Evolution of Land Plants from Algal Ancestors That Were Already Terrestrial (IMAGE)
Caption
This graphic shows key events in the establishment of a land flora. These were the primordial terrestrialization event by a unicellular ancestral charophyte followed by evolution of a novel cell wall in response to the new types of selection pressure. A particular successful lineage evolved the multicellular sporophyte as a platform for the development of complex body plans and vascularization, the latter facilitated by the new cell wall. Other lineages established themselves as extant terrestrial charophytes, here exemplified by Klebsormidium growing on a stone, while other taxa secondarily adopted an aquatic lifestyle yet retained the terrestrial traits in their cell wall as clues to their terrestrial ancestry.
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Panny Kondor
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