Evolution of Micro-organisms and Plants

Cambrian Period, 541 - 485.4 MYA

Perhaps the evolution of plants began on land, when algae are left high and dry between tides. When they stayed ashore, they adapted to the new open-air lifestyle with great success. To survive in air, they thickened their walls, thus staying wet on the inside while the air dried them on the outside. Fungi, a kingdom including molds, mushrooms, and yeasts, also now appear

		on shores, where they practice the ability to digest organic food with excreted enzymes before consuming it. Some fungi cooperate with algae to form a single-organism partnership called lichens (see Figure 10). Figure 11 shows the structure of lichen with the algae under the upper fungal layer. The bodies of the fungi are in the middle in the form of filaments called hyphae. Lichens are able to live on rock, dissolving its minerals and photo-synthesizing food. Lichens, like algae before them experiment with plantlike forms.
Figure 10 Lichen [view large image]	Figure 11 Lichen Structure [view large image]

Plant cells are more complex than those of either animals or fungi because they have both mitochontria and chloroplasts. The first real plants to evolve are mosses, often found in close association with fungi. From the time they invent a cooperative lifestyle as lichens until today, plants and fungi have a very close association. It may even be that the first plants are a genetic fusion of the two. Ninety percent of plants have fungi called mycorrhizal (root fungus) living in special co-evolved compartments inside their roots or in the soil, intertwined with roots, making food for each other according to specialty and recycling wastes.