why plants are the fittest organism for the survival on earth ?
Answers
Taking as our starting point a proper definition of “fittest", which means “most suitably designed to thrive in the particular niche in which an organism finds itself", it is obvious that plants are forced to follow this pronciple more rigorously than animals, by virtue of the fact that an individual plant (maybe the banana is an exception) can't move its location to a more favourable one. If a location were too hot for an animal it can move to shade. If the European winter is too cold for a swallow, it can fly to Africa. Given a gradually changing environment, an animal too could adopt the strategy of gradually evolving to more closely match the prevailing conditions such as the original black skinned inhabitants of Europe evolving paler skins to allow more vitamin D production.
Plants can in fact move, but only in a generational sense inasmuch as their seeds can be dispersd at a distance from the parent plant. So you could envisage an oak forest in Eurasia gradually moving south as the jays disperse their acorns. Those dropped to the south had a marginally better chance of survival than those dropped in other directions. I don't think anybody has measurd this movement, maybe it was a kilometer a century or 100 kilometers. For the oak forest to survive, the creep had to be faster than the advance of the ice-sheet.
But when not engaged in seed dispersal movement, a plant's best chance of survival as a species was to have a great deal of genetic diversity so that all of its thousands of progeny had countless differences in countless traits. One seedling might be just a bit more resistant to frost, another to drought, another to salinity, another to browsing, another to light intensity, another to chestnut blight or Dutch elm disease. It is the principle of survival of the fittest that allows those specimens with the most useful traits to breed to match the ever changing environment.
Even the hardiest cactus in the driest desert has to produce at least some seeds that require more moisture than their present environment can supply, because the mountains could wear down, the rains could come again and leaves will once agajn be more useful than spines
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Answer:
Taking as our starting point a proper definition of “fittest", which means “most suitably designed to thrive in the particular niche in which an organism finds itself", it is obvious that plants are forced to follow this pronciple more rigorously than animals, by virtue of the fact that an individual plant (maybe the banana is an exception) can't move its location to a more favourable one. If a location were too hot for an animal it can move to shade. If the European winter is too cold for a swallow, it can fly to Africa. Given a gradually changing environment, an animal too could adopt the strategy of gradually evolving to more closely match the prevailing conditions such as the original black skinned inhabitants of Europe evolving paler skins to allow more vitamin D production.
Plants can in fact move, but only in a generational sense inasmuch as their seeds can be dispersd at a distance from the parent plant. So you could envisage an oak forest in Eurasia gradually moving south as the jays disperse their acorns. Those dropped to the south had a marginally better chance of survival than those dropped in other directions. I don't think anybody has measurd this movement, maybe it was a kilometer a century or 100 kilometers. For the oak forest to survive, the creep had to be faster than the advance of the ice-sheet.
But when not engaged in seed dispersal movement, a plant's best chance of survival as a species was to have a great deal of genetic diversity so that all of its thousands of progeny had countless differences in countless traits. One seedling might be just a bit more resistant to frost, another to drought, another to salinity, another to browsing, another to light intensity, another to chestnut blight or Dutch elm disease. It is the principle of survival of the fittest that allows those specimens with the most useful traits to breed to match the ever changing environment.
Even the hardiest cactus in the driest desert has to produce at least some seeds that require more moisture than their present environment can supply, because the mountains could wear down, the rains could come again and leaves will once agajn be more useful than spines.