Final answer:
The tremendous diversity of life on Earth is attributed to evolution, which is the gradual process of change in a population or species over time.
Step-by-step explanation:
The tremendous diversity of life on Earth is attributed to evolution, which is the gradual process of change in a population or species over time. Evolutionary biologists study the evolution of living things, from microscopic organisms to entire ecosystems.
It is through the mechanism of evolution that new species arise from older ones, resulting in the vast array of life forms that exist on our planet.