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Uncannily Organic: Navigation Is More than Genes

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Photo: A bowerbird, by Holgi via Pixabay.

Eric Cassell’s new book Animal Algorithms tackles a subject often passed over in discussions of origins because of its complexity: instinct.

We give difficult concepts labels sometimes as placeholders for ignorance. Instinct is one of those labels. When we say a bowerbird instinctively knows how to build its complex nest, are we speaking from genuine understanding? Where is the bird’s knowledge stored? How is it expressed? 

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.

Cassell opens his book by elaborating on the history and philosophy of the term instinct, called now the science of ethology, and delineating requirements for calling a behavior instinctive or innate. Then he treats readers to a mind-boggling series of chapters about bees, ants, birds, turtles, termites, and other creatures that excel at navigation and other behavioral feats. Regarding navigation, for instance, he lists six strategies for getting back to a starting point. An amazing thing is that these strategies can be found at work in completely unrelated organisms, from mammals to reptiles to insects. How did these “algorithms” get programmed into an ant brain? A bigger brain does not seem to be necessary to get the job done. And how did organisms learn to use the sensory tools at their disposal, such as the Earth’s magnetic field (which we humans hardly experience), the positions of the stars, the sun compass, or exquisite olfactory cues? Cassell’s book is a welcome read offering hours of astonishment. This article looks at a few news items that add to the wonder.

Wandering Without Getting Lost

The Smithsonian’s National Zoo and Conservation Biology Institute published an article about three species of Arctic birds called jaegers that never seem to get lost. Reminiscent of Illustra’s story in Flight about Arctic terns, wherein a team used geologgers to discover that the terns took alternate paths to the Antarctic feeding grounds, scientists used loggers on these birds to find that they also vary their routes. “These birds connect the world,” they exclaimed: “Biologging Tech Tracking of Nearctic Seabirds Surprise Scientists with Diverse Migratory Paths from Shared Breeding Site.” The paper in Ecology and Evolution by Harrison et al., “Sympatrically breeding congeneric seabirds (Stercorarius spp.) from Arctic Canada migrate to four oceans,” tells why they were surprised. 

Here, we report on three related seabird species that migrated across four oceans following sympatric breeding at a central Canadian high Arctic nesting location. [Emphasis added.]

They breed near each other, but then split four ways, wandering all over the Pacific, Atlantic, and even Indian oceans, as Figure 1 in the open-access paper shows. When food is on their mind, they can give Arctic terns some competition, but when love is in the air through hormones activating by circadian rhythms, they know the way home and how to arrive together.

Tiny Calculator

News from Rockefeller University offers to explain this phenomenon. See, “How a fly’s brain calculates its position in space.” An illustration caption says, “Fly brains are capable of performing vector math to calculate direction of travel.” How many of us use that ability on the fly? This is a big challenge for a tiny fly that is easily blown off course.

Navigation doesn’t always go as planned — a lesson that flies learn the hard way, when a strong headwind shunts them backward in defiance of their forward-beating wings. Fish swimming upriver, crabs scuttling sideways, and even humans hanging a left while looking to the right contend with similar challenges. How the brain calculates an animal’s direction of travel when the head is pointing one way and the body is moving in another is a mystery in neuroscience.   

A new study makes significant headway on solving this mystery by reporting that the fly brain has a set of neurons that signal the direction in which the body is traveling, regardless of the direction in which the head is pointing. The findings, published in Nature, also describe in detail how the fly’s brain calculates this signal from more basic sensory inputs.  

This — in a fly brain? How about the brain of a mosquito or gnat? They must have this ability, too. Rockefeller scientists can describe what happens, but do they really explain it? How did neuron cells learn to do “mental math” involving vector calculus? 

Vector math is more than just an analogy for the computation taking place. Rather, the fly brain appears to be literally performing vector operations. In this circuit, populations of neurons explicitly represent vectors as waves of activity, with the position of the wave representing the vector’s angle and the height of the wave representing its length. The researchers even tested this idea by precisely manipulating the length of the four, input vectors and showing that the output vector changes just as it would if flies were literally adding up vectors.

Rats in the Dark

Another totally different organism — a mammal — does math in its brain: the rat. A paper in Nature by Poo et al., “Spatial maps in piriform cortex during olfactory navigation,” tackles the mystery of how rats know their way around in the dark. Their keen sense of smell is one important cue, but a sense that doesn’t map to a brain that knows how to utilize data would not be any help. Here’s what they found:

Odours are a fundamental part of the sensory environment used by animals to guide behaviours such as foraging and navigation. Primary olfactory (piriform) cortex is thought to be the main cortical region for encoding odour identity. Here, using neural ensemble recordings in freely moving rats performing an odour-cued spatial choice task, we show that posterior piriform cortex neurons carry a robust spatial representation of the environment. Piriform spatial representations have features of a learned cognitive map, being most prominent near odour ports, stable across behavioural contexts and independent of olfactory drive or reward availability.

This is surely admirable experimental work, but it only scratches the surface of the wonder behind the ability to form maps in the brain. The animal must be able to update its map constantly as new cues are encountered and calculate paths back home. Doing this in the walls of your house is probably easier than doing it in the wild, where olfactory cues can be overwhelming.

The Holistic Organism 

How do evolutionists explain these exquisite abilities? They don’t. Cassell gently but repeatedly shows that of the possible causes for animal algorithms, Darwinism is the least likely contender. He shows irreducible complexity along a whole new axis. 

In a book-in-progress online, Evolution as It Was Meant to Be, biologist Stephen L. Talbott takes his fellow Darwinists to task for their failure to consider the holistic organism in their mechanistic theories. He stresses that “Every organism composes its life as a purposive and living narrative.” Talbott is part of a “new way” of evolution movement at the Nature Institute. He is to be commended for his very gentle but forceful take-down of neo-Darwinism and his understanding of the problems confronting the old way of explanation.

Intelligent design advocates can learn from this holistic approach to the organism. A rat, a bird, or a fly is much more than the sum of its parts. You could put all the parts together with all the right connections, and program it with all the right genetic software, and it would still be dead. Our world is a world of astonishing, vivid life. Let us never oversimplify it or feel satisfied when we merely have the parts list right.