Birds Learning Target Objectives :

1. Birds Learning Target Objectives: Distinguish between the 3 major chordate divisions and between classes of fish, amphibians, reptiles, birds, and mammals, listing examples of each. Compare and contrast features of organisms that make them unique or help place them in a particular class. Identify body structures (anatomy) and functions (physiology) for each type of vertebrate. Differentiate between types of births: oviparous, ovoviviparous, and viviparous. Vocabulary: Archaeopteryx * endotherm/ectotherm * amniote egg * furculum * allantois * amnion * chalaza * chorion * albumen * yolk * flight/contour/down feathers * preening * molting * brood patch * shaft * vanes * quill * barbs * barbules * sternum * cranium * pelvic girdle * furculum * pygostyle * proventriculus * duodenum * uric acid * trachea * syrinx * air sacs * cerebellum * cerebrum * incubation * precocial * altricial *

2. Birds Class Aves – evolved from reptiles - feathers seem to be modified scales - feet & legs are still covered by scales - Archaeopteryx shows evolutionary link between reptiles & birds 150 million years ago. Reptile chars. Bird characteristics large skull feathers teeth “wishbone” of fused collar “solid” bones bones (furculum) Long tail, (fleshy) Claws on forelimbs - hollow bones MOSTLY, sternum is not hollow - stand on 2 hind limbs (forelimbs are wings) - toothless beak -Endotherms (internal temperature control) - 4 chambered heart with single aortic arch - amniote eggs with calcium carbonate shell

3. The Amniote Egg: Has a shell that is much harder than a reptile’s due to the calcium carbonate. But it is still porous enough to allow some gas exchange, etc. Parts of the egg: Amnion – surrounds embryo. Amniotic fluid helps protect embryo from damage. Allantois – grows out of digestive tract & fuses with chorion to eliminate wastes. Chorion – the membrane lining the shell, helps eliminate waste. Chalaza – keeps yolk and embryo suspended & correctly positioned in egg (rope-like) Albumen – (egg white) food source, high in protein

4. The Feather: (2 functions) 1) Lift for flight 2) Provide insulation (warmth) 2 Types of Feathers: 1) Down – short, soft undercoat. These are usually the first feathers seen on baby birds (provide the best insulation) 2) Contour feathers – add extra insulation, are longer, stiffer, and add color to the bird. Those that cover the wings & tail are called flightfeathers. Feathers develop from within skin follicles. They are made of dead material when fully grown. The feathers are coated by oil from a gland near the base of their tails. This oil helps waterproof the feathers. Cleaning and spreading oil over the feathers is called preening.

5. Molting – birds usually shed their feathers in late summer. This ensures strong, full feathers for migration or winter protection. Those species that display bright mating colors may lose their dull feathers in early spring as well. Nesting females often lose a patch of feathers on their chests. This is called a brood patch. It allows contact of skin with eggs which helps keep the eggs warm. Feather Structure: Shaft – center of feather, comes from follicle area Vanes – flattened area of feather on each side of the shaft Quill – hollow part of the shaft Barbs – main “branches” coming off the shaft Barbules – small “branches” off barbs. They’re hooked at ends of contour feathers but not at ends of down feathers.

6. Feet: Perching birds feet are designed so that the feet curl up when the tendons are relaxed. This allows birds to stay perched while sleeping (without falling off). Internal Anatomy: Bones are hollow except for the sternum (breast bone), cranium (skull), and pelvic girdle (hip bones). These areas contain marrow which is used to make blood. Many bones are fused (joined solidly together) to add strength to these lightweight bones. The furculum (wishbone) is unique to birds. It helps support the sternum where most flight muscles are attached. The pygostyle is made of the last few vertebrae. Here the tail muscles attach to the vertebrae.

7. Digestive System: Because birds are endothermic, they burn large amounts of energy (high metabolism). A high metabolism also increases the rate of respiration (high oxygen intake for aerobic respiration within cells). Digestion is fast. Beak  esophagus  crop (stores & moistens food) proventriculus (1st part of the stomach where digestive fluids start to work)  gizzard (contains stones to grind food)  pyloric sphincter  small intestine (duodenum = 1st part)  cloaca Excretory System: 2 kidneys produce uric acid (whitish) which is not stored (No bladder) but passes to the cloaca & released with solid digestive wastes.

8. Respiratory System: Air enters the nostrils/mouth  trachea (air tube lined with rings of cartilage), then past the syrinx (song box)  bronchi (air tubes) with 1 branching to each lung 25% to each lung 75% of air to 9 posterior air sacs & even into the hollow bones. Then when the bird exhales, this air exits through the lungs which means fresh air enters the lungs even when breathing out ! Circulatory System: - 4 chambered heart - right atrium receives “blue” blood  right ventricle  lungs (red blood now)  left atrium  left ventricle  arteries  arterioles  capillaries  venuoles  veins  right atrium - most have rapid heart rate due to high metabolism/oxygen needs

9. Nervous System & Sensory Organs: Large brains Well developed sight with color vision (optic lobes) Cerebellum – movement of muscles Cerebrum – migration behavior, nesting, other instincts Hearing: ear canals  eardrum  semicircular canals which regulate balance Reproductive System: Female usually has one ovary (on left side) The shell gland secretes a calcium carbonate, protective shell around the egg and yolk, etc. From egg release to finished egg it takes about 2 days. Eggs require incubation (warming) unlike amphibians & reptiles. Some birds hatch well feathered, eyes open – precocial Blind, naked bird babies are called - altricial