Why is variation beneficial to the species but not necessarily for the individual?

Variation is beneficial to a species as a whole because it increases the chances of survival and adaptation. Here's why:

1. Survival: Variation within a species increases the likelihood that at least some members of the species will survive under changed environmental conditions. For example, if a disease strikes, not all individuals will be equally susceptible. Those with the right variation may survive and continue the species.

2. Adaptation: Variation allows species to adapt to new environments. If all individuals in a species were identical and the environment changed in a way that none of them could survive, the species would go extinct. But with variation, some individuals might have traits that allow them to survive, reproduce, and pass on their genes.

3. Evolution: Variation is the raw material for evolution. It provides the genetic diversity that is acted upon by natural selection, leading to the evolution of new species.

However, variation is not always beneficial for the individual. Some variations may be harmful or neutral in their effects. For example, a variation that makes an individual more visible to predators would not be beneficial. Similarly, a variation that does not affect an individual's survival or reproduction would not be beneficial or harmful. It's also important to note that whether a variation is beneficial or not can depend on the environment. A variation that is beneficial in one environment may be harmful in another.