Practicle #7

Question 1

Mammal evolution

Answer 1

Synapsides (mammal-like reptiles) split from sauropsids (reptiles+birds) –> small, shrew-like mammals formed –> mass dinosaur extinction –> mammals filled roles of extinct animals

Question 1

Mammalia apomorphies

Answer 1

• secondary bony palate
• muscular, thoracic diaphragm
• 4 chambered heart
• endothermy
• single bone in lower jaw
• heterodont dentition
• middle ear (3 bones)
• mammary glands
• hair
• viviparous
• cloaca lsot
• expanded gray matter in brain
• ear flap well developed
• nipples/teats
• males with external gonads
• chorioallantoic placenta

Question 2

Mammals

Answer 2

• massive size variation
• mostly terrestrial
• one airborne
• occupy all continent, oceans, islands

Question 3

Heterodont dentition

Answer 3

Many types of teeth in one mouth, allows for better chewing, aids digestion.
- canines
- incisors
- premolars
- molars

Question 4

Secondary bony palate

Answer 4

Sperates mouth from nasal cavity, allows for breathing while we chew.

Question 5

Middle ear

Answer 5

Composed of 3 bones (stapes, malleus, incus), allows for better hearing, sensitiviy to more bandwidth.

Question 6

4 chambered heart

Answer 6

Left aortic arch only, separation of pulmonary and systemic circuits.

Question 7

Muscular diaphragm

Answer 7

Helps with breathing, increased volume of thoracic cavity.

Question 8

Mammary glands

Answer 8

Modified sweat glands that provide young with nourishing milk.

Question 9

Endothermy

Answer 9

“Warm blooded,” allows animals to remain active in cold condition.

Question 10

Hair

Answer 10

Used for insulation, sensation, camouflage, defense.

Question 11

Monotremes

Answer 11

Platypus, echinda.

• adults lack teeth
• oviparous
• lack nipples
• have cloaca

Question 12

Theria

Answer 12

Marsupialia, eutheria/placentalia.

• viviparous (embryos develop in uterus, nourished in placenta, birthed live)
• large cerebrums
• anus and urethral opening
• have piannae
• external gonads and/or nipples

Question 13

Marsupials

Answer 13

• Choriovitelline placenta
• further development occurs in marsupium (pouch)
• short gestation periods

Question 14

Eutherians

Answer 14

• chorioallantoic placenta
• long gestation periods
• corpus callosum = connection between cerebral lobes

Question 15

Afrotheria

Answer 15

Hyraxes, sirenians, elephants, aardvarks, elephant shrews, hedgehods, etc.

Question 16

Xenarthra

Answer 16

Armadillos, tree sloths, anteaters.

• reduced dentition
• low metabolic rates
• 1 color vision

Question 17

Boreoeutheria

Answer 17

Most mammals…

Pangolins, moles and shrews, carnivora, primates, ciroptera, rodents, lagomorphs, perissodactyle, artiodactyla

Question 18

Euliptyphla

Answer 18

Moles, shrews.

Question 19

Carnivora

Answer 19

Dogs, cats, bears.

• shearing teeth
• not all carnivores
• carnassials
• walk on toes

Question 20

Primates

Answer 20

• tropical/arboreal
• opposable digits
• big brains
• good eyesight
• herbivorous/omnivorous

Question 21

Chiroptera

Answer 21

Bats.

• eat insects, fruit, pollinate
• powered flight
• echolocation

Question 22

Rodentia

Answer 22

Largest mammal group.

• mostly herbivores
• upper and lower pair of every-growing, self-sharpening incisors

Question 23

Lagomorpha

Answer 23

Rabbits and pika.

• herbivores
• elongate ears and hindlimbs
• two sets of upper incisors

Question 24

Perissodactyla

Answer 24

Horses, rhinos, tapirs.

• 1 or 3 toed hooves

Question 25

Artiodactyla

Answer 25

Giraffes, deer, moose.

• various types of head ornamentation
  1) horns = bone core with permanent keratin sheath
  2) antlers = bones that are shed annually
  3) proghorns = bone core with hair sheath, shed annually
  4) ossicones = permanent skin covered bone growths

Question 26

Cetaceans

Answer 26

Whales and dolphins.

• lost hind limbs
• nostrils on to of head
• echolocation
• toothed or baleen