Southern Ocean Southern Hemisphere, with the greatest concentration located on and around Antarctica. Four of the 18 penguin species live and breed on the mainland and its close offshore islands. Another four species live on the subantarctic islands. Emperor penguins have four overlapping layers of feathers, keeping them warm. They are the only Antarctic animal to breed during the winter. There are relatively few fish species in few families in the Southern Ocean. The most species-rich family are the snailfish (Liparidae), followed by the cod icefish (Nototheniidae) and eelpout (Zoarcidae). Together the snailfish, eelpouts and notothenioids (which includes cod icefish and several
Flightless fruit fly Flightless fruit fly Flightless fruit flies (Order Diptera) encompasses a variety of different species of fly, such as "Drosophila melanogaster", "Bactrocera cucurbitae", "Bactrocera dorsalis", and "Drosophila hydei", with genetic mutations that cause them to be flightless. These genetic mutations may have different results such as the development of muscles that cannot support flight or even result in the lack of wings entirely. Flightless fly models have been especially useful for the study of human neuromuscular diseases such as spinal muscular atrophy, spinobulbar muscular atrophy, myotonic dystrophy, dystrophinopathies and other inherited neuromuscular diseases. Other applications of flightless flies include using them