Who Wrote the Book of Life?

The "D'Arcy Machine" and the quest for the 'Book of Life'.

In order to effectively search for life on other planets, we first have to come to an understanding about what life IS. One way to do this is to study the forms that life can take, and this is just what NASA is currently studying with the 'Book of Life' project.

In his 1917 work, "On Growth and Form," D'Arcy Thompson altered mathematical functions in order to visualise how species changed shape over time.

Scientists are using Thompson's biomathematical studies of life forms on Earth to postulate about life forms throughout the universe. There are certain universal conditions that will always affect the shape of a life form, wherever that life may be.

"Everywhere Nature works true to scale, and everything has a proper size accordingly," wrote Thompson"Cell and tissue, shell and bone, leaf and flower are so many portions of matter, and it is in obedience to the laws of physics that their particles have been moved, moulded and conformed."

Gravity, for instance, acts on all particles and affects matter cohesion, chemical affinity and body volume. Other influences that are consistent throughout the universe are temperature, pressure, electrical charge and chemistry.

But before we can conduct a comprehensive search for unknown extraterrestrial forms of life, there needs to be an extensive classification of known life forms on Earth. The history of life on Earth provides us with a good model for how life can evolve in the universe. Fossils, even microbial fossils, can tell us a great deal about all the different life forms that have at one time or another shown their face on our planet.

"Some fossils in the ancient Burgess shale are so alien we can't determine which end of the creatures are up, and yet these monsters evolved right here on Earth from the same origins that we did," wrote Johan Forsberg, a Swedish psychologist.

By becoming forensic scientists, researchers can develop an encyclopaedia of microbial life forms that have developed on Earth. Because so many life forms need to be catalogued, the scientists are working to develop a "D'Arcy Machine" to help them create a comprehensive "Book of Life."

This Book of Life project has three phases. Phase 1 - compiling a beginning database of microbial life forms - has already been completed. This image database is composed of 10,000 examples and distinguishes the basic microbial shapes such as rods, spheres, filaments, clusters that look like grapes (cocci), and spirochete (spirals). A computer neural network has been trained to recognise and classify these microbial life forms with 90 percent accuracy.