Classification

Classification is one of the most intimidating topics when it comes to the animal kingdom; it's no wonder so many misunderstandings happen.

  The main ranks are: 

1. Kingdom

2. Phylum

3. Class

4. Order

5. Infraorder

6. Parvorder

7. Superfamily

8. Family Phocoenidae

9. Genus

10. Species

  I am sure you’ve learnt the difference between a dolphin and a whale, but then you learn that dolphins are actually included in the parvorder Toothed Whales (Odontoceti), making them also whales. That means all dolphins, including porpoises as they’re dolphins too, are also whales.

Scientific classification of porpoises:

• Kingdom: Animalia

• Phylum: Chordata

• Class: Mammalia

• Order: Artiodactyla

• Infraorder: Cetacea (cetaceans)

• Parvorder: Odontoceti (toothed whales)

• Superfamily: Delphinoidea (dolphins)

• Family: Phocoenidae (porpoises)

But then we dig deeper (pun intended) until we reach the extinct Mosasaur: a Dinosauria (dinosaur). Right?

  But actually, the infamous Mosasaurus was never a dinosaur but instead a marine reptile. But dinosaurs were reptiles, right? Some were reptiles, and some were birds. But here is where it gets tricky because did you know birds are reptiles? I’ll get more into that in a moment, but first I want to tell you more about marine reptiles. Most people are introduced to marine reptiles through the Mosasaurus from the beloved Jurassic World movies, which is why Mosasaurus is seen as a dinosaur - although they did live during the dinosaurs, they are not dinosaurs themselves.

   Marine reptiles are completely separate from dinosaurs, but all dinosaurs were reptiles, including the birds. But wait… doesn’t that mean that dinosaurs never went extinct?

  All around us today, from the common pigeons to the largest ostrich, dinosaurs are still alive today! Furthering on from the conversation about birds - birds are included in the clade Dinosauria, and all dinosaurs are reptiles - that means all birds are also reptiles. I remember being so mind-blown I refused to believe it at first!

  Now what about crocodilians (Crocodylia)?

  Well, a huge misunderstanding is that crocodilians today are descendants of dinosaurs, but that’s completely false. Crocodilians were never a part of the dinosaur clade; in fact, crocodilians have existed millions of years before the first dinosaur evolved.

  Now back to the more modern animals, pinnipeds. Is it a seal (Phocidae) or a sea lion (Otariidae)?

  Sea lions have external ears and can walk using their elongated flippers, whereas seals are unable to walk and have internal ears.

  However, the same idea as with dolphins and whales is that sea lions are also seals, as they are classed in the family Otariidae, which means ‘eared seals.’

  Basically, what we learn from classification is that the beauty of evolution is much more complex and much less obvious than we grew up believing. A bird isn’t just a bird, its also a reptile and a dinosaur. Classification can be intimidating with all the terminology and fancy words, but once you realise how much it opens your mind, you realise it’s like evolution has a mind of its own. Dolphins and bats haven’t met in evolution in 80 million years, and yet they both eventually evolved to have echolocation! How is that possible when they almost couldn’t be further apart when it comes to classification? We may never know how, but that doesn’t make it any less fascinating.