As in this example, living things that do not exist and will not exist are called “forbidden phenotypes”. The phenotype (external structure) is the reflection of the characteristics created by genetic and environmental factors in the external appearance of living things. It is usually determined by genes.
The main factor in the emergence of living things with this feature is genes. Here are the details of this turning point that shaped us as if we were toy dough in the evolutionary process:
Although they are not three-legged, some animals can use their tails and fins as a third foot.
Meerkats that get support from their tails to stay upright, woodpeckers that use their tail feathers to stay balanced on the tree trunk, kangaroos that use their tails as legs to spend less energy while walking, and three-dimensional creatures while “walking” on the ocean floor. Tripod fish using their fins are among the prominent animals among these examples.
Six-legged insects’ legs move in a team of three. Half of the legs are in the air while the other half is on the ground. This is called a “wavering three-legged” gait.
Although some living things seem to need three legs, why did no such creature ever arise?
The reason for this goes back a long, long time. Phylogenetics is the strongest constraint on evolution. This concept is the evolutionary development of biological species through various forms, and these relationships are called phylogeny. The related concept, phylogenesis, is the evolutionary development of a biological species through various forms. The term is also used for the development of a particular trait of an organism. The adjective form of this term is phylogenetic.
A bilaterally symmetrical body plan that occurred before limbs emerged was adopted early genetically. This greatly limits the evolution of any three-legged animal. This is how our codes are, ingrained in our DNA very early in life’s evolution. It may even have occurred before limbs such as legs, fins, and wings evolved.
Due to amputees and mutations, it is possible to come across creatures with three legs.
Four-legged animals with amputated limbs or three- or five-legged creatures may be seen due to mutations and birth abnormalities. As long as appropriate treatments are provided, these creatures can continue their lives normally.
Although the idea of three or five animals may sound strange, it is often used in science fiction works.
Who knows, maybe creatures with three or five legs evolved somewhere in the universe and they think how difficult it would be to walk on two legs.
Sources: 1, 2, 3, 4, 5
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