Emergence of Life on Earth: A Historical and Scientific Overview

No scientific theory has yet to succeed in providing a fully convincing account of the emergence of life on Earth. However, in this book Iris Fry provides the reader with the history and facts of the origin of life studies, starting with Empedocles and Aristotle, and finishing with contemporary theories. (It should be noted that nothing significant has been discovered since the publication of this book.)Every living cell known to us is made up of nucleic acids—DNA and RNA—and proteins. And these two fundamental components of the cell are completely interdependent. And that interdependence is the stumbling block of origin of life theories today, a problem that fry appropriately dubs "the chicken and the egg": They are too complex to have emerged simultaneously on the primordial earth, so how could one have been produced without the other?Many ideas have been proposed to get around this problem, but nothing yet concrete. The most popular of these ideas is the 'RNA world hypothesis', which suggest that RNA could have done the job of both nucleic acids and proteins. Another interesting hypothesis, called Panspermia, proposes that life developed elsewhere in the universe and then arrived to Earth on top of meteorites, comets, etc.At the end of the book, Fry goes on to discuss the possibility of extraterrestrial life. Most scientist seem to agree that extraterrestrial life most probably exist. Intelligent extraterrestrial life on the other hand is a completely different issue. Many scientists view the evolution of intelligent life as extremely improbable. "We have to realize," Stephen Jay Gould states, "that the origin of Homo sapiens was a tiny twig on an improbable branch of a contingent limb on a fortunate tree." So, while there’s a very big chance that we will find life somewhere else, that life will most likely not be intelligent.Iris Fry is an accomplished scientist and historian, and knows what she’s talking about. And although her book may have been a bit of a heavy read at times, I found it very informative.

Great book! Simply the best book in origins of life to have a broad and complete notion of both philosophical, historical and scientific domains in this subject.

Chock full of goodness! And very readable.

From the ancient Greek philosophers through Enlightenment science to today's high-tech world, how life originated has been a compelling question. Fry presents the thinkers and their ideas about this enigma with penetrating skill. Her recapitulation of the philosophical questions set in their historical perspective demonstrates the persistence of many concepts regarding life's history. "Spontaneous generation", now considered a quaint idea, dominated the view of theologians and natural scientists alike. Even when empirical experiments demonstrated the falsity of the notion, versions of it remained, deflecting other proposals.Fry shows how Darwin's idea of natural selection over vast periods of time allowed tracing a view of life back to simple, microscopic life forms. Darwin's famous "warm little pond" may have been an incomplete picture, but it demonstrated a break with established notions. Complex life evolved from simple life, not fully blown from a soiled shirt. Only in the 20th Century did technology and the discovery of unanticipated life forms in extreme conditions allow a look at the chemical basis of life before complexity could emerge.Fry carefully and skillfully examines all these steps, giving each thinker his due while placing him in historical context. There's more than one surprise here for those who don't know the lives of researchers such as Pasteur, Eigen or Oparin. As she reveals the progress of thinking on the subject, Fry examines the roots of various proposals, their advances and their shortcomings. Was life's beginning protein-based? Are amino acids the foundation or the product of life? Did RNA precede DNA or the reverse? Science proceeds on a step-by-step basis and Fry describes that halting, but useful process far better than most. While Fry's descriptive prose reflects a thesis style, the wealth of information here overrides that limited criticism.Among the modern thinkers on life's origins, Fry provides the best summation available on the ideas of two men, Graham Cairns Smith and Gunther Wachtershauser. Both men have offered theories of chemical beginnings of life, the one suggesting clay crystals as replication models, the other utilising the iron-sulfur energy capacity of pyrite. These two concepts are united by Fry in light of the processes found associated with deep sea-floor vents.Fry's conclusion deals with the likelihood of life on worlds other than Earth. The dispute over whether the Antarctic Martian meteorite exhibits organic residues serves to show how limited current information actually is on pre-life chemistry. More research, more examination and more questions need to be posed. Fry's book provides a solid foundation for the next steps. [stephen a. haines - Ottawa, Canada]