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Circannual rhythms are evident in a range of organisms, including birds, mammals, fish, and insects, facilitating their adaptation to the cyclical nature of their habitats. Circannual cycles can be defined by three primary characteristics: persistence in the absence of apparent time cues, the capacity for phase shifting, and stability against ...
The Arctic tern has the longest migration journey of any bird: it flies from its Arctic breeding grounds to the Antarctic and back again each year, a distance of at least 19,000 km (12,000 mi), giving it two summers every year. [19] Bird migration is controlled primarily by day length, signalled by hormonal changes in the bird's body. [20]
The guppy (Poecilia reticulata), also known as millionfish or the rainbow fish, [3] is one of the world's most widely distributed tropical fish and one of the most popular freshwater aquarium fish species. It is a member of the family Poeciliidae and, like almost all American members of the family, is live-bearing. [4]
Many species of salmon are anadromous and can migrate long distances up rivers to spawn Allowing fish and other migratory animals to travel the rivers can help maintain healthy fish populations. Fish migration is mass relocation by fish from one area or body of water to another. Many types of fish migrate on a regular basis, on time scales ...
An average of 2,332 new species per year are being described. [2] [3] Marine life is studied scientifically in both marine biology and in biological oceanography. By volume, oceans provide about 90% of the living space on Earth, [4] and served as the cradle of life and vital biotic sanctuaries throughout Earth's geological history.
Kingfishers feed on a wide variety of prey. They are most famous for hunting and eating fish, and some species do specialise in catching fish, but other species take crustaceans, frogs and other amphibians, annelid worms, molluscs, insects, spiders, centipedes, reptiles (including snakes), and even birds and mammals. Individual species may ...
Fish-eating birds of prey, such as sea eagles and ospreys, are also typically excluded, however tied to marine environments they may be. [6] Some birds, such as darters and anhingas, are primarily found in freshwater habitats, but may occasionally venture into marine or coastal areas as well; [7] [8] such birds are generally not considered to ...
Osteichthyes (bone-fish) or bony fishes are a taxonomic group of fish that have bone, as opposed to cartilaginous skeletons. The vast majority of fish are osteichthyans, which is an extremely diverse and abundant group consisting of 45 orders, with over 435 families and 28,000 species. [21] It is the largest class of vertebrates in existence today.