January 29, 2013
Cetacean is the classification that is given to dolphins, whales, and porpoises. Odontoceti is the same classification given to smaller, faster whales, dolphins, and porpoises. This classification is given to them because they have teeth. The dolphin, around 50 million years ago, is said to have been suited for living on land with four legs. Throughout time they have evolved from four legged, fur covered, land dwelling animals; to hairless, leg less, ocean dwelling mammals. The fore legs of the primitive land dolphin have since become pectoral flippers. It is said that the dolphin’s ancestor the “Mesonix” was in existence about 95,000,000 years ago. Although the animal lived on land, it obtained its food from the water. Throughout time it became more adapted to aquatic living. The complete structure of the dolphin has changed since that long time ago. Certain external organs that were characteristics of the older species of dolphins, have since moved or relocated to a more efficient place to suit their environmental needs. Dolphins use echo location to communicate with other dolphins in their pack. The larynx allows them, like humans, to create vibrations and clicks from their throat. They used echo location to find food, other dolphins, predators, and to determine their surroundings. Although a dolphin does not possess a strong sense of smell, and aside from echo location, they still possess vision. Dolphins may be adapted to living in water, but they require oxygen to survive because they have lungs. Because the modern dolphin does not have hair, except for at birth, it would not be suited to live on land, but it is extremely suited to aquatic animals and therefore the external environment of the dolphin has therein shaped its appearance in that aspect. According to "Mother & Calf" (n.d.), “without a thickened...
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