Final answer:
Biodiversity is measured in terms of species diversity, which refers to the number of different species in an ecosystem. This measure takes into account both the number of species and their relative abundance.
Step-by-step explanation:
Ecologists commonly measure biodiversity in terms of the number of species present in an ecosystem, which is known as species diversity. This measure considers both the number of species and their relative abundance. Species diversity is the most common way to quantify biodiversity, as it provides a comprehensive understanding of the variety of species in a given area.