Natural selection is the process where organisms that are best suited to their environment survive and pass on their genetic traits in increasing numbers to successive generations.
Where they live:
Whales inhabit all oceans of the world, from temperate oceans and the tropical waters around the equator to the polar waters of the Arctic and Antarctic oceans. Whales are also found in many seas, such as the North Sea and the Mediterranean.
What they eat :
Baleen whales eat mostly plankton and krill (tiny ocean creatures similar to shrimp). toothed whales eat mostly fish such as tuna and salmon as well as seals and other small mammals
Their predators :
The primary predators of whales are human beings, sharks, and killer whales. The polar bear can attack whales, but humpback whales would be much too large for a single polar bear.
Change in environment:
The rapid warming of the planet is leading to a loss of habitat for whales and dolphins and greater competition for a diminishing amount of prey species. It is affecting the timing and ranges of their migration, their distribution and even their ability to reproduce.
How they were able to survive:
Some land-living ungulates favored munching on plants at the water's edge which had the added advantage of allowing them to easily hide from danger in shallow water. Over time their descendants spent more and more time in the water and their bodies became more adapted for swimming.
How did whales tails evolve?
Their front legs became flippers and a thick layer of fat called blubber replaced their fur coats to keep them warm and streamlined. Eventually, their tails became bigger and stronger for powerful swimming and their back legs shrunk.
Did you know that whales survived the ice age? :
The gray whales survived the ice ages, that cut off their migration routes and compromised their diets.