mammals Flashcards
monomermes
egg laying; e.g. platypus
marsupial
pouched e.g. kangaroos
placentals
e.g. gorilla
mammalia development from synamsid
post orbital opening merges with orbit
synapsids are
mammal like reptiles
characteristics of mammals
mammary glands hair endothermic homeothermic diapgram, 4 chambered heart, red blood cells without nuclei live birth (minus monotrmes) heterodton teeth disphydonty determinate growth secondary palate single jaw bone 3 middle ear bones repsirotory turbinates large brains double articulations upright posture
mammal characteristics derived from fossilr ecord
heterodton teeth disphydonty determinate growth secondary palate single jaw bone 3 middle ear bones repsirotory turbinates large brains double articulations upright posture
heterodont teeth
different types of feeth
dyphydonty
two sets of teeth
secondary palate
seperate breating and feeding passages
pelycosaurs
first synapsids mammal ancestors in fossil record 306 mya had sprawling gait quadrate articular jaw joint nasal passages open into mouth
synasid evolution
pelycosaurs therapsids cynadonts mammal like reptiles mammals
what traits evolved into mammals
- posture (sprawling to upright)
- respiration (formation of secondary palate)
- post dentary jaw bones to middle ear elements
therapsids
275/200 mya
more upright stance
quadrate articular jaw joint but dentary expanding up and back
some taxa with partial or complete secondary palata
cynodonts
255-170 mya
more upright posture
still quadrate articular jaw joint but post dentary jaw reduced
partial or complete secondary palate in all taxa
only two sets of complex teeht
earliest mammals
210 mya; mainly small and insectivorous and nocturnal
upright gait
complete secondary palate
at first; both quadrate articular and squamosal jaw joint
e.g. harocosium (mous like)
what did the articular and the quadrate evelop into
malleus and incus
cenzoic
age of mammals
meozoic
reptile age
palezoic
synapsid age
jurassic
mammalia evolution of shrews
creatacous
large animals start evoling
age of mammals
after k/pg extinction 65 mya;
mammals that made it through diverisifed quickly in terms of body size especially and specialization
what are mammal clades based on
reproductive strategies
