Killer Whales Quickly Evolving?

Scientists led by Andrew Foote of the Natural History Museum of Denmark have watched as orcas (another name for the whales) living near Antarctica appear to be diverging into two types, B and C. Type B orcas are among the largest known and feed on seals, while type C orcas are small and mainly eat fish. The two types also have distinct head markings.

Curious to learn more, Foote’s team compared the genes of the two orca types and discovered two notable differences. All type B orcas showed a mutation on a gene known as site 279, while most type C orcas have a separate mutation, at site 193. The genes are both involved in directing how the whales’ cells produce energy. Foote explained:

The gene under selection is important in producing energy for the body’s cells, and so the mutations are probably linked to the metabolic requirements of these two types. Both types live in the Antarctic pack ice and therefore the low temperature of this habitat could be one selective pressure. But the two mutations should have the opposite effect on metabolism to one another, suggesting divergent evolution.

According to the researchers, neither mutation is present in the genome of what is thought to be the two orca types’ most recent ancestor, dating from before the two types split off an alleged 150,000 years ago.

As with most supposed examples of evolution in action, however, these orcas’ divergence can be explained within a biblical, creation-based biology framework. Genetic mutations and the workings of natural selection do appear to have led to two new orca types; yet neither shows an increase of genetic information or diversity relative to either the other or to the hypothesized common ancestor. Furthermore, the whales are still whales. Foote’s team has thus helped reveal another interesting case not of molecules-to-man-style evolution, but of a population of creatures adapting to its environment.