Consider the following claim:

Question

"Abiotic factors help determine the populations of an ecosystem."

Evaluate this claim using the mangroves of the estuaries of the Florida Everglades as evidence. Then discuss how a biotic factor could affect the mangrove population.

Passage below:

Estuaries are wetlands that form near the mouths of rivers along ocean coastlines. Many trees fail in estuaries, but mangroves are an exception. Mangroves are common in tropical estuaries, especially the Everglades of southern Florida. They thrive in the Everglades because they tolerate much greater salinity (salt) levels than other plants do. They also have prop roots that support their weight in the Everglades soil. The soil is wet and spongy, and often is covered in water.

While the adaptations of mangroves are ideal for the Everglades, they are less useful for other tropical regions, such as tropical rain forests. They can survive in these regions, but are less common there.

18. The evidence in the passage most strongly supports which of these explanations of the range of mangroves?

Your answer

Answer 1

The claim "Abiotic factors help determine the populations of an ecosystem" is strongly supported by the evidence provided in the passage about the mangroves of the Florida Everglades. Key abiotic factors include salinity, soil conditions, and water availability, all of which play crucial roles in the thriving nature of mangroves in this estuarine environment.

1. Salinity: Mangroves have adaptations that allow them to tolerate higher salinity levels than most other plant species. This is particularly important in estuarine environments where freshwater from rivers mixes with saltwater from the ocean. The ability of mangroves to thrive in such conditions is a direct result of their tolerance to salinity, an abiotic factor.

2. Soil Conditions: The passage highlights that mangroves have prop roots that support their weight in wet and spongy soils. This adaptation allows them to stay anchored in unstable substrates that other plants might find difficult to grow in. The waterlogged and anaerobic conditions of the soil also facilitate specific adaptations in mangrove species, allowing them to efficiently take up nutrients and withstand periods of flooding.

3. Water Availability: The presence of standing water contributes to the mangrove ecosystem's stability, allowing these plants to sustain their populations despite the fluctuating salinity levels.

The combination of these abiotic factors creates a unique environment in the Everglades that is well-suited to mangrove growth and reproduction, explaining why they flourish there compared to other tropical regions.

In contrast, considering biotic factors that could affect the mangrove population, an example would be herbivory from animals such as deer, insects, or other organisms that feed on mangrove leaves and young plants. If herbivore populations increase significantly, they could reduce the number of mangrove seedlings and saplings, impacting the overall population. This could lead to reduced growth rates, lower reproductive success, and even a decline in mangrove coverage. Thus, while abiotic factors enable mangroves to establish and thrive, biotic factors can exert pressure that influences their population dynamics and health within the ecosystem.