We imagine ourselves as Earth’s
rugged generalists, but in truth we are frail. We share the planet with microbes
that would be at home in boiling water or deep rock or pure salt or battery acid.
Their diverse forms are represented in spectral color. Life has radiated into every
conceivable environmental niche. Robust is biology’s middle name—it’s our fragility
that is unusual.
The binding of life is DNA. This
delicate molecular ladder both codes and transmits information, and whatever experimentation
might have taken place on the primeval Earth, organisms using DNA superseded and
consumed all others. As James Watson once said, “Life is digital information.” A
base pair is like a letter, a gene is like a sentence, the genome is like an encyclopedia,
and all aspects of the organism are coded in genetic material and its complex interactions
with the environment. The concept of life as information leads to the possibility
of artificial life: life without carbon and water. Biologists are tinkering with
molecular Legos in the lab, trying to improve on nature and built an organism from
scratch. Humans are heading towards a post-biological future, when we pass through
the membrane of progress where technology usurps the organism. There is tension
between the reductionist view of life fostered by genetics and our suspicion that
there is something special about the spark of life.
Humans are temporary visitors in
an overwhelmingly microbial world. The modern tree of life based on DNA places us
and all animals as a peripheral twig. Genetic diversity and complexity at the microscopic
level is amazing. We are not so special—we share half our DNA with yeast. There
are more microbes in our gut than there are people on the planet, and there is more
microbial DNA in a teaspoon of seawater than in the human genome. The extremophile
microbes thrive in places we can’t live: in pores deep within rocks, bathed in acidic
runoff from an abandoned mine, rapidly repairing their radiation-damaged DNA in
the shadow of a nuclear reactor. We can visualize water bears no bigger than the
head of a pin, albino fish foraging near an undersea volcano, and pink sea worms
undulating from a sheet of methane ice on the ocean floor.
All this is one planet: Earth. Life
beyond Earth might not only be stranger than we imagine, it might be stranger than
we can imagine. Rumpled bed sheets suggest landscapes and the contours of the imagination.
Our biology may just be one solution for life, a pleasant valley but not the only
dwelling place, and not necessarily the best of all possible worlds. In the prodigious
biological possibility of the universe, some versions may be wildly different.
About the Artist
Heather Green is a graduate student in the College of Fine Arts at the University
of Arizona and a second generation Tucsonan. Her current work is informed by her
lifelong relationship with the headland of La Cholla near Puerto Peñasco, Mexico,
a passion for old science books, and her love of the natural world. She has designed
exhibits about sustainable fisheries and materials for conservation initiatives,
and is currently developing a virtual museum about La Cholla.