Why is variation useful over population?
Answers
Variation is important for any species because it allows the species to adapt to a changing environment.
Also, the presence of diseases and parasites maintains variation in a species, particularly those associated with blood groups.
The first response of a species confronted with environmental changes, such as climate change, is to shift its range[1][2]. So a species could move poleward, or to higher altitudes. When that does not work variations help individuals survive in harsher conditions, and adapt to the changes.
A problem at present is that global warming is happening fast and many species have already been reduced to smaller populations. This reduces the available variation, making the species less adaptable. This can also happen if the range gets broken up, and individuals in one area can no longer breed with those in another
Variation is useful over population by providing benefit of survival in environmental change