Final answer:
Pioneer species are the first to colonize new land, like that created by volcanic lava. They start the process of primary succession by breaking down rock into soil and paving the way for other species.
Step-by-step explanation:
The first species to live on new land, such as that formed from volcanic lava, are called pioneer species. These organisms are capable of colonizing barren environments that lack soil. Primary succession occurs when these pioneer species, often hardy organisms like lichens and some plants, move in and begin the process of ecological succession. They contribute to soil formation by breaking down the mineral-rich substrate. Over time, as these early species grow and decompose, they enrich the soil, allowing for the establishment of less hardy but more competitive species such as grasses, shrubs, and trees. Eventually, this leads to a mature ecosystem that is quite different from the initial one that was colonized by the pioneer species.