Middle ear to sounds of higher frequency, because these are better taken up by the inner ear (which also responds to higher frequencies than those of non-mammals). The malleus, or "hammer", evolved from the articular bone of the lower jaw, and the incus, or "anvil", from the quadrate. In other vertebrates, these bones form the primary jaw joint, but the expansion of the dentary bone in mammals led to the evolution of an entirely new jaw joint, freeing up the old joint to become part of the ear. For a period of time, both jaw joints existed together, one medially and one
Anvil (insecticide) ingredient is used to treat (4.2 kg/km²). The active ingredients in Anvil break down quickly in sunlight and do not bioaccumulate. There are no reentry precautions for Anvil. Anvil has been tested in 43 field trials in the United States against 30 mosquito species. Sumithrin was registered for use by the U.S. Environmental Protection Agency in 1975 and Anvil is registered for ground and aerial application in outdoor residential and recreational areas. Anvil is manufactured and distributed by Clarke Mosquito Control. In 2003, Anvil was used to treat more than a million acres (4,000 km²) in Larimer County, Colorado during