The origin of life

II. Origin of Life.
A. A history of ideas:
1. Thales, 600 b.c.--organisms
originated from the sea slime by the interaction of sea, sun, and air. Other Greek philosophers added to this by injecting development in stages.
2. Thus, the theory of the spontaneous generation of life was born. This could be
referred to as the instantaneous spontaneous generation of life, and one that holds that life can arise from non-living matter, such as flies from rotting meat. Now we know
that this does not occur, as from these tests/experiments done long ago.

a. Redi, 17th century--experiments on rotting meat demonstrated that maggots came from fly eggs and not directly from the meat.

b. Pasteur, 1850s--long series of experiments that proved that this instantaneous spontaneous generation of life does not occur--all life comes from other pre-existing forms of life.

B. Where could life have originated or how?

1. Life could have arisen from a supernatural event.

2. Life came from outer space.

3. Life arose from a very impro

4. Life arose from favorable conditions existing in the oceans of the primeval earth.

a. Haldane, 1928, maintained that there is no real asic theoretical reason that life could not have arisen spontaneously on earth if, at the time of origin, there was no life present.

b. Oparin, 1933: life could have originated on primitive earth if methane, hydrogen, nitrogen, and oxygen (water provides hydrogen and oxygen) were abundant under a vital source of energy within a reducing atmosphere (no free oxygen).

C. What is life?

1. Characteristics of a living organism:

a. Transforms energy.

b. Responds to stimuli or environmental changes.

c. Reproduces itself.

d. Undergoes change and remembers that change/mutations.

D. Evolutionary time scale, probable theoretical scale:.

1. Formation of earth--more than 5 billion years (bya) before the present.

2. Chemical evolution--approximately 4 bya.

3. Organic evolution--3-4 bya.

4. First good fossil algae (blue-green)--2.7 bya in Rhodesia; 2.4 bya in Canada.

5. First invertebrates--2 bya.

6. First vertebrates--1 bya.

7. First mammals--500 million years ago.

8. Humans--1-3 mya.

Note: If we set 12 inches or 1 foot = 1 billion years, then #1 above = 5 feet; #2 = 4 feet; #3 = 3-4

feet; #4 = 2.5 feet; #5 = 2 feet; #6 = 1 foot; #7 = 6 inches; #8 = 1-2 inches.

Or, if we use a football field, where 100 yards = 5 billion years = formation of the earth (#1), 80 yards (#2); 60 yards (#3); 54 yards = Rhodesia fossil algae and 48 yards = Canada fossil algae (#4); 40 yards = first invertebrates (#5); 20 yards = first vertebrates (#6); 10 yards = first mammals (#7); and man did not come into being until 0.8 yards, or 2.4 feet, or 29 inches from the goal line (#8).

Chemistry and the origin of life
1. Ammonia + electrical spark experiments by Miller at the University of Chicago in 1950 yielded many organic compounds, among which were amino acids, within a reducing atmosphere.

2. Calvin, at the University of California, Berkeley, in 1951, got similar results with carbon dioxide and high energy radiation within an oxidizing atmosphere.

------------------------------------------------------------------------------------------------------------------------------- Amino acids too heavy to float in mist or air; thus, they drop on land or the primeval ocean or float about on the ocean’s surface if they fell into the se

Blown by winds or surface currents into shallow, warm waters such as estuaries or bays.

Combined into larger compounds under the catalysis of radiant e.

These, being denser, sink in the shallow depths and kept growing to form the solution that Haldane termed the "organic soup of life."

Compacted into cells, and, with the chance formation of dna, grew at the
expense of other compounds, reproduced, underwent mutations, and ultimately produced "LIFE.

Why is there no spontaneous generation of life now?

1. Imagine a tank of sea water without any living organisms in it but with various organic substances dissolved or suspended in the water. If left alone for a long time, the synthesizing process would take place but at an extremely slow pace. Perhaps, after many millions or even billions of years, this might lead to another "origin of life."

2. But, if one were to introduce organisms already in existence, such as bacteria, the more highly developed (when compared to organic chemicals) biological f orm of organizations would come to the fore and totally dominate the environment.

3. Then, the transformation of inert materials to living matter could not follow the slower processes, but would proceed in the "new way" through the metabolic conversion of organic substances in the solution into living protoplasm with tremendous rapidity.

4. Therefore, the primitive origin of life would simply not have enough time to take place and not occur at all.