Final answer:
True, small populations are typically less capable of enduring major environmental changes because they are more susceptible to genetic drift, have reduced genetic diversity, and are more exposed to the effects of inbreeding and limited resources.
Step-by-step explanation:
The statement that 'the smaller the initial population size the less likely it will endure a major environmental change' is typically considered true. Small populations are more vulnerable to environmental changes due to several factors. One of the most significant is genetic drift, which is a mechanism of evolution that refers to random fluctuations in the numbers of gene variants in a population. Genetic drift tends to have a more pronounced effect on smaller populations, leading to a reduction in genetic diversity.
For example, if an environmental change occurs, a population with less genetic diversity is less likely to have individuals with traits that might allow them to survive and adapt to the new conditions. This vulnerability is intensified due to the fact that a single event can wipe out a large percentage of the population if the population size is small. Furthermore, small populations are more susceptible to inbreeding, which can lead to an increase in the expression of deleterious recessive alleles, further compromising the survival of the population.
In addition to genetic concerns, smaller populations can also struggle due to more mundane factors such as more limited resources and less complex social structures, which can be critical for the survival of certain species.