Copyright Pearson Prentice Hall Biology Copyright Pearson Prentice Hall

32-1 Introduction to the Mammals Photo Credit: ©Zefa (RM)/M. Botzek/Masterfile Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall Mammals Chapter 32 p821 What are the characteristics of a mammal? Hair mammary glands (in female) breath air 4 chambered hearts endotherms Copyright Pearson Prentice Hall

Form and Function in Mammals p822 Body Temperature Control – like birds, mammals are endotherms; their bodies can generate heat internally. endotherms have a higher metabolic rate than ectotherms (most other chordates) external body hair helps keep mammals warm. subcutaneous fat, which is a layer of fat located beneath the skin also helps to conserve body heat. Copyright Pearson Prentice Hall

Form and Function in Mammals Sweat glands help to keep an animal cool. Mammals, like wolves, that lack sweat glands, pant to rid themselves of excess heat. The ability of mammals to regulate their body heat from w/in is an example of homeostasis. Copyright Pearson Prentice Hall

Form and Function in Mammals Draw a diagram that depicts the internal feedback mechanism of sweating. List 4 possible ways that a mammal regulates its body temperature. 1. 2. 3. 4. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall Feeding p822 B/c of its high metabolic rate a mammal must eat nearly 10X as much food as a reptile of the same size to maintain homeostasis. mammals can be herbivores, carnivores, omnivores; most whales are filter feeders. The form and function of a mammals jay and teeth enables it to eat foods other than insects. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall Feeding Mammals have specialized teeth – incisors, canines, molars and premolars. Mammals teeth enable food to be processed efficiently. Mammals have a digestive tract to break down and absorb the food it eats. B/c digestive enzymes readily break down meat carnivores have a shorter intestine than do herbivores or omnivores. Incisors Molars and premolars canines Wolf Horse Herbivore Carnivore Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall Feeding Herbivores usually have a specialized digestive organ, called the rumen to break down plant matter. Newly swallowed plant food is stored and processed in the rumen. The rumen contains symbiotic bacteria that digest the cellulose of most plant tissues. The processed food in the rumen gets regurgitated from the rumen into the mouth. The partially digested food is chewed and swallowed again. After several cycles of regurgitation, the food moves to the stomach and through to the intestines. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall Feeding What is the function of the rumen? Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall Respiration p824 Use lungs to breath. The lungs are controlled by two sets of muscles: Intercostal muscles (found btw each rib) Diaphragm (found below the rib cage) The contraction of the intercostal muscles expands the rib cage, increasing the volume of the chest cavity. The contraction of the diaphragm pulls the chest cavity downward which further increases its volume. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall Respiration When the muscles relax, the rib cage lowers and the volume of the chest cavity decreases. Organs of respiration include: Nostrils Pharynx Trachea bronchus bronchioles alveoli – alveoli is where gas exchange occurs. What are the characteristics of a respiratory surface? Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall Circulation p824 2 separate loops with a 4 chambered heart. The right side of the heart receives oxygen poor blood from all over the body and pumps it to the lungs. After picking up oxygen in the lungs, the oxygen rich blood is returned to the left side of the heart, then pumped through blood vessels to the rest of the body. refer to diagram on page 824 Copyright Pearson Prentice Hall

Form and Function in Mammals Mammalian heart Left atrium Right atrium Left ventricle Right ventricle Complete division Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall Excretion p824 Excretory organs: Kidney ureter urinary bladder urethra The kidneys help maintain homeostasis by filtering urea from the blood, as well as by excreting excess water or retaining water as needed. The kidneys also can retain salts, sugars and other cmpds the body should not be losing. The presence of kidneys is what enables some animals to live habitats with minimal water. Copyright Pearson Prentice Hall

Form and Function in Mammals Response p825 The brain consists of three parts: Cerebrum Cerebellum Medulla oblongata What is the function of each part? Mammals have large brains in proportion to their body size. Most of the brain is taken up by an enlarged cerebrum, which contains a well-developed cerebral cortex. Copyright Pearson Prentice Hall

Form and Function in Mammals Response p825 A mammals cerebrum contains a well-developed outer layer called the cerebral cortex, which is the centre of thinking and other complex behaviours. Mammals rely on highly developed senses to detect and respond to stimuli from their external environment. The degree of development is animal specific. For example, dogs have a highly developed olfactory organ; dogs, bats and dolphins can detect sounds at much higher frequencies that we can. Not all mammals have color vision. Color vision is most useful to animals that are active during the day. Copyright Pearson Prentice Hall

Response: Chemical Controls Along with the nervous system, the endocrine system is involved in controlling body responses. Endocrine glands produce and release chemicals called hormones which enter the blood stream and carried to the hormones target organ. Ex. Calcitonin, Parathyroid hormone – regulate calcium levels Copyright Pearson Prentice Hall

Response: Chemical Controls Calcitonin is produced by the thyroid gland and acts on the digestive system and on bones. Parathyroid hormone is produced by the parathyroid gland and acts on bone and the digestive tract. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall Rat anatomy What structures are involved in: -digestion? -circulation? -respiration? Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall 32-1 Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall 32-1 One characteristic commonly used to determine whether fossils are mammals is subcutaneous fat. mammary glands. a jaw joint that allows movement from side to side. hair or fur. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall 32-1 How many chambers do mammalian hearts have? 2 3 4 6 Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall 32-1 Mammals are called endotherms because they produce milk to nourish their young. have well-developed sense organs. have powerful jaws and specialized teeth. generate their body heat internally. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall 32-1 The first true mammals appeared in the fossil record soon after the extinction of the dinosaurs. about the same time as the first reptiles. during the Triassic when dinosaurs were the dominant land animals. long after the extinction of the dinosaurs. Copyright Pearson Prentice Hall

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