The animal kingdom is a unique place, filled with a cast of enigmatic and intriguing characters we never tire of learning about. When it comes to birds, we have more than a few questions about the way they work. Like why do some birds fly and others don’t?
Their odd body structure does leave us scratching our heads from time to time and poses the question of whether birds are vertebrates or invertebrates.
What is the meaning of vertebrates?
Vertebrates are animals with a backbone. Within the animal kingdom, which contains ten different phyla, only one has animals with a spine. This phylum, called Chordata, houses three subphyla.
Out of those three, only animals apart of the Vertebrata subsection have backbones, making up a monumental finding that less than five percent of animals on earth actually contain a spine. Crazy, right?
Are birds a vertebrate?
Birds are definitely a part of the vertebrate family, though they may use their skeletal structure a little differently than we use ours. In general, the spine exists to provide structural support for each creature. It also protects the spinal cord, which contains nerves essential to communicating with the brain and coordinating movements.
For birds, in particular, the bone density is much lighter, with more of the bones fused together to assist them with flying. Whereas humans consist of more cartilage, joints, and therefore more flexibility to do the wide range of motions we need to throughout the course of a day.
Equally, birds possess increased flexibility in their neck, permitting practically every species to turn their heads a full 180 degrees.
This movement allows for better grooming while also keeping an eye out for both predators and prey.
You may want to check Are Birds Warm-Blooded Creatures?
What are the similarities between invertebrates and vertebrates?
Despite the many differences across the animal kingdom, there are still quite a few similarities between invertebrates and vertebrates alike.
Both respirate in one form or another as a means to push nutrients throughout their multicellular bodies.
They also experience a life cycle that spans from birth to death and reproduces, albeit through various means.
Unlike their skeletal structures, which appear either on the outside or inside of their bodies depending on the species, blood remains inside the body for both vertebrates and invertebrates.
What do all vertebrates have in common?
Beyond a spine and a central nervous system, the other two characteristics found in all vertebrates are gills and a tail. Fish have gills on the outside of their bodies to filter out gases from the water they take in, allowing them to breathe.
Humans, as well as other vertebrates, possessed these slits in their pharynx to sift out food particles from fluids, but mostly during the stage of life when they were an embryo.
No matter how long the species had it for, these pseudo-gills still qualify as a shared characteristic.
So what about that tail? Animals’ tails exist for many reasons. They owe the extremity’s purpose to a form of communication, use as an extra appendage, or to maintain balance.
Birds use them for everything from steering to balance to attracting a mate.
Humans retain a small trace of a tail, which remains just below the skin, known as a coccyx or your tailbone. Just like gills and your appendix, it’s unsure if the tailbone serves any real purpose for us now.
However, many believe it is an evolutionary remnant that once assisted us with balance while running, walking, or sitting.
Check Birds And Humans: Are They Secondary Consumers?
10 Examples of Vertebrates and Invertebrates
So what are some examples of animals that fall under each category? Below are some of the most well-known species from each
Vertebrates:
1. Birds
We already established that these lovely creatures are vertebrates and how they use those amazing backbones of theirs.
There are five types of animals, including birds, that make up the types of vertebrates in the world.
2. Dogs and Cats
Cats and dogs rarely get along, but they share more than a few things in common. Just like humans and all other mammals, they have spines.
Most use theirs for balance along with their tails, which can be anywhere between half their size to two-thirds of the animal’s size.
3. Snakes
With their highly flexible appearance and the way they seem to just simply sit there, it might be easy to assume snakes are invertebrates.
However, just like other reptiles, these scaly creatures rely heavily on their spines to move even one inch. In fact, they have some of the longest spinal columns, consisting of up to 600 bones depending on the species.
4. Amphibians
Another surprising animal with a prominent backbone is the frog.
All amphibians, including salamanders, newts, and toads, maybe slimmer and more flexible than most creatures, but they are also vertebrates.
5. Fish
Confoundingly enough, fish are probably the best example of vertebrates on earth. Not only do they have a spine, pharyngeal slits (those gills we talked about), and tails, some also retain their notochord throughout their entire life.
This notochord is another popular trait of vertebrates but, like most vertebrate characteristics, fades early on in the development process.
Invertebrates:
1. Jellyfish
These incredibly flexible creatures do not have a spine. In fact, some of them don’t even have a brain, subsisting on a series of nerves that control their senses and ability to move.
There is even a species of jellyfish considered “immortal” due to its regenerative powers of turning back time once it gets too old.
2. Octopus
Octopi and other members of the cephalopod group are invertebrates. The term “cephalopod” comes from a Greek term meaning “head food” and refers to the near-comedic way the octopi’s feet seem to spring forth from its head.
Other tentacle toting cephalopods are squid, cuttlefish, and nautiluses.
3. Spiders
Arthropods like spiders and scorpions, as well as insects like ants and butterflies, do not contain a spinal column. Instead, they rely on their hearty exoskeletons for protection and structure.
4. Earthworms
Looking so similar to snakes, it’s a wonder how earthworms don’t need a spine to get around. Rather than relying on their bone structure, however, they use little bristles on the outside of their body to grip their surroundings and propel them forward.
5. Crabs
Using a similar structure to spiders and insects, all crustaceans have a hard exoskeleton visibly recognized as their shells. Different types of crustaceans include crabs, lobsters, krill, and many more.
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