Mammals & Birds

1. Mammals & Birds

2. Scientific Names • The Black Bear • aka Ursusamericanus • The North American Black Bear is the best known and most widespread of the North American bears. • The Polar Bear • aka Ursusmaritimus, which means "sea bear” • Discovered 1774 by Commander C.J. Phipps • The Northern Cardinal • akaCardinaliscardinalis • North American bird

3. Evolution • Mammals • Two groups formed from amniotes about 300 million years ago • One to dinosaurs, birds, and modern reptiles • One to synapsis and therapsids • Gave rise to mammals and their extinct relatives • First mammals coexist with first dinosaurs during the Triassic period for more than 150 million years • 100 million years ago, during the Cretaceous period, three groups formed • Monotremes – oviparous • Marsupials – viviparous • Placental mammals - viviparous

4. Evolution (cont.) • Birds • Evolution thought to have begun in Jurassic era from small, fast-running carnivorous dinosaurs • Evidence show evolution from theropod dinosaurs • First classified bird fossils were from the genus Archaeopteryx • Begun diversifying early Cretaceous period • Survived global catastrophe that killed dinosaurs and underwent rapid evolutionary radiation • Modern bird orders originated by 40 million years ago

5. Symmetry and Body Cavity • Bilaterally symmetrical • Two similar halves when divided about a single plane • Cephalization • Development of a head – in which sense organs, brain, and feeding organs are concentrated – in animals

6. Structural Support • Endoskeleton • Skeleton on the inside of an animal body • Comprised of a skull, vertebral column, pectoral and pelvic girdles, ribs, and limb or fin elements • Gives shape and support to the body, protects vital organs and provides a system of rigid levers to which muscles can attack and produce movement. • Allows steady growth • Present in chinoderms and other invertebrates

7. Structural Support • In birds, skeleton combines lightness with strength • Bones are thin and hollow • Many are fused making more rigid skeleton than reptiles or mammals • Provides flight stability

8. Nutrition and Digestion • Mammals • Incisors, canines, premolars, molars assist in feeding process • Food moves through esophagus to stomach • Gastric juices kill bacteria transfers into small intestine • Colon reabsorbs excess water and stores feces until they’re eliminated • Birds • Don’t chew; food passes straight to esophagus • Crop, proventriculous, gizzard, small intestine to bloodstream • Very rapid

9. Transportation / Circulation • Birds • Wings • Flight movements possible by large, powerful flight muscles on breast and wings • Account for up to 50 percent of body weight • 4-chambered heart + two incompletely separate ventricles • Double-loop circulation • Similar to reptiles and mammals • Mammals • Forelegs and hind legs, limbs, appendages • Two atria and two ventricles • Septum completely separated ventricle • Allows efficient oxygen transportation through the body

10. Respiration • Birds • Lots of oxygen for high metabolism • Air enters through nostrils on beak fills lungs while 75% go to air sacs (usually 9) that store air • Air sacs reduce density, aid in flight • Mammals • Lungs – contain millions of alveoli enable efficient gas exchange • Large surface area + small sacs for gas exchange • Two mechanisms • Thoracic cavity– holds lungs; strenuous activity • Diaphragm – below rib cage, enlarges thorax connects to thoracic cavity; used when at rest

11. Water Balance • Birds • Kidneys are similar to ones in their ancestor reptiles • Limited intake of water-filters only enough for excretion • Uric acid is converted nitrogen waste compound • Uric acid can be excreted with little water • Mammals • Urea requires more water than uric acid in birds • Kidneys regulate water balance inside the mammal • Reabsorb large amounts of nephric filtrate

12. Excretion • Birds • Two kidneys filter uric acid (nitrogenous waste) from blood • Concentrated levels goes through ducs called ureters to the cloaca and exit through vent • Mammals • Kidneys and accessory urinary organs • Solid waste out of large intestine • Urea and lactic acid expelled through sweating

13. Reproduction • Sexual Reproduction • Fertilization • Internal fertilization - sperm fuses with an egg inside the female’s body • Amniotes – animals that produce an amniotic egg • Amniotic – eggs with embryo that is always contained inside water • Marsupials – offspring are born and develop in external pouch • Some mammals develop placenta • organ w/ blood vessels that carry oxygen, nutrients and waste to and from the embryo

14. Reproduction (cont.) • Types of offspring birth • Oviparous – eggs hatch outside of the mothers body (all birds/3 mammals) • Viviparous – no shell forms around the egg, and the young are kept inside of the mother’s body until they are mature enough to be born (most mammals)

15. Nervous System • Cephalization • Formation of sensory organs usually towards the anterior • Neurulation • Develops neural tube, gives rise to brain and spinal cord • Center of nervous system is brain • In vertebrates spinal cord and brain are the Central Nervous System (CNS)

16. Nervous System (cont.) • Birds • Relatively large brains • Highly developed cerebellum and cerebrum • Cerebellum coordinates movement and flight-related functions • Cerebrum controls complex behavioral patterns • Large optic lobes receive and interpret visual stimuli

17. Nervous System (cont.) • Mammals • Brain 15 times heavier than those of fish, amphibians and reptiles • Large cerebrum • Largest and most outer region of the brain • Folded and fissured, increases surface area • Evaluates input from sense organs • Controls movement, initiates and regulates behavior and functions in memory and learning

18. Unique Characteristics • Birds • Feathers • Insulate body to heat loss • Wings • Modified forelimbs covered by feathers • Lightweight rigid skeleton • Thin-walled and hollow • Endothermic metabolism • Rapid and supplies energy for flight • Unique respiratory system • Air sacs • Beak • Tough, horny sheath • Oviparity • Calcium-containing shell that encase offspring

19. Unique Characteristics • Mammals • Endothermy • Regulate body heat through metabolism and heat loss • Hair • Insulation • Completely divided heart • Milk • Nutritious fluid produced by mammary glands on thorax/abdomen • Single jawbone • Lower jaw composed of single bone • Specialized teeth • Modified for different functions

20. Resources Used • Bailey, Jill. Animal Life. New York: Oxford University Press. Inc., 1994. • Hine, Robert. "cephalization." The Facts On File Dictionary of Biology, Fourth Edition. New York: Facts On File, Inc., 2005. Science Online. Facts On File, Inc. http://www.fofweb.com • Hine, Robert. "endoskeleton." The Facts On File Dictionary of Biology, Fourth Edition. New York: Facts On File, Inc., 2005. Science Online. Facts On File, Inc. http://www.fofweb.com • Postlethwait, John, and Hopson, Janet. Modern Biolody. Austin: Holt, Rinehart and Winston, 2006. Print. • "Reproduction of Living Organisms." Science Online. Facts On File, Inc. http://www.fofweb.com • Zerucha, Ted. "development of the central nervous system." Human Development, Your Body: How It Works. New York: Chelsea House Publishing, 2003. Science Online. Facts On File, Inc. http://www.fofweb.com