Isolation refers to the division of a species’ population into smaller units, where organisms in these subunits are hindered from interbreeding by barriers known as isolating mechanisms.
Different type of reproductive isolation are as follows:
I. Geographical Isolation:
• Physical barriers like rivers, oceans, mountains, or glaciers divide the original population.
• Organisms can’t cross these barriers, preventing interbreeding.
• Separated groups adapt to different environments, acquiring new traits through mutations.
• Distinct gene pools form, leading to the evolution of new species (e.g., Darwin’s Finches, African and Indian elephants).
II.Reproductive Isolation:
• Even without geographical barriers, populations can be reproductively isolated.
• Changes in genetic material, gene pool, and genital organ structure prevent interbreeding, fostering speciation.
III. Types of Reproductive Isolations:
1. Pre-zygotic (pre-mating) Mechanisms:
• Prevent individuals from mating.
• Various mechanisms maintain isolation.
2. Post-zygotic (post-mating) Mechanisms:
• Allow mating, but the outcomes are unfavorable.
• Populations remain genetically isolated.