Question

Predict how the population growth curves will appear when the species are grown alone and when they are grown together. Be sure to include WHY you predict those results.

Answer 1

To predict the population growth curves of species grown alone versus those grown together, we need to consider several ecological and biological principles, particularly competition and mutualism.

1. **Population Growth When Grown Alone:**
- When a species is grown alone, its population growth is likely to follow the classic logistic growth model. Initially, the population will grow exponentially when resources are abundant. However, as the population increases, resources such as food, space, and nutrients become limited, leading to increased competition within the population. This will eventually result in a leveling off of the growth curve as the population reaches the carrying capacity of the environment.
- The growth curve typically looks like an S-shape (sigmoidal curve), where the population accelerates during the exponential phase, slows down as it approaches the carrying capacity, and eventually stabilizes.

2. **Population Growth When Grown Together:**
- When two species are grown together, the interaction between them can significantly affect the population growth curves for both species. The outcome will depend on the nature of their interaction:
- **Competition:** If the species compete for similar resources, we might see a lower population growth for both species compared to when they are grown alone. The population curves could show increased fluctuations or even a decline for one or both species if one outcompetes the other (competitive exclusion).
- **Mutualism:** If the species have a mutualistic relationship (where both species benefit), we might see enhanced growth rates for both species compared to when they are grown alone. Their growth curves could show elevated growth rates due to synergistic effects.
- **Predation/Parasitism:** If one species acts as a predator or parasite on the other, then the growth curve of the prey or host species would be negatively impacted. The predator population may grow initially as it has more food, but once the prey decreases, the predator population might crash.

In summary, when grown alone, species are likely to exhibit a logistic growth curve; however, when grown together, the outcome will heavily depend on the interactions (competition, mutualism, predation) between the species, resulting either in cooperative growth or competitive suppression. The population curves could show more complexity and variability when grown together compared to the more predictable S-shaped curves observed when species are grown alone.