A Level Biology Practice Exam

Which of the following best describes species evenness?

1. The diversity of genetic material within species

2. The relative abundance of different species in a community

3. The total number of species present

4. The ability of a species to adapt to environmental changes

The correct answer is: The relative abundance of different species in a community

Species evenness is a key concept in ecology that refers to how evenly individuals are distributed among the different species in a community. It assesses the relative abundance of each species and indicates how close in numbers each species is. High evenness means that species are represented in similar quantities, whereas low evenness indicates that a few species dominate the community while others are relatively rare. In this context, species evenness is often used alongside species richness, which refers to the total number of different species present. While species richness gives a count of the number of species, it does not provide information about the distribution of individuals among those species. Therefore, understanding species evenness is crucial for comprehensively measuring biodiversity, as it reflects both the variety of species and their relative abundance within ecosystems. This is why the correct description is focused on the relative abundance of different species in a community.