There is astounding variety of very different mammals living in the oceans. These sea mammals (whales, seals, walruses, dolphins, sea elephants, etc.) are highly specialized, with each species perfectly designed for its own particular nitch.
For example, the mother whale has an ingenious device for giving milk to her baby. The baby’s mouth fits snuggly into his mother’s body so that sea water cannot get mixed with the milk. The baby whale’s windpipe is also elongated above the gullet so milk cannot flow into its lungs.
This design had to be perfect in both the mother and the baby whale from the very first time a baby whale was born and needed to nurse underwater. It could not have evolved by gradual changes.
These are the types of specifically designed features which have led many biologists to reject evolution in favor of creation as the best explanation for our existence.
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