TIL: Killer Whales Evolved From Wolves (Not)! (& A Quick Lesson on Convergent Evolution)

I don't remember where, [update: it was from here] but somewhere today I stumbled upon this meme:

The meme was titled "Killer Whales Evolved From Wolves!" or something, which to be honest surprised me a bit. True, I am not an expert in evolution but I would never imagine killer whales to have evolved from wolves.. or to be more precise, the two to share a direct common ancestor. Wolves would definitely somewhere in the bottom of the list!

So, is it true? Are wolves the closest relative to killer whales? 

Well, after some googling I came across this study. Apparently, there was some truth in the title of that meme, although the guy who posted it got the animals mixed up, as killer whales are actually  more closely related to cows than wolves.

The study in question examined four different marine mammals:

• Killer Whales
• Walruses 
• Manatees
• Bottlenose  dolphins

The study showed that despite their many morphological similarities, killer whales, walruses, bottlenose dolphins and manatees don't share a common ancestor. Instead, killer whales along with bottlenose dolphins are actually more closely related to dogs and wolves, walruses to cows and manatees to elephants:

credit

But why is that? How can these three mammals share so many similar traits but not share the same immediate ancestor? This is all thanks to a process called  convergent evolution which is the process by which species of different lineages develop similar features. 

A great example of convergent evolution are dolphins and sharks. On the outside, the two look very similar but on the inside they are so different and their common ancestor is very far far far away.  

(credit)

Convergent evolution "happens" when different species develop similar traits to adapt to a similar environmental factor. For example, in the marine mammals, that were the case of this study,  all three "lost" their hind legs which "transformed" to a tail for swimming.

But the study had another, even more interesting find.  These marine animals mostly used different genes to develop similar adaptions! Only 15 genes actually evolved similarly, genes that were mainly responsible for adaptations responsible for bone density, blubber, ear bone structure, blood thickness, and blood coagulation.

Other "important" marine adaptations like the tail and the torpedo-shaped body came from different genetic paths that achieved similar results. 

So now you know. Killer whales are actually more closely related to cows than wolves. Hope you enjoyed the post, like always, feel free to check the references down below if you want to learn more about the study!

References & Further Reading

• Sciencenordic.com
• Nature.com
• Wikipedia.org/wiki/Convergent_evolution

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