Mammals Flashcards
What are some general features of mammals? (8)
Endothermic, covered in hair, provide milk to young, 7 neck vertebrae, jaw with heterodonty teeth (incisors, molars, premolars, canines) as well as diphyodont, upper and lower teeth occlude for shear/grind/crush food, 2 way ventilatory flow through respiratory organs
What are features of mammalian hair? (8)
Thin shaft of keratin, structurally simpler than feathers, functions for insulation, camouflage, display, defence, tactile probing and insect deterrence
What are the three ways mammals can locomote? Explain them.
Running/walking: use close to erect posture, cursorial mammals use two fore or hind limbs to contact the ground simultaneously and have a suspended phase where no limbs touch the ground
Swimming: some taxa have no hind limbs and instead have expansion of the tail to form a fun (fluke), which undulates vertically to generate propulsion and use paddle like arms to steer
Aerial (flying): only chiroptera can fly, use wing with skin and supported by four digits, leaving the thumb free, bones are lightly mineralized allowing them to be more pliable especially at the fingertips, wing is much more compliant than bird wings and can adjust tension/shape (camber), bats have lower lift/drag ratios than birds BUT more maneuverable
What are some features of Monotremata? What three species are contained within it?
Ornithorhynchus anatinus (platypus), Tachyglossus aculeatus (short beak echidna)
Zaglossus (3 species, long beak echidna)
They lay non calcified eggs, have leathery bill with electroreceptors, have cloaca for one opening for everything, do not have a nipple, they secret milk through their fur, partly sprawled stance and low temp, venomous spur on males
What are some features of marsupials? What clades are included here?
Have pair of epipubic bones attached to the pelvis to support the pouch, young are born tiny and underdeveloped, nourished with mammary glands in the pouch, have cartilaginous kneecaps.
Includes: Ameridelphia, Diprotodontia, and Australidelphia
What are some features of Ameridelphia?
Majority of them belong to Didelphidae (opossums) and they are mostly arboreal omnivores, Chironectes minimus is a semi aquatic, and Caenolestidae is a shrew/rat and they are faunivorous
What are some features of Diprotodontia?
Their two front incisors are procumbent, most belong to Macropodidae, they contain Phascolarctos cinereus which is the koala and has good sense of smell to detect toxic levels of eucalyptis
What are some features of Australidelpha?
Contains Dasyuromorphia which includes:
Myrmecobius: numbat, long snout, eat ants
Sarcophilus harrisii: tasmanian devil, big carnivore with larger fore than hind limbs
Thylacinus: tasmanian tiger, stripes, carnivore, do not hunt in pack
What are some placental features? What are the two large groups of placentals?
Most successful, no epipubic bones and pouch, young born more developed but still show she precocial and altricial continuum similar to birds
Atlantogenata: evolutionary root in south america and includes Xenarthra (armadillos, sloth, anteater) as well as Afrotheria
Boreoeutheria: evolutionary roots in North America and eventually migrates to SA and africa, contains Afrosoricida
What animals are includes in Xenarthra?
Armadillos: carapace made of osteoderms, defensive ball, susceptible to leprosy, long, omnivores
Sloth: arboreal, slow, long arms to hang upside down, slow shuffle when walking, and can swim okay
Anteater: long snout, toothless, insectivores, feed with long thin tongue anchored to sternum
What are animals included in Afrotheria?
Orycteropus afer: stout, long nose, big ears, insectivores and dig into ant/termite nests to eat with large claws and long tongue with no incisors or canines
Hyrax: small, hoof like claws, trees/rocky, multichambered stomachs
Sirenia: aquatic, large, herbivorous, manatee and dugong
Elephant: 3 species, African bush elephant is largest mammal
Chiroptera: microchiroptera are nocturnal/echolocate/ insects, include vampire bats, and Megachiroptera are diurnal frugivores
Eulipotyphla: soricidae, moles are specialized burrowers
What are the animals included in Boreoeutheria?
Laurasiatheria: Ferungulata:
Caniforms: dog like, omnivorous, giant panda, seals etc
Feliforms: highly carnivorous, small ones may eat diff diet
NOSE SLIT IN BOTH OF THESE: aerodynamic valve odor molecules do not get flushed out when exhaling
Perissodactyla: odd, tapir, horse, rhino,
Artiodactyla: even, herbivorous, cloven hoof, ruminant with multichambered stomach where they vomit and rechew to make cud
