The Black Bear aka Ursus americanus The North American Black Bear is the best known and most widespread of the North American bears. The Polar Bear aka Ursus maritimus, which means "sea bear” Discovered 1774 by Commander C.J. Phipps The Northern Cardinal aka Cardinalis cardinalis North American bird 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 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 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 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 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 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 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 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 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 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 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 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) Cephalization Neurulation Formation of sensory organs usually towards the anterior 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) 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 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 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 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 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