Search results
Results from the WOW.Com Content Network
Birds are a group of warm-blooded vertebrates constituting the class Aves (Latin:), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweight skeleton.
Birds are the only living vertebrates to have fused collarbones and a keeled breastbone. [17] The keeled sternum serves as an attachment site for the muscles used in flying or swimming. [17] Flightless birds, such as ostriches, lack a keeled sternum and have denser and heavier bones compared to birds that fly. [18]
The vertebrates make up the subphylum Vertebrata with some 65,000 species, by far the largest grouping in the phylum Chordata. The vertebrates include mammals, birds, amphibians, and various classes of fish and reptiles. The fish include the jawless Agnatha, and the jawed Gnathostomata.
They are among the characteristics that distinguish the extant birds from other living groups. [4] Although feathers cover most of the bird's body, they arise only from certain well-defined tracts on the skin. They aid in flight, thermal insulation, and waterproofing. In addition, coloration helps in communication and protection. [5]
[14] [15] The bee hummingbird – only 6 centimetres (2.4 in) long and weighing about 2 grams (0.071 oz) – is the world's smallest bird and smallest warm-blooded vertebrate. [ 14 ] [ 16 ] Hummingbirds have compact bodies with relatively long, bladelike wings having anatomical structure enabling helicopter -like flight in any direction ...
Sometimes known as perching birds, passerines generally have an anisodactyl arrangement of their toes (three pointing forward and one back), which facilitates perching. With more than 140 families and some 6,500 identified species, [ 1 ] Passeriformes is the largest order of birds and among the most diverse clades of terrestrial vertebrates ...
Bird netting or anti-bird netting is a form of bird pest control. It is a net used to prevent birds from reaching certain areas. Bird protection netting comes in a variety of shapes and forms, The most common is a small mesh (1 or 2 cm squares) either extruded and bi-oriented polypropylene or woven polyethylene.
The first vertebrates with limbs and digits evolved ... between older groups and descendant groups with markedly different characteristics. For example, the birds ...