1. Hannah Reagan 3 rd period

2.  Class Mammalia  Have hair and mammary glands (produce milk to nourish the young)  Also, mammals breathe air, have four- chambered hearts, and are endotherms that generate body heat internally

3.  Though you can’t see hair nor mammary glands in fossils, some fossilized mammal characteristics include: lower jaw connected by a joint directly to the skull, teeth that are replaced once in a lifetime, and discrete features of limbs and backbone  Mammals descend from reptiles  First appeared during late Triassic period; 220 million years ago

4.  High metabolic rate  Hair  Subcutaneous fat: layer of fat located beneath the skin  Some have sweat glands and others often pant

5.  As mammals evolved, the form and function of their jaws and teeth became adapted to eat foods other than insects  Because of high metabolic rate, mammals have to eat 10 times more food as a reptile  Specialized teeth: 1. incisors 2. canines 3. molars 4. premolars  Carnivores have short intestine because digestive enzymes can quickly digest meat  Herbivores have long intestine because tough, fibrous plant tissue is hard to break down  Rumen: stomach chamber in which newly swallowed plant food is stored and processed

7.  All mammals use lungs  Diaphragm: powerful muscle that pulls the bottom of the chest cavity downward, which further increases volume when breathing in  2 separate loops with a four chambered heart  Right ventricle and atrium pump oxygen poor blood from body to lungs. Left ventricle and atrium pump oxygen rich blood from lungs to the rest of the body.

9.  The kidneys of mammals help maintain homeostasis by filtering urea from the blood, as well as by excreting excess water or retaining needed water.  Kidneys also help retain sugars, salts, etc.  Kidneys allow mammals to live in different habitats just by being able to stabilize the amount of water in the body efficiently

10.  Highly developed brains: main parts include cerebrum-thinking and learning, cerebellum- muscular coordination, and medulla oblongata-involuntary body functions  The cerebrum outer layer is the cerebral cortex: center of thinking and other complex behaviors  Many have well developed sense of smell, sight, and hearing

11.  Endocrine glands regulate body activities by releasing chemicals called hormones that affect other organs and tissues  Immune systems help stop pathogens from infecting the mammal (includes skin barrier, and specialized cells that recognize and destroy pathogens)

12.  Backbone  Shoulder and pelvic girdles  Diversity in limb bones of climbers, runners, diggers, flyers, and swimmers. Pictures of limbs on page 826!

13.  Internal fertilization  All newborn mammals feed on their mother’s milk  Strong parental care and interaction

14. A. Covering of the olfactory bulb Covering of the olfactory bulb B. Outer layer of the cerebrum Outer layer of the cerebrum C. Helps in excretion Helps in excretion D. Another name for the medulla oblongata Another name for the medulla oblongata

15. A. Four chambered heart Four chambered heart B. Breathe air Breathe air C. Generate their body heat internally Generate their body heat internally D. All of the above All of the above

16. A. Triassic Period; 220 million years ago Triassic Period; 220 million years ago B. Jurassic Period; 206 million years ago Jurassic Period; 206 million years ago C. Permian Period; 260 million years ago Permian Period; 260 million years ago D. Carboniferous Period; 330 million years ago Carboniferous Period; 330 million years ago

17. A. Nervous Nervous B. Digestive Digestive C. Excretory Excretory D. Circulatory Circulatory

18. A. Asexual reproduction Asexual reproduction B. External fertilization External fertilization C. Internal fertilization Internal fertilization D. They don’t reproduce They don’t reproduce

19. CORRECT!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!

20. WRONG!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!