We have observed that certain vertebrates and invertebrates have the capability to fly. Some birds have wings but cannot maintain their flight positions for a longer period. In this context, we humans did not evolve with wings. In fact, a human with wings just exists in mythologies. What is the science behind it?
From the aspects of evolutionary science, mammals with wings such as bats can fly. What about humans? We have a different type of physiological organisation that makes us flightless. If we look closely at the evolution of fish with no arms, wings, legs or even jaws 500 million years back, we will find out how land animals evolved from them. Let us take a peek into such events and find out why humans are incapable of flying.
Humans are mammals that have a vertebral column and a four-limb organ system. This system enables humans to stand, walk, run, and even swim. Humans do not have the organs to make their bodies lighter and to use the laws of physics to fly. We are tetrapods, like many other mammals, with two arms and legs.
It all happened when fishes developed fins. In fact, they are the first animals to develop a skeletal system. This skeletal system comprises bones that form fins. These fins were developed for the movement and locomotion of fish.
If we look back into evolutionary biology then fish with simple organ systems evolved into tetrapods. They walked out of the depths of the ocean and evolved certain features to live on land. We, humans, are also a part of this clan.
We went through several anatomical evolutions and transformations that led to the foundation of terrestrial habits. In fact, our hands have evolved from the frontal fins of aquatic animals. We have evolved digits to catch and hold things. So, our body plan is what the basic vertebrates have. Some of the species have evolved their front limbs into wings with feathers to fly but humans have evolved differently.
As mentioned earlier, fish evolved and emerged on land with better limb structures. It is easier to swim in water with a streamlined body than to walk and crawl on land. This is where an intricate structure of limbs originated from the fins.
The modifications of limbs can be witnessed in different animals based on their uses. For instance, birds are also vertebrates but they do not have digits. Their front limbs have become wings with feathers developed to use the laws of physics to fly.
Pterodactyl, a dinosaur, had a film of skin linked with the front limbs and spanning out to form wings. They used their skin to fly, not feathers. They also had jaws with teeth. Eventually, dinosaurs started gaining feathers and they even lost a lot of body weight to become lighter.
This is how birds evolved with flight powers. If we observe closely, we will find that birds that can fly have low body weight, lighter bone structure, and excellent plumage to support flight. Considering these developments, flying humans with wings seems to be a far-fetched possibility.
The evolution of humans is entirely different from that of birds. We evolved from the apes and have developed a certain set of genes that develops our limbs. This code of development is controlled by genes. We have limbs with digits for a certain purpose. This purpose is not flying.
To explain it in simpler words, we have hox genes. These genes have a certain set of DNA sequences called homeobox. These genes decide the development of organs in a foetus. All animals have genes that decide and control the development of organs.
Due to these genes, it is impossible to find humans born with wings. Our limbs will develop according to the instructions encoded in such genes. It is because of these genes, a spider will form 8 legs but no wings.
Can Humans Grow Wings and Fly?
As per the discussions in the above sections, we can clearly understand that humans cannot fly. We have seen many sci-fi movies where mutants with wings can fly. It is practically impossible to find real humans with wings due to the set of hox genes we have.
Here is a list of reasons that make us flightless.
Our body mass and volume ratio are quite high. Our musculoskeletal system is heavier than birds. We cannot support our weight and fly as the laws of physics will not let us do it.
We cannot overcome gravity as we do not have certain organs or features to do it. We cannot even levitate as we fall under the universal laws of physics.
In order to lift ourselves, we need to create a thrust to move upward and forward. We do not possess that volume in our limbs to create such speed and thrust.
We cannot even overcome the air resistance called drag to hover in the air and move forward.
Even if we develop wings, we will still be unable to fly. To support an adult human body, our wings need to be very big. We also need the muscle power to support the movement of such big wings.
Can humans grow wings? What if we had wings from the beginning? Well, we know why we cannot grow wings. If we evolved with wings, there might have been a possibility of flight. We would have evolved into a lighter species that can support its body weight and hover in the air. Practically, we cannot fly and our body has evolved accordingly.