snyapsids and mammals

Question 1

Describe (Clade) Synapsida.

Answer 1

(Amniote clade) Early group of amniotes with a single temporal skull opening; includes pelycosaurs, therapsids, and mammals; evolved in the Permian.

Question 2

Describe (Order) Therapsida.

Answer 2

Advanced synapsids; sometimes called “mammal-like reptiles”; had differentiated teeth, upright gait, early warm-blooded traits; ancestors of mammals.

Question 3

Describe (Class) Mammalia.

Answer 3

Warm-blooded vertebrates with hair, mammary glands, single lower jaw bone, three middle ear bones, large braincase, and a secondary palate for simultaneous breathing and feeding.

Question 4

Describe (Genus) Morganucodon.

Answer 4

Early mammal from the Late Triassic (Wales); small, insectivorous, nocturnal; transitional features between reptiles and mammals.

Question 5

Describe (Order) Monotremata (monotremes).

Answer 5

Primitive egg-laying mammals (e.g., platypus, echidnas); milk secreted onto skin/hair; found in Australia and New Guinea.

Question 6

Describe (Infraclass) Marsupialia (marsupials).

Answer 6

Pouched mammals; young develop externally in pouch (e.g., kangaroos, opossums); show convergent evolution with placentals.

Question 7

Describe (Infraclass) Placentalia (placental mammals).

Answer 7

Mammals with long gestation supported by placenta; first appeared in the Cretaceous; major radiation after dinosaur extinction.

Question 8

Describe (Superorder) Afrotheria.

Answer 8

African-origin mammals like elephants, manatees, aardvarks, hyraxes.

Question 9

Describe (Superorder) Xenarthra.

Answer 9

South American-origin mammals like sloths, armadillos, glyptodonts.

Question 10

Describe (Superorder) Laurasiatheria.

Answer 10

Mammals from the Laurasian landmass; includes bats, whales, carnivores, horses.

Question 11

Describe (Superorder) Euarchontoglires (Euarchontoglirans).

Answer 11

Includes primates (apes, humans), rodents, lagomorphs, tree shrews.

Question 12

Describe (Order) Ungulata (ungulates).

Answer 12

Hoofed mammals including horses, deer, camels, and their descendants like whales and elephants.

Question 13

What features distinguish (Class) Mammalia from (class) reptiles?

Answer 13

Hair, mammary glands, single lower jaw bone, three middle ear bones, larger brain, secondary palate.

Question 14

What advantage did hair provide early (Class) Mammalia?

Answer 14

Insulation to conserve heat in small, warm-blooded animals.