Class Mammalia

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Class Mammalia
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External Structure Locomotion
1. Skin- important for A. protection from
injury B. invasion of bacteria C. UV
rays D. temperature regulation E. Sensory
perception F. Excretion G. Water regulation
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2. Hair- keratinized strands of dead cells A.
some it is reduced to a few bristles B. 2 kinds
make up the pelage or fur coat 1. Guard hair-
long outer hairs for protection
coloration 2. Underhair- dense, soft, shorter
hairs for insulation
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C. Stops growing when it reaches a certain
length D . Molting 1. all at once(most
mammals) 2. gradually throughout
life(humans) E. Important for 1.
Camouflage 2. Sensory perception 3.
Thermal regulation F. Hair color determined by
the amount of a pigment called melanin in the
hair shaft
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Monotremata

• - egg laying mammals
• - Echidna (spiny anteater)
• Duck-billed Platypus

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3. Claws- used for locomotion, offensive
defensive behavior A. can be modified
into 1. Claws- for digging 2. Nails- for
grasping (arboreal animals-primates) 3.
Hooves- reduced digits for walking on hard
ground, rocks
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4. Glands-variety of functions A.
sebaceous(oil) glands- lubricates waterproofs
the skin B. Sudoriferous(sweat) gland- cools
skin releases excess salt, urea, water
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C. Scent/musk glands- on face, feet, anus to show
territoriality, sex, recognition D. Mammary
glands- secrete milk containing nutrients for
young
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Bones Teeth

• Secondary palate- separates the nasal oral
  pathways so can breathe while chewing
• 2. Are heterodonts- teeth are specialized for
  different function.
• ( reptiles are homodonts-all teeth are the same
  shape)

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• 3. Two sets of teeth
• Deciduous teeth-lost very early milk teeth
• Permanent teeth- last set of teeth

Permanent teeth
Deciduous teeth
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4. Types of teeth A. incisors- two front teeth
chisellike used for gnawing or nipping B.
Canines- long, stout, conical catching,
killing, tearing prey
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C. Premolars- broad flat teeth for chewing D.
Molars- same as premolars
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5. A. Herbivores (deer, horses, rodents) have
reduced canines, more prominent molars for
grinding plant food
B. Carnivores(dogs, cats, coyotes) have enlarged
canines for tearing, less dominant molars
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C. Omnivores-(humans) have equally dominant teeth
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• 6. Three types of horns
• True horns- bone arises from skull not branched
  not shed seen in both sexes(sheep cattle)

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B. Antlers- covered with velvet that falls off
before the breeding season antlers
are lost after the breeding
season a few months later regrow, more
elaborate than before
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C. Rhinoceros horn- mass of hair-like keratin
fibers. Not bone
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Nutrition the Digestive System

• Mammals digestive systems are specialized(like
  teeth) for a variety of needs
• Ruminants- most herbivores
• Eat plant material containing cellulose that is
  hard to digest
• Have very large digestive tracts that aid in
  digestion of cellulose. (this is why these
  animals have very large bellies)

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C. Most have 4 stomach chambers filled with
special bacteria that help break cellulose down
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D. Will regurgitate or chew cud to continue
breaking down cellulose E. Some will eat their
fecal pellets (rabbits, elephants) to get more
nutrients from the plants they eat
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Gas Exchange

1. Have larger, more vascular lungs
2. Have a diaphragm- the muscle that separates the
   abdominal and thoracic cavities- to help in
   drawing in large amounts of air at a time

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• Circulation
• Have a four chambered heart
• Keeps oxygenated blood deoxygenated blood
  separate

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• Temperature Regulation
• Endotherms
• Maintain warmth- A. hair B. fat
  deposits-blubber
• Cool off- A. panting B. sweat
  glands
• C. large ears to dissipate heat(rabbits
• elephants)
• D. nocturnal

Cutting blubber cubes from seal to test for
contamination (bioaccumulation)
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• Which is not a gland associated with mammals?
• Sebaceous c. Sudoriferous
• Mammary d. Jacobsons
• Which characteristic do mammals and birds share?
• a. Feathers b. Dry scaly skin c. endotherms
• Hair is important for
• Temperature regulation c. As a sensory organ
• Camouflage d. All of these
• A ruminant
• Has long digestive tract b. Is a carnivore
• c. Lacks hair
• By looking at the teeth, what type of animal is
  this?
• a. Carnivore
• b. Herbivore
• c. omnivore

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• Behavior
• Migration- move long distances to avoid drought
  or temperature extremes
• Winter sleep- animals retreat to burrows where
  they become less active but relatively alert
  easily aroused(bears, raccoons)
• Hibernation-respiration, heart rate, metabolism
  all slow down considerably. Will store large
  amounts of fat to rely on in winter. ( moles,
  shrews, rodents, bats)

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• 4. Pheromones- used to
• Recognize members of same species
• Attract mate
• Establish territories
• Recognize parents

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5. Auditory tactile communications important
especially to herd animals
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6. Vocalizations tactile communications
important to social animals like primates that
groom each other 7. Territoriality-
defend/protect certain area
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Nervous Sensory System

1. Larger brains compared to body size
2. Good sense of touch
3. Olfaction very important
4. Well developed sense of hearing
5. Vision is also important. Color vision not as
   well developed in most( scientists believe
   because ancestor were nocturnal). It is well
   developed in primates, squirrels and a few others

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Excretion

1. kidney
2. Produce urea- liquid urine with some water- as a
   waste product.
3. Can afford to lose some water because of our
   better abilities to maintain homeostasis

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• Reproduction Development
• Females go through an estrus cycle where they are
  receptive to males and release eggs for
  fertilization
• Reproduction usually occurs when climate is right
  and resources are available
• Three types of estrus A. monestrus- only
  one estrus/year- pandas, bears, sea lions
• B. Diestrus- 2 estrus/ year- domestic dogs

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C. polyestrus- many estrus/year- humans 4.
Modes of development A. monotremes- lay eggs-
platypus echidna
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B. marsupials- short gestation inside
mother(8-40 days) when born must crawl to
marsupium (pouch) to complete development. Will
attach to nipple in pouch for additional 60-270
days
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C. Eutherian (placental)mammals- longer gestation
periods (20-19 months) Offspring are nourished by
the placenta. The longer the gestation
period, the longer the offspring can take to
develop, the more complex structures and/or
functions will be.
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Orders of Mammals

• Monotremata
• - Most primitive mammals
• - Egg laying mammals
• - Echidna (Spiny Anteater)
• - Duckbilled Platypus

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Marsupialia

• - pouched mammals
• kangaroo, possum,
• koala, Tasmanian devil

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• Orders of Mammals
• Order Insectivora- small, primitive mammals 3rd
  largest order.
• Ex hedgehogs, moles, shrew

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2. Order Chiroptera- bones of arms hands are
elongate slender have flight membranes most
insectivores, some fruit eater, blood or fish
feeders Ex- bats
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3. Order Primates- increased agility in
arboreal(tree-dwelling) habitats omnivores,
unspecialized teeth, grasping digits, enlarged
eyes cerebral hemispheres Ex lemurs,
tarsiers, monkeys, great apes, humans
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4. Order Xenartha- incisors canines absent
hind foot is four toes, forefoot with 2/3
prominent toes with large claws limbs for
climbing or digging Ex- anteaters, sloths,
armadillos
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5. Order Lagomorpha- two pairs of upper incisors,
one pair of lower incisors. Incisors are always
growing worn down by feeding on
vegetation. Ex- rabbits
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6. Order Rodentia- largest mammals order upper
lower jaws have single pair of always growing
incisors. Ex- squirrels, chipmunks, rats, mice,
beavers, porcupines
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7. Order Cetacea- streamlined, nearly hairless
insulated by blubber forelimbs modified into
flippers, hindlimbs reduced nostrils on top of
head Ex- toothed whale, porpoises, baleen whales
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8. Order Carnivora- predatory mammals well
developed sense of smell canines are well
developed Ex- dogs, cats, bears, raccoons, sea
lions, seals, walruses, otters
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9. Order Proboscidea- long, muscular trunk with
1-2 finger like projections Ex- African and
Indian elephants
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10. Order Sirenia- large, aquatic herbivores
nearly hairless with thick, wrinkled skin
forelimb is flipperlike hindlimb is
vestigial Ex- manatee, dugong
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11. Order Perissodactyla- skull usually elongate
large molars/premolars, odd toed ungulates
(hoofed animals) primarily grazers. Ex-
horses, rhinoceroses, zebras, tapirs
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12. Order Artiodactyla- even toes hoofed animals
grazing animals Ex- pigs, hippopotamuses,
camels, deer, sheep, giraffe, cattle
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Demoptera

• Flying Lemurs

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Pinnipedia

• Seals Walruses