What would most likely happen to the legume population if rhizobia bacteria suddenly became extinct?

• A. The legume population would increase because of less competition for resources.
• B. There would be no significant change in the legume population.
• C. Legumes would begin to fix nitrogen on their own without any symbiotic partners.
• D. The legume population would decrease due to reduced nitrogen availability.

Answer: (D)

Verified step by step guidance

1. Understand the symbiotic relationship between legumes and rhizobia bacteria: Rhizobia bacteria live in nodules on the roots of legumes and help fix atmospheric nitrogen into a form that plants can use, such as ammonium (NH₄⁺). This process is crucial for legumes to obtain sufficient nitrogen for growth.
2. Recognize the importance of nitrogen for plant growth: Nitrogen is a key component of amino acids, proteins, and nucleic acids, which are essential for plant development and reproduction. Without adequate nitrogen, plants struggle to grow and reproduce effectively.
3. Analyze the impact of rhizobia extinction: If rhizobia bacteria were to become extinct, legumes would lose their primary source of nitrogen fixation. Since most plants, including legumes, cannot fix nitrogen on their own, they would face a significant reduction in nitrogen availability.
4. Consider the consequences for the legume population: With reduced nitrogen availability, legumes would experience stunted growth, lower reproduction rates, and potentially higher mortality. This would lead to a decrease in the legume population over time.
5. Conclude that the legume population would decrease due to reduced nitrogen availability, as they rely heavily on their symbiotic relationship with rhizobia bacteria for survival and growth.