Following in the footsteps of the great tradition of paleontologists like Stephen Jay Gould, and evolutionary biologists such as Ernst Mayr, Neil Shubin, professor in the Department of Organismal Biology and Anatomy at the University of Chicago, has spent a considerable part of his career discovering fossils around various parts of the world. These have changed the way we think about many of the key transitions in evolution. He famously discovered tiktaalik roseae, a 375 million years old fossil fish, in Canada in 2004. This discovery provided valuable data in helping us understand how fish evolved into land animals.
In his latest book, The Universe Within, Shubin shows how the origin of the Moon is tied to our internal body clocks and how tiny imbalances in the chaos immediately following the Big Bang, can explain why matter, and human beings, eventually came to life. Shubin posits that what lies within the bodies and minds of every human being, has its roots in the crusts of the earth, the water of the oceans, and in atoms in celestial bodies.
He spoke to the Spectator about how our body clocks are important to our well being, why technology is going to determine the eventual fate of human beings, and why humans will eventually have to leave earth for the survival of their very existence.
How is the history of the universe deeply embedded inside every human being?
By looking at the fossil record, or if you analyze the DNA alive in every creature today, you see how these creatures develop embryologically. Or looking at their amitotic structure, what you will find is that we are deeply connected to other creatures — like mammals, reptiles, fish, and microbes — through a shared history to life on the rest of the planet. By looking at the history of the universe, each one of those things has impacted on the history of life. So, for example, the atoms which make our bodies: the carbon, oxygen, hydrogen, and so forth — all of those connect us to the Big Bang, and to the fusion reactions that go on in stars. The atomic stuff that makes us was born in the stars, and in the supernovae, and is continually recycled in the universe.
Some of these connections are more apparent than others though?
Yes. The ones we take for granted: that we are light and time dependent creatures. Well that is written in our DNA, and our proteins. If you look inside the cells of our body, the cycling inside the DNA and protein of each cell happens on a 24-hour clock. So aspects of that clock are shared with everything from other mammals to flies. This dependency on light and dark, i.e. : the spinning of the earth, and its shared relationship with the moon, is seen within our DNA and our cells. Less obvious is how the history of our species relates to the changes in the orbit of our own planet. For example, the waxing and waning of the glaciers, happens on a series of rhythms. Those rhythms correspond very broadly to the changes and variations to the earth’s orbits: known as the Milankovitch cycles. This was very important in human history, particularly with how our type of walking — bipedalism — came about.
You also state that our dependence on the planet Jupiter is vital for us to exist as a species, how is that so?
Well the position, size and shaping of the earth, were all vital components for life to flourish, because we are the right distance, and temperature from the sun.
But that really depended on the formation of the planet over 4.6 billion years ago. What we know is that the solar system formed like a disc of particles. Over time, the planets congealed within that disk, through the forces of gravity. The big player in that relationship — as the planets were competing for matter — was Jupiter. What we don’t understand is why Jupiter formed in the position it did. But we do know that it affected the formation of the Earth. Once that was set, all these other properties came into being: namely the size of the earth and its position from the sun.
If Jupiter had formed further from the sun, we would likely have rockier planets. If it formed closer to the sun, we would probably have fewer and larger rockier planets. So it’s not unreasonable to think that the size and shape of our bodies — which depends on gravity — is related to where the Earth formed, which is related to how and when Jupiter formed.
You also posit that in the next billion years earth will lose its water, superheating the surface of our planet. Will this overheating process be gradual, and what implications will it have for life on our planet?
It is something that would happen over millions, if not billions of years. The question is: will our species even be around in that billion-year timeframe? What I have learned as a paleontologist — by looking at species over time and at the fossil record — is that extinction is inevitable.
What is the fate of our own species when we think about the planet in these terms?
There are many ways that our species can develop and change. One possibility is a kind of science-fiction-type situation: where we find a way to leave Earth in that billion-year time frame. That is very conceivable when you consider how ingenious our species is. If we don’t destroy ourselves in that time frame, we will find a new home.
What kind of progress is being made into establishing if life is sustainable on other planets?
We are discovering that there are a lot of worlds out there. The space observatory mission, Kepler in particular, is identifying a number of planets and a number of solar systems that are very similar to ours. What we are seeing is that Earth may not be an unusual kind of planet that is capable of containing liquid water, and life itself. Having said that, we are also at a very critical period in human history. While technology can bring us many benefits, it also has the capability to destroy us. So it’s still a very open question what the fate of our species is, particularly over that long time frame.
You discuss in the book how our body clocks are deeply embedded inside us. What is the basis for these innate daily rhythms that we have as a species?
Well DNA makes proteins. And there is a rate at which the DNA is generating those proteins, which migrate throughout the nucleus and cell, and then they regulate the DNA. It cycles because of a complex interaction of these DNA and protein constituents that negatively regulate each other. If we think of it like a pendulum that swings back and forth between low and high levels of activity, it makes perfect sense.
Is this clock very important to our health?
Absolutely. Disruptions to this natural cycle of time can make us more susceptible to various diseases, like cancer and so on. So remarkably this 24 hour clock that is embedded in each of our cells, is fundamental not only our biology, but to other animals as well. Time — as defined by the planet, and by the moon — is deeply embedded in all living creatures, except maybe those that are at the bottom of the ocean.
What are the main factors that contribute to various species becoming extinct at certain periods in our planet’s history?
Well there is about five defined time periods where the diversity of life contracts globally: in the oceans, and sometimes on land. So the hunt for paleontologists has been to explain how that happens? We have a number of theories about what drives those extinction events. One that many people will be familiar with is the asteroid extinction hypothesis: where sometime in the past, an asteroid hit the Earth, released a lot of energy and dust particles into the atmosphere, which causes an ecological catastrophe, leading to a reduction of species. But there are other mechanisms, such as changes in volcanism: intense periods of volcanic activity, which changes the chemistry of the ocean and the atmosphere: as well as the movement of the continents, which may be associated with the change in the range of creatures.
What is the most likely event that led to the extinction of the dinosaurs 65 million years ago?
The asteroid theory is the most likely culprit. What is interesting about that event is that if it hadn’t happened, we most likely eould not have evolved as a species. If you look at our lineage — the mammals — they were reasonably diverse in number but they didn’t have the same level of adaptive diversity. It’s really not until dinosaurs are removed from the scene 65 millions years ago that mammals truly began to flourish.
Speaking about the changing pace of technology and its impact on human civilization you pose two very interesting questions: ‘Is Darwin No longer behind the steering wheel? Has the result of millions of years of human evolution been to disconnect us from the planet and evolution itself?’ What do you mean by this?
Well think about what drives our lives today. We are creatures that have the planet bedded in our biology. We have clocks inside of every cell. But are we tied to that? No. We live in artificial light. We have disconnected in many ways from our biological heritage. One of the ways we have done this is through our ideas and culture: the ways we interact with one another, and share information. For better or for worse, that is impacting our cells and the planet. We now live in world where the information flow from one human to the next is part biological and part cultural.
Is culture becoming a greater force — in evolutionary terms — than our genes in directing the fate of the human species?
For a human being, technology can drive what we do. Our capabilities are less driven by our biological inheritance than they are by our cultural and socio economic inheritance. But that is not true of everybody on the planet. If you think of most of humanity: the cause of death is infectious disease, malaria and diarrhea. In the future it will be technology that is driving the fate of our species, not biological evolution. Human beings are becoming both a biological and technological creature. Whether in the future, computers become individuals who are capable of making decisions, I don’t know. But technology is certainly impacting our biological evolution. There is no doubt about that.Tags: evolution, Non-fiction, Science