The origin of plants. The main stages of the development of the plant world. - presentation

The earth was formed - more than 5 billion years ago. There are five stages in the evolution of the plant world. The first living organisms appeared 3.5 - 4 billion years ago in water. They were similar in structure to bacteria. Organic and mineral substances dissolved in water were used for food, the supply of which was gradually depleted and chlorophyll appeared in some cells, which led to the occurrence of the process of photosynthesis. From the ancient protozoa, unicellular algae originated. Among the algae, those attached to the bottom appear, which led to the dismemberment of the body into parts: some serve for attachment, others carry out the process of photosynthesis.

Devonian system: Plants managed to move away from the water's edge and soon vast areas of land were overgrown with dense primeval forests. The number of various vascular plants has increased. Spore glycophytes (ploons) and horsetails appeared, some of them developed into true trees 38 m high.

Permian system: Forests of large seed ferns, glossopteris, have spread over the southern land masses. The first conifers appeared, quickly populating inland areas and high mountains. Among terrestrial plants, articular ferns and gymnosperms predominated.