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The evolution of mammalian auditory ossicles was an evolutionary process that resulted in the formation of the mammalian middle ear, where the three middle ear bones or ossicles, namely the incus, malleus and stapes (a.k.a. "the anvil, hammer, and stirrup"), are a defining characteristic of mammals.
The evolutionary process leading to a three-ossicle middle ear was thus an "accidental" byproduct of the simultaneous evolution of the new, secondary jaw joint. In many mammals, the middle ear also becomes protected within a cavity, the auditory bulla, not found in other vertebrates. A bulla evolved late in time and independently numerous times ...
The ossicles (also called auditory ossicles) are three irregular bones in the middle ear of humans and other mammals, and are among the smallest bones in the human body. . Although the term "ossicle" literally means "tiny bone" (from Latin ossiculum) and may refer to any small bone throughout the body, it typically refers specifically to the malleus, incus and stapes ("hammer, anvil, and ...
The evolution of the digestive system has formed a significant influence in mammal evolution. With the emergence of mammals, the digestive system was modified in a variety of ways depending on the animal's diet. For example, cats and most carnivores have simple large intestines, while the horse as a herbivore has a voluminous large intestine. [127]
Parallel to the evolution of the cochlea, prestin shows an increased rate of evolution in therian mammals. Prestin is the motor protein of the outer hair cells of the inner ear of the mammalian cochlea. [15] [16] It is found in the hair cells of all vertebrates, including fish, but are thought to have initially been membrane transporter ...
These bones form the middle ear in later mammal groups (see Evolution of mammalian auditory ossicles); they include the incus , malleus , ectotympanic and prearticular. [1] In Mesozoic mammals these bones gradually change position and size until they are incorporated in the middle ear. [1]
Within mammals and other synapsids the columella has evolved into the stapes, a homologous bone within the newly evolved inner ear. As the tympanic cavity evolved to reduce in size, the columella shortened in length. The stirrup-shaped articular processes of the columella inspired a new name for this auditory ossicle, the stapes. The auditory ...
Evolution of mammalian auditory ossicles – Middle ear bones evolved from jaw bones; Evolution of nervous systems – Origin and subsequent variation and development of neurons and neural tissues and organs; Evolution of snake venom – Origin and diversification of snake venom through geologic time