Moss antheridium Moss archegonium Moss sporangium Specimens Lilium flower bud Staminate cone Ovulate cone Tilia stem cs Zea stem cs Page 1 of 3 Major Evolutionary Changes in Plants Plants have had 4 major evolutionary changes so far in history The first one is the move to land from water This happened 450 million years ago due to a drought that affected freshwater algae and believed to facilitate the move The second is the evolution of vascular tissues Mosses liverworts and hornworts are all non vascular plants which then lead to vascular plants such as ferns conifers and flowering plants This occurred about 420 million years ago with The third is the evolution of seeds and pollen in plants This allows reproductive adaptations that are better than before The first seeded plants were cones which are known as gymnosperms The Evolution of plants producing flowers and fruits is the 4th and final step of the evolutionary history This occurred after the gymnosperms in angiosperms where seeded plants evolved to produce flowers that contain ovaries which form fruits One thing that happened before any of this could occur is the oxygen revolution which allowed for oxygen to be used and for organisms to use oxygen and for carbon dioxide to be converted to oxygen Plants are the organisms which complete this action through photosynthesis which allows for humans and every other aerobic organism to live having stalked cones The five traits that were added to the tree include No roots the use of photosynthesis cell walls reproduce sexually by tiny spores usually having bark and Page 2 of 3 Page 3 of 3
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