Presentation on theme: "31-2 Birds Created by: Tate Smith Darwin Lucero. What is a Bird? Birds are so diverse that it is difficult to find characteristics shared by all members."— Presentation transcript:
31-2 Birds Created by: Tate Smith Darwin Lucero
What is a Bird? Birds are so diverse that it is difficult to find characteristics shared by all members. Birds are reptile like animals that maintain a constant internal temperature. They have: 1. An outer covering of feathers 2. Two legs covered with scale used for walking or perching 3. Front limbs modified into wings The single most important characteristic of birds are Feathers Feathers are made mostly of Proteins and develop from pits in the birds’ skin.
Evolution of Birds Paleontologists agree that birds evolved from ancient reptiles due to the resemblance of their body structure, embryological and physiological characteristics. Many believe birds evolved directly from dinosaurs. However there is evidence that birds and reptiles both evolved from an earlier ancestor. The origin of birds is not yet completely resolved.
Birds Birds have a number of adaptations that enable them to fly. These adaptations include: 1. Highly efficient digestive, respiratory, and circulatory systems 2. Aerodynamic feathers and wings 3. Strong, lightweight bones 4. Strong chest muscles.
Body Temperature Control Birds are endotherms, which means they can generate their own body heat. Endotherms have a high rate of metabolism compared to ectotherms such as reptiles. Metabolism produces heat. A bird’s feathers insulate its body enough to conserve most of its metabolic energy. This allows birds to warm their body more efficiently than most animals.
Beaks and Bills Birds beaks are adapted to the type of food they eat. Insect-eating birds have short, fine bills that can pick ants and other insects. Seed-eaters have short, thick bills. Carnivorous birds shred their prey with strong hooked bills. Long, thin bills can be used for gathering nectar from flowers or probing soft mud. Large, long bills help birds to pick fruit from branches, while long, flat bills are used to grasp fish
Digestion Birds lack teeth and therefore can not break down food by chewing it. Birds have a crop which is located at the lower end of the esophagus where food is stored and moistened before it moves further. During nesting season, the crop produces a substance that is rich in protein and fat. Parents regurgitate this substance and feed their newly hatched young with it. Carnivorous birds have an expandable area in which large amounts of food can be stored. Birds that eat seeds or insects have a gizzard that helps in the mechanical breakdown of food by grinding it.
Digestive System Diagram
Respiration When a bird inhales, most air first enters large posterior air sacs in the body cavity and bones. The air then flows through the lungs in a series of small tubes. The complex system of air sacs and breathing tubes ensures that air flows into the air sacs and out through the lungs in a single direction. The one-way flow constantly exposes the lungs to oxygen- rich air. The constant, one-way flow of oxygen-rich air helps birds maintain their high metabolic rate. Birds need a high metabolism to maintain body temp. and provide the large amounts of energy required for flight.
Circulation Birds have four-chambered hearts and two separate circulatory loops. A birds heart has two separate ventricles, the right and left ventricle. One half of the heart receives oxygen-poor blood from the body and pumps this blood to the lungs. Oxygen-rich blood returns to the other side of the heart to ne pumped to the rest of the body. This double-loop system ensures that oxygen collected by the lungs is distributed to the body tissue with maximum efficiency.
Excretion Nitrogenous wastes are removed from the blood by the kidneys, converted to uric acid, and deposited in the cloaca. There, most of the water is reabsorbed, leaving uric acid crystals in a white, pasty form that you may recognize as bird poop!!!!!!!
Response Birds have well-developed sense organs, which are adaptions that enable them to coordinate the movements required for flight. Birds also have a brain capable of quickly interpreting and responding to incoming signals. The senses of taste and smell are not well developed in most birds, however their sight and hearing is extraordinary.
Movement Although the bones in a bird’s wings are homologous to the bones in the front limbs of other vertebrates, they have very different shapes and structures. In flying birds, large bones, such as the collarbone, are fused together, making a bird’s skeleton more rigid than a reptile’s. These bones form the sturdy frame that anchors the muscles used for flight. Air spaces make many bones lightweight. Birds also have large chest muscles that power the upward and downward wing strokes.
Reproduction In birds, both male and female reproductive tracts open into the cloaca. Mating birds press their cloaca's together to transfer sperm from the male to the female. Bird eggs are similar to reptile eggs, except they have harder outer shells. Most birds nurture their eggs until they hatch. When the chick is ready to hatch, it uses its bill to peck its way out.
Groups of Birds Birds are one of the most diversified types of animals. There are nearly 30 different orders, including: Pelicans and their Relatives Parrots Birds of Prey Perching Birds Cavity-Nesting Birds Herons and their Relatives Ostriches and their Relatives There are over 5000 species of Perching Birds!
Ecology of Birds Because birds are so numerous and diverse, they interact with natural ecosystems and human societies in many different ways. For Example: Hummingbirds pollinate flowers Many birds disperse seeds over great distances Insect-eating birds control insect populations Birds are known for their seasonal migrations over long distances. Many birds have survived endangerment recently due to new protection laws and conservation efforts.
QUIZ TIME!!!!!!! YAYAYAYAYAYA!!!!!! =D
Quiz Time 1. The single most important characteristic that separates birds from other animals is the presence of _____? A. Hollow Bones B. Feathers C. Two legs D. Wings 2. Which of the following features is especially adapted to support flight? A. Cloacas B. Gizzards C. Bills D. Chest Muscles
Quiz Time 2. The muscular part of a bird’s stomach that contains gravel, which crushes food is ________? A. Cloaca B. Gizzard C. Crop D. Air Sac 3. Both female and male Birds’ reproduction tracts open into the ______? A. Cloaca B. Crop C. Kidney D. Optic Lobe
Quiz Time 5. Birds excrete nitrogenous wastes mostly in the form of ______? A. Urine B. Ammonia C. Uric Acid D. Urea 6. Birds are known to generate their own body heat, these types of animals are known as _____? A. Mammals B. Ectotherm C. Passerine D. Endotherm
Quiz Time 7. Birds are believed to be closely related to _____? A. Reptiles B. Mammals C. Amphibians D. Arthropods 8. Unlike other vertebrates, birds have respiratory systems that ______? A. Take in oxygen and release carbon dioxide B. Excrete nitrogenous wastes C. Maintain a one way flow of air D. Have modified scales