Final answer:
Features of a biological succession that bring about an increase in the index of diversity include the sequential replacement of species and the colonization of new areas by different species with varying adaptations.
Step-by-step explanation:
In a biological succession, the increase in the index of diversity is due to certain features of the succession process. These features include the sequential appearance and disappearance of species over time, as well as the colonization of newly exposed or formed land by living organisms. As the succession progresses, different species with varying adaptations and abilities to utilize resources colonize the area, leading to an increase in species richness and overall biodiversity.
For example, in primary succession, pioneer species like mosses and grasses are the first to colonize the newly created soil. These species are followed by other plants that can grow and reproduce quickly, such as grasses, which further improve the soil. Over time, shrubs and small trees replace the grasses, and eventually, larger trees dominate the area. Each new wave of species brings new adaptations and traits, increasing the overall diversity of the community.
In summary, the increase in the index of diversity in a biological succession is a result of the sequential replacement of species and the colonization of new areas, allowing for the establishment of different species with varying adaptations and abilities to utilize resources.