Final answer:
The initial population size of the species is 67 when rounded to the nearest whole number, and the population after t years can be found using the function P(t) = \frac{600}{1 + 8e^{-0.18t}}.
Step-by-step explanation:
To determine the initial population size and the population size after t years for a species, we can use the provided population model function P(t) = \frac{600}{1 + 8e^{-0.18t}}. To find the initial population, we substitute t = 0 into the function. The exponential term e^{-0.18t} becomes e^0, which is 1, and the population model simplifies to P(0) = \frac{600}{1 + 8}, which calculates to 600/9. After simplifying, we find that the initial population size is 66.67, which when rounded to the nearest whole number is 67.
To find the population size after t years, we use the given function directly. For any non-zero value of t, the value of the population P(t) will be a function of t and can be calculated by substituting the value of t into the model function.