Hundreds of millions of years ago, algae appeared on the earth. Green algae is one of them. It is not so different from other algae. It has no chlorophyll and can only rely on the external environment for nutrition. In the later stage, there were cyanobacteria in the ocean. They appeared photosynthetic bacteria. Strictly speaking, they were the origin of plants. They could absorb sunlight and release energy for their own growth. Plants will be from simple to complex, from aquatic to terrestrial. They are algae that appear in the ocean at first, and gradually leave the ocean as they grow. Note that if we divide organisms into plants and animals by binary division, then fungi are the earliest plants. If we divide them by other methods, then the birth of primitive plants is algae.
At the beginning, algae is only a single cell plant. After a long process of evolution, they have evolved into multicellular algae, and their growth structure is gradually complex. Later, due to the violent movement of the earth's crust, some of the original oceans evolved into land, among which the algae in the ocean evolved into ferns, which could more easily adapt to the land environment. Later, because the land climate is relatively dry, ferns will also evolve into gymnosperms, which can completely get rid of the dependence on water.
