Final answer:
To find the temperature for a 1:1 sex ratio in turtles, one should conduct an experiment by exposing turtle eggs to various temperatures and recording the resultant sex ratios, as this information is directly related to temperature-dependent sex determination.
Step-by-step explanation:
To determine the temperature at which one would obtain a 1:1 sex ratio in a particular species of turtle, the most direct and effective experiment from the given options would be to expose turtle eggs to different temperatures and observe the resulting sex ratios (Option 1). This experimental approach allows for the controlled manipulation of the variable of interest, which in this case is temperature. By collecting data on the sex of hatchlings in relation to the incubation temperatures, researchers can identify the temperature range that yields a balanced sex ratio. This method is directly concerned with temperature-dependent sex determination (TSD), a critical phenomenon where environmental temperature influences sex differentiation during the middle third of egg development in some reptiles, such as turtles and alligators.
For turtles, it has been observed that cooler temperatures often produce male offspring, while warmer temperatures tend to produce females. However, this pattern can vary across different species of turtles, and in some species, moderate temperatures might produce a balanced sex ratio. This experiment is needed because environmental conditions like temperature can profoundly influence population dynamics by altering the sex ratio, which could affect future mating and reproductive success within a population.