Can this condition result in speciation?

Question

Imagine that major advances in space travel have allowed humans to explore outside our solar system. A group of humans is stranded on an isolated, but habitable planet far from Earth. Would they become a different species from the remaining humans on Earth? Explain.

Answer 1

Possibly.

Three things would likely be occurring if there was no interbreeding between the humans on earth and the other planet.

1. The Founder population on the new planet would likely have a genetic make up that was somewhat different than the overall genetic make-up of people left on earth.  For example, maybe 15% of the people on earth have green eyes and 40% of those who went to the new planet do.

2. Genetic Drift would occur because the random fluctuations in allele frequencies on the new planet would be larger and likely in a different direction than the fluctuations in the earth population.

3. Natural selection would also likely be occuring because the new planet might have somewhat different conditions that favor certain alleles.

So, if over time these three create enough differences between the two populations that they can no longer produce viable offspring when they try to mate, then speciation would have occurred.  This would be an example of allopatry through the founder effect.

Answer 2

Yes.  

That is the textbook example of what causes speciation ... genetic isolation.

Any mutations that were to arise in one population could not make it to the other population.

Coupled with the radically different environment (i.e. selective pressures) + the relatively small population size (which causes rapid spreading of new mutations), and this is a recipe for speciation ... *provided* the isolation was for a long enough time (a few thousand generations).