Final answer:
The three types of mating systems based on sex ratios are monogamy, where one male pairs with one female; polygyny, where one male mates with multiple females; and polyandry, where one female mates with several males.
Step-by-step explanation:
The three types of mating systems that can form from different operational sex ratios are monogamy, polygyny, and polyandry. Monogamy is when one male pairs with one female, potentially for multiple breeding seasons, and this system can be influenced by mate-guarding, male-assistance, or female-enforcement hypotheses. In polygynous systems, one male mates with multiple females, resulting in less paternal care for offspring but benefits for the females of mating with genetically fit males. Finally, polyandrous systems, though rarer than polygynous systems due to high energy devotion by females to offspring, involve one female mating with several males. This is often seen in species where females control valuable resources that attract multiple males.