When considering classical mathematics, the Greeks must be a main focus of our attention. In fact, the primary reason for discussing earlier mathematics is to understand what the Greeks inherited and what they left to their posterity.
The organisms that engage in primary succession are known as pioneer species. Typical pioneer species include simple lichens, algae, and fungi. These simple organisms begin breaking down the resources in the environment and make it suitable for the later introduction of more complex species, such as vascular plants.
zoom_in. Secondary succession follows a major disturbance, such as a fire or a flood. The stages of secondary succession are similar to those of primary succession; however, primary succession always begins on a barren surface, whereas secondary succession begins in environments that already possess soil.