What is the Difference Between Prezygotic and Postzygotic?
🆚 Go to Comparative Table 🆚The main difference between prezygotic and postzygotic barriers lies in the stage of reproduction at which they occur. Prezygotic barriers prevent fertilization, while postzygotic barriers reduce the viability or reproductive capacity of hybrid offspring.
Prezygotic Barriers:
- Occur before fertilization.
- Examples include behavioral isolation, which prevents mating due to unique mating behaviors, and temporal isolation, where species have non-overlapping breeding schedules.
Postzygotic Barriers:
- Occur after fertilization and zygote formation.
- Examples include hybrid inviability, where hybrid offspring do not survive past the embryonic stage, and hybrid sterility, where hybrid offspring are born sterile and unable to reproduce.
Both prezygotic and postzygotic barriers play a crucial role in maintaining species' reproductive isolation, which is necessary for species to diverge and evolve along separate paths.
Comparative Table: Prezygotic vs Postzygotic
The main difference between prezygotic and postzygotic isolation lies in the stage of reproduction at which they occur. Here is a comparison of the two types of reproductive isolation:
| Feature | Prezygotic Isolation | Postzygotic Isolation |
|---|---|---|
| Timing | Occurs before fertilization | Occurs after fertilization and zygote formation |
| Purpose | Prevents the union of sperms and eggs | Prevents the formation of viable or fertile offspring |
| Mechanisms | Habitat isolation, behavioral isolation, mechanical isolation, gametic isolation | Zygote mortality, hybrid inviability, hybrid sterility |
| Effect on Speciation | Prezygotic isolation prevents speciation | Postzygotic isolation allows for gene exchange, then prevents the passing of genes of hybrids through non-viability or sterility |
Both prezygotic and postzygotic isolation are types of reproductive isolation that prevent the production of fertile offspring. They are important evolutionary processes that contribute to speciation through various mechanisms, behaviors, and physiological processes.
- Monozygotic vs Dizygotic Twins
- Gametic Sporic vs Zygotic Meiosis
- Embryo vs Zygote
- Zoospore vs Zygote
- Pollination vs Fertilization
- Sporogony vs Schizogony
- Parapatric vs Sympatric Speciation
- Genetic Male Sterility vs Cytoplasmic Male Sterility
- Pachytene vs Zygotene
- Zoospore vs Zygospore
- Plasmogamy vs Karyogamy
- Apospory vs Apogamy
- Interspecific vs Intraspecific Hybridization
- Gametogenesis vs Embryogenesis
- Allogamy vs Xenogamy
- Gametophytic vs Sporophytic Self Incompatibility
- Allogamy vs Autogamy
- Allopatric vs Peripatric Speciation
- Allopatric vs Sympatric Speciation