DECENT WITH MODIFICATION 6 We really shouldn’t speak of animal colonization of land without a word or two concerning the move of plants from the sea to a terrestrial existence. There were a few groups of green algae which inhabited coastal waters and which once in a while were caught above the waterline and temporarily dried out. Some algal genetic combinations provided structural features which made some plants resistant to this drying to the extent that those which were more resistant to drying were the ones which were the mostly to survive any prolonged periods of drying. Along the shores, slowly over a couple of million years those plants which were resistant to drying were favored in the seashore environment until they were eventually able to function independently from the requirement for being submerged at all. Along the shore, they were less subject to aquatic predators also so the characteristics favoring Terrestrialization became more and more prominent until they became fully land adapted. The numbers of potential habitats and niches on this primitive landscape were mostly unlimited and with the seeds of terrestrial plant evolution planted, the process took off with a vengeance! Plants which mostly resembled horsetail rushes took off and Tree Ferns and “”Club Mosses” diversified and formed huge growths as the tree ferns, horsetails, mosses and liverworts as well as ground hugging ferns joined with them to form some of the so-called carboniferous forest associations which developed to a penultimate degree in the Carboniferous period between the Devonian and Permian. The Mass Extinction event at the Permian/Triassic border changed the picture a bit and allowed the fledgling Gymnosperms groups of Cycads, Ginkgos and Conifers to begin the road to botanical prominence. It would not be until the end of the Cretaceous period and the end of the Age of Dinosaurs that Flowering plants (Angiosperms) started to truly come into their own becoming the dominant groups of land plants as they are today.
Posted on: Mon, 19 Jan 2015 21:17:51 +0000