Transcript I Aves PPT
Phylum: Chordata Class: Aves (Birds) Classification Kingdom Animalia ---Phylum Chordata ------Subphylum Vertebrata ---------Class Aves Aviation = flight Order: Apodiforma Hummingbird Tucan Order: Falconiformes Peregrine falcon Order: Galliformes Dove Class: Gaviiformes Loon Penguins Origin and Early Evolution Evidence from fossils and studies of comparative anatomy indicates that birds evolved from reptiles Their features and their fragile hollow bones do not preserve well. copyright cmassengale Evolution of Birds (from reptiles) • Archaeopteryx - “ancient wing” • Reptile like - Had teeth in beak, bony tail, claws on wings • Bird like = Had feathers, & fused collarbone (wishbone) • Could not fly – could glide for glide short distances Aves Characteristics 1. Forelimbs modified into wings 2. Thin layer of epidermis; No sweat glands 3. Feathers – made of keratin 4. Hollow, lightweight bones 5. Endothermic 6. Efficient respiration 7. Heart with a completely divided ventricle (4 chambers) 8. Scaled feet (birds are related to reptiles) 9. Furculum (wishbone) Body Plan Bilateral symmetry Forelimbs modified into wings Bony skeleton with air pockets Beak, no teeth Single bone in the middle ear Endothermic Skeleton The sternum supports the large breast muscles The humerus, ulna, and radius, along with the pectoral girdle and the sternum, support the wing. The pygostyle, the terminal vertebra of the spine, support the tail feathers, which also play an important role. copyright cmassengale Feather Types 1. Contour feathers Has a hollow quill, main shaft, and barbs, barbules Covers, streamlines body, and allows flight; coloration 2. Down feathers Light and fluffy conserve heat (birds are endothermic) 3. Filoplume feathers Hair-like/no known function • Feathers are covered in oil to keep them water proof - "like water off a duck's back" - this oil is secreted from a preen gland • Preening is a behavior that replaces the oil on feathers, and repairs broken links on the vanes Feather Types Feather Structure Endothermy Generate and regulate body heat internally Enables birds to inhabit both cold and hot climate Body temperature ranges from 4046 degrees Celsius. To help conserve body heat, birds fluff out their feathers to insulation. copyright cmassengale Nervous System response Well develop sense organs A large brain Cerebrum = thinking, decision making Cerebellum = coordinated movement Medulla oblongata = basic body process Optic lobes = vision Olfactory lobes = taste and smell Respiration Highly advanced respiration Posterior and anterior air sacs with tube in between Continuous one way flow 2 functions of the lungs Oxygenate tissue Cooling (no sweat glands) Nutrition Carnivores There is a bird to hunt nearly every insect Omnivores Nectar feeders Have specially developed beaks to accomplish feeding task Birds can eat up to 100% of their weight in food every day Digestion No teeth/poorly developed salivary glands Grinding occurs in the gizzard Pebbles are swallowed by the bird to help the gizzard grind the food Pharynx—Esophagus—Crop— Stomach—Gizzard—Intestines— Ceca(in herbivores only, ferments)—Rectum—Cloaca Excretion Paired metanephridic kidneys Urine is formed by filtration Uric acid is formed Advanced animals, because it has low solubility it can be excreted with little water loss Salt glands aid in removing salt Territoriality and Courtship During the breeding season many male birds establish an area that they defend against other males of their species, a behavior called territoriality. The male then attempts to attract a female to share this territory. Once a territory is established most birds engage in a period of courtship, behavior that is designed to attract a mate. Many males attract females by means of their brightly colored feathers. Some males combine song with flight displays. copyright cmassengale Reproduction Sexual reproduction flamboyant coloration to attract mate Monogamy is general rule in Aves Seasonal Lifetime—swans, geese Internal fertilization Birds lack a penis, so cloaca must meet Oviparous Why Monogamy? Provide food, it must be gathered Need for a nest Eggs must be incubated Males are chosen because they have secured a territory Announced through song Development Direct development Egg Juvenile—must be cared for Adult Many baby birds are born helpless and without feathers. These baby birds require lots of care from their parents. Some babies hatch with feathers and can follow their mom around, swim and eat on their own. Movement • Flightless (ostrich, penguin…etc) • Forelimbs modified for flight = wings • Collarbones are fused making a strong base for flight muscles fused bone is the furculum • Air spaces make the bones light in weight • Strong chest muscle attach to a keel of the sternum (breastbone) What allows flight? Feathers Air cavities in bones decrease density Beaks rather then heavy jaws Extremely high metabolic rate Large hearts and high-pressure circulation Keen vision Excellent neuromuscular coordination Environmental Interaction Occupy almost any habitat on earth 9,000 species Largest group of vertebrates except fishes Almost half the species migrate Predators, prey, scavengers,herbivores, omnivores Migration Why migrate Increases food availability Breeding Avoid predators Reduce interspecies competition Northern hemisphere Breeding summers Southern hemisphere winters Migration How do birds migrate? Many follow landmarks such as rivers, coastlines. It is thought that they may also use the earths magnetic field The sun and the stars are also used as compass directors Some can travel as far as 11,200 miles Stimulus for migration Long days stimulate gonads to grow, fat deposits to increase and the urge to migrate north.