Key Idea.
Section 1
Separation and Isolation
How does one species become two? It usually starts with geographic Isolation.
Imagine a single population is separated by a newly formed river, a rising mountain range, or an expanding ocean. Now there are two isolated groups.
Section 2
Divergence into New Species
Once isolated, the two groups face different environments. Group A might adapt to cold mountains (thick fur), while Group B adapts to hot valleys (thin skin).
Over thousands of generations, these differences stack up. Eventually, the genetic and physical differences become so great that even if the physical barrier were removed, the two groups could not produce healthy offspring together.
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Section 1
Separation and Isolation
How does one species become two? It usually starts with geographic Isolation.
Imagine a single population is separated by a newly formed river, a rising mountain range, or an expanding ocean. Now there are two isolated groups.
Section 2
Divergence into New Species
Once isolated, the two groups face different environments. Group A might adapt to cold mountains (thick fur), while Group B adapts to hot valleys (thin skin).
Over thousands of generations, these differences stack up. Eventually, the genetic and physical differences become so great that even if the physical barrier were removed, the two groups could not produce healthy offspring together.
Book overview
Jump across lessons in the current chapter without opening the full course modal.
Continue this chapter