Geographic barriers, like mountains, rivers, and oceans, can cause new species to form. When groups of the same species get separated by these barriers, they can't share genes. This leads them to evolve differently over time.

1. Example of Speciation:

   • A great example is Darwin's finches found in the Galápagos Islands. These birds have turned into 15 different species because they've been isolated from each other.

2. Statistics:

   • It's estimated that around 60% of all species on Earth develop because of these geographic separations.

3. Process:

   • As time goes on, different genetic traits build up in these separated groups, which can eventually result in the creation of a new species.

In conclusion, geographic barriers help increase the variety of life on Earth by encouraging new species to form through isolation.