Since Australia is located in the Pacific ocean, extremes of weather and climate happen throughout a season. El Niño is traditionally defined as a dry climate with reduced rainfall; in this happens to be more extreme in Australia because of its location. La Niña on the other hand is traditionally defined as a wet or cool climate with lots of rainfall; and this is indifferent as La Niña in Australia tend to be more extreme too.
<span>"Genetic drift is more likely to have an impact on small populations."
Genetic drift is changing the frequency in the allelic pool of a population. This phenomenon impacts mainly smaller populations because these populations have only a few copies of the alleles present. If a change in the frequency of the alleles happens then it may cause the disappearance of certain alleles because there are only so many copies.</span>