Page 95 - Design in Nature

Communication and Target Location Systems 93

a number of different pieces assembled together in very delicate balances
and is a clear sign of "design". The eye is created flawlessly.
Biochemist Michael Behe comments on the chemistry of the eye and the
theory of evolution in his book Darwin's Black Box:

Now that the black box of vision has been opened, it is no longer
enough for an evolutionary explanation of that power to consider only
the anatomical structures of whole eyes, as Darwin did in the
nineteenth century (and as popularizers of evolution continue to do
today). Each of the anatomical steps and structures that Darwin
thought were so simple actually involves staggeringly complicated
biochemical processes that can not be papered over with rhetoric. 33

Beyond Seeing
What has been explained so far is the first contact of photons, reflected
off a friend's body, with a man's eye. The retinal cells produce electrical
signals through complicated chemical processes as described above. In these
signals there exists such detail that the face of the man's friend in the
example, his body, hair colour and even a minute mark on his face have been

encoded. Now the signal has to be carried to the brain.
Nerve cells (neurons) stimulated by retinal molecules show a chemical
reaction as well. When a neuron is stimulated, protein molecules on its
surface change shape. This blocks the movement of the positively charged
sodium atoms. The change in the movement of the electrically charged
atoms creates a voltage differential within the cell, which results in an

electrical signal. The signal arrives at the tip of the nerve cell after travelling
a distance shorter than a centimetre. However, there is a gap between two
nerve cells and the electrical signal has to cross this gap, which presents a
problem. Certain special chemicals between the two neurons carry the
signal. The message is carried this way for about a quarter to a fortieth of a
millimetre. The electrical impulse is conducted from one nerve cell to the
next until it reaches the brain.
These special signals are taken to the visual cortex in the brain. The