Mammals Flashcards
2 extant subclasses of Mammalia
Prototheria and Theria
2 infraclasses contained within subclass Theria
Metatheria and Eutheria
two key extinct Mammalian groups
Therapsids and Cynodonts
characters of Therapsids
first group to evolve limbs underneath body
characters of Cynodonts
heterodont teeth and secondary palate, dominant lineage of Therapsids
extinct Mammalian group that gave rise to all extant mammals
Cynodonts
common characters of mammals
integument with hair and mammary glands, three ear bones, heterodont teeth, diphyodont tooth replacement, secondary palate, viviparity (except in Monotremes), negative pressure ventilation
mammalian hair
unique to mammals, consists of hollow cuticle filled with keratin
milk production in Monotremes
secrete milk from mammary patch on belly
3 ear bones in mammals
incus, malleus, and stapes
modifications to the amniotic egg in mammals
amnion stays the same, and chorion, allantois, and yolk sac fuse to form the umbilical cord
reproduction in mammals
internal fertilization via male penis, all have live birth but Monotremes
order within subclass Prototheria containing platypuses and echidnas
order Monotremata
characters of Monotremes
only mammals without mammary glands who lay eggs
infraclass of subclass Theria known as marsupials
infraclass Metatheria
characters of Metatheria
live mostly in Australia, rudimentary placenta, embryo develops in marsupium following birth
infraclass of subclass Theria containing rodents, carnivores, and primates
infraclass Eutheria
general characters of infraclass Eutheria
long gestation period, offspring born relatively precocial, shorter nursing period than other mammals
order within infraclass Eutheria containing rats, mice, and hamsters
order Rodentia
general characters of order Rodentia
large gap between incisors and cheek teeth for gnawing, mostly herbivorous
order within infraclass Eutheria containing bats
order Chiroptera
general characters of Chiropterans
nocturnal or crepuscular, mostly insectivores, many echolocate, only mammals with true flight
differences between Chiropteran flight and Avian flight
Chiropteran wings are homologous to animal hands, can’t soar like birds (can only flap), wing membrane less adjustable than feathers, weight distributed across body –> less stability but more maneuverability
order within infraclass Eutheria containing seals, bears, cats, etc.
order Carnivora