Документ взят из кэша поисковой машины. Адрес оригинального документа : http://zebu.uoregon.edu/postscript/life.ps Дата изменения: Sat Jul 2 02:14:37 1994 Дата индексирования: Mon Oct 1 22:16:18 2012 Кодировка: Поисковые слова: m 5

How to Make Some Critters
Evolutionary Advantage Drives Everything!
Step 1: Rapid chemical synthesis of raw materials
in the atmosphere produces amino acids:
NH 3
+ 2CH 4
+ 2H 2
0 + energy = C 2
H 5
O 2
N + 5H 2
5H 2
CO = Ribose(food)
5HCN+UV +NH 3 = Adenine(anotheraminoacid)

Step 2: Monomers loosely mixed in early oceans
and shielded from UV
Step 3: Local Evaporation, monomers concentrated
in clays whose silicate surfaces act as a catalyst
Step 4: L­monomers organize themselves into poly­
mers (peptide chains)
Step 5: Trial­and­Error polymers ``mate'' together
in correct manner so as to reproduce themselves: DNA!!!;
search for genetic code now over. This search takes 1
billion years!
Step 6: Prokaryotes (Bacteria): How to feed a mul­
tiplying population:
6a: Feed them organic molecules (food supply prob­
lem)
6b: Use UV light from Sun to metabolize H 2
S in
oceans ­ anerobic photosynthesis
6c: Develop chlorophyll to more efficiently absorb
UV light to then metabolize H 2
0 and give off O 2
as a
waste product (a good thing)

Step 7: Now we have to wait a long time. Dissolved
Fe ++ (supernova again) in Oceans scavenges most of
the O 2
! FeO 2
. Finally, 600 million years ago, O 2
can go into the atmosphere and make O 3
Step 8: Prokaryotic Cells gradually evolve (?) to
Eukayotic cells (nucleated cells) which can metabolize
O 2
leading to rapid cell division via mitosis Evolution
from prokaryotic cells to eukaryotic is not understood,
although their is an obvious need to protect DNA
from a now O 2
rich environment.
Step 9: Make a Thicker Ozone layer:
O 2 +O +M = O 3
ffl O 2
at bottom of atmosphere
ffl O at top of atmosphere
ffl M density gradient
Hence O 3
is in ``middle'' of atmosphere ! 10 -- 20
km up