Page 124 - Darwinism Refuted

DARWINISM REFUTED

The Origin of Bats
One of the most interesting creatures in the mammalian class is
without doubt the flying mammal, the bat.
Topping the list of the characteristics of bats is the complex "sonar"
system they possess. By means of this, bats can fly in the pitch dark,
unable to see anything, but performing the most complicated maneuvers.
They can even sense and catch a caterpillar on the floor of a dark room.
Bat sonar works in the following way. The animal emits a continuous
stream of high-frequency sonic signals, analyses the echoes from these,
and as a result forms a detailed image of its surroundings. What is more,
it manages to do all of this at an amazing speed, continually and
unerringly, while it is flying through the air.
Research into the bat sonar system has produced even more
surprising results. The range of frequencies the animal can perceive is very
narrow; in other words it can only hear sounds of certain frequencies,
which raises a very important point. Since sounds which strike a body in
motion change their frequency (the well-known "Doppler effect"), as a bat
sends out signals to a fly, say, that is moving away from it, the sound
waves reflected from the fly should be at a different frequency that the bat
is unable to perceive. For this reason, the bat should have great difficulty
in sensing moving bodies.
But this is not the case. The bat continues to catch all kinds of small,
fast-moving creatures with no difficulty at all. The reason is that the bat
adjusts the frequency of the sound waves it sends out toward the moving
bodies in its environment as if it knew all about the Doppler effect. For
instance, it emits its highest-frequency signal toward a fly that is moving
away from it, so that when the signal comes back, its frequency has not
dropped below the threshold of the animal's hearing.
So how does this adjustment take place?
There are two groups of neurons (nerve cells) in the bat's brain which
control the sonar system. One of these perceives the echoed ultrasound,
and the other gives instructions to the muscles to produce echolocation
calls. These regions in the brain work in tandem, in such a way that when
the frequency of the echo changes, the first region perceives this, and
warns the second one, enabling it to modify the frequency of the sound
emitted in accordance with that of the echo. As a result, the pitch of the

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