Vertebrate of BC Part 2 Flashcards Preview

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Flashcards in Vertebrate of BC Part 2 Deck (484)
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121

turbinate bones

reabsorb water when exhale, present in almost all endotherms, important indicator

122

heterothermy

animals that exhibit characteristics of both poikilothermy and homeothermy

123

poikilotherm

organism whose internal temperature varies considerably. It is the opposite of a homeotherm, an organism which maintains thermal homeostasis

124

nocturnality

widespread amounts mammals, possibly ancestral behavioural pattern, appeared early in synapsid history (before mammals)

125

zygomatic arch

cheek bone, temporal bar arches behind the orbit, allow masseter muscle to attach to lower jaw

126

First True Mammal

Morganucodon, evolved from small bodied cynodont, late Triassic, ~10cm in light (small rat)

127

cynodont-mammal transition

locomotion
nearly complete separation of nasal passage from mouth
turbinate bones
hair (whiskers)
lactation
dentary-squamosal jaw hinge
anisognathus jaw, precise occlusion of molar teeth

128

lizard locomotion, breathing

lateral undulations, air flows side to side rather than in and out

129

mammal locomotion, breathing

bounding locomotion, dorsoventral flexion, facilitates exhalation/inhilation

130

facilitated dorsoventral flexion, mammal breathing while running

loss of lumbar ribs

131

why its hard to trace the origin of endothermy

attribute of the 'soft anatomy' which does not fossilize

132

soft anatomy of endothermy

complex lungs, elevated blood oxygen carrying capacity, mitochondrial density

133

fossilized parts of endothermy

nasal turbinates - may have evolved in association w/ origin of elevated ventilation rates

134

evolution of 'mammalian' oxygen consumption rates

Late Permian, 260mya
Therocephalia & Cynodontia, independently

135

how long for the full evolution of mammalian endotherm

40-50million years

136

muscles required for lactation

major facial muscles- generating a suction seal

137

when was transition from cynodont to true mammal

Cenosoic (probably Jurassic)

138

why did endotherms fall at the end of the paleozoic

oxygen crash

139

isognathus jaw

polyphyodont teeth
reptiles, early synapsids

140

anisognathus jaw

diphydont teeth
Cynodont, modern mammal

141

Poluphyodont

continuous tooth replacement

142

Diphydont

2 successive sets of teeth
milk teeth, and adult teeth with enamel

143

Cretaceous mammals

very small (shrew-rabbit size)
insectivore (from teeth)
3 major groups

144

Cretaceous mammal groups

Allotheria
Prototherian
Therians

145

Allotheria

Multituberculates
rodent-like
longest-lived mammalian group (100my)
arboreal, fossorial (feet)
complex, multicasted teeth - grinding
possible early distinct branch of cynodont

146

Allotheria time

Jurassic - Eocene
longest lived mammalian group

147

Allotheria distribution

predominantly Laurasia (N)

148

Prototheria

monotremes
triangular teeth, extant, early branch of mammals, lay eggs, heterothermic, cervical ribs,

149

extant prototherians

duck-billed platypus, echidna
Australia & New Guinea

150

Prototheria distribution

Gondwana (S hemisphere, Australia, SA)