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