Final answer:
The example of small elephant seals mating while avoiding competition with larger males demonstrates 'alternative mating strategies,' which help maintain genetic diversity.
Step-by-step explanation:
The scenario described where the large alpha male elephant seal fends off medium-sized males, allowing small males to sneak copulation with females is an example of what's known in Biology as alternative mating strategies. These strategies are evolutionary adaptations that allow individuals with different characteristics, often those who are not dominant, to successfully reproduce and pass on their genes. In this case, it highlights a situation where smaller males use stealth and timing to their reproductive advantage in a system dominated by larger males.
Such strategies are crucial in maintaining genetic diversity within a population and can lead to a variety of adaptations that cater to different environmental conditions or social structures. It is also a clear indication of the complexity of natural selection and the various paths that evolution can take in shaping the behavior and attributes of organisms in a given ecosystem.