Scientists don't typically break down evolution into two "categories" in the way you might be thinking. However, there are two main processes that drive evolution:

1. Microevolution: This refers to changes in the genetic makeup of a population over time. It involves changes in allele frequencies within a population, which can be driven by factors like natural selection, genetic drift, mutation, and gene flow. This is the level of evolution that can be observed directly in relatively short time scales.

2. Macroevolution: This refers to the larger-scale evolutionary changes that occur over long periods of time, often leading to the formation of new species or higher taxonomic groups. This is the process that results in the diversity of life we see on Earth today. Macroevolution is essentially the cumulative effect of many microevolutionary events.

It's important to note that these processes are interconnected. Microevolutionary changes accumulate over time and can eventually lead to the significant changes that characterize macroevolution.