Learn from Trilobite Eyes

Learn from Trilobite EyesOne of the more interesting fossils you will ever find is a trilobite. This three-lobed ocean-going creature was an arthropod related to insects and crabs. Its closest living relative is probably the horseshoe crab, although behaviorally, it may have been more like a lobster or crayfish. Today we find beautifully preserved trilobite specimens in rocks dating back to the beginning of life on Earth. What can we learn from trilobite eyes?

We can study and learn from trilobite eyes because they were made of the mineral calcite. Calcite is the same mineral that makes up limestone, so it is quite hard and efficiently preserved. In its purest form, it is perfectly clear. Calcite possesses what scientists call a double index of refraction. Because of the arrangement of atoms in calcite, light arriving at one angle passes undisturbed while light at another angle will be split into two beams.

In addition to being made of calcite, the trilobite eye was made up of a honeycomb of hexagons. There could be several thousand hexagons in the eye arranged so that light from any angle would be refracted into the animal’s eye. If it came perpendicularly, the light would go straight to the back of the eye. If it came at an angle, the double index of refraction would still bring the light to the back of the eye. There was a small wall between the hexagons so that light from the hexagons did not overlap each other. When arthropods grow, they molt their outside layer, and the new larger layer hardens. The eye material would add hexagons as the animal got larger.

This kind of eye is similar to the eye of a housefly. Like flies, trilobites would have been especially good at detecting motion. They also would not have a problem with near-sightedness or far-sightedness. Something an inch away or a mile away would both be in focus at the same time.

There is one vision problem the trilobite would have. It’s called spherical aberration. The thickness of the materials in each hexagonal lens would not be the same, and that difference could distort the image. In the trilobite eye, this problem was solved by magnesium atoms added to the calcite in a way that corrects the aberration. Modern opticians do this with what they call a doublet lens.

Scientists have observed other special features in various species of trilobites. They have found some eyeless trilobites that probably lived in areas with no light, such as very deep in the ocean. Other eyes were mounted in ball-like structures that could move. Still others were positioned so that the animals could bury themselves in the sand like a stingray while their eyes could still look out for food or enemies.

There are many lessons we can learn from trilobite eyes. The incredible complexity is a tribute to God’s wisdom and design. In this case, the complexity is of particular interest because trilobites were some of the first animals to live on this planet. That fact presents a problem for those who say complexity is a result of evolutionary forces over a very long time. Trilobites already had a sophisticated visual system when they first appeared in the fossil record in the Cambrian period 500 million years ago. Darwinistic models cannot explain the trilobite eye, but the God of the Bible can.
— John N. Clayton © 2019

Best Animal Eye

Best Animal Eye
What is the best animal eye? Engineers at the University of Illinois have been researching that question. They have now built the world’s best camera by copying that animal. Their new camera could help military drones see camouflaged or shadowed targets. Their discovery also will allow surgeons to perform many kinds of operations more accurately. They have learned all this from the animal which possesses the best eye known to science. The best animal eye belongs to a small creature known as the mantis shrimp. Here are some of the ways the mantis shrimp’s eyes are superior to all others:

The eye of a mantis shrimp has a dozen different kinds of light receptor cells so they can sense properties of light invisible to other animals. Human eyes have only three types of light receptor cells.

The mantis shrimp eye can sense polarized light which has waves that undulate in one plane. Light reflecting off of a surface is always polarized. This ability allows the mantis shrimp to see objects that would otherwise be invisible because of blending into the background.

A mantis shrimp’s eyes are constructed so that each pixel has a rhabdom which is a rodlike structure made of light receptors. The rhabdoms have threadlike structures called microvilli alternately stacked at right angles. That means the shrimp has cells in the two hemispheres of the eye which are tilted 45 degrees to each other allowing their eyes to detect four polarization directions.

The eye of the mantis shrimp can detect an extensive range of light intensities of light to dark known as the dynamic range. This means that they can see clearly even when there is a very bright area next to a very dark area.

The mantis shrimp is the only animal that can sense a full spectrum of colors and can see the polarization of each color. That means that when there is a complicated background, the animal can still get a clear image.

Electrical and computer engineer Victor Gruev and his research team have already made a camera based on the best animal eye. It has a dynamic range which is about 10,000 times higher than today’s commercial cameras. Gruev and the team are working on a commercial version of their camera. Produced in bulk quantities the improved sensors would cost only $10 each.

There seems to be little doubt that this will be the camera of the future, and science has learned how to make it by studying the best animal eye of one of God’s smallest creatures.
–John N. Clayton © 2019

Data from Scientific American, February 2019, Page 12, or online HERE.
To see our earlier report on the mantis shrimp’s visual system click HERE.

Amazing Human Eye

Amazing Human Eye
Eyes are among the great challenges to those who insist that unguided, naturalistic evolution created all living things. Eyes are complex devices that display engineering design skill. A significant problem for naturalists is that some very complex eyes appear early in the fossil record, such as the trilobite eye. Each animal has eyes well-designed for the life they live. That is certainly true of the amazing human eye.

Many things about human eyes make them amazing. One of those is the cornea, the clear front covering of our eyes. Corneas must be perfectly clear to allow light to pass through for an unobstructed view of the world around us. Because of the need for complete transparency, they have no blood vessels. Our corneas get their nourishment from the aqueous humor (the liquid inside the eye) and the tear fluid on the outside. They get oxygen from direct contact with the air.

Corneas must be designed to fit a curving surface full of a fluid which maintains the critical pressure inside the eye. However, there is a problem with the cornea being exposed to the air with all of the contaminants it contains – pollen, dust, chemicals, and grit. Corneas can become scratched. Over time, any surface exposed to dirt and grit, and sometimes bumps and blows, can get tiny scratches. How is it possible for corneas to remain transparent with so much abuse?

When you cut your skin, as the cut heals, scar tissue forms. Scratches in our corneas must heal without scar tissue. When the outer layer of the cornea gets scratched, the surrounding cells move toward one another and close the scratch leaving no scar tissue. This is only one feature of corneas which consist of five different layers each having an important function and showing evidence of design.

Think what it would be like if scar tissue formed every time the surface of our corneas got scratched. By the time we reached middle-age, we would certainly be looking through cloudy lenses. If you can read this, you should be thankful for just one of the features of the amazing human eye!
–Roland Earnst © 2018