Friday 3 July 2015
SMARTS Update: Those Sexy Eyes
My new book SMARTS delves into evolution, a process that not only made life smart, but is itself a form of ever-more intelligent behavior operating at a vast scale. Most of us think of it as a theory about why species change over time, but it is so much more. For example, in the last twenty years it has become a computation method used to produce programming for smarter robots. This capaciousness is the mark of a theory so insightful about the fundamental operating principles of nature that it can be used in fields very far removed from its origin.
As SMARTS recounts,when Darwin and his competitor Alfred Wallace first published their argument about why species change in 1859, they argued that it comes about through chance mutations which prove useful as circumstances shift. Competitors without the useful mutation die out, those that have it have more successful progeny. The nub of their argument is that evolution is a random, slow, and competitive process. This became evolutionary theory's first orthodoxy. There have been radical revisions since.
At the turn of the 20th century a Russian scientist working with soil microbes said wait a minute, wait a minute, I see other, quicker means of species change going on that look more like merger and acquisition, cooperation and coordination, not slow, random mutation. As this was a very unorthodox claim, it was ignored for decades. Less threatening revisions were made in the middle of the 20th Century to take into account new information from the burgeoning field of genetics. Then punctuated equilibrium came along. Its proponents (especially Stephen J. Gould) argued that after each of the major die-offs that have occurred in the history of life, many survivor species changed quickly to fill suddenly available ecological niches.
Those who promoted punctuated equilibrium took hard knocks from orthodox evolutionists. The American microbiologist, Lynn Margulis, endured much worse when she brought the Russian theory back to life in the late 1960s. Her critics said she was crazy.
I first heard of Margulis as the co-founder, with James Lovelock, of the Gaia theory. Together they argued that life functions as a planetary circulatory system, mediating the chemical reactions that tie the earth's surface and oceans and atmosphere together, and by so doing, maintaining conditions suitable to sustain life. It was Margulis' observations about how early evolution worked that gave the Gaia theory real legs. Margulis argued that in the first two billion years, life on earth was mainly organized as single-celled organisms living off the transformational power of chemistry, and each other. Sometimes, instead of one cell digesting another, the two merged, learning to cooperate, coordinate, and even reproduce in concert. A merger meant the new cell acquired new capacities, making it more fit to deal with whatever might come. Eventually, Margulis said, mergers, and looser forms of cooperation, resulted in the complex animals and plants we see around us now, each organism consisting of trillions of cells with different attributes which nevertheless cooperate, each of those cells containing smaller organelles that once were free-living organisms. Margulis called this evolutionary process symbiogenesis. She insisted that it is not random, not slow, and that for a very long time it was more important in the shaping of life forms than Darwinian competition.
The howls of outrage from orthodox evolutionists only died down in the early 1980s after the bacterial origin of mitochondria, the little organelles that power animals cells, was demonstrated.
This week, a Letter appeared in the prestigious journal Nature, again demonstrating the truth of Margulis' elastic version of evolution. Gregory Gavelis, a doctoral student at the University of British Columbia working in the lab of Brian Leander, and in cooperation with two other labs at UBC, outlined the results of their remarkable research. They have found a feature that seems to function like an eye in a single-celled organism called a warnowiid.
The structures of animal eyes are so complex that Darwin's critics used them as an example to refute his random mutation theory. The eye had to have been designed by God, his critics said. Random forces could never have done it. Eyes are made of different kinds of cells which organize themselves to make a lens, cornea, iris and retina.
Warnowiids are rare and weird plankton, living proof of ancient mergers between the precursors of plants, animals, and algae. They are single-celled and have a nucleus. They carry mitochondria (like animals). They also carry plastids (like plants) that apparently originated in an ancient symbiosis with a red alga.They live in the Pacific off the coasts of BC and Japan. They are dinoflagellates (they move in the water by means of a whirling tail) and they eat other plankton which they spear with a harpoon-like structure. Warnowiids have evolved a structure which may allow each cell to 'see' the polarized light given off by its transparent plankton prey. According to a UBC press release, this ocelloid, or eye-like organelle "looks so much like a complex eye that it was originally mistaken for the eye of an animal that the plankton had eaten." According to Gavelis, it is made of a collection of organelles organized "very much like the lens, cornea, iris and retina of a multi-cellular eyes found in humans and other large animals."
UBC (and my morning newspaper) described this as an example of convergent evolution--which is how scientists explain two very distant organisms on the evolutionary bush (for example, humans and octopuses) developing the same kind of structure (a lensed eye). They did not refer to the real surprise. As the authors say in Nature, it is very strange that a single celled critter has developed a complex organelle on a par with what is seen in many-celled organisms. "Multi-cellularity is often considered a prerequisite for morphological complexity, as seen in the camera-type eyes found in several groups of animals," they wrote. Yet these warnowiids have made a similar structure using "subcellular analogues to a cornea, lens, iris and retina."
As SMARTS lays out, in the last thirty years some microbiologists have begun to focus on the complex and intelligent group behaviors displayed by very small single-celled organisms. (SMARTS describes the investigations of one scholar, James A. Shapiro, of the University of Chicago.) In labs, their behavior as isolates on plates is different from how they live in the real world struggling to find food and to reproduce. In the real world they communicate with each other and take note of their competitors. They cooperate, hunt, make war, make peace, merge and acquire just like animals and plants. In other words, they have societies.
Warnowiids are not grown on lab plates at all and are hard to find in nature. It was only when they were caught and examined very closely that their eye-like ocellids, comprising "a cornea-like layer made of mitochondria and a retinal body made of anastomosing plastids," were discovered.
If you want to have a look, click here.
So a warnowiid is a boundary-buster, making mock of all fixed ideas about how evolution works and where intelligence may be found. It is neither animal nor plant nor alga, yet it incorporates structures found in all three. It may be only one cell, yet it has found a way to arrange its even smaller organelles, normally used to make energy, to do something else entirely. In other words, the internal cooperation between formerly free-living organisms has made warnowiids into more formidable competitors.
Margulis would have been thrilled to hear of them.