It is suggested that you source the abstract of the article:_ Koen De
Smet,_ Baleen whale's genes capture echoes of the past, _New Scientist, 20
February 1993. _(The article relates to some of the concepts covered in
Area of Study 2 and includes a revised cladogram [1] showing the
evolutionary history of the whales.)
The classification of whales and dolphins is likely to be revised on the
basis of evidence from DNA analysis. The new hypothesis states that the
sperm whale and the pygmy sperm whale, both toothed, are more closely
related to baleen whales than other toothed whales. Myoglobin (a muscle
protein) of 10 whales and dolphins was examined. The findings help to trace
the origin of echolocation. The traditional view was that the ancestor of
the toothed whale developed it while the baleen whales did not. The revised
classification suggests that the ancestor of all whales used echolocation
but the baleen whales lost the ability.
