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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.
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 ...
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 ...
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 ...
The stapes is one of three ossicles in mammals. In non-mammalian tetrapods , the bone homologous to the stapes is usually called the columella ; however, in reptiles , either term may be used. In fish, the homologous bone is called the hyomandibular , and is part of the gill arch supporting either the spiracle or the jaw, depending on the species.
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
A microbiologist is proposing the idea that the reign of dinosaurs forced mammals to speed up their reproductive cycle, eliminating key longevity genes.
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]