Reproductive Isolation is The Foundation of Speciation
Definition
Reproductive isolation
Reproductive isolation occurs when populations are prevented from interbreeding, creating separate gene pools. This isolation ensures that evolutionary changes in one population do not affect the other.
- Once populations are reproductively isolated, they are subjected to different environmental pressures, which drive divergence.
How Differential Selection Works
- Different Selection Pressures: Isolated populations experience unique environments (e.g., climate, predators, food availability).
- Natural Selection: Traits that enhance survival and reproduction in each environment are favored.
- Accumulation of Differences: Over time, these traits become more pronounced, leading to genetic, behavioral, and morphological divergence.
Bonobos and Chimpanzees
After the Congo River formed, it separated populations of a common ancestor into two groups:
- Chimpanzees (north of the Congo):
- Faced intense competition for food and resources.
- Evolved aggressive behaviors and hierarchical social structures to cope with competition.
- Bonobos (south of the Congo):
- Lived in resource-rich environments with less competition.
- Evolved peaceful, cooperative behaviors and greater emphasis on social bonding.
- Over time, reproductive isolation and differential selection created two distinct species with unique behaviors, morphology, and genetics.
