A revolution in the study of human evolution is under way thanks to the invention of techniques that enable DNA sequencing of not only modern humans, but also ancient humans. Modern humans (Homo sapiens) and archaic humans called Neanderthals (H. neanderthalensis) shared a common ancestor in Africa but diverged in different geographic areas. When modern humans migrated out of Africa and dispersed around the world starting about 100,000 years ago, they overlapped with Neanderthals in Europe. This scenario is best described as a. species living in sympatry following allopatric speciation b. species living in sympatry following sympatric speciation c. species living in allopatry following allopatric speciation d. species living in allopatry following sympatric speciation

Verified step by step guidance

1. Understand the terms: 'Sympatry' refers to different species living in the same geographic area, while 'Allopatry' refers to species living in separate geographic areas. 'Speciation' is the evolutionary process by which populations evolve to become distinct species.
2. Identify the initial condition: Modern humans and Neanderthals shared a common ancestor in Africa but diverged when modern humans migrated out of Africa. This initial divergence in separate geographic areas indicates allopatric speciation.
3. Analyze the interaction: After migrating out of Africa, modern humans overlapped with Neanderthals in Europe, meaning they lived in the same geographic area, or sympatry, after their initial divergence.
4. Match the scenario with the correct option: Since the species initially diverged in different areas (allopatric speciation) and later lived together in the same area (sympatry), the correct answer describes this sequence.
5. Select the correct answer: The scenario is best described as 'species living in sympatry following allopatric speciation', which corresponds to option (a).

Key Concepts

Allopatric Speciation

Allopatric speciation occurs when a population is geographically separated, leading to the evolution of distinct species due to isolation. This process often involves physical barriers, such as mountains or rivers, that prevent gene flow between groups. Over time, genetic divergence can result in the emergence of new species, as seen in the case of modern humans and Neanderthals, who evolved separately after migrating to different regions.

Sympatric Speciation

Sympatric speciation happens when new species evolve from a single ancestral species while inhabiting the same geographic region. This can occur through mechanisms such as polyploidy in plants or behavioral changes in animals that lead to reproductive isolation. Unlike allopatric speciation, sympatric speciation does not require physical barriers, making it a fascinating aspect of evolutionary biology.

Sympatry and Allopatry

Sympatry refers to species or populations that coexist in the same geographic area, while allopatry describes species that are separated by physical barriers. Understanding these concepts is crucial for analyzing evolutionary relationships, as they influence how species interact, compete, and evolve over time. In the context of human evolution, the overlap of modern humans and Neanderthals in Europe exemplifies sympatric living following their allopatric divergence.