Why do some stickleback populations lack pelvic spines In la

Why do some stickleback populations lack pelvic spines? In lakes where there are no large predatory fish, there is no advantage to having pelvic spines. In lakes with dragonfly larvae, pelvic spines can be disadvantageous, allowing the predatory larvae to grab the fish. Freshwater fish have evolved different types of protective armor to keep them safe from predators. In freshwater, a marine stickleback sheds its spines. Pelvic spines are homologous to legs in four-legged animals and freshwater sticklebacks don\'t need hind limbs to move.

Solution

1.The correct answers are:

In lakes where there are no large predatory fish, there is no advantage to having pelvic spines.

In lakes with dragonfly larvae, pelvic spines can be disadvantageous, allowing the predatory larvae to grab the fish.