WebJun 17, 2009 · Bird wings clearly share ancestry with dinosaur "hands" or forelimbs. A school kid can see it in the bones. But paleontologists have long struggled to explain the so-called digit dilemma. WebAn example of this is the wings of bats and birds. These structures are homologous in that they are in both cases modifications of the forelimb bone structure of early reptiles. But birds’ wings differ from those of bats in the number of digits and in having feathers for flight while bats have none.
How Bird Feet Work - Birds and Blooms
WebFigure 2.5 Homologies in vertebrate forelimbs. In fact, all four-limbed animals (or tetrapods )–amphibians, reptiles, birds, and mammals–have similar limbs. Anatomical similarities, such as those that characterize tetrapod limbs, are used as evidence for common ancestry. In other words, these similarities suggest that pterodactyls, bats ... sharon hofer creating a masterpiece
5.17: Living Species - Biology LibreTexts
WebBird flight is the primary mode of locomotion used by most bird species in which birds take off and fly. Flight assists birds with feeding, breeding, avoiding predators, and migrating . Bird flight is one of the most complex forms of locomotion in the animal kingdom. Bird anatomy, or the physiological structure of birds' bodies, shows many unique adaptations, mostly aiding flight. Birds have a light skeletal system and light but powerful musculature which, along with circulatory and respiratory systems capable of very high metabolic rates and oxygen supply, permit the bird … See more Birds have many bones that are hollow (pneumatized) with criss-crossing struts or trusses for structural strength. The number of hollow bones varies among species, though large gliding and soaring birds tend to have the most. … See more Scales The scales of birds are composed of keratin, like beaks, claws, and spurs. They are found mainly on … See more Birds have a four-chambered heart, in common with mammals, and some reptiles (mainly the crocodilia). This adaptation allows … See more Crop Many birds possess a muscular pouch along the esophagus called a crop. The crop functions to … See more Most birds have approximately 175 different muscles, mainly controlling the wings, skin, and legs. Overall, the muscle mass of birds is concentrated ventrally. The largest muscles in the bird are the pectorals, or the pectoralis major, which control the wings … See more Due to the high metabolic rate required for flight, birds have a high oxygen demand. Their highly effective respiratory system helps them meet that demand. Although birds have lungs, theirs are fairly rigid structures that do not expand and contract as they do … See more Male birds have two testes which become hundreds of times larger during the breeding season to produce sperm. The testes in birds are … See more WebFore-limb of a bird. The fore-limb of a bird, when in a state of rest, exhibits a great change of position if it be compared with that of an ordinary reptile; and this change is of a character similar to, but in some respects greater than, that which the arm of a man presents, when compared with the fore-limb of a quadrupedal mammal. The ... popul bing homepage disappeared