Class Mammalia External Structure & Locomotion 1. Skin- important for A. protection from injury B. invasion of bacteria C. UV rays D. temperature regulation.

Class Mammalia

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

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

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 perception3. Thermal regulation

F. Hair color determined by the amount of a pigment called melanin in the hair shaft

Monotremata

• - egg laying mammals

• - Echidna (spiny anteater)

• Duck-billed Platypus

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

4. Glands-variety of functions:

A. sebaceous(oil) glands- lubricates & waterproofs the skin

B. Sudoriferous(sweat) gland- cools skin; releases excess salt, urea, & water

C. Scent/musk glands- on face, feet, anus to show territoriality, sex, recognition

D. Mammary glands- secrete milk containing nutrients for young

Bones & Teeth

1. 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)

3. Two sets of teeth:

A. Deciduous teeth-lost very early; milk teeth

B. Permanent teeth- last set of teeth

Permanent teeth Deciduous teeth

4. Types of teeth:

A. incisors- two front teeth; chisellike & used for gnawing or nipping

B. Canines- long, stout, &

conical; catching,

killing, & tearing prey

C. Premolars- broad flat teeth; for chewing

D. Molars- same as premolars

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

C. Omnivores-(humans) have equally dominant teeth

6. Three types of horns:

A. True horns- bone arises from skull; not branched; not shed; seen in both sexes(sheep & cattle)

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

C. Rhinoceros horn- mass of hair-like keratin fibers. Not bone

Nutrition & the Digestive System1. Mammals digestive systems are

specialized(like teeth) for a variety of needs

2. Ruminants- most herbivores

A. Eat plant material containing cellulose that is hard to digest

B. Have very large digestive tracts that aid in digestion of cellulose. (this is why these animals have very large bellies)

C. Most have 4 stomach chambers filled with special bacteria that help break cellulose down

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

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

Circulation

1. Have a four chambered heart

2. Keeps oxygenated blood & deoxygenated blood separate

Temperature Regulation

1. Endotherms

2. Maintain warmth-A. hair

B. fat deposits-blubber

3. 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)

1. Which is not a gland associated with mammals?

a. Sebaceous c. Sudoriferous

b. Mammary d. Jacobson’s

2. Which characteristic do mammals and birds share?

a. Feathers b. Dry scaly skin c. endotherms

3. Hair is important for

a. Temperature regulation c. As a sensory organ

b. Camouflage d. All of these

4. A ruminant

a. Has long digestive tract b. Is a carnivore

c. Lacks hair

5. By looking at the teeth, what type of animal is this?

a. Carnivore

b. Herbivore

c. omnivore

JOURNAL• You have discovered an unknown

organism. What are three characteristics that would help you identify it as a mammal?

• GET OUT YOUR MAMMAL NOTES

• PLEASE TURN IN:– Signed grade printout– Solving a Mammal Mystery WKST

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)

4. Pheromones- used to:

A. Recognize members of same species

B. Attract mate

C. Establish territories

D.Recognize parents

5. Auditory & tactile communications important especially to herd animals

6. Vocalizations & tactile communications important to social animals like primates that groom each other

7. Territoriality- defend/protect certain area

Nervous & Sensory System1. 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

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

Reproduction & Development

1. Females go through an estrus cycle where they are receptive to males and release eggs for fertilization

2. Reproduction usually occurs when climate is right and resources are available

3. Three types of estrus:A. monestrus- only one

estrus/year- pandas, bears, sea lions

B. Diestrus- 2 estrus/ year- domestic dogs

C. polyestrus- many estrus/year- humans

4. Modes of development:

A. monotremes- lay eggs- platypus & echidna

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

C. Eutherian 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.

Orders of Mammals

1. Order Insectivora- small, primitive mammals; 3rd largest order.

Ex; hedgehogs, moles, shrew

2. Order Chiroptera- bones of arms & hands are elongate & slender; have flight membranes; most insectivores, some fruit eater, blood or fish feeders

Ex- bats

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

4. Order Edentata- 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

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

6. Order Rodentia- largest mammals order; upper & lower jaws have single pair of always growing incisors.

Ex- squirrels, chipmunks, rats, mice, beavers, porcupines

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

8. Order Carnivora- predatory mammals; well developed sense of smell; canines are well developed

Ex- dogs, cats, bears, raccoons, sea lions, seals, walruses, otters

9. Order Proboscidea- long, muscular trunk with 1-2 finger like projections

Ex- African 7 Indian elephants

10. Order Sirenia- large, aquatic herbivores; nearly hairless with thick, wrinkled skin; forelimb is flipperlike & hindlimb is vestigial

Ex- manatee, dugong

11. Order Perissodactyla- skull usually elongate; large molars/premolars, odd toed ungulates (hoofed animals); primarily grazers.

Ex- horses, rhinoceroses, zebras, tapirs

12. Order Artiodactyla- even toes hoofed animals; grazing animals

Ex- pigs, hippopotamuses, camels, deer, sheep, giraffe, cattle

Monotremata

• -Egg laying mammals

• - Echidna (Spiny Anteater)

• - Duckbilled Platypus

Marsupialia

• - pouched mammals

• -

Demoptera

• Flying Lemurs

Hyracoidae

• Hyrax

Pholidata

Pinnipedia

• Seals & Walruses

Tubulidentata• Aardvark