Question

which of these types of environments experiences the least change in the total number and type of species over time? a an ecosystem with only pioneer species b an ecosystem that is in primary succession c an ecosystem that is in secondary succession d an ecosystem with a climax community

Explanation:

To determine which ecosystem experiences the least change in species number and type over time, we analyze each option:

• Option A: Pioneer species are the first to colonize, and ecosystems with only pioneer species are in early succession, so species composition changes rapidly as succession progresses.
• Option B: Primary succession starts from bare rock (no soil), so species diversity and composition change drastically as soil forms and new species colonize.
• Option C: Secondary succession occurs after a disturbance (e.g., fire), so species quickly recolonize, and composition changes as the ecosystem recovers.
• Option D: A climax community is a stable, mature ecosystem where species composition and number remain relatively constant (minimal change) because it has reached ecological equilibrium.

Answer:

D. an ecosystem with a climax community