Class Mammalia

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monotremes
marsupials
egg layers
viviparous with pouch
6 species
250 species
Class Mammalia
placentals
placental viviparity
3,800 species (17 orders)
2

• Age of mammals- beginning of Tertiary period-
  70 mya
• First mammals small with delicate skeletons,
  acute senses and possibly nocturnal

3
Characteristics

• Hair or fur called pelage
• Keratinized derivative of epidermis
• Periodically molted
• Insulating layer
• Important to sense of touch
• Most have claws, nails or hooves

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• Glands
• Sebaceous- oil
• Sudoriferous- sweat
• Scent or musk- pheromones
• Mammary (functional in females)- milk
• Monotremes- no nipples

sebaceous
sudoriferous
mammary
musk
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• Skull and teeth
• Single articulation of jaw bone
• 3 middle ear ossicles
• More extensive secondary palate- can chew and
  breathe
• Specialized teeth set into sockets of jaw
• Most two sets- deciduous and permanent
• Dental formula to identify
• Types of teeth based on diet

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• Skeleton and muscles
• Most have 7 cervical vertebrae
• Trunk divided into thoracic and abdominal
  cavities by diaphragm
• Skeleton bears body weight- muscles concentrated
  in upper appendages

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• Nutrition and digestion
• Specialized to diet
• Some have cecum- fermentation pouch (rodents)
• Some ruminants- 4 stomach chambers (cows)

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• Circulation and gas exchange
• 4 chambered heart
• Placental mammals exchange nutrients from
  maternal to fetal blood
• High metabolic rate
• Efficient lungs

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• Warm blooded
• -heat production by shivering and brown fat
• -heat reduction through ears, tails, panting,
  burrowing or finding shade

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• Some go into winter sleep or hibernation

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• Nervous system
• Complex- enlarged cerebral cortex
• Acute senses- touch, smell, auditory, vision
  (most not color)

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• Excretion
• Metanephric kidneys excrete urea (more water loss)

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• Reproduction
• Most have cycles (ova mature)- hormone regulated
• Estrus (heat)
• Some induced cycles (menstrual)

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• Behavior
• Complex- often visual
• Pheromones and marking
• Grooming
• Territoriality

15
hedgehogs
moles
Order Insectivora
(third largest)
tenrecs
shrews
16
Order Chiroptera
bats
(second largest)
17
Order Primates
18
Order Edentata
19
Order Lagomorpha
20
Order Rodentia
(largest)
21
(No Transcript)
22
Order Cetacea
23
Order Carnivora
24
Order Proboscidea
25
Order Sirenia
26
Order Perissodactyla
27
Order Artiodactyl
28
largest colonies
largest rodent
capybara
prairie dogs
can kill snakes
can roll in ball
mongoose
pangolin
29
highest altitude
"man of the forest"
yak
orangutan
largest monkey
largest herds
mandrill
springbok