Evolution of the cochlea signals that displace the eardrum by a mere picometre. Because of its prominence and preserved state in the fossil record, until recently, the ear had been used to determine phylogeny. The ear itself contains different portions, including the outer ear, the middle ear, and the inner ear and all of these show evolutionary changes that are often unique to each lineage [14]. It was the independent evolution of a tympanic middle ear in the Triassic era that produced strong selection pressures towards improved hearing organs in the separate lineages of land vertebrates. The cochlea is the tri-chambered auditory detection portion
Evolution of the cochlea at the same time as the water-to-land transition of vertebrates, approximately 380 million years ago. The actual coiling or spiral nature of the cochlea occurred to save space inside the skull. The longer the cochlea, the higher is the potential resolution of sound frequencies given the same hearing range. The oldest of the truly coiled mammalian cochleae were approximately 4 mm in length. The earliest evidence available for primates depicts a short cochlea with prominent laminae, suggesting that they had good high-frequency sensitivity as opposed to low-frequency sensitivity. After this, over a period of around 60 million years, evidence suggests