Final answer:
Pioneer species are the first organisms to move into an area following a primary disturbance, such as bacteria and lichens. They facilitate the formation of soil that allows other plant species to grow and lead to ecological succession until a climax community is established.
Step-by-step explanation:
The type of organisms that first move into an area after a primary disturbance are called pioneer species. Pioneer species can include organisms such as bacteria and lichens that are capable of living on bare rock. Through their life processes, including weathering the rock and forming soil, they create a more hospitable environment that allows grasses and other plants to grow, which can thrive in thin, poor soil at first. As the organic matter from these plants accumulates and decomposes, it enriches the soil, enabling larger plants like shrubs and trees to establish themselves in the area, leading to an ecological succession until a stable climax community is formed.