Transcript MAMMALS

ZOOLOGY
MAMMALS
MAJOR CHARACTERISTICS
Endothermy
 Hair
 Completely divided heart
 Milk – mammary glands
 Single Jaw Bone
 Specialized teeth
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ENDOTHERMY
Body temperature regulation through
metabolism and insulation
 Homeostasis
 Allows mammals to live in cold climates
 Allows for energy to perform strenuous activity
for extended periods
 Faster metabolism requires more food and
oxygen
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ENDOTHERMY
Adaptations to environment
- blubber – whales, seals
- thick fur – polar bears
- large ears – elephants
- panting – lions, dogs
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HAIR
Provides insulation and protection
 Made of the protein keratin
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DIVIDED HEART
Efficient
 Two atria
 Two ventricle
 Septum completely divides ventricles
preventing mixing of oxygen rich blood and
oxygen depleted blood.
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MILK
Mammary glands located on thorax
 Milk contains carbs, proteins, and fats
 Modified sweat glands
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SPECIALIZED TEETH
Breakdown of food begins with chewing
 Provides large surface area for enzymes to
digest food
 Incisors – cut
 Canines – grip
 Premolars – shear, cut, shred
 Molars – grind, crush
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SINGLE JAW BONE
Lower jaw made up of one bone
 Mammal fossils often identified by jaw bone
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RESPIRATORY SYSTEM
Efficient
 Large surface area
 Two mechanisms – diaphram, rib-cage muscle
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DIGESTIVE SYSTEM
Special adaptations for plant digestions
 Rumen – four part stomach “chewing the cud”
 Cecum – large sac branched from small
intestine – allows for fermentation
 Both utilize microorganisms
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NERVOUS SYSTEM
Mammal brain 15 times heavier than fish,
reptile or amphibian
 Large cerebrum – evaluates input from sense
organs, controls movement, regulates behavior
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DIVERSITY OF MAMMALS
Monotremes – oviparous
 Marsupials – viviparous
 Placental – longer development in uterus
receives nourishment from placenta
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MAMMALIAN ORDERS
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Monotremata
Marsupialia
Insectivora
Chiroptera
Dermoptera
Primates
Scandentia
Macroscelidea
Tubulidentata
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Lagomorpha
Rodentia
Pholidota
Carnivora
Cetacea
Artiodactyla
Perissodactyla
Hyracoidea
Sirenia
Proboscidea
MONOTREMATA
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Lay eggs
Ancient
Platypus
Two echidna species
(spiny anteater)
MARSUPIALS
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Super order marsupialia
Seven orders
280 species
Most live in Austrailia
Only U.S. species is the
Virginia opossum
XENARTHRA
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30 species
Anteaters, armadillos,
sloths
Feed on insects with
long sticky tongue
Many are toothless
Have unique structure
of lumbar vertebrae
Strong teeth, claws
LAGOMORPHA
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Rabbits, hares, pikas
Native to many
countries
Double row of upper
incisors that continue to
grow
Herbivore
RODENTIA
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Largest mammalian
order
Found on every
continent except
Antartica
1800 species
Mice, rats, porcupine
PRIMATES
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235 species
Apes, monkeys, lemurs
Humans
Forward facing eyes
allows for dept
perception
Wide range of sizes
Grasping hands and
feet
CHIROPTERA
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Only flying mammals
Bats
900 species
Modified forelimb
Echolocation
Large ears
INSECTIVORA
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390 species
Shrews, hedgehogs,
moles
Feed primarily on
insects
Long pointed nose and
sharp teeth allow them
to hold prey
CARNIVORA
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274 species
Feed on meat
Strong jaws
Large teeth
Claws
Pinnipeds – aquatic
carnivores (sealions)
ARTIODACTYLA
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Ungulate
Even number of toes
Most are ruminants
Deer
Cattle
Giraffes
Pigs
PERISSODACTYLA
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Ungulate
Odd number of toes
Horses
Zebras
Rhinos
Tapirs
Have a cecum
CETACEA
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Related to Artiodactyla
Whales, dolphins
Adapted to aquatic
environments
Hairless except for
snout
SIRENIA
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Related to elephants
Look similar to whales
due to convergent
evolution
Live in tropical seas,
estuaries, and rivers
Lack hind limbs
PROBOSCIDEA
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Nose modified into long
boneless trunk
Elephant
Asian and African
Modified incisors called
tusks