Evolution of cetaceans "Caperea marginata") all have derived characteristics presently unknown in any cetothere and vice versa (such as a sagittal crest). The adaptation of echolocation occurred when toothed whales (Odontoceti) split apart from baleen whales, and distinguishes modern toothed whales from fully aquatic archaeocetes. This happened around 34 million years ago in a second cetacean radiation. Modern toothed whales do not rely on their sense of sight, but rather on their sonar to hunt prey. Echolocation also allowed toothed whales to dive deeper in search of food, with light no longer necessary for navigation, which opened up new food sources. Toothed whales
Types of modern dance Types of modern dance Modern dance is an evolution of choreography and performance that came after ballet. It can be divided into multiple types. This style was founded by dancer Lester Horton, who was born in 1906. Horton studied Native American dance in Indiana. Horton choreographed for theater and film. Horton studied the human body, and developed exercises focused on strengthening and preparing it for performances. A typical Horton class starts standing up with roll-downs and flat backs and later moves on to more complex moves. Alvin Ailey was one of Mr. Horton's students. Many companies use Horton including Alvin