AP BIOLOGY

Detailed explanation-1: -Gill, birds must instead rely on the muscular stomach-like pouch called the gizzard to crush down their food. Many species swallow stones and grit to aid in digestion. These stones remain in the gizzard and crush the food as the gizzard contracts.

Detailed explanation-2: -Birds with thick gizzards frequently pick up grit-little stones, sand, and small shells. These items collect in the gizzard. When food and digestive juices enter the gizzard, the thick muscles and grit help pulverize the food.

Detailed explanation-3: -Among living vertebrates, gastroliths are common among crocodiles, alligators, herbivorous birds, seals and sea lions. Domestic fowl require access to grit. Stones swallowed by ostriches can exceed a length of 10 centimetres (3.9 in). Apparent microgastroliths have also been found in frog tadpoles.

Detailed explanation-4: -It might not surprise you but other poultry have gizzards too, like turkeys, ducks, fowl, emus, doves, and pigeons. A little more surprising might be that crocodiles, alligators, earthworms, some fish and crustaceans, and even dinosaurs have gizzards.

Detailed explanation-5: -Many animals like crocodiles and seals eat rocks to help with digestion-they’re called gastroliths. The rocks that the dinosaurs carried are recognizable to geologists because they are smooth, different from their surroundings, and near dinosaur remains.