Original sentence: Just how different the two are is currently under debate, with some earlier authorities suggesting that the New World vultures are more closely related to storks.The exact taxonomic placement of this genus and the remaining species of New World Vultures remains unclear.Though both are similar in appearance and have similar ecological roles, the New World and Old World Vultures evolved from different ancestors in different parts of the world
Edited sentence: Cathartes is one of the six genera of New World Vultures.The New World and Old World Vultures are similar in appearance and have similar ecological roles, but evolved from different ancestors in widely separated parts of the world.The relationships between the two vulture groups is a matter of debate, with some earlier authorities suggesting that the New World vultures are more closely related to storks.The taxonomic placement of these vultures  remains unclear