first photox bacteria evolved 3.6 bya billion years ago

Divide the wires into two main branches: 22 for Bacteria and the remainder for the Archaea and their later descendants, the Eukaryota, and split them off very near the base as these two domains split off quite early on (about 3.6 to 3.9 bya). The model should show time by length of wire, so let's make the wires 40 cm long or 10 million years per millimeter. Let's make the model by taking a bundle of 56 wires, and binding them at the base-the beginning of life about 4 billion years ago (bya). Of the still over 50 remaining divisions, kindly note that each is as genetically different from the other as plants are from the fungi/animals.

Another would be labeled 'Fungi/Metazoa Group.' The metazoans (the multicellular animals) it turns out, are not so different from fungi as to warrant a separate division of their own-another blow to our collective ego. One of these would be 'Viridiplantae,' the green algae and green plants. There would be over 50 terminal branches. One would show the Big Picture, the 3 Domains of Life: Bacteria, Archaea, and Eukaryota along with the major divisions of each. One aid to understanding would be to construct 3-D models of the tree of life. It is difficult to grasp this view of life-life's enormous diversity and age. Every human we know by name lived and died (or soon will) within this band. It is within this band that all of human history is contained. On your screen the sapiens branch appears to be about 4 cm long and the band at the tip is about 1 mm wide-about the width a dull pencil might make. Note near the tip is a small band the color of black ink. Crank up the power until you can see the hair-like branch labeled 'Homo sapiens.' Crank the power up to maximum. To see more, move over to the electron microscope. Many were 'done in' in one way or another by other species of Homo in a process that lead to there being only a sole surviving member of the genus: Homo sapiens. There's a lot of dead wood here - Homo antecessor, Homo cepranensis, Homo erectus, Homo ergaster, Homo floresiensis, Homo georgicus, Homo habilis, Homo heidelbergensis, Homo neanderthalensis, Homo rhodesiensis, Homo rudolfensis, and probably a few more yet to be discovered. On the left you'll see the twig labeled 'Homo,' the genus containing all humans-the bipedal apes. Note the tiny branch labeled 'Hominidae' that includes all the Great Apes. So on the Great Tree of Life (the one for earth, anyway) imagine a 'You are here' arrow pointing to a barely discernable speck labeled 'Primates.' Get out your microscope and dial in the 10x objective for 100x power. Then, after reading just a few pages from the RNA Book of Life, biologists collectively gasped, mouths dropped, eyes bugged out (you get the picture) as they caught a glimpse of the true diversity of life. By the 1970's biologists had pretty much realized there were more than two Kingdoms, and the Five Kingdom System (Bacteria, Protista, Fungi, Plants, Animals) was proposed and eventually found its way into the textbooks. It wasn't that long ago that Baby Boomers were being taught that all living things could be classified as either Plants or Animals. Could we be any more insignificant? Now, thanks to insights gleaned from decoding the RNA/DNA Book of Life, biologists have at last gotten into the spirit of things.

Next, recall the poster of a spiral galaxy with another 'You are here' arrow pointing to another speck representing our sun. Imagine seeing on the Great Map of the Universe one of those 'You are here' arrows pointing to a microscopic speck representing our galaxy.

Most of us, the truth be told, have failed to fully absorb the implications of the 16th century discovery that 'our' earth is not the center of the universe-and fewer of us have recovered from the more recent shock of 'billions and billions.' Well, prepare yourself for another shock. Over the past decade or so, biology, in the field of phylogenetic systematics, has been quietly undergoing a revolution not unlike astronomy's Copernican Revolution.

First photox bacteria evolved 3.6 bya billion years ago