Why it is unlikleythat the human population will give rise to a new species?Please providewebsitefor reference

Question

Why it is unlikley that the human population will give rise to a new species?
A) the human population is too large
B) geographical isolation is unlikely to occur.
C) a change is chromosome number would be fatal
D) the human population is too diverse
E) natural selection cannot affect humans
Please provide website for reference. Thank You

Answer 1

By new species, I presume you mean separate species. We will eventually evolve, probably over a million years or so, to a "new species".

Probably B - geographic isolation gives rise to variation in a population by the exertion of different selective pressures. eg, after an earthquake, a large group of rodents is split into two by a new, impassable rift. On one side of the rift, there is plenty of food and no predators. On the other side, there is food, but savage predators. This group will need to adapt to its harsher conditions. Chances are, given enough time, the two groups will eventually become separate species.

The population size does not come into it, except in the impact it has on lack of isolation. Chromosome changes are the basis of mutation, not all are fatal, those that are not fatal, will survive (too simple, really). Diversity is also a driving force in species change. If sudden changes occur and wipe out most of the population, some will survive, based on genetically based diversity. eg, if a nuclear disaster occurs, some people will be more immune to radiation damage, will survive and have offspring, who will be more immune to radiation damage, etc. Natural selection does indeed effect humans. Most people in the world do not have enough access to health care to avoid death by treatable illnesses, such as appendicitis, malaria, gastroenteritis etc, so those that are naturally immune will have a greater chance of surviving to adulthood, and have more offspring.

Answer 2

I don't have a website, but I choose answer B. As long as we have people moving around and interbreeding, we share our differences and stay one species.