Emergence of Multi-Level Biological Systems
More than a dozen intermediate stages of
emergence in the universe were required to give rise to
multicellular life, and they all still play important roles in
Many successive levels of emergence led to life on the planet
Earth today. They cannot be known precisely but the story,
begins at the “big bang” with quarks and gluons
and strings (Oh My!). A brief sketch of the many levels of
emergence thereafter are outlined below:
- A couple of seconds after
the big bang, the quarks, gluons, leptons, etc. condensed into
sea of disassociated particles such as neutrons,
electrons, positrons, and neutrinos.
- As the universe expanded and cooled over a few hundred
many of these particles joined into small stable sets of
protons, and electrons thereby becoming simple atoms
– mostly hydrogen atoms with some helium and a tiny admixture
next lightest nuclei: deuterium, lithium and beryllium. None
of the heavier atomic elements, many of which are vital to
universe then, not even carbon, the sixth smallest element.
- Perhaps 600 million years pass and the universe continues
cool until gravity exaggerates slight differences in the
matter in vast sub regions of the universe
to create the third level organization: the first galaxies and
- Deep inside these first-generation stars, gravitational
pressure created the enormous temperatures that ignite fusion
reactions. The lightest
nuclei, hydrogen and deuterium, fuse together to create
nuclei. This process continues, creating the elements up
to iron, including carbon, oxygen and the majority of other
elements vital to life as we know it.
- However, some of the heavier elements also vital to life,
iodine, are not created in first-generation stars because
processes cannot create elements with nuclei heavier than iron,
The heavier elements are created by neutron capture processes
those that take place in the brief, violent death of stars in
supernovas. Supernovas not only create many of the remaining
elements, but also their violent explosions spew
these newly created elements out into interstellar space
- Time passes, stellar dust from supernovas, containing all
eventually condenses again by gravitational attraction.
generation stars with
planetary systems form. They include the full complement
of chemical elements
for rock, water, air and, ultimately, life.
- In our own little solar system much more time passes and
the earth cools enough for liquid
water to condense: liquid water without which life as we know
it cannot exist. All sorts of catalytic chemical reactions in
the earth’s oceans and atmosphere create the early
carbon-based compounds that combine to create successively
larger and more complex organic compounds
- Eventually, small protocells are thought to have arisen:
water and complex sets of organic chemicals that are
surrounded by fatty acid membranes that encapsulate and protect
their inside from the different composition of the external world.
membrane vesicles are reminiscent of simple cells, but are
not alive, i.e., they cannot replicate. [Note: the details of
this step are still speculative. An
alternative "first step toward life" posits agglomeration of
organic molecules on tiny grains of clay rather than inside
- Perhaps 3.8 billion years ago, mechanisms that allowed
protocells to replicate emerged via unexplained “magic”.
Replication marks the emergence of simple single-cell life.
- For a couple of billion years thereafter, single cell organisms
evolve dizzying complexity in many steps: developing motility,
absorbing mitochondria and chloroplasts that had been free-living
simple cells, creating the nucleus, and so forth.
- About 3.5 billion years ago, cyanobacteria evolved physically
co-located cooperative relationships held together by sticky
secretions from the cells (e.g., gel or slime). This is
first step toward multicellular life. These colony bacteria are
believed to be responsible for the conversion of Earth's early
carbon dioxide atmosphere into the oxygen-rich atmosphere of
- Between a billion and 600 million years ago
true multicellular (Metazoan) organisms evolve that develop
from a single fertilized cell and share the same DNA. Colonies
of single cell organisms such as biofilms still play important
roles in our planet's ecology. However, they consist of many
single cell species each with its own independent genome
rather than sharing one common genome.
From the early multicellular organisms to mammals, then
to humans, requires yet another series of emergent levels too
complex and too
poorly understood to explore in this brief story. [That is not to
imply that we understand levels 8-12 all that much better.]
All of the levels described above are
evident in every living cell or organism today. The
biochemistry that emerged in the Earth’s oceans
operates in every cell. Virtually all of the energy
used by every living cell comes from that produced by nuclear
fusion in the sun and captured via photosynthesis in plants.
All the hydrogen in our cells was created in the big bang itself.
And many of the random events that generate novel mutations
that evolution exploits are due to UV radiation from
the sun, or cosmic rays from distant galaxies, or neutrinos,
some of which are from the big bang itself! Thus, every one
of the dozen or so layers of emergent behavior still
participates in a great cosmic dance, one small figure
of which is Earth’s biosphere containing all the various
species of living organisms.
Including copper, zinc, tin, iodine, silver, gold, lead, and
uranium, many of which are needed for life. Zinc, for
example, is crucial to many DNA binding proteins that control
expression. Molybdenum is crucial to bacterial and eucaryotic
oxotransferase enzymes. Cobalt is crucial to some
methyltransferases. Copper is crucial to the function of
cytochrome c oxidase, a central enzyme in the generation of
ATP in mitochondria.
For example, carbonyl sulfide (COS), a simple volcanic gas,
formation of polypeptides from individual amino acids in water
solution. Science, vol
8 October, 2004, pp. 283-286. For a more extensive
review of the
geophysical, geochemical, and biological processes involved in
long process, see the Review paper: Mineral evolution,
Hazen, et al, American Mineralogist,
Vol. 93, pp.
1693–1720, 2008 A
can be found here.
We don’t know the steps that led to the evolution of the
fantastic mechanisms dependent upon RNA, DNA, and
replication, hence life. The term “magic” simply reflects
that ignorance. It is not intended to endorse any particular
system, either scientific or theological
This time estimate is very imprecise in part because the
metazoans were probably
small, soft, creatures that did not leave fossils.
Last revised 6/1/2014