Question

what is the main difference between adaptive radiation and other forms of speciation?
○ adaptive radiation is a mechanism for evolution.
○ adaptive radiation happens over a relatively short time.
○ adaptive radiation requires a founding population.
○ adaptive radiation occurs only on islands.

Explanation:

1. Analyze Option 1: All speciation is a mechanism for evolution, so this is not unique to adaptive radiation.
2. Analyze Option 2: Adaptive radiation is characterized by the rapid (relatively short time) diversification of a single ancestral species into many species, often to fill various ecological niches. Other speciation processes (like allopatric speciation over long geographic isolation) can take longer.
3. Analyze Option 3: Many speciation types (e.g., allopatric) also can involve a founding population, so this is not unique.
4. Analyze Option 4: Adaptive radiation can occur in other environments too, not just islands (e.g., after mass extinctions in mainland ecosystems), so this is incorrect.

Answer:

B. Adaptive radiation happens over a relatively short time.