Undeniable (37 page)

A SECOND GENESIS—OF LIFE?

I was a child of the space age; I crouched in front of a black-and-white vacuum-tube television in 1969, when humans first set foot on the Moon. When I think about an alien form of life, with all that it would tell us about the process of evolution, I naturally picture something on another world. But a few researchers, including Paul Davies at Arizona State University, offer a drastically different perspective. They suggest that aliens—microbial aliens, that is—might be right here on Earth, right now. If these researchers are right, we've been missing out on one of the most powerful ways to understand the origin of life. There might be a whole other Tree of Life all around us hiding in plain sight.

The possibility of a second type of life getting a foothold here on Earth is called the second genesis. If we could find a second kind of living thing, it would change our world. Right now everything we know comes from an example of one. If we could compare two totally different types of organisms, we could begin to find out experimentally whether there are alternatives to DNA, other kinds of metabolisms, whole other life chemistries. The practical implications are as mind-boggling as the scientific ones. And I wonder: What would the creationists say?

I can almost hear your objections. How could there be unknown organisms on Earth, considering how thoroughly biologists have studied all the microbes around us? Well, think about the challenges of recognizing alien microbes. The same is true right here at home. There are two basic ways to find a new microbe: You can grow it in a petri dish, or you can sequence its DNA. If it doesn't eat the same things that other microbes eat, and if it doesn't have the standard kind of DNA (or doesn't use DNA at all), it would basically slip through the cracks of modern biology.

A huge lesson from the past few decades is that Earth is full of surprising and unexpected organisms. When we examine oil well tailings (the rocks and soil brought up by the drill bits), we find entire ecosystems of slow-growing bacteria. These organisms date back millions of years and they've never seen the light of day. They still have DNA. We have a common ancestor. But they are drastically unlike anything that lives on the surface.

One cannot help but wonder what else is down there. Is there a system of living things that we know nothing about? In an area referred to as the Illinois Basin, there are enormous coal mines extending kilometers in several directions underground. When you look around down there you cannot help but notice the scale trees, an extinct fernlike species that lived in primordial swamps about 300 million years ago and later turned to coal. There were probably whole microbial ecosystems in those areas that we know nothing about. These would be types of living things that we don't recognize today. They may be so different that we wouldn't know them even if they were staring right back at us up through our microscope lenses.

There may be countless places to look. Most of Earth is covered by the ocean. There is far more wet land underneath the sea surface than there is dry land above. There are billions of tons of silt and detritus down there. Perhaps a different style of life lives in the ooze. Under the Antarctic ice there is a freshwater lake that had been untouched by surface creatures for millions and millions of years. Maybe a spark was lit down in the lightless cold that still drives an alien life form even today. There are extraordinarily remote places high in the Himalayan and Andes mountain ranges. Is there a niche where an alien lifestyle is being lived? Maybe we've had samples in our labs and just overlooked that life, because it is alien in so many ways. Any of the organisms in these examples would be from our Earth but completely alien to us. Imagine it: an entire new domain of living things—no, a whole separate Tree of Life, the result of a whole separate, second genesis.

It's an exploration we must pursue. It could lead to a new branch of life science. Whatever the second genesis life forms are like, you can bet they have followed the same principles that our ancestors did. The other life may be on a different course, but I'm sure we play by the same evolutionary rules.

You might call this the outer limit of evolutionary thinking. Darwin looked at organisms as they are; we are speculating about organisms that might be. When he drew his first Tree of Life, Darwin was looking at the scheme that connected all living things; we are looking for organisms that stand stunningly apart. Yet, none of this would be possible without Darwin's discoveries and without the inquisitive spirit of evolutionary thinking that he embodied.

 

37

LIFE'S COSMIC IMPERATIVE

At the end of the journey of this book, I find myself thinking about the end journey of evolution itself. Not just human evolution, but the process as a whole. I have long wondered whether there is some kind of cosmic imperative for life to spread from world to world. On Earth we see that organisms colonize every possible niche. We see that living things move into new environments and beget new species. Is life destined to colonize the solar system, the Milky Way, and ultimately to spread out through the whole universe? Darwin described the “Struggle for Life” that drives evolution on this planet; perhaps in the future that same struggle will expand to a cosmic scale. Are you and I genetically driven to build starships and wander the universe? Wow, it knocks me back a little just writing it.

You may have picked up hints of this idea in the past few chapters, when I talked about the ways in which life might arise on different worlds or get randomly spread from planet to planet. But it's not hard to imagine that someday humans might start spreading life deliberately. As we explore the planets, asteroids, and comets of the solar system we already have to be extremely careful not to bring microbial life with us. What if our truly space-faring descendants choose to create colonies, and bring other living things with them intentionally? In understanding the process that led from a simple cell to us, we are beginning to sketch out a grand evolutionary process. Going from world to world, or even star to star, is entirely consistent with the ways in which life evolves to fill every possible environment on Earth.

Even in this far-out realm of speculation, others have already begun taking measure of the lay of the land. We could purposely leave genetically modified microbes on Mars that would somehow change the atmosphere there to have more oxygen, and thereby be more habitable. Perhaps we could do the same for something in the cloud tops of Venus. Craig Venter has raised the idea of a DNA fax that could read the genome of (possible) living things on Mars and send the data home so we could re-create them here on Earth. It's not so far-fetched that a reverse technology is possible: We could send bioreactors to other worlds, complete with instructions to assemble microbes adapted to the local environment at the other end.

Keep going, and the ideas just keep getting wilder. If we are not alone in the universe, we might
really
not be alone in the universe. What if every civilization throughout the galaxy or universe does the same thing by accident—or on purpose? What if we are the descendants of some such galactic seeding campaign, Johnny Appleseed's trek writ galactically large?

The only way to get the answers is to keep looking at living things and learning more about the process by which we all came to be. Evolution happens here no matter how we all got started. But now we can start to ask meaningfully about origins and destinies as well. We will go to thrilling places—unimaginable places—if only we keep our minds open to new ideas, our faculties keen to significant pieces of evidence, our youthful curiosities forever engaged.

Where did we come from? Are we alone? Search on!

 

ACKNOWLEDGMENTS

This book would not have been possible without my parents Ned and Jacquie, in whose home science was celebrated and academic achievement was expected. I wouldn't have ever come to be if it weren't for my sister, Susan, who made me do my homework, and my brother, Darby, the funniest and most thoughtful man I know. Many thanks to my academic colleagues, Don Prothero, Michael Shermer, and Eugenie C. Scott, without whose guidance that debate in Kentucky and a great deal of this book would have been a mess. Nina Jablonski took a great deal of time to help me and our excellent fact checker Kate Baggaley make the skin color argument accurate and compelling; thank you, thank you.

It was my editor, Corey Powell, who, along with his quick-witted journalistic guidance, convinced me to “bottle” my voice in compact chapters. I'm grateful for all his help. All this work would not have been possible without my trusted agents, Betsy Berg and Nick Pampenella, along with their assistant, Ariella Mastroianni; thanks to all. Jennifer Weis at St. Martin's Press directed me to take on this project; thank you indeed. And everyone knows, I owe tremendous thanks to my trusted attorney, Andy Salter, and my amazing assistant, Christine Sposari.

Finally, the Stars of the Show:

I am so very thankful for all my remarkable teachers, but most especially Mrs. McGonagle, Mrs. Cochran, Mr. Lawrence, Mr. Flowers, Mr. Cross, Ms. Hrushka, Mr. Morse, Mr. Lang, and Professor Sagan. Each of these people influenced me in extraordinary ways. I would be a very different person without them; I am a very fortunate man.

BILL NYE

THE DELAWARE SHORE

Many wonderful contingencies brought me into this project. I owe my mother for making my childhood self hunt down a paleontology curator when she couldn't answer my dinosaur questions. At
Discover
magazine, Tina Wooden coached me through countless conversations with creationists; another dear
Discover
colleague, Pam Weintraub, challenged me to become a better writer and introduced me to Jennifer Weis, the devoted editor of this book. My wife, Lisa Gifford, supported me generously during the many times when I seemed to vanish (both intellectually and temporally) from my family.

And I am honored to have worked with Bill Nye, who inspired me throughout with his passionate commitment to spreading knowledge and changing the world.

COREY S. POWELL

SOMEWHERE IN BROOKLYN

 

INDEX

 

The index that appeared in the print version of this title does not match the pages in your e-book. Please use the search function on your e-reading device to search for terms of interest. For your reference, the terms that appear in the print index are listed below.

abiogenesis

acacia trees

Adam and Eve

Africa: desertification; flora and fauna; human origins in

Africans, skin color

Afrikaners, genetic disease of

afterlife, belief in

age (geologic time unit)

airplanes

allopatric

altruism: defined in a formula; evolution of

altruistic punishment

Alvarez, Luis

Alvarez, Walter

Ambulocetus

Americas, populating of

amino acids

ammonia

Ampère, André-Marie

analogous structures

Anaximander

Animalia (kingdom of life)

animals, similarity to humans

Answers in Genesis

Antarctica

antibiotics: developing new ones; discovery of; overuse of, and resistance

antibodies; attacking viruses

ants

apes

Archaea (domain of life)

Archaeopteryx

“Are we alone in the universe?” question

“Are we still evolving?” question

Aristotle

arm bones

artificial intelligence

artificial selection

asexual reproduction

Asimov, Isaac

asteroids: composition of; crashing into Earth; and mass extinctions

astrobiology

Australia

bacteria: attacked by antibiotics; attacked by viruses; defenses of; as form of life; fossil; genes exchanged by; living underground; number of, on Earth; reproduction of; toxins produced by, making us sick

Bacteria (domain of life)

bacteriocins

bacteriophages (phages)

Baer, Karl Ernst von

“balance of nature”

barnacles

basalt

Batman

bats

Becquerel, Henri

bees; ability to fly

beetles, species of

Bell, Thomas

Belyaev, Dmitri

beneficial adaptions

Bethe, Hans

Bible, The
: on Earth's history; errors in; on human fertilization; literal interpretation of

Big Bang

BigThink.com

binary fission

biodiversity; damage to, unpredictable results of; gradients of, with distance from equator; productivity of, vs. monoculture

birds: descent from dinosaurs; egg nests of; flight of; structure of

Black Death

blacksmiths, Lamarck on

blastocyst

blue-green bacteria

bodybuilding

Boeing company

bottlenecks,
see
genetic bottlenecks

bottom-up design

Boy Scouts

brain, animal

brain, human: brain-to-body ratio; connection to emotions through the body; design flaws; great potential of; irony in evolution of; size of

breeding (in farming, racing)

bristlecone pine trees

Britain

British royal family, genetic disease of

B-2 bomber

Burgess Shale Formation; crazy critters in

calcium

“Cambrian Explosion”

Cambrian Period

Canada

cancer

carbon-14 dating

carbon dioxide: as greenhouse gas; industrial emissions of

carbonic acid, in oceans

Carroll, Lewis

catastrophes and contingencies, and species origination

cattle, multicolored

cell membranes

Cenozoic Era

Centers for Disease Control and Prevention (CDC)