Mammalogy test 1

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5400
how many species of extant mammals are there today?
prototheria and theria
what are the two subclasses of mammalia
-egg laying mammals
-mammary glands but no nipple or teat
-males have abdominal (undescended) testes
-multiple sex chromosomes
-mechanoreceptors & electroreceptors on rostrum the detect prey
-cloaca (monotreme means 1 hole)
-teeth are absent
-lower jaw and juggle reduced
describe characteristics of the order Monotremata
Trachyglossidae and Ornithorhynchidae
what two families are in the order monotremata?
trachyglossidae
echidna or spiny aneater are in what family?
Ornithorhynchidae
duck billed platypus are in what family?
Metatheria
what is the marsupial infraclass?
42%
how many mammals are rodents
skin glands, hair, air moving into lungs through negative pressure created by diaphragm and expansion of intercostal muscles around ribs, bear live young, single lower jaw bone (dentary),
Name characteristics that are unique to mammals
True
(T/F) Cuticle scale patterns and medulla pigment distinct among species
endothermy
mammals maintain stable body temp through metabolic activity, fat storage, brown adipose
tissue, behaviors (shivering, huddling, nesting)
differential reproduction, heredity, genetic variation
natural selection can only occur with these three things
mutation, genetic drift, gene flow, and natural selection
what are the mechanisms of evolution?
Evolution
change in genetic structure of a population through time "Descent with modification"
Natural Selection
differential survival and reproduction
based on adaptations to particular environments
gene flow
movement of individuals into/out of populations
genetic drift
random, chance events that result in
differential survival of variants in the population
mutation
changes in DNA that affect phenotype; must
occur in gametes to affect offspring
devonian period of the paleozoic era (first)
when did the tetrapods appear?
during the mississippian period of the paleozoic area (2)
when did amniotes appear?
anapsid, synapsid, diapsid
Temporal openings (fenestrae) were defining features for 3 main groups of amniotes?
during the triassic/jurassic periods of the mesozoic era
when did the synapsids appear?
tetrapods - amniotes - synapsids- therapsids- cynodonts
order of mammal orgins