Final answer:
Macroevolution is the process of evolution that occurs above the species level over geologic time. It involves the emergence of new species through a process called speciation. Speciation can occur through different mechanisms such as allopatric speciation, sympatric speciation, and parapatric speciation.
Step-by-step explanation:
Macroevolution is the process of evolution that occurs above the species level over geologic time. It involves the emergence of new species through a process called speciation. Speciation can occur through different mechanisms such as allopatric speciation, sympatric speciation, and parapatric speciation.
Allopatric speciation happens when two subpopulations of a species become geographically isolated, which prevents gene flow between them. Over time, the isolated populations accumulate different genetic changes and eventually become reproductively isolated, forming two new species.
Sympatric speciation, on the other hand, occurs when new species evolve within the same geographic area. This can happen due to factors such as polyploidy (the presence of more than two sets of chromosomes), ecological differentiation, or sexual selection.
Parapatric speciation occurs when two subpopulations of a species occupy different but adjacent habitats. Limited gene flow occurs between the two populations, leading to reproductive isolation and the formation of new species.
Overall, speciation is a complex process that can occur through different mechanisms, resulting in the formation of new species.