se bf placing an "Xi in the 20. _X 10. Birds waterproof their feothers with oil, taken from a gland at the base of their tail.

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1 Name: See resources on my website to COfT\plete thjs assignment. Mark each statement below true or fa l se bf placing an "Xi in the apropriate column. Then without lifting your pencil connect in numerical order all the dots in the diagram related to the statements you marked true. The line you form in doing so will speji out a word related to birds. _ x _ l i: 2 E 3 G 9 12 i3 r, ia I. The ancestors of modern birds were reptiles _x 2. Diets of birds include nectar, seed, insects, and small animals X_ 3. All birds can fly, though some may fly better than others _X 4. The bones of a bird are l'ght and porous. _X 5. Birds' beoks are toothless _X 6. All birds are endothermic (i.e. worm blooded) (see last page to answer) X_ 7. Birds eat small amounts of food at a time because the have poor digestive systems. _X 8. Generally speoking, fema l es are not as brightly colored as males so they blend in better. X_ 9. Birds have a well developed sense of smell. _X 10. Birds waterproof their feothers with oil, taken from a gland at the base of their tail. X_ 11. Compared to other animals, birds have a low body temperature and low metabolism. _X 12. A bird molts its feathers at least once every year, sometimes more. X_ 13. Bird have small, weok hearts that beat relatively slowly compared to mammals. _X 14. The form a bird's beok is closely related to the nature of its diet. _X 15. Birds have excellent vision and a remarkable ability to judge distances X_16. In all species of bird, the female assumes responsibilty for nesting and feeding the young. _X 17. The feet of birds vary grejtly in structure, and are related to the environment they live in _X 18. Birds of prey have stronger claws than those of other birds. _X 19. Food is stored in the crop before passing on into two separate divisions of the stomach X_ 20. The eggs of birds must be fertilized before they can be laid.

2 1. Besides the obvious, like feathers and wings, birds have many special features that allow them to fly. Explain how each of the characteristics are specialized to help birds fly. A. Skeletal System- bones are light and porous. The furcula (wishbone) keeps the wings from flapping into each other. The keel serves as point for muscle attachment. The pygostyle (tailbone) is used for steering and maneuvering.

3 B. Circulatory System Birds have four chambered hearts (like us). Oxygenated blood is kept separate from deoxygenated blood. This means more O2 gets to the mitochondria of the cells, which means more ATP.

4 C. Reproductive System Females have only one ovary that is functional. Two ovaries would mean more eggs produced and too much weight to fly. In addition, the amount of calcium that is taken from the bones to make extra egg shells would make the female s bones too brittle and they would break under the stress of flight.

5 D. Digestive System- Birds are eating machines and process food very quickly. This is why they can eat berries, etc, that would be poisonous to us. (refer to picture of digestive system in the class handout)

6 E. Respiratory System- Birds have air sacs that help keep them buoyant. Gas exchange does not take place in the air sacs. (refer to picture of the respiratory system in the class handout)

7 F. Excretory System Birds lack urinary bladders, thereby reducing the water weight it must carry. It concentrates its waste into a slimy, semisolid, highly acidic compound. (SEE POOPY PORSCHE BELOW!) 2. Using an appropriate illustration and words, describe the physics of flight.

8 Bernoulli s Principle: A Swiss physicist named Daniel Bernoulli discovered the following in 1738: The pressure exerted by a stream on an object, is decreased the faster that stream goes. Faster moving air over a curved surface results in a difference of pressure on either side of the wing. The slower moving air from underneath exerts a greater pressure and results in lift.