How does biodiversity tend to increase over time?

Biodiversity increases over time primarily through the process of speciation, which is the formation of new and distinct species through evolution. This gradual process occurs as populations adapt to different environments, experiences mutations, or undergo geographical isolation. Over generations, these adaptations can lead to the emergence of new species, thereby enhancing the richness and variety of life forms within an ecosystem.

This concept is rooted in the understanding of evolutionary biology, where genetic diversity and natural selection play crucial roles. Factors such as environmental changes, ecological interactions, and genetic variations contribute to the complexity and dynamism of biodiversity over long timescales. This ongoing process is fundamental to the resilience and health of ecosystems, as it enables them to adapt to changes and maintain functional integrity.

The other options focus on aspects that may contribute to biodiversity but do not represent the primary mechanism through which biodiversity naturally increases over time. Human intervention, habitat preservation, and environmental stability can influence biodiversity levels, but they do not drive the natural increase in species diversity in the same inherent manner as speciation does.