Chapter 2. Biological Eye  Designs

Chapter 3. Eye
 Design Illustrations
A. Plant light sensing
1. Grass, simple vines, 
and stems
2. Flowers
B. Lower animal eyes
1. Flatworms
2. Clams and Scallops 
3. Nautilus
4. Shrimp
5. Crab
6. Octopus and 
   giant squid
7. Spiders
8. Scorpions
8. Brittle Star 
C. Insect eyes 
1. Bees
2. Dragonflies
3. Butterflies
4. Flies
5. Ants
6. Moths
7. Beetles
8. Wasp
D. Fish eyes 
1. Shark
2. Flounder
3. Four-eyed fish 
E. Amphibian eyes
1. Frog
2. Salamander
F. Reptile eyes
1. Boa constrictor 
2. Rattle snake
3. Lizard
4. Turtle
5. Crocodile and 
    alligators
G. Bird eyes
1. Eagles
2. Hummingbirds
3. Owls
4. Ostrich
5. Cormorants
H. Mammal eyes
1. Whales
2. Elephants
3. Lions, tigers, and 
   other cats
4. Monkeys
5. Rats and mice
6. Bats
7. Tarsier
I. Human eyes
1. Iris
2. Lens
3. Retina

Chapter 4. Eye 
 Reproduction

Chapter 5. Optical 
 Systems Design 

Chapter 6. The Eye Designer

Related Links

Appendix A - Slide Show & Conference Speech by Curt Deckert

Appendix B - Conference Speech by Curt Deckert

Appendix C - Comments From Our Readers

Appendix D - Panicked Evolutionists: The Stephen Meyer Controversy
 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

EYE DESIGN BOOK
Chapter 3
Section B
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3. EYE DESIGN ILLUSTRATIONS
B. Lower animal eyes
Lower animal eye designs are extremely creative and diverse, compared to complex animal eyes. They include variations of all of the major optical design categories that we can sample from categories already discussed in section II. The primary function of the least-complicated lower-animal eyes is to provide indications of the environmental light intensity for sensing danger or for food gathering. For most simple eyes, this is their main function. Some simple eyes do not even have a pinhole optical element to form a simple image.

1.Flatworms and other Worms      The flatworm has very simple eyes. It provides one example of small pinhole optics with a limited number of image detectors. Its eyes are among the smallest simple eyes. It is paradoxical that the flatworm even has an eye, because its brain is so small. Thus, its visual image processing capability is quite limited with a very crude image in contrast to the human eye. Worms don't need camera-type eyes to function in their less complex role. Tapeworms don't have eyes since they live in the digestive tract of other animals.

2. Clams and Scallop       Some shellfish have rows of small eye sensors inside the outer shell structure, therefore, the shell must be open for it to see. The clam's eye design is small and simple, relative to its size, compared to most aquatic animal eyes. However, its eyes use a curved concave mirror design approach. This is quite advanced optically, as compared to the pinhole design of the flatworm eye. The clam concave mirror, with its semi-transparent retina, is a more efficient eye than that of the flat-worm. Its optics provide better resolution for defense to detect an enemy in time for clams to close  their shell and flush water through their system to move away from danger.      Scallop eyes also use reflective mirror optics to gather light for the sensors of each small retina. Their eyes are very sensitive to movement or changes of light. It is questionable whether they process the total output of their rows of eyes into a single image. When a scallop senses selected rapid movements, it closes its shell over its eyes for protection. (P. 322, Readers Digest, Exploring the Secrets of Nature, 1994)       The interesting detail of the scallop eye is shown in Figure 3.5a Scallop Eye (Reference: plate 1e, p. 117, Animal Eyes, Michael F. Land, Dan-Eric Nilsson, Oxford Animal Biology series, Oxford University Press, 2002- Please see their book for more details )

Figure 3.5 Scallop Eyes (Like Fig. 2-8) Figure 3.5a Scallop Eye Figure 3.6 Nautilus Eye (Like Fig. 2-6).

3. Nautilus
      The nautilus (Fig 3.6) is a small mollusk with squid-like tentacles. It is one of the better examples of animals with medium-resolution pinhole optics, which require more light than camera-type eyes, in order to see quality images. 
     Since the nautilus is able to see polarized light to determine their course of direction, they navigate with respect to sunlight. Their resolution compares to the eyes of some larger animals and man-made vision systems. Since the nautilus has complex arms to control, it requires more visual information than less complex animals such as flatworms. (P. 281, Readers Digest, Exploring the Secrets of Nature, 1994)

4. Shrimp
      Some crustaceans, such as shrimp, have light-sensitive sensors on their bodies and tails in addition to their primary eyes. Shrimp eyes appear to be more complex than those of many small animals such as the nautilus. They use multiple eye facets to sense specific areas of a scene. In addition, they use a reflecting superposition optical approach, which requires a considerable amount of image processing in their small brain. One might ask why a reflecting optical system was used for shrimp eye design. 

As they learn more of their unique roles, future scientists will  discover an answer.  New studies of shrimp eyes show them to have complex  vision systems with a wide variety of color capabilities using a variety of pigments distributed on the light-sensitive parts of their bodies. (P. 189, Readers Digest, Exploring the Secrets of Nature, 1994)

Figure 3.7 Shrimp Eyes.

5. Crab       Crabs have eyes that use some reflection optics along with refractive optics. They need a unique vision system because they have many enemies to define. For example, a horseshoe crab accepts light polarized by water differently than it does light that is not polarized. Because of this ability it can sense the direction of sunlight.  The ancient trilobite eye may be similar to that of the present horseshoe  crab because both have  a very early history in similar fossils.        The king crab has a refractive lens above a compound type of eye to improve optical correction and provide some protection for the compound eye. This is another primitive creature whose eye lens arrangement would be unlikely for natural selection and mutation to design, develop and integrate from less complicated eyes. (Fig 3.8 from p 91 middle, Readers Digest, Exploring the Secrets of Nature, 1994) (Fig 3.8b a M. Westermeier Photograph)

Figure 3.8a Hermit Crab Eyes (Like Fig. 2-19) Figure 3.8b Crab Eyes

6. Octopus and giant squids      The octopus has a fairly advanced camera type eye, with an active rectangular iris which contracts to a narrow slit. It can focus its eye lens for near and far vision, but does not have well-defined vision, like humans. This intelligent animal needs adjustable focus eyesight to provide a basis of control for all its arms, as well as look for food and watch for predators.       The giant squid eye is amazingly well developed, with fairly good vision. Since the giant squid is about 180 feet long, it has the largest biological eyes in the world. Its eyes are about 100 times as large as human eyes. Like many eyes, its light-sensitive cells point toward the light, rather than away from it as ours do. Its image processing is well beyond that of many man-made robots. This eye has both a wide field of view and smaller areas of increased resolution. It sees blue-green light well, because its eye pigment color passes blue-green light better than other colors. The eye can also detect polarized light to determine the direction of sunlight. These would be interesting eyes to study, but they are difficult to obtain. Now we get into some land-based versions of small simple eyes.      The Octopus Eye shown in Figure 3.9c has a very interesting slit pupil. It also indicates an interesting design. (Reference: plate 1c, p. 117, Animal Eyes, Michael F. Land, Dan-Eric Nilsson, Oxford Animal Biology series, Oxford University Press, 2002- Please see their book for more details ) 7. Spiders      Spiders have simple eyes, compared to the compound eyes of many insects. Spiders with only six eyes do not have primary eyes. These include daddy longlegs and many weaving spiders. In spiders that have eight eyes, the number of eyes does not necessarily classify complexity or define a more advanced vision system. For example, the wolf spider has multiple eyes that have various roles. Some provide forward vision while others may scan to provide for peripheral vision. The eye signals going to the brain are combined to provide peripheral vision, distance estimating,and image formation. Spiders do not have complex lens focusing, but they have multiple eyes for limited color vision at different distances. Some spiders also detect polarized light. Eyes of some spiders have a narrow field in one direction, but they may also be able to scan in that direction by moving the eye.       Their visual pigments transmit in the ultraviolet and green-spectral regions. Spider image processing is astounding. Their brain processes several optical fields of different angular dimensions at the same time. It is really amazing that their small brains carry out complex image processing approaching that of complex man-made multi-sensor weapon or robotic systems.      The black widow spider could be a true stealth weapon, if it could be controlled by man at some  reasonable cost. It has multiple eyes for fixed wide-field vision to see enemies, find food, and to do close work in building webs. Most spiders do not have good vision at longer distances. Their eyes are like camera eyes, but they do not focus as well as modern cameras. (Figure 3.10a, p.24 upper left, Readers Digest, Exploring the Secrets of Nature, 1994) (Figure 3.10b courtesy of www.pbrc.hawaii.edu/bemf (c)MicroAngela Black & white images colored for visual effect.)      A few spiders see in very low levels of light, which indicates unique vision capabilities.  One example is the net casting spider (fig3-10c), which can see about 2,000 times better than jumping spider. To achieve this capability, it has eight eyes. At least one pair of these eyes has an f/stop (like control of the effective aperture of camera optics) of approximately f/0.58. This is equivalent to a very fast lens useful for detecting low levels of light. It is very difficult to design. This is actually approaching an optical limit for a camera type of eye lens design. (P. 170 upper, Readers Digest, Exploring the Secrets of Nature, 1994)

Figure 3.9a Giant Pacific  Octopus Eye.  by Bruce Chambers Figure 3.9b Octopus Eye. M. Westermeier Photograph Figure 3.9b Octopus Eye. Figure 3.10a Typical  Spider Eyes. Figure 3.10b Jumping  Spider Eyes. Fig 3.10c Net  Casting Spider

In general, spider eyes have very creative optical designs. They appear to have been designed for specific purposes. Although spiders are not insects, some of their small, less-complex eyes are somewhat similar to some insect eyes facets.       Figure 3. 10d. is a spider photo by Geoff Woodard, who has a number of excellent insect and other related photos on the web. This photo illustrates a spider with four eyes to note the diversity of spider eye arrangements.      In general, spider eyes have very creative optical designs. They appear to have been designed for specific purposes. Although spiders are not insects, some of their small, less-complex eyes are somewhat similar to some insect eyes facets.       Figure 3.10e Spider Eyes. Note the variation in Spider eye configurations. This photograph was done with a scanning electron beam microscope for an ugly bug contest. (reference:Biophotonics International, June 2002, page 86) 8. Scorpions      Scorpion eye design is really different in that they may have zero to twelve eyes. The average is about eight for most of the common types. Some eyes are arranged in three widely-spaced clusters. Because they have potent stingers it is expected that their eyes have not been studied up close in nature as much as other animals. They work at night. When you shine UV light on them they appear to be fluorescent. They do not see as well as many animals, but they sense shock waves with two of their feet.      Scorpions have four pair of walking legs, one pair of pincers, a pair of appendages to act as jaws, and another pair having vibration-sensing ability. They can orient their stinger or eyes toward the source of the vibration or shock wave. (P. 166 lower, Readers Digest, Exploring the Secrets of Nature, 1994)  9. Brittle Star      The brittle star is a seemingly primitive creature with an advanced distributed vision system that can detect and react to light. Its vision system may be similar to that in some other plants and animals, but it appears to be uniquely designed. It has to process information in a different manner than most other Eyes.

Figure 3.10d Spider Figure 3.10e Spider Eyes Figure 3.11 Scorpion Eyes Figure 3.12b Brittle Star -  day and night

Distributed processing indicates intelligence to do the optical processing to control all of its members for fast motion and  provide for changing of color form day to night. Its nodule-like eyes form a micro-lens array that also act as part of the surface structure. This somewhat diffuse vision system has to control complex movements and provide signals for overall color changing.      There is current research to study the optical design and construction of the large amount of eyes that cover much of its body. Because of possible current applications in the communication industry requiring their fine focusing ability, these lenses are good evidence of advanced lens array design. It wasn't long ago that we did not appreciate this optical design that illustrates a strong example of intelligent design that has survived many years. The following illustrations give some indication of the overall design. (Figure 3.12b - d from p. 20, R Fitzgerald, These Stars Have Eyes, Physics Today, Oct 2001) effect.)

Figure 3.12c Brittle Star Detail Figure 3.12e Brittle Star M. Westermeier Photograph

Figure 3.12d Brittle Star  Fine Detail Figure 3.12f Brittle Star  by Schayeri

Figure 3.12g Brittle Star  Fossil

     Click the following link for a good example of why scientists use the word design when discussing the profound complexity of eyes, even in a very early organism like the trilobite, extinct for more than 200,000 years. The advantage of good eye design in "The Trilobite Eye" by S. M. Gon III

     If one were looking at the brittle star from the point of view of evolution one might suspect that you would see an eye something like that of a squid or shellfish eye. From what we have seen this far, what would drive evolution in this direction?
     How would you design a replication system for this multiple eye vision system?

     Although there are many interesting eyes, the following area of design application includes many variations of different eye designs within a variety of insects. These illustrate some of the significant variations in insect eye designs.