Feedback Loops in Ecosystems

What is a characteristic of a negative feedback loop?

• It amplifies changes in a system

• It stabilizes and reduces changes in a system

• It leads to a new equilibrium

• It only occurs in artificial systems

Answer explanation

A negative feedback loop stabilizes a system by reducing changes. It counteracts deviations from a set point, promoting equilibrium, unlike positive feedback which amplifies changes.

In the DaisyWorld Model, what role do negative feedback loops play?

• They cause irreversible changes

• They help maintain balance in the environment

• They stimulate rapid population growth

• They eliminate all species competition

Answer explanation

In the DaisyWorld Model, negative feedback loops help maintain balance in the environment by regulating population dynamics and resource use, preventing extreme fluctuations and promoting stability.

How does a predator-prey relationship exemplify a negative feedback loop?

• Prey populations always remain constant

• Predator numbers increase indefinitely

• Predator and prey populations stabilize each other

• Prey populations become extinct

Answer explanation

In a predator-prey relationship, as prey populations increase, predator numbers also rise due to more available food. Conversely, as predators consume prey, their numbers decline, stabilizing both populations in a negative feedback loop.

What happens when nutrient availability increases in a pond ecosystem?

• Herbivore populations decrease

• Algae populations decrease

• Algae populations increase

• All organisms stop reproducing

Answer explanation

When nutrient availability increases in a pond ecosystem, it often leads to an increase in algae populations due to enhanced growth conditions, while herbivores may not immediately decrease.

What is a dynamic state of equilibrium in ecosystems?

• A state with no fluctuations

• A point where ecosystems collapse

• A state where organisms stop evolving

• Constant change around an equilibrium point

Answer explanation

A dynamic state of equilibrium in ecosystems refers to constant change around an equilibrium point, where populations and environmental conditions fluctuate but maintain overall stability.

In a steady-state equilibrium, how are conditions maintained over time?

• Through positive feedback loops

• By preventing any changes

• With the help of stabilizing negative feedback loops

• By random fluctuations

Answer explanation

In a steady-state equilibrium, conditions are maintained over time with the help of stabilizing negative feedback loops, which counteract changes and promote stability, unlike positive feedback or random fluctuations.

During ecological succession, what is the role of negative feedback loops?

• To prevent species from establishing

• To promote species dominance

• To stop over-dominance and maintain balance

• To eliminate pioneer species

Answer explanation

Negative feedback loops during ecological succession help to stop over-dominance of certain species, ensuring a balanced ecosystem. This allows for diverse species to coexist rather than allowing one to dominate the environment.

How do pioneer species contribute to primary succession?

• By breaking down rocks to form soil

• By creating disturbances

• By outcompeting all other species

• By remaining unchanged

Answer explanation

Pioneer species contribute to primary succession by breaking down rocks through weathering, which helps form soil. This process creates a suitable environment for other plants to grow, facilitating ecosystem development.

What is an example of a positive feedback loop in nature?

• Predator-prey population balance

• Ice-albedo effect leading to increased ice melt

• Nutrient cycling in a pond

• Shade creation by trees

Answer explanation

The ice-albedo effect is a positive feedback loop where melting ice reduces the Earth's reflectivity, causing more solar absorption and further ice melt. This amplifies the initial change, making it a clear example of positive feedback in nature.

How do positive feedback loops affect a system?

• They amplify disturbances and destabilize the system

• They drive the system towards equilibrium

• They stabilize the system

• They have no effect on the system

Answer explanation

Positive feedback loops amplify disturbances, leading to greater changes in the system. This can destabilize the system, as opposed to driving it towards equilibrium or stabilizing it.