THE ORIGIN OF LIFE
Robert C. Newman
The Goal: What is Life?
Minimally, a self‑reproducing material system
From Christian perspective, may be more complex, but need not be.
Alternative Proposals for the Origin of Life
1. Life has always existed.
2. Life arose by supernatural intervention.
3. Life arose by purely natural means.
Major Scenarios for Naturalistic Origin
1. Organic Soup Model
Reducing atmosphere needed (no free oxygen, etc.)
Energy source to break atm molecules: ultraviolet, lightning, volcanism
Organic molecules produced when broken molecules recombine
Organic soup develops
Macromolecules formed in organic soup
Reproducing macromolecules formed
2. Clay as Matrix Model
Clay as template and/or protection
Macromolecules form on clay
Clay phased out
Some Problems for These Models
1. Organic Soup
Oxygen in early atmosphere due to photodissociation of H2O
Water opposes polymerization
Handedness of life molecules (amino acids left-handed, sugars right-handed)
Randomness => organization?
Far less research here so far
Competing reactions still a problem
Handedness of life molecules still a problem
Disposal of clay (switching horses in midst of stream?)
Randomness => organization?
The Problem of Randomness Producing Order
Is it really true that if you give enough monkeys enough time, they will eventually type the Encyclopaedia Britannica? How many monkeys? How much time?
1. Monkeys Typing the text "ENCYCLOPAEDIA BRITTANICA"
at 3 char/sec on 33-key typewriter
3 x 1036 combinations
3 x 1028 monkey‑years
Can be done by 1.5 billion billion monkeys in 20 billion yrs
2. Formation of a Particular 100‑Link Amino Acid
Under assumptions given, 3 x 104 combs/sec
Takes 5 x 1037 years within Hubble radius
So 1 chance in 1028 in age of universe
3. Van Neumann's Self‑Reproducing Automaton
80x400 body cells w/ tail of 150,000 cells
At 21 bits/body cell + 1 bit/tail cell
750,000 bits => 150,000 letter‑word!
=> 10 to the 250,000th combinations
4. Langton's Self‑Reproducing Automaton
Much simpler, but nearly trivial
Body: 86 non‑zero cells in one of 7 states
7 to the 86th = 4.8 x 1072 combinations
Plus transition rules: 190 specifying one of 7 states:
7 to the 190th = 2 x 10160
Both together: 10 to the 233rd combinations
Naturalistic origin a matter of faith with many.
Life looks too organized to be explained without Designer.
Denton, Michael. Evolution: a theory in crisis. Bethesda, MD: Adler and Adler, 1986. See esp. chapter 11.
Gange, Robert. Origins and destiny: a scientist examines God's handiwork. Waco, TX: Word Books, 1986. See esp. chap. 9.
Kemeny. "Man Viewed as a Machine" in Mathematics in the modern world: readings from Scientific American. San Francisco: W.H. Freeman and Co., 1968. See chap. 50.
Langton, Christopher G. "Self‑Reproduction in Cellular Automata," Physica 10D (1984), 135‑144.
Pitman, Michael. Adam and evolution. London: Rider, 1984. Distributed in the U.S. by Baker Book House. See esp. chap. 9.
Shapiro, Robert. Origins: a skeptic's guide to the creation of life on earth. New York: Summit Books, 1986.
Taylor, Gordon Rattray. The great evolution mystery. New York: Harper and Row, 1983. See esp. chap. 11.
Thaxton, Charles B., Walter L. Bradley and Roger L. Olsen. The mystery of life's origin: reassessing current theories. New York: Philosophical Library, 1984.
Von Neumann, John. Theory of self‑reproducing automata. Urbana, IL: Univ of Illinois Press, 1966.