The children had spread up and down the beach, and some of them had even ventured into the surf where the tall green waves crashed down upon them. Glaring from a deep blue sky, the sun burned on the yellow sand. A wave broke into foam, surging far up the shore with a soundless rush. The sharp clap-clap of Teacher's hands could easily be heard in the sunlit silence.
"Playtime is over — put your clothes back on, Grosbit-9, all of them — and the class is about to begin.”
They straggled towards Teacher, as slowly as they could. The bathers emerged dry from the ocean, while not a grain of sand adhered to skin or garment of the others. They gathered about Teacher, their chatter gradually dying away, and he pointed dramatically at a tiny creature writhing across the sand.
"Uhggh a worm!" Mandi-2 said and shivered deliciously, shaking her red curls.
"A worm, correct. A first worm, an early worm, a protoworm. An important worm. Although it is not on the direct evolutionary track that we are studying we must pause to give it notice. A little more attention, Ched-3, your eyes are closing. For here, for the first time, we see segmentation, as important a step in the development of life as was the development of multicellular forms. See, look carefully, at those series of rings about the creature's body. It looks as though it were made of little rings of tissue fused together — and it is."
They bent close, a circle of lowered heads above the brown worm that writhed a track across the sand. It moved slowly towards Grosbit-9 who raised his foot and stamped down hard on the creature. The other students tittered. The worm crawled out through the side of his shoe and kept on.
"Grosbit-9, you have the wrong attitude," Teacher said sternly. "Much energy is being expended to send this class back through time, to view the wonders of evolution at work. We cannot feel or touch or hear or change the past, but we can move through it and see it about us. So we stand in awe of the power that permits us to do this, to visit our Earth as it was millions of years ago, to view the ocean from which all life sprung, to see one of the first life forms on the ever-branching tree of evolution. And what is your response to this awe-inspiring experience? You stamp on the annelid! For shame, Grosbit-9 for shame."
Far from feeling shameful, Grosbit-9 chewed a hangnail on his thumb and looked about out of the corners of his eyes, the trace of a smirk upon his lips. Teacher wondered, not for the first time, how a 9 had gotten into this class. A father with important contacts, no doubt, high placed friends.
"Perhaps I had better recap for those of you who are paying less than full attention.” He stared hard at Grosbit-9 as he said this, with no apparent effect. "Evolution is how we reached the high estate we now inhabit. Evolution is the forward march of life, from the one-celled creatures to multicelled, thinking man. What will come after us we do not know, what came before us we are now seeing. Yesterday we watched the lightning strike the primordial chemical soup of the seas and saw the more complex chemicals being made that developed into the first life forms. We saw this single-celled life triumph over time and eternity by first developing the ability to divide into two cells, then to develop into composite, many-celled life forms. What do you remember about yesterday?"
"The melted lava poured into the ocean!"
"The land rose from the sea!"
"The lightning hit the water!"
"The squirmy things were so ugghhy!"
Teacher nodded and smiled and ignored the last comment. He had no idea why Mandi-2 was registered in this science course and had a strong feeling she would not stay long.
"Very good. So now we reach the annelids, like our worm here. Segmented, with each segment almost living a life of its own. Here are the first blood vessels to carry food to all the tissues most efficiently. Here is the first hemoglobin to carry oxygen to all the cells. Here is the first heart, a little pump to force the blood through those tubes. But one thing is missing yet. Do you know what it is?"
Their faces were empty of answers, their eyes wide with expectation.
"Think about it. What would have happened if Grosbit-9 had really stepped on this worm?"
"It would have squashed," Agon-1 answered with eight-year-old practicf lity. Mandi-2 shivered.
"Correct. It would have been killed. It is soft, without a shell or a skeleton. Which brings us to the next branch on the evolutionary tree."
