Evolution of Leaves

During the evolution of plant leaves have originated at least two separate occasions. The legacy of these historical evolutionary events is represented in the floras current by microphylls of lycophytes ( club mosses , Selaginella and Isoetes ) and the eufilofitas megafilos ( ferns , gymnosperms and angiosperms ). It is considered that the microphylls, with its characteristic vasculature and its absence of branching, have evolved from thorny excrescences and megafilos predate the fossil record of terrestrial plants. Of greater importance, however, was the source of vascular plants in megafilos through the modification of the development of lateral branches since the great majority of the 250,000 flowering plant species existing as well as most gymnosperms, use a flat sheet megafilo a network of veins to capture solar energy and photosynthetic carbon assimilation. The megafilos altered, in fact, the evolutionary path of plants and terrestrial animals, biogeochemical cycles of nutrients, water and carbon dioxide and energy exchange between the land surface and atmosphere. This primary production provides energy for almost all forms of terrestrial life on Earth , especially tetrapods and insects , and link many ecosystems and biogeochemical processes. Obviously, the leaves are evolutionary success of land plants. First, the paleontological evidence shows that the structural framework required for assembly of a single sheet evolutionary were set between plants long before the advent of large megafilos. Second, during the same interval had an unprecedented explosion of evolutionary innovation in the history of plant life, which witnessed the rise of the trees from ancestors arable , and the evolution of life cycles complexes, including the invention of the seed . Third, the small plant megafilo Eophyllophyton bellum from the early Devonian, shows that plants were able to produce a single megafilo long time before these structures were generalized. In nearly all existing plants leaves are an adaptation to increase the amount of sunlight that can be captured for photosynthesis.