Final answer:
Toad tadpoles produce chemicals that kill early-stage frog eggs, halting their hatching and showing natural selection at work to prevent premature hatching which could lead to offspring mortality. Frogs produce large numbers of offspring and typically do not provide parental care after hatching.
Step-by-step explanation:
Natural selection can inhibit frog eggs from hatching any earlier than two days before the expected time through various adaptive mechanisms. In the context of toad control, toad tadpoles secrete chemicals that cause 100% mortality of early-stage frog eggs. This chemical interference ensures that eggs do not hatch too early, which would be detrimental as premature hatching could lead to the death of the offspring due to a lack of development and survivability.
It's also important to note that frogs, as amphibians with a strategy to produce many offspring, often do not nurture them post-hatching. Instead, they rely on large numbers of offspring to increase the chances that some will survive to adulthood. This is a trade-off strategy where resources are allocated to producing many eggs instead of parental care.