Page 136 - The Evolution Impasse 2

134 Origin of Viruses

The oldest chordate Pikaia fossil to appear in the Cambrian Period

be cause up to now the ver te brates were small or gan isms. It was lat er es tab -
ab sent from the big bang of life, as we lished in de tailed stud ies con duct ed
call it—that is, the great ear ly un der the elec tron mi cro scope that
Cambrian ex plo sion, where all the ma - these were struc tur al ly very dif fer ent
jor an i mal groups ap peared sud den ly and that they lived sole ly as par a sites
in the fos sil record . . . It is prac ti cal ly in the cell.
cer tain that these are ver te brates. 145
No mat ter how many vir i ons one or a
few en zymes con tain, this en zyme se -
ries is still in suf fi cient for es tab lish ing
ORIGIN OF VIRUSES a vir i on. (vir i on, the state in which vi -

Some ev o lu tion ists main tain that rus es have the ca pac i ty to cause in fec -
vi rus es rep re sent the bi o log i cal be - tion). 147
gin ning of life: Viruses mul ti ply as par a sites in
the cells of a for eign or gan ism. They
When we look at the pre-cel lu lar sta ges
of life, we see ev o lu tion here, too. The have no me tab o lisms be yond those
first, most prim i tive forms of bi o log i cal of the host cells. Since vi rus es have
or gan isms are not cells, but vi rus es. 146 no me tab o lisms and abil i ty to be
On the one hand, while ev o lu - stim u lat ed they do not pos sess the
tion ists seek to ac count for the or i gin fea tures of in de pend ence unique to
of life in terms of vi rus es, they al so life, and are there fore not tru ly alive,
say that vi rus es can not rep re sent the in the usu al sense.
foun da tion of life. This im pos si bil i ty Viruses are known as vir i ons
is men tioned in a num ber of ev o lu - when they are still out side the cell.
tion ist sour ces: Virions are not alive. Only two of the
key proc ess es in liv ing things are
Viruses were in i tial ly re gard ed as very
found in vi rus es: rep li ca tion and

The Evolution Impasse II