1

Getting Started

You who read this are a unique collection of one hundred trillion cells, all agreeing to work together, to intensely specialize into about two hundred different kinds of cells, conglomerating into organs, each with their specific job, so that you can exist.

You were originally one cell, just like a bacterium or an amoeba, when your mother and father each contributed half your DNA. Although just one cell, you were made up of billions of atoms that bonded together into complex structures like proteins, fats and nucleotides. These atoms were created long ago in a star, of which the Sun is the remnant, where intense heat allowed nuclear fusion to combine smaller atoms into bigger ones.

The final proportions of your atoms, like carbon, hydrogen, oxygen, sulphur and nitrogen, both now and when you were one cell, are approximately the same as those of the universe. As the saying goes, biology parallels geology — or to put it simply, life stepped out of the rocks. We take this for granted, mostly because we don’t know how it happened, partly due to that kind of inquiry always spiralling into a fathomless vortex of mystery that leaves us unsatisfied. Add to that the complication of spirituality and the worldwide variety of viewpoints of God, and the big conversation about life shuts down.

When you were one cell, you started your life on Earth totally dependent on your mother for sustenance. The fertilized egg divided into two, then four, eight, sixteen, etc., until a ball of cells was produced that rolled around in the nutrient-rich elixir of the uterine fluids, gathering nutrients by simple absorption — much like the method that many tiny species of organisms still employ. When you became a little too big for the surface-absorption method of staying alive, a few millimetres in diameter, you adapted by sending down roots in the form of blood vessels, which eventually became the placenta, a clever interface you made between your mother’s blood supply, with all its oxygen and nutrients, and your blood supply. Most mammals, from mice to elephants, do this but the interfaces differ.

As you developed from embryo to fetus, your body went through stages that many other vertebrates go through. The earlier the stage, the more difficult it was to tell the difference between you and a fish, a salamander, a frog, a chicken or a d