Written by the Fiveable Content Team • Last updated September 2025
Verified for the 2026 exam
Verified for the 2026 exam•Written by the Fiveable Content Team • Last updated September 2025
Definition
Postzygotic isolation refers to mechanisms that prevent successful development and reproduction after fertilization has occurred between members of different species.
Related terms
Hybrid Inviability: When hybrids fail to develop or reach sexual maturity due to genetic incompatibility between the parent species.
Hybrid Sterility: When hybrids are viable but cannot produce offspring due their inability to produce normal gametes.
Hybrid Breakdown: When first-generation hybrids are viable and fertile, but when they mate with another species or with either parent species, their offspring are feeble or sterile.