Here's how they each exhibit aquatic adaptations:
* Platypus: This unique mammal has a duck-like bill for foraging in water, webbed feet for swimming, and a dense fur coat for insulation. It also possesses electroreceptors in its bill to detect prey in murky water.
* Duck: Ducks have webbed feet for efficient swimming, a streamlined body shape that reduces drag, and waterproof feathers that keep them dry.
* Frog: Frogs have webbed feet, powerful legs for leaping, and a smooth, mucus-covered skin that reduces friction in the water. They also have special adaptations for breathing underwater, such as external gills in tadpole stages and the ability to absorb oxygen through their skin in adulthood.
* Turtle: Turtles have streamlined shells, webbed feet or flippers for swimming, and the ability to hold their breath for extended periods. Some species, like sea turtles, have evolved flippers and salt glands for life in the ocean.
Convergent evolution is the process where unrelated organisms independently evolve similar traits due to similar environmental pressures. In this case, the need to live in water has led to the development of similar physical features in the platypus, duck, frog, and turtle.