1. Mammals Chapter 45

2. Cenezoic Era Age of mammals (70 mya) Mesozoic Era Age of reptiles (200 mya)

5. Rise of mammals Climate changes favored survival of mammals –Mammals are endothermic “warm-blooded” –Abrupt change Colder Fewer swamps and veggitation

7. 1. Eohippus (Hyracotherium) -Eocene epoch (65 mya) - 4 toed -size of a small dog 2. Mesohippus -Oligocene epoch (38 mya) - 3 toed -size of a sheep 3. Equus -pliestocene epoch (2.5 mya) - one toed -size varies from miniature to draft horse

8. Origin of Horses and camels First appeared in N. America Migrated to Europe, Asia and Africa via land bridges Became extinct in N. America Reintroduced to N. America by Europeans

9. Extinction Death of an entire species –Examples: Wooly Rhino, Wooly Mammoth, Saber toothed tiger, Hump-less Camel, Straight Horned Bison –Natural process: can be hurried by man –Has occurred in the past, is ocuring NOW and will continue in the future!

10. Extinct species

12. Characteristics of Mammals mammary glands to feed young body covered with hair or fur live birth lung breathing endothermic diaphragm breathing muscle four chambered heart seven cervical vertebrae pectoral and pelvic girdles- two pairs of limbs highly developed brain cerebrum (emotions) cerebellum (equilibrium and movement)

13. Organ Systems Most highly developed of vertebrates –Thermoregulation- maintain constant body temperature –Hypothalamus- part of the brain that controls thermoregulation –Metabolic rate- respiration, heart rate chemical processes –Endothermic- internal control of body temp (Exothermic- external control of body temp) –Surface to volume ratio!- keeps exothermic organisms small, optimize surface area in comparison to body volume

14. Endothermy- Internal regulation of body temperature

15. Respiratory System A.Air Flow 1.Nasal passage- warms, moistens and cleans 2.Sinuses- warm and moisten 3.Pharynx- back of throat 4.Larynx – voice box with vocal cords 5.Trachea – windpipe allows air to go to the lungs (cartilage rings) 6.Right/Left Bronchi- Branches of windpipe that enter lungs 7.Right/Left Bronchail Tree- bonchioles enter lung tissue 8.Right/Left Lung a.Alveoli – Respiration takes place here b.Arterioles/venules c.O 2 /CO 2 gas exchange

16. Respiratory System

17. Mammalian Heart Compare hearts of –fish (2 chamber) –Reptile (3 chamber) –Amphibian (3 chamber) –Mammal (4 chamber)

18. Heart comparison Fish Frog Mammal

19. Mammalian Heart 1. Chambers- four with a septum dividing 2. Most efficient- there is no mixing of O+ and O- blood 3. Steps of circulation in the body a. Body send blood without O2 to the i.Superior (above the heart) and inferior vena cava ii.Right atrium iii.Tricuspid Balve iv.Right Ventricle v.Pulmonary Arterey i.Lung 1.Pulmonary Vein ii.Left Atrium 1.Bicuspid valve 2.Left ventricle iii.Aorta 1.Carotid – to head 2.Brachiocephalic- to neck / chest 3.Subclavian – body (color code the order above as red (O+) or blue (O-) by highlight or underline)

20. Circulatory System

21. Mammalian Nervous System a. Largest b. Cerebrum: controls voluntary movements, thought, emotion, memory c.Cerebellum: controls involuntary movements, muscle coordination, equilibrium d.Medulla oblongota: controls vital body functions, internal organs

22. Nervous System

23. Mammal Brain

25. Mammalian Reproductive system and parental care a.Grouped by increased efficiency of reproduction 1.Monotremes 2.Marsupials 3.Placentals

26. 26 Mammal Orders There are 19 orders of mammals in the class Mammalia in which 17 nourish unborn young in the placenta, egg laying mammals and marsupials

27. Monotremes: egg layers 1.Order monotremata- oviparous 2.Examples a.Duck- billed platypus b.Spiny echnida