Descent with Modification

Descent with Modification

Passing traits from parent organisms to offspring.

Heredity

The process of passing on traits.

Genes

The basic units of heredity, containing information about an organism's characteristics.

Post-zygotic

Isolation mechanisms leading to nonviable or weak hybrids.

Hybrid inviability

Failure of fertilized eggs to develop past early embryonic stages.

Hybrid sterility

Sterility in hybrids due to abnormal gonad development or chromosome segregation.

Hybrid breakdown

Normal F1 hybrids but weak or sterile F2 generation individuals.

Reproductive isolating mechanisms

Preventing fertilization and zygote formation.

Pre-zygotic

Barriers to mating before zygote formation.

Allopatric speciation

Geographic separation prevents gene flow.

Sympatric speciation

Divergence into different species within the same habitat.

Parapatric speciation

Evolution of separate species in neighboring groups with reduced gene flow.

Allopatric isolation

Mates occupy different areas.

Temporal isolation

Groups are not reproductively mature simultaneously.

Mechanical isolation

Differences in reproductive organs hinder interbreeding.

Behavioral isolation

Different courtship patterns.

Gametic isolation

Incompatibilities between egg and sperm.