Which of the following is not an example of convergent evolution?

Convergent evolution occurs when unrelated species independently evolve similar traits because they adapt to comparable environments or ecological niches.

Let’s examine each option:

1. Wings of butterflies and birds – Butterflies are insects, while birds are vertebrates. Their wings evolved independently for flight, making this a classic case of convergent evolution.

2. Flippers of penguins and dolphins – Penguins are birds and dolphins are mammals. Both have streamlined flippers for swimming, but these structures arose separately, so this is also convergent evolution.

3. Fore limbs of whales and bats – Whales and bats are both mammals. Their fore limbs share a common ancestral origin (the tetrapod limb). The differences in shape (whale flippers vs. bat wings) are modifications of a homologous structure, not independent inventions. Therefore, this is **not** an example of convergent evolution.

4. Eyes of octopuses and mammals – Octopuses are mollusks and mammals are vertebrates. Both groups developed complex camera‑type eyes independently, which is another well‑known example of convergent evolution.

Since only the fore limbs of whales and bats are derived from a shared mammalian ancestor and not from separate evolutionary paths, they do not represent convergent evolution.

Hence, the correct answer is the fore limbs of whales and bats.