Which of the following best describes the main difference between primary and secondary succession?

• A. Primary succession happens after a forest fire, while secondary succession happens on volcanic lava flows.
• B. Primary succession results in less biodiversity than secondary succession.
• C. Primary succession involves only animal species, while secondary succession involves only plant species.
• D. Primary succession occurs on newly formed or exposed surfaces where no soil exists, while secondary succession occurs in areas where a disturbance has left the soil intact.

Answer: (D)

Verified step by step guidance

1. Step 1: Understand the concept of ecological succession. Ecological succession refers to the natural process by which ecosystems change and develop over time. It can be categorized into two types: primary succession and secondary succession.
2. Step 2: Define primary succession. Primary succession occurs in areas where no soil exists initially, such as newly formed volcanic lava flows, bare rock exposed by glaciers, or other surfaces that have not previously supported life. The process begins with pioneer species, such as lichens and mosses, which help create soil over time.
3. Step 3: Define secondary succession. Secondary succession occurs in areas where a disturbance (e.g., forest fire, flood, or human activity) has disrupted an existing ecosystem but left the soil intact. This allows plants and animals to recolonize the area more quickly compared to primary succession.
4. Step 4: Compare the two types of succession. The main difference is that primary succession starts on surfaces without soil, requiring the formation of soil before other organisms can establish themselves, while secondary succession begins in areas where soil is already present, allowing for faster recovery and regrowth.
5. Step 5: Apply this understanding to the problem. The correct answer is: 'Primary succession occurs on newly formed or exposed surfaces where no soil exists, while secondary succession occurs in areas where a disturbance has left the soil intact.' This explanation aligns with the definitions and processes of ecological succession.