Final answer:
The amount of parental care would likely have the least effect on how successful a species is at adapting to a new environment because it does not directly influence the genetic diversity necessary for adaptation.
Step-by-step explanation:
In determining which of the factors would have the least effect on how successful a species is at adapting to a new environment, we can analyze each of the factors given. Population size is important because a larger population has more genetic variation, and genetic variation is crucial for a species to adapt to new environmental challenges. Generation time can affect how quickly a population adapts because shorter generation times mean more opportunities for beneficial mutations to spread through the population. The amount of parental care is less directly connected to species adaptation, as parental care strategies primarily influence offspring survival rather than genetic variation which is necessary for adaptation. Genetic variation itself is fundamental for adaptation because it provides the raw material for natural selection to act upon. Finally, the rate of environmental change can force species to adapt quickly or face extinction.
Of these options, the amount of parental care would likely have the least effect on a species' ability to adapt to a new environment because it does not directly influence the genetic diversity available for adaptation. While it affects offspring survival, it is not as directly linked to the ability of a species as a whole to quickly adjust to new environmental pressures.