Mammals

Chapter 45

Extinct species

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)

Endothermy

Respiratory System

Heart comparison

Fish

Frog

Mammal

Circulatory System

Nervous System

Mammal Brain

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

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Monotremes and MarsupialsOnly 5 percent of all mammalian

species are in the orders Monotremata and Marsupialia.

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Monotremata• Oviparous or egg laying mammals• Only 3 in existence• Duck-billed platypus and two species of

spiny anteaters called echidna.• Not completely endothermic (their body

temperature is lower and fluctuates more than other mammals)

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Marsupials• Marsupials give birth to tiny

immature young that crawl to a pouch on the mothers belly immediately after they are born.

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They attach themselves to milk secreting nipples nursing until they are mature enough to survive outside the pouch.

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250 species of marsupial species exist in Australia, New Guinea, Tasmania, And the Americas

• .

Tasmanian Devil

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American Marsupial

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Placental Mammals

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Characteristics of Placentals• Placental mammals carry unborn young in

the uterus until young can survive in the wild.

• Oxygen and nutrients are transferred from mother’s blood to baby’s blood

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Placental Characteristics

• The placenta is a membrane providing nutrients and waste & gas exchange between the mother and developing young

• Gestation period-is the time which mammals develop in mother’s uterus

Classification of Mammals- teeth

foot structure

toes and fingers, claws and nails

Insectivora

Chiroptera

Rodentia

Lagomorpha

Edentata

Cetacea

Sirenia

Proboscidea

Carnivora

Perissodactyla

Artiodactyla

Primates

Anthropoids