to them genetically. (I place "altruistically" in quotes because benefiting your genetic makeup is not what we usually think of when we think of altruism.)

- Group selection describes how larger social groups help each other and compete with other groups for survival. This one is controversial as some think it exists (E. O. Wilson is a famous proponent) and some think it's a fiction. (I think it sounds plausible, but that doesn't mean it's real.)

- Reciprocal altruism is another mechanism that can cause organisms to help each other, in a tit-for-tat way. Game theory has lots of useful names to describe how organisms and other entities interact.

- The term "culture" is used to describe the social passing on (teaching) of knowledge (such as how to make a stick into a termite-catching tool) in some non-human species. Whether this use of the term is legitimate has been under debate for a long time.

- Eusociality, or a regulated social order, exists in some insects (like bees and ants), crustaceans (some shrimp) and mammals (the naked mole rat is the famous example). In eusocial species, "queens" usually control the social order (using pheromones), with individuals being born into defined "castes" that define their choices. The colony acts in some ways as an individual, but only partly due to self-organization (since pheromonal control is not self-organization but organization).

- A colonial organism (or collective organism or superorganism) consists of individual organisms that sometimes self-organize to take on the roles of specialized "organ" cells and sometimes don't. Examples are slime molds and some kinds of sponges. Whether these things are many organisms or one depends on when and how you ask the question.

- A modular organism is one whose components have specific functions, but whose total form is essentially a Lego-like composition of modules. Plants are modular organisms. It is hard to say whether a modular organism is an organism or a very highly regulated colony.

- A clonal colony is an association among genetically identical organisms (clones) that, while seeming to be separate, are actually connected. (Think spider plants.) The most famous example of a clonal colony is Pando, a giant colony of quaking aspen in Utah that covers over 100 acres. Though Pando looks like a forest, it is actually one giant tree.

In the places where the taxonomical kingdoms meet (plants, animals, fungi, bacteria, other tiny things) there are many cases of species where it is unclear which of these mechanisms are going on. Reading about them makes your whole sense of what is individual and what is collective lose its coherence.

Between species:

- Guilds are associations among species that forage together. The species in guilds are not related, but seek similar (though not identical) food sources that are found in the same places. Guilds tend to protect each other to a minimal extent. For example, animals in guilds usually heed alarm calls of other species in the guild.

- Mobs are temporary groups that can form among species that face predation together. You might see several species of small birds joining up to mob (attack) a hawk flying overhead. These associations are opportunistic and shifting.

- Mutualism is a relationship between species that depend on each other. A perfect example of mutualism is the relationship of people with their gut bacteria. Neither of us could survive without the other.

- Parasitism is the long-standing reliance of one species on another, to the detriment of the species being relied on - though never detrimental enough to kill the species (or individual), because then the arrangement would cease to be useful to the parasite.

- Commensalism is a relationship between species where they help each other, but so indirectly that you have to look closely to notice it. Usually such indirect help passes through the environment. When a beaver builds a dam, many species such as fish, frogs, and the water fowl that eat fish and frogs gain critical habitats through the self-interested actions of the beaver, which is largely unaffected by their use of the beaver pond.

- Symbiosis is the long-standing reliance of two or more species on each other, such as the relationship between clownfish and anemones. These connections are not temporary or opportunistic or even cognitive, but develop evolutionarily, over long periods of time.

Species can pass back and forth over the boundaries between mutualism, commensalism, parasitism, and symbiosis over evolutionary time, as the costs and benefits to each species can vary. Some relationships among species are hard to classify and can depend on other factors such as the environment in which both species find themselves. Is that bird picking lice on a wildebeest's back helping or hurting? How about when it pecks a little harder and starts to drink the wildebeest's blood? How about when the lice become more dangerous to the wildebeest? It gets tricky.

- Coevolution is a situation where species affect each other's genetic evolution. Coevolution can involve any of the interactions between species mentioned here (and probably more I've forgotten to list). For example, many flower shapes and colors evolved in such a way that their pollinators could find them more easily. Mimcry is another interaction that often comes up in coevolution.

As to whether any of these terms work as metaphors for people doing positive things together: they all do, and they all don't. My advice for anyone who wants to use a metaphor from science to describe human social endeavors is: read enough about the term to understand its full implications. Explore its internal arguments. I've seen so many people "go shopping" in science for metaphors that will prove their point, then ignore what the word actually means in order to shoehorn it into whatever meaning they want it to have. As one example, people often use "coevolution" to mean cooperation. That's a mistake, because coevolution can go horribly wrong and often does.

My personal preference is to avoid metaphors that turn people into non-people, because those metaphors always tend to be, well, dehumanizing. As I see it, there are already lots of useful terms that describe people interacting with each other in positive ways. After all, we've been doing it for a while.

No comments: