What can science tell us about Life? Lots! We learn that the oldest visible fossils date back 2.7 billion years. Ancient bacteria supplied the earth’s atmosphere with oxygen. Life suddenly burgeoned 575 million years ago, a phenomenon called
punctuated equilibrium. Prehuman forms appeared about 4 million years ago. An array of Genus Homos with differing DNA and biology appeared simultaneously, and some coexisted, as did humans and Neanderthals.This is a sculpture of Australopithecus africanus, an early player.
Cells, fundamental to life, come in twoforms: prokaryotes (on the right) and eukaryotes. The former, usually bacteria, lack a nucleus. The latter is 10 times larger, has a nucleus, and is the building block of complex organisms. Bacteria are extremely widespread and can adapt to extreme conditions. There are many single
DNA is a very long twisted molecule containing four letters, A,T, C, and G, connected in four combinations, AT, TA, GC, and CG. In groups of three, these base pairs code for 20 amino acids. The possible combinations are invariant and are collectively called the genetic code. By this code, DNA is transcribed by RNA to make multitudinous proteins.
Almost all of life is composed of 20 amino acids that are formed by strict rules called the genetic code. The code is extremely optimized and hence minimizes damage done by mutations.
DNA, copied by RNA, leads to the building of proteins via the genetic code. The body is largely composed of and supported by proteins. Receptors are lock
For life to grow, cells must divide. DNA must be separated and meticulously copied. Mistakes must be repaired. These processes are extremely efficient, but errors are made and can add up. Bacteria divide by fission, and bodies of eukaryotes grow by mitosis. The special cell division that results in sperm or eggs is called meiosis.
During the growth of an embryo, cells switch on and off to form tissues. It is thought that tissues are arranged in space not by the genome, but by fields in which structure begets structure. But nobody has seen a field. Could the templates have originally been an image in God’s eye?
Life, through a maze of intricate networks, is able to regulate its physical functions. Genomic restructuring, hypermutation, and induced local mutations are strategies that Life deploys. Life is an agent in its adaptations.
Life is in constant motion. All Life is animated. There is a dynamic principal undergirding living matter that contradicts construing biological life as machine.
We can with science reduce Life to its most fundamental denominators, but there is no answer to the problem of animated, organized complexity, nor to the conundrum of what animation is or where it comes from. At this point, we have to admit that our understandings of Life boil down to a matter of faith: faith that Life is only material, or faith that there is a mystical aspect to Life. Whether we consciously realize it or not, what we think Life ultimately is rests on our assumptions.