Ta tưởng vũ trụ của chúng ta là một nguyên tử thì các hành tinh của vũ trụ chúng ta là các electron chuyển động theo các quỹ đạo xác định và trung tâm của vũ trụ chúng ta cũng như nhân của phân tử theo thuyết này thì vũ trụ mà ta đang sống là một không gian vô hạn không xác định được trong đó luôn tồn tại các hệ vũ trụ khác nhau. | TREE OF LiFE cited possible risks to human health and the environment. World Food Programme officials told them that what was good enough for 280 million Americans was good enough for them. To the question Who decides about transgenic crops the answer seemed to be no one in particular. E For more about natural gene mobility see Tree Of LIFE. TREE OF LIFE A STAGNANT pool was a treat for Lynn Margulis when as a young biologist at Boston University she liked to descant on the little green bugs that can so quickly challenge human notions about how a nice pond should look. Her favourites included the blue-greens often called algae but in fact bacteria which have played an outstanding role in steering the course of life on the Earth. Margulis became the liveliest and most stubborn advocate of the idea that we are descended from bacteria-like creatures that clubbed together in the distant past. Others had toyed with this proposition but she pushed it hard. In 1970 she published a book Origin of Eukaryotic Cells and she followed it in 1981 with Symbiosis in Cell Evolution. These are now seen as landmarks in 20th-century biology and the keywords in their titles eukaryotic and symbiosis go to the core of the matter. You are the owner of eukaryotic cells. Each of the billions of microscopic units of which you re built safeguards your genes of heredity within a nucleus or karyon in Greek. So in the grandest division of living things into just two kinds you belong to the eukarya. That groups you with other animals with plants with fungi and with single-celled creatures called protoctists represented by 250 000 species alive today and often ambiguous in nature. The other great bloc of living things the prokarya are all single-celled and the genes just slop about within them. The earliest forms of life on the planet were all of that relatively simple kind meaning bacteria and similar single-celled 681 TREE OF LiFE organisms called archaea. They ruled the world alone for half its
