The first plants appeared about 2.5 billion years ago and since then passed a long evolutionary way. Now on Earth about 400 thousand plant species among which prevail gymnospermous and floral.
Instruction
1. Scientists consider the first plants blue-green seaweed - large bacteria which provided themselves with energy by means of photosynthesis in the course of which oxygen was emitted. They appeared no later than 2.5 billion years ago and exist still. Blue-green seaweed considerably influenced development of life on Earth as they became the reason of sharp saturation of the atmosphere oxygen. At the moment they produce by different estimates from 20 to 40% of all oxygen on the planet.
2. During the Proterozoic era (2700-570 million years ago) wildlife was finally divided into heterotrophic (the kingdom of animals) and autotrophic (the kingdom of plants) organisms. Along with blue-green seaweed the set of other bacteria autotrophs - green seaweed, red seaweed, iron bacteria, etc. appeared.
3. About 450 million years ago the first plants appeared on the land, it were already the higher plants which, unlike seaweed, had differentiation of fabrics. The first plants on the land call riniofitam, they grew to 20 cm in height and covered huge land areas with a continuous carpet. At the moment these primitive plants completely died out. In them for the first time there were special cages - tracheitises which provided movement of nutrients and water in a plant. In the same time mosses and lichens appeared.
4. Later 50 million years there were first polypodiaceae which the same as riniofita, bred disputes, but were more perfect. Some ferns reached the huge sizes. The ferny woods were formed. The humid hot climate of this period promoted prosperity of sporous.
5. Ferny and others sporous gradually evolved in gymnospermous. During the Permian Period (230-280 million years ago) sporous practically disappeared from the face of the earth, and replaced them coniferous and ginkovy which prospered in the Triassic and Jurassic Period. At this time there was a huge number of species of gymnospermous plants, some of them even had yagodovidny fruits.
6. At the beginning of the Cretaceous, that is about 137 million years ago there were first Angiospermae which actively developed during this period. Such plants as grapes, a beech, a willow, a poplar, a ficus, an eucalyptus, a payment, laurels, a magnolia, appeared then.
7. The Cenozoic Era which began 67 million years ago and lasts to this day, became an era of angiospermous plants, already at its beginning the terrestrial landscapes resembled modern. In Ice Age the species of Angiospermae sensitive to cold appeared.