Among the more recent accomplishments of science are:
• The human genome project compels us that all life is related, e. g., we all have the same genetic code.
• Ecology demonstrates that all life is connected, e. g., a single human organism actually is made of as many as 1000 species of organisms.
• Reducible complexity, e. g., the eye as an organ as well as the prairie as a system (see https://en.wikipedia.org/wiki/Irreducible_complexity for a discussion). Irreducible complexity is a tenet of ‘intelligent design/creation science.’
This latter topic is the focus of this essay. The human eye and the prairie ecosystem provide excellent examples. For more details, consider https://en.wikipedia.org/wiki/Irreducible_complexity for a generalized introduction to the concept as a debate. First let us consider the eye.
The human eye is extremely complex. It functions as a window to the world in that it provides the data used by the brain to create images. I used to describe it as working much like a camera with a brain attached but now we have cameras with brains attached that use digital technology instead of early silver technology. The digital image can be further modified by the computer in the camera or moved to another more powerful computer for potentially millions of modifications. Thus these new cameras with their brains are even better examples for comparison to the eye.
In humans, a thousand different kinds of eyes can see and form images that our brains can interpret!!! Andreas Wagner’s book (2014) entitled ‘Arrival of the Fittest: Solving Evolution’s Greatest Puzzle’ emphasizes the law of unintended consequences in that it provides examples of molecules (DNA, RNA and proteins) evolving to form thousands of varieties with a significant fraction of them retaining the ability to perform a specific function while others develop new and novel ‘unintended’ functions. The eyes of humans take this concept to the organ level, and we see thousands of kinds of human eyes—each able to provide sufficient information to the brain to permit the brain to interpret images that can be used to ascertain what is being viewed. When examining the ability of the eye to provide information for the brain, the quantity and quality of the information can be measured in a number of ways. Statistically, these abilities can be quantified and qualified and distributed along a parabolic expression known as the standard normal curve. Thus while the thousands of kinds of eyes work to some degree, we can assume that the majority of them can be defined as normal using the methods that we use to measure them, i. e. the Snellen chart, Ishihara charts, etc.
How complex are our eyes? There are many muscles involved in making visual images: 6 muscles that move the eye, 2 muscles that open the lids, a circular muscle that constricts and dilates the pupil, and a circular muscle that changes the shape of the lens for focusing. Each of these muscles is controlled by a different part of the brain, and in some cases, the parts are radically different, e. g., the nerves that control the movement of the eye (3 separate cranial nerves, III, IV and VI in the somatic efferent system) versus the autonomic nerves that control the iris diaphragm encircling the pupil (both parasympathetic and sympathetic nerves in the autonomic efferent system). All of these muscles must be coordinated in their movement by the brain in order for the eyes to provide useful information to the occipital lobes for interpretation and image generation.
The normally functioning eye is measured in a number of ways. The most common is the designation of the emmetropic eye, which is defined with an acuity of 20/20—an eye that detects at 20 feet what a designated normal eye detects at 20 feet using one of the Snellen Charts. Of course, this measurement is like many other physiological measurements, where the range of measurements can be represented as a normalized curved with the emmetropic eye as the mean, which means there are lots of eyes that are not normal (both better and worse—the worse get all the press) and yet remain able to provide enough information to the brain to permit the brain to construct an image. It is in these anomalies (mainly the worse ones have been studied) that the eye clearly demonstrates reducible complexity. Literally a thousand variations exist in human eyes—we often refer to these varieties as things that can go wrong and do go wrong with the eye, and yet the eye is capable of doing its job; however, the job may be less acceptable and require remediation in our society.
Some of the anomalies include:
1. the eyeball is too long or too short (myopia or hyperopia)
2. the lens is too weak or too strong (myopia or hyperopia)
3. the lens or cornea is wrinkled or abnormally curved (astigmatism)
4. the lens is cloudy (cataracts)
5. the intraocular fluid is under too high pressure (glaucoma)
6. quivering of the eye (nystagmus)
7. abnormal cones (color blindness—a dozen kinds)
8. damaged retina
9. diabetic nerves
10. macular degeneration.
The eye is also supplied with lachrymal (lacrimal) glands that make tears delivered by lacrhrymal ducts and drained by lachrymal canals into a nasolachrymal duct into the nasal passage. Thus the eye is constantly being washed, lubricated and nourished. Dysfunction leads to dry eye symptoms and conjunctivitis. Internal fluid dynamics (aqueous humor and vitreous humor in their respective chambers) and the tear system are dynamic unto themselves, and in this they demonstrate that human eyes are actually several systems interacting over a lifetime.
The retina (sensory part) of the human eye is an intricate structure made of 6 layers with rods and cones and a variety of nerves served by a rich blood supply. This complex tissue is highly susceptible to a number of kinds of insult. Through a complex process of photoreception, electrical impulses are generated by the photosensitive cells (rods and cones) and neurons and sent to the brain where they are sorted and used to create an image. The brain works with what information it gets and relies heavily on accumulated information to create images that obscure our blind spot and permit images to have focal points and 3 dimensions. Although we usually depend on both eyes working in concert to generate 3- dimensional images, a single eye’s image does contain information, e. g., relative image sizing, that permits the brain to create a 3-dimensional image. When examining the embryology of the eye, the formation of eye sacs and optic nerves directly off of the brain stem is obvious.
Color vision is a remarkable development as rod-like cells were coopted to function as cones in color photoreception. While some humans lack color vision altogether, most humans have some color vision; however, males often are red-green colorblind or color weak. However, these individuals have what I call a superpower in that they can do things that we normal humans cannot. For example, some of them can see what would be camouflaged to those with normal vision—a handy talent if you are looking for enemy encampments in aerial photographs or looking for animals or plants relying on camouflage to thwart predators. Further, while humans see visible light (ROYGBIV), other animals have different color spectra. Mosquitoes see colors in the infrared spectrum (otherwise perceived by our thermoreceptors), while bees see colors in the ultraviolet spectrum (all those yellow flowers in the prairie are actually ultraviolet blues with distinctive markings in their vision. But butterflies take the prize since they are credited with seeing not only the visible spectrum of humans but also both the ultraviolet and infrared spectra. Just color vision itself provides a wealth of information on the evolution of vision, and I really enjoy topics where physics, aka the study of electromagnetic waves, is intertwined with biology.
The point is the eye and the brain evolved together as a unit. Numerous papers have been written to illustrate the intimate way that they work together as well as literally thousands of examples across the animal world where eyes and brains have co-opted parts of the skeletal and muscular and glandular systems in order to accomplish their functions. Literally thousands of kinds of eyes are known, and that is not even mentioning the thousands of kinds of eyes that are found in humans. Thus the complexity of the human eye is evident and evidently the result of thousands of variations on the evolutionary theme of an eye both within our species and across the millions of animal species, with the differences between human and chimp eyes almost imperceptible and for the most part hidden within the tremendous variation of the human eyes.
The prairie is even more complex as it contains thousands of species of plants and animals (in the air, soil and water), each representing a distinctive evolutionary line as well as possessing thousands of reducibly complex organs. The prairie is a community of organisms not dissimilar to our bodies, which are now known to be ecological communities. The prairie itself appears to be a reducibly complex structure in that we can literally take it apart piece by piece all the while appreciating many of the contributions of each piece. All these pieces are interacting all the while filling ecological niches that are literally entwined in space and time. The prairie is literally destroyed when it is plowed—a literal ripping of ecosystem into shreds. Our attempts to restore this habitat literally involve reintegrating these pieces into a network and waiting to see if they will interact and begin the reconstruction of the ecosystem. Our restorations are meager compared to the original ecosystems, but they appear to work in ways that are similar to the original ecosystems—unless it gets too dry or too wet or too hot or too cold or some other extreme or combinations of extremes—then the system shows signs of stress, and fragile species literally disappear. With enough stress, e. g., an explosion of exotics, the restorations begins to function less and less like the original ecosystem. This simple comparison does not link the need for pollinators and other animals into our discussion, but their presence and roles are likewise reducibly complex.
Reducing complex phenomena is a central function of science. Whereas in medicine, the focused effort is on finding every single signaling molecule in order to give potential therapies for treating diseases, we, in ecology and prairie restoration, are involved in understanding the intricate links between organisms and between organisms and their environment. Only then can we begin to make headway in our goal of rehabilitating habitat. In both medicine and ecology, we are just beginning to make discoveries that will permit us to make better decisions. Understanding that all living things are related and connected is a start, while appreciating that the reducible complexity in nature is a result of the co-optation of seemingly unrelated structures is a central theme in the evolution of life and communities of life within ecosystems.
Posted by M. F. Vidrine