Story of Evolution,
Evolution of Stories
Bryn Mawr College, Spring 2004
First Web Paper
On Serendip
Is Death Responsible for Diversity?
Bethany
Some of the hardest questions we struggle to answer in life surround the phenomenon
of death. What happens when we die? Is there something beyond death? Is one
way to go better than another? Is it possible to escape death? Why do we die,
anyway? Why couldn't we just live forever? One explanation for death may come
from the story of evolution.
To explore this question, let us imagine a hypothetical situation, a world in
which nothing dies. (We will imagine also, for now, that organisms would continue
to evolve along the same trajectory as they do at present.) Every organism that
has ever existed in the past would exist now, along with every organism present
and every organism that has yet to exist. Not only would the world contain these
organisms, but all potential organisms. "However many ways there may be of being
alive, it is certain that there are vastly more ways of being dead or rather,
not alive." – Richard Dawkins (p 104, Dennett) All the representations of the
ways of being 'not alive' would be there, including those that we could not
possibly fathom, those that are not necessarily contingent to our present environment.
What this signifies, this absence of death, is a lack of natural selection.
When nothing can die, everything is selected for, nothing is selected against.
No death implies; no tests, no judgments of fit or unfit, no randomness or weeding-out
of the genome, no consequence to anything that is potentially detrimental to
the species.
This hypothetical situation is a look at the unchanging set of all possible
options, every combination of DNA that could potentially give rise to life.
Every possibility is valid. This version of the world could only exist if we
ignore three crucial points; the second law of thermodynamics, the definition
of a niche as it pertains to the environment and to evolution, and the fact
that without these influential factors, evolution, at least in the sense that
we now know it, would not exist.
The second law of thermodynamics states that energy tends to go from a state
of high concentration to a state of expansion, or being spread out. In other
words, there is a tendency to move away from potential energy. As we know it,
the sun 'dies', gives off energy. This energy is taken in by plants, which die
and fertilize more plants with that energy. They also give energy to any plant-eating
animals, which in turn give energy in decomposing to more plants. Organisms
give energy to other, carnivorous organisms by being eaten, by dying. There
is no way to create something new if some form of work is not done. Energy must
be transferred, and the manifestation of this in evolution is the process of
death, and consequent creation or new life. It is not possible to acquire something
from nothing, the energy must be used, given out, recycled.
In the hypothesis version of the world, there is no transfer of energy; there
is only accumulation of life. This would quickly exhaust the supply of energy
and available space. Another enormous side effect is that evolution would cease,
at least as it exists now. A driving factor for this process is the idea of
competition, which relies on a loser, which implies death or extinction. "Indeed,
the gist of every selection is to favor individuals that have succeeded in finding
a progressive answer to current problems. The summation of all these steps is
evolutionary progress." (p 215, Mayr) A situation in which there is no death
is a situation in which everything is constant. Therefore there would always
be the same current problems and no catalyst to inspire any changes. "Elimination
does not have the 'purpose' or the 'teleological goal' of producing adaptation;
rather, adaptation is a by-product of the process of elimination." (p 150, Mayr)
No adaptation without elimination.
Death is also vital to the evolutionary niche, and the expansion and contraction
that occur within this niche. If death were non-existent, we might have niches,
but they would not be necessary. Every organism would be able to live anywhere,
to co-exist with any other organism. This side effect of the absence spits in
the face of our current situation. According to Mayr, a niche is a "constellation
of properties of the environment making it suitable for occupation by a species."
(p 288) It's important to remember that an environment is partially defined
by what organisms inhabit it. So a niche evolves and changes with its living
constituents.
"Open ecological niches or zones are often repeatedly colonized by entirely
unrelated organisms that, once adapted to these niches, become by convergence,
extremely similar." (p 156, Mayr) This supports the hypothesis that the definition
of a niche includes the organisms to which it is home, and it also spotlights
the huge influence of selection pressure; what worked then will work now, what
worked there will work here. If the niches are similar, they will probably yield
similar organisms and similar lineages. But if there is no selection pressure
then you could have penguins in the Savanna, giraffes on the South Pole. There
would be nothing barring these organisms from different environments, because
there is no death, no consequence for a lack of compatibility between inhabitant
and habitat. The world would be just one big niche, where anything goes, anything
is possible.
If we do away with natural selection, then we must consequently do away with
change, with evolution, with boundaries. "Whenever a species acquires a new
capacity, it acquires, so to speak, the key to a different niche or adaptive
zone in nature." (p 208, Mayr) The key merited is contingent to the change only
because the niche is 'locked' before the change occurs. The boundaries we see
are what create the selection pressures that cause organisms to change and are
often products of selection pressures themselves. There is a direct relationship
between these phenomena. If we have change (evolution) and niches, then death
and natural selection are mandatory.
Sources -
Mayr, Ernst. What Evolution Is.
New York; Basic Books, 2001.
Dennett, Daniel. Darwin's Dangerous Idea.
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