Question

Adaptive radiation in placental mammals and Australian Marsupials leading to similarity between distant species is an example of

• A. genetic drift
• B. divergent evolution
• C. convergent evolution
• D. founder effect

Hint:

• Adaptive radiation within a single group (e.g., Darwin's finches or Australian marsupials alone) is an example of divergent evolution.

• However, comparing adaptive radiations across two distinct lineages (Placentals vs. Marsupials) in similar environments shows convergent evolution.

• Analogous organs are the anatomical outcomes of convergent evolution.

Answer 1

The Correct Option is C

Step 1: Understand the scenario described.
Placental mammals in one region and marsupials in Australia each underwent adaptive radiation, yet distant species ended up looking similar. We must name this pattern.
Step 2: Recall what adaptive radiation gives.
Adaptive radiation means one ancestral stock spreads into many ecological niches, producing many forms. This happened separately in both groups.
Step 3: Spot the key word, similarity between distant species.
The point is that unrelated groups (placentals and marsupials) became alike, for example placental wolf and Tasmanian wolf, or flying squirrel and flying phalanger.
Step 4: Rule out genetic drift and founder effect.
Genetic drift is random change in allele frequency, and the founder effect is a special case of drift. Neither explains the systematic look-alike adaptations across continents.
Step 5: Rule out divergent evolution.
Divergent evolution makes closely related forms become different, which is the opposite of what we see here.
Step 6: Identify convergent evolution.
When distantly related lineages independently develop similar traits because they live in similar niches, it is convergent evolution. That fits perfectly.
\[ \boxed{\text{convergent evolution}} \]