Final answer:
At the joint equilibrium point in predator-prey dynamics, both predator and prey populations have zero growth, maintaining a balance influenced by limiting factors. Option 3 is correct.
Step-by-step explanation:
At the joint equilibrium point in a predator-prey system, option 3) Both predator and prey populations have zero growth, is what happens to the populations. The predator and prey populations are limiting factors on each other, maintaining a state of balance.
As the prey population increases, there is more food available for predators, leading to an increase in the predator population. However, once the number of predators gets high enough, they capture more prey, which results in a decrease in the prey population. This decrease in prey then leads to a subsequent decline in the predator population due to food scarcity, and the cycle potentially continues indefinitely, with populations fluctuating over time.
The key component to understand in predator-prey dynamics is the delayed response between the two populations. Initially, an increase in prey availability allows predator numbers to climb, but as predators exert more pressure, prey numbers start to fall, followed by a decline in the predator population.
These fluctuations often follow a cyclical pattern, as seen in the historical data of lynx and snowshoe hares. The equilibrium point is reached when the growth rates of both populations are zero, and any deviation from this point results in opposing forces that drive both populations back towards equilibrium.