Question

If rabbits are introduced in an isolated grassland for the first time, which of the following growth curves (shown using dashed line) is/are theoretically possible population dynamics over time?

• A. P
• B. Q
• C. R
• D. S

Hint:

In ecological studies, population growth models often assume an initial exponential growth phase followed by a leveling off when resources become limited, commonly represented by a logistic growth curve.

Answer 1

The Correct Option is A, B, D

When rabbits are introduced to a new isolated ecosystem, their population will typically grow exponentially initially as they reproduce quickly. Over time, however, environmental limitations such as food, space, and predation will slow this growth, leading to a leveling off of the population. Let’s analyze the options: 
- (P): This curve shows an exponential increase in population initially followed by a plateau. This pattern is consistent with typical population growth when resources are abundant initially and then constrained over time, leading to a stabilizing population size. This is a feasible population dynamics scenario, making \( P \) a correct option. 
- (Q): This curve also shows an exponential growth initially but then levels off at a lower number than the first. This represents a scenario where the population reaches carrying capacity but with some fluctuations, which could be due to environmental disturbances or slight changes in resource availability. This is also a plausible outcome for rabbit population growth, making \( Q \) a correct option. 
- (R): This curve shows a rapid increase in population, followed by a decline after reaching a peak. This could represent an overshoot scenario where the population grows too large for the resources available, leading to a crash. While this is theoretically possible in some environments, it is less common in well-established ecosystems where a balance is reached, so this scenario is less likely. Thus, \( R \) is not a correct option. 
- (S): This curve shows a population that increases rapidly and then levels off at a low level. This could represent a scenario where the rabbits were introduced but faced immediate environmental resistance (such as predation or disease) that prevented a high population growth. This could happen in a newly introduced isolated ecosystem with harsh conditions, making \( S \) a plausible scenario, so it is also a correct option. 
Thus, the correct answers are \( A \), \( B \), and \( D \), as all these curves represent theoretically possible population dynamics.