Page 96 - The Evolution Impasse 2

94 Origin of the Bats

Yet that is not ac tu al ly the case, ing com mands to par tic u lar mus cles.
and bats con tin ue to de tect all kinds These two types of neu ron work to -
of mov ing ob ject with no prob lem at geth er, so that when the fre quen cy
all, be cause they raise the fre quen cy of the ech oes chan ges, the first neu -
of the sound waves they emit to - ron de tects this and caus es the oth er
wards mov ing ob jects, just as if they neu ron to adapt to the ech o's fre -
were tak ing the Doppler Effect in to quen cy, ei ther by sup press ing or
ac count. For ex am ple, a bat will emit stim u lat ing it. As a re sult, the bat
the hi ghest fre quen cy sounds in the chan ges its fre quen cy ac cord ing to
di rec tion of a fly mov ing away from its sur round ings, us ing it in the most
it, so that when the sound ech oes ef fi cient man ner.
back, it will not fall be low a de tect a - It is easy to re al ize the le thal blow
ble fre quen cy. that this sys tem deals to the the o ry
Two types of neu rons or nerve of ev o lu tion's ex pla na tion of grad u al
cells in the bat's brain su per vise the im prove ments by way of ran dom
so nar sys tem; one of these per ceives mu ta tions. The so nar sys tem in bats
the ul tra sound emit ted, and the oth - has an ex ceed ing ly com plex struc -
er ad justs the bat's squeaks by is su - ture, and can nev er be ac count ed for

The old est known fos sil bat, found in Wyoming in the USA. This fos sil, some 50 mil -
lion years old, is iden ti cal to mod ern bats.

The Evolution Impasse II