Strangely organic: navigation is more than genes
Eric Cassell’s new book Animal algorithms tackles a topic often overlooked in discussions of origins due to its complexity: instinct.
We sometimes label difficult concepts as placeholders for ignorance. Instinct is one such label. When we say that a garden bird instinctively knows how to build its intricate nest, are we talking about real understanding? Where is the bird’s knowledge stored? How does he express himself?
There are cases that seem to require inherited know-how. How does a sea turtle “naturally” swim to its feeding ground hundreds of miles through murky waters and return to its exact nesting beach 35 years later? How do Pacific Golden Plover chicks find the Hawaiian Islands, mere dots in the ocean with no trace, having never been there before? How do monarch butterflies in Canada reach the same trees in Mexico that their great-grandparents overwintered on? Some of these natural miracles cannot be easily dismissed with other labels such as “map meaning” or other art terms.
Cassell opens his book by elaborating on the history and philosophy of the term instinct, now called the science of ethology, and delimiting the requirements to qualify a behavior as instinctive or innate. Then it offers readers a series of mind-blowing chapters about bees, ants, birds, turtles, termites, and other creatures that excel in navigation and other behavioral feats. Regarding navigation, for example, he lists six strategies for returning to a starting point. An amazing thing is that these strategies can be found at work in completely independent organisms, from mammals to reptiles to insects. How were these “algorithms” programmed into an ant brain? A bigger brain doesn’t seem necessary to do the job. And how did organisms learn to use the sensory tools at their disposal, such as the Earth’s magnetic field (which we humans barely experience), star positions, the sun’s compass, or exquisite olfactory cues? Cassell’s book is welcome reading providing hours of amazement. This article takes a look at some news that adds to the wonder.
Stroll without getting lost
The National Zoo and the Smithsonian’s Institute for Conservation Biology published an article about three species of arctic birds called skuas that never seem to get lost. Reminiscent of Illustra’s history in Flight about arctic terns, where a team used geologists to find that terns take alternate paths to feeding grounds in Antarctica, scientists used loggers on these birds to find that they also vary their routes. “These birds connect the world,” they exclaimed: “Technological biologging tracking of Nearctic seabirds surprises scientists with diverse migratory routes from a shared breeding site.” The paper in Ecology and evolution by Harrison et al., “Congeneric seabirds that reproduce symmetrically (Stercoraire spp.) from the Canadian Arctic migrate to four oceans,” explains why they were surprised.
Here we report three related seabirds species which migrated across four oceans from sympatric breeding at a nesting site in the central Canadian High Arctic. [Emphasis added.]
They spawn next to each other, but then separate in four ways, roaming the Pacific, Atlantic, and even Indian oceans, as shown in Figure 1 of the open access article. When they think about food, they may compete with arctic terns, but when love is in the air thanks to hormones activated by circadian rhythms, they know the way home and how to get together.
News from Rockefeller University offers to explain this phenomenon. See “How a fly’s brain calculates its position in space”. An illustration caption reads: “The brains of flies are able to perform vector math to calculate the direction of travel. How many of us use this ability on the fly? This is a big challenge for a small fly that is easily blown away.
Navigation doesn’t always go to plan – a flying lesson learns the hard way, when a strong headwind pushes them backwards in defiance of their forward-beating wings. Fish swimming upstream, crabs scurrying to the side, and even humans hanging left while looking right face similar challenges. How the brain calculates the direction an animal is moving when the head is pointing one way and the body is moving another is a mystery in neuroscience.
A new study makes significant progress in solving this mystery by reporting that the fly’s brain has a set of neurons that signal the direction the body is moving, regardless of which direction the head is pointing. The findings, published in Nature, also describe in detail how the fly brain calculates this signal from more basic sensory inputs.
This – in a fly brain? How about the brain of a mosquito or a midge? They must also have this ability. Rockefeller scientists can describe what is happening, but do they really explain it? How did neuronal cells learn to do “mental calculations” involving vector calculus?
Vector math is more than just an analogy for the current calculation. On the contrary, the brain of the fly seems to be literally performing vector operations. In this circuit, the populations of neurons explicitly represent the vectors as waves of activity, with the position of the wave representing the angle of the vector 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 literally added vectors.
rats in the dark
Another totally different organism—a mammal—does calculations in its brain: the rat. A paper in Nature by Poo et al., “Spatial maps in the piriform cortex during olfactory navigation”, tackles the mystery of how rats know how to find their way in the dark. Their keen sense of smell is an important clue, but a sense that doesn’t match a brain that knows how to use data wouldn’t help. Here is what they found:
Smells are a fundamental part of the sensory environment used by animals to guide behaviors such as foraging and navigation. Primary olfactory (piriform) cortex is considered the primary cortical region for encoding odor identity. Here, using neural ensemble recordings in freely moving rats performing an olfactory spatial choice task, we show that the neurons of the posterior piriform cortex carry a robust spatial representation of the environment. Piriform spatial representations have characteristics of a learned cognitive map, being most prominent near scent ports, stable in all behavioral contexts and independent of the olfactory drive or the availability of rewards.
It’s 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 continuously as new clues are encountered and to calculate routes back home. Doing this within the walls of your home is probably easier than doing it in the wild, where the 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 of animal algorithms, Darwinism is the least likely candidate. It shows irreducible complexity along a whole new axis.
In a book in progress online, Evolution as it was meant to be, the biologist Stephen L. Talbott criticizes his Darwinist colleagues for not having taken into account the holistic organism in their mechanistic theories. He points out that “Each organism composes its life as a finalized and living story.Talbott is part of a “new path” of the evolutionary movement at the Nature Institute. He is to be commended for his very gentle but forceful dismissal of neo-Darwinism and his understanding of the problems facing the old method of explanation.
Proponents of intelligent design can learn from this holistic approach to the body. A rat, bird or fly is more than the sum of its parts. You could put all the pieces 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 amazing and vivid life. Let’s never oversimplify it or feel unsatisfied when we just have the right parts list.