A second part of the discussion between Eric Cassell, author of Animal Algorithms: Evolution and the Mysterious Origin of Ingenious Instincts (2021), and Casey Luskin on such questions as how do Monarch butterflies from Canada get to the same trees in Mexico as their great-grandparents landed in?
Casey Luskin: We already talked about this a little bit, the idea of path integration, where animals keep track of their compass heading and distance traveled so they can fly directly home — but not necessarily along the path that they took. And you say that they can do this without necessarily following landmarks. You talk about honeybees and their ability to navigate using the sun’s angle. So they can learn how to navigate using the sun’s angle at different times of day to find their way home, regardless of what time it is. Or they can use polarized light by studying different regions of the sky to determine the position of the sun. (21:23)
This requires doing trigonometry, spherical geometry, and other complex math. They [insects] have a brain with a million neurons and I have supposedly a hundred billion neurons in my brain. And I don’t think I can do those kinds of calculations in my brain. I find this all incredible.
There are cases that seem to require inherited know-how. How does a sea turtle “innately” know how to swim to its feeding area hundreds of miles through murky water and return to its exact nesting beach 35 years later? How do chicks of the Pacific golden plover find the Hawaiian Islands, mere specks in the trackless ocean, never having been there before? How do monarch butterflies in Canada get to the same trees in Mexico their great-grandparents wintered on? Some of these natural miracles cannot be dismissed easily with other labels like a “map sense” or other terms of art.
Evolution News, “Uncannily Organic: Navigation Is More than Genes” at Evolution News and Science Today (January 26, 2022)
Casey Luskin: So the fact that these kinds of features evolved really just makes me wonder, how could they arise by an unguided, stepwise Darwinian process. I’d love to see a stepwise evolutionary explanation for this, if it exists. And I’m wondering, are you aware of attempts to explain behaviors like this through a standard typical Darwinian model? (21:58)
Eric Cassell: The short answer is no. I have not come across any name in the literature about those kinds of behaviors and how they could have evolved. I think it’s such a daunting task to try to explain how something is sophisticated as an algorithm, particularly a mathematical type of algorithm, could have evolved in the first place. It has to be in the genome somehow. And then that information that’s in the genome has to be encoded in a neural network when the brain develops, and then it all has to be run, as the animal is performing the behavior. So there’s a lot of unanswered questions about how all that takes place. (22:42)
News, “Can animal behavior simply be transferred into the genome?” at Mind Matters News (January 31, 2022)
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Takehome: Navigator Eric Cassell thinks that the hundreds of thousands of genetic changes that turn solitary insects into social ones cannot be random mutations.
Here’s the earlier portion of the episode, with transcript and notes.
Neuroscience mystery: How do tiny brains enable complex behavior? Eric Cassell notes that insects with brains of only a million neurons exhibit principles found only in the most advanced manmade navigation systems. How? Cassell argues in his recent book that an algorithm model is best suited to understanding the insect mind — and that of many animals.
You may also wish to read: A navigator asks animals: How do you find your way? The results are amazing. Many life forms do math they know nothing about. The question Eric Cassell: asks is, how, exactly, is so much information packed into simple brain with so few neurons?