Speciation is the process of how new species evolve over time. There are two main types: one where a single species changes gradually, and another where a parent species splits into two or more new species. This split can happen in different ways, like when species live in the same area (sympatric), next to each other (parapatric), or in different places (allopatric). Plants often evolve new species by mixing with other species. Most new species are thought to form in different areas. Scientists are still figuring out the best way to define what makes a species, which can be tricky when looking at fossils.