Life of the Oceans - Ocean Worlds: The Story of Seas on Earth and Other Planets - page 127

can one comprehend the complexity within such a tiny organism?
In one small cell there is the control centre of the nucleus, and
the organelles for processing proteins, making energy, transporting
nutrients around the body, and expelling excess water. Moreover,
such cells can assemble into multicellular colonies, with each cell then
being charged with a particular task. This seems like a jigsaw puzzle
with 4 billion pieces—and with no picture on the front of the box to
help get it started. It has, mind you, taken nature around 4 billion
years to assemble all of the pieces.
There is, alas, no fossil record on Earth that shows how this com-
plexity began. Almost certainly it involved a whole series of precur-
sor steps, rather than Hoyle's notion of assembly in one single action.
The steps may have involved processes such as autocatalysis, in which
some chemical reactions become self-sustaining, thus involving a
simple form of reproduction that fulfils one of the characteristics of
life. 73 For such autocatalytic reactions to ultimately develop into life,
though, there is a need to invoke Darwinian evolution so that the
reactions evolve to a level of complexity that produces life.
A stumbling block here may be the means of accurately transmit-
ting information from one generation to the next without a genetic
code. 74 Without genes there is no easy way to convey good designs to
the next generation, and no way to prevent bad designs propagating.
To transmit encoded information to your children, a complex mole-
cule such as ribonucleic acid (RNA) or deoxyribonucleic acid (DNA)
is needed. But these molecules are complex, and it is almost as unbe-
lievable as Hoyle's aeroplane analogy to believe that they came into
existence in a single step, from an array of nucleic acids synthesized
in some primordial soup. An alternative hypothesis, therefore,
involves the development of a self-replicating proto-RNA molecule.
This may have been composed of different 'bases' from the four we all
learned in biology at school—adenine, guanine, cytosine, and uracil.