Which Organisms Are Typical Pioneers In Primary Succession?

• A. Lichens And Moss
• B. Large Trees
• C. Grasses
• D. Deserts

Answer: (A)

In primary succession, the first organisms to appear on bare rock or newly formed land are those that can survive with very little soil or nutrients. Lichens, which are a partnership between fungi and algae, along with mosses, fit this role well. They can colonize harsh, nutrient-poor surfaces and tolerate dry, exposed conditions. As they grow, they slowly break down the rock and contribute organic material when they die, forming a thin layer of soil. That tiny amount of soil lets other plants—starting with grasses and then shrubs and eventually trees—take root, continuing the process of building a richer, more complex ecosystem. Large trees need established soil with more nutrients and moisture, so they aren’t the first to appear in primary succession. Deserts describe a habitat, not organisms, and don’t explain who starts the succession on bare surfaces. So lichens and mosses are the typical pioneers.