Science Clarified - Gaia Hypothesis
Field of reference: Interdisciplinary, Ecology, Biology
Description: The simplest of bacteria formed symbiotic relationships—relationships that benefitted both organisms.
"Cooperation over competition
Lovelock was supported in his hypothesis by American microbiologist Lynn Margulis (1918– ) who became his principal collaborator. Margulis not only provided support, but she brought her own scientific ability and achievements to the Gaia hypothesis. In her 1981 book, Symbiosis in Cell Evolution , Margulis had put forth the then-unheard of theory that life as we know it today evolved more from cooperation than from competition. She argued that the cellular ancestors of today's plants and animals were groups of primitive, formless bacteria cells called prokaryotes (pronounced pro-KAR-ee-oats). She stated that these simplest of bacteria formed symbiotic relationships—relationships that benefitted both organisms—which eventually led to the evolution of new lifeforms. Her theory is called endosymbiosis (pronounced en-doe-sim-bye-O-sis) and is based on the fact that bacteria routinely take and transfer bits of genetic material from each other.
Margulis then argued that simple bacteria eventually evolved into more complex eukaryotic (pronounced you-kar-ee-AH-tik) cells or cells with a nucleus. These types of cells form the basic structure of plants and animals. Her then-radical but now-accepted idea was that life evolved more out of cooperation (which is what symbiosis is all about) than it did out of competition (in which only the strong survive and reproduce). The simple prokaryotes did this by getting together and forming symbiotic groups or systems that increased their chances of survival. According to Margulis then, symbiosis, or the way different organisms adapt to living together to the benefit of each, was the major mechanism for change on Earth.
Most scientists now agree with her thesis that oxygen-using bacteria joined together with fermenting bacteria to form the basis of a type of new cell that eventually evolved into complex eukaryotes. For the Gaia hypothesis, the Margulis concept of symbiosis has proven to be a useful explanatory tool. Since it explains the origin and the evolution of life on Earth (by stating that symbiosis is the mechanism of change), it applies also to what continues to happen as the process of evolution goes on and on."
| שייך לנושאים: 1-13 - חינוך אינטגרלי, -מקורות מדעיים, הטבע, 2. הטבע כמערכת |
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