Final Flashcards
(128 cards)
1
Q
what are the 2 amniote lineages
A
synapsids and sauropsids
2
Q
when did the dominance shift from amphibians to amniotes
A
permian
3
Q
what is the largest mass extinction
A
end permian extinction
4
Q
what does the end permian extinction mark the boundary of
A
palaeozoic-mesozoic boundary
5
Q
what is the issue between running and breathing un early amniotes
and the solution
A
used same muscles to run and breathe, making it hard to run and breathe at same time
solution: legs shift below body and lumbar ribs are lost, develop diaphragmatic breathing
6
Q
how does diaphragmatic breathing work (+ and - pressure)
A
- inhalation: expansion of rib cage (negative pressure pulls air in
- exhalation: contraction of ribs ( + pressure)
7
Q
what are the evolutionary trends in skeletons
A
- shift to upright posture
- shorter toes
- shift in phalangeal formula
- loss of lateral flexion
- loss of lumbar ribs (gain of diaphragm)
- gain of dorsal ventral flexion
- increase in sacral vertebrae
8
Q
what is the atlas
A
first vertebra
9
Q
what is the axis
A
second vertebrae
modified to form rotational joint with the atlas
10
Q
what is the occipital condyle
A
hinge joint that allows for vertical motion
11
Q
what are the evolutionary trends in the skull
A
- shifts from a single to a double occipital condyle
- appearance of temporal fenestra
- reorganization and increase in jaw muscles (dentary bone increases)
- middle ear bones
- mammals develop a complete bony palate
12
Q
how did middle ear bones develop
A
loss of AQ joint frees articular and quadrate bones to become the middle ear bones
13
Q
what happens when the dentary bone develops
A
a joint is added between the articular and squamosal jones
14
Q
what was the function of a complete bony palate
A
protects braincase during feeding
allows for simultaneous chewing + breathing
15
Q
what 3 evolutionary trends did mammals have (and what is this evidence of)
A
- sustained running
- more efficient eating+ more food intake
- hearing
provides evidence of higher metabolic rate
16
Q
what did early fossil records of mammals suggest they were like
A
-small
- nocturnal
- insectivorous
17
Q
how are mammalian sensory systems from other tetrapods
A
- eyes have higher ratio of rods to cones (good vision in low light, and poor colour vision)
- enhanced olfactory sensitivity
- hearing with a broader frequency range
18
Q
how do primates differ from other mammals (in terms of senses)
A
good vision and weak olfaction
19
Q
what are the 3 types of glands in mammal skin
A
sebaceous - oil glands
eccrine glands - sweat
apocrine glands - secrete pheromones
20
Q
what do arrector pills muscles do
A
controls position of hair
21
Q
what are the 2 hypotheses of the origins of mammal hair
A
- insulation hypothesis: evolved to keep them warm (suggests they were already endothermic)
- sensory hypothesis: hair may have evolved as a sensory tactile structure (later contributed to insulation)
22
Q
what did mammary glands evolve from
A
apocrine glands
23
Q
what does suckling require
A
- lip muscles
- ability to breathe and feed at same time
- absence of teeth
24
Q
what do mammal’s facial muscles allow them to do
A
manipulate food
suckle
express emotions
25
what 2 factors caused diphyodont dentition to evolve in mammals
- delayed eruption of first teeth in response to suckling
- skulls with determinate growth (skulls stop growing and dont need to continually add teeth)
26
True or false: diphyodint dentition allows for more efficient chewing with cheek teeth and more specialization
true
27
what does sinoatrial node arise from
sinus venousus in incorporated into right atrium
28
what is the function of the sinoatrial node
pace maker - generates the action potentials that initiate contraction of the heart
29
what side of mammal heart delivers oxygenated blood to body
left
30
what side of mammal heart delivers deoxygenated blood to lungs
right
31
what kind of lungs do mammals have and what is the benefit of them
alveolar lungs
have more SA for gas exchange
32
what are alveoli
tiny sacs located at end of bronchioles
surrounded by capillary beds
site of gas exchange
33
why did lactation evolve
originally it functioned to keep eggs moist and to transfer antimicrobial chemicals for protection
over time selected for glandular secretions and inclusion of nutrients
34
what is a marsupium
pouch in which young develop
35
what does oviparous mean
egg laying
36
what does viviparous mean
give birth to altricial young at very early stage of development
37
what does precocial mean
still fed from mom, but more independent
38
what is the defining feature of eutherian mammals
formation of a chorioallontoic placenta
39
is the following a constraint/benefit of marsupial or eutherian reproduction:
pregnancy is low cost + low risk and can be easily terminated if mother is stressed (ex: food shortage)
marsupial
40
is the following a constraint/benefit of marsupial or eutherian reproduction
possibility of marine/flying lineages
eutherian
since marsupial baby has to have well developed hands for climbing/grasping
41
is the following a constraint/benefit of marsupial or eutherian reproduction
female can support multiple babies at different stages
marsupial
42
is the following a constraint/benefit of marsupial or eutherian reproduction
fewer constraints on development of forelimbs and jaws
eutherian
43
when did mammals start diversifying
mesozoic
44
what did end-creatcous extinction mark the end of
end of cretaceous period and mesozoic era
45
what were the short term effects of end-cretaceous meteorite
- volcanoes + earthquakes
- dust + ash in atmosphere (darkness and cooling)
- massive tsunamis
- acid rain
- hige fires
46
what were the mid term effects of end-cretaceous meteorite
- nuclear winter
- freezing temperatures
47
what were the long term effects of end-cretaceous meteorite
ecological collapse
48
when was the age of mammals
cenozoic era
49
what is an ecomorph
body type adapted for an ecological lifestyle
50
what is cursorial for and what is the body like
for running
long limbs with fewer joints on ground
51
what is fossorial for and what is body like
digging
short muscular forelimbs with strong claws
52
what is scansorial for and what is body like
for climbing
grasping hands/feet/tails
53
what are semiaquatic animal bodies like
streamlines body and webbed feet q\
54
what are volant animal bodies like
gliding
so skin between limbs
55
what are the 2 categories of herbivores
foregut fermenters: modified stomachs
handgun fermenters: modified large intestines/cecum
56
what does dinural mean
active during day
57
what does crepuscular mean
active at dawn or dusk
58
what does cathemeral mean
active day or night
59
what are the 2 types of testudines
cryptodira: hidden neck (retracting neck)
pleurodira: side neck (side bending neck)
60
what are the 2 parts of a turtle shell
carapace: upper
plastron: lower
61
what are turtle shells made out of
layer of bone covered by a layer of scutes (keratin)
62
what is special about turtle vertebrae
fewer vertebrae than ancestral amniote
elongated thoracic vertebrae that are fused with carapace
increased flexibility and rotation in the cervical vertebrae
63
how do turtles breath
inhalation: muscular contraction pulls guts down, pulling lung down
exhalation: muscular contraction compresses organs against the lungs
64
what non-pulmonary breathing methods can some turtles use
buccopharynx
skin
cloacal bursae
65
why do turtles also use non-pulmonary breathing
allows them to stay underwater longer and helps with hibernation
66
what is advantage of turtle heart
can simultaneously pumo blood to 2 different systems (pulmonary and systemic)
67
what is blood shunting
restrict blood flow to the lungs by constricting the pulmonary trunk
this redirects blood to the aortic arches (systemic system)
68
why do reptiles do blood shunting
- if rate of breathing is low
- when swimming/hibernating
- when head is retracted into shell (turtles)
to direct more blood to digestive system
69
did carapace or plastron evolve first
plastron
70
did ribs get wider/flatter before/after shell evolved in turtles
before
71
what are the two hypotheses for how turtle shell evolved
- protection
- fossorial lifestyle
72
what is evidence that turtle shell evolved for protection
plastron evolved first, protection from attacks from blow in aquatic environments
73
what is an issue with protection hypothesis
intermediate shell (broad ribs) wouldn't provide much protection, also make it hard to breathe and reduce stride length
74
what is evidence for fossorial hypothesis for turtle shells
broad ribs would provide lots of muscle attachments for strong digging arms
75
what are the hypotheses for turtle neck folding evolution
- protection: though half folded neck doesn't provide much protection
- feeding: slow moving bodies and fast moving neck. Thrust head forward to suck in prey (only works in water)
76
what are the shared characteristics of lepidosaurs
- keratinous scales
- 3 chambered heart
- caudal autotomy
- paired hemipenis
77
what is cranial kinesis
additional joints in the skull result in a more flexible skull
allows for a larger gape (jaw opening) though with a less powerful bite force
78
what are the defining characteristics of snakes
- absence of eyelids
- reduced colour vision
-highly modified skull
- lack of external ear
79
what is snake skull like
have cranial kinesis
lost second temporal bar
left and right joints of skull can move independently
left and right halves of lower jaw can separate
reduces bite strength but allows for more complex movements of skull
80
can snakes unhinge their jaws
no
they use extra joints
81
what are the hypotheses for evolution of snakes
- swimming hypothesis: snakes share skull characteristics with mosasaurs
- burrowing hypothesis: many unique snake characteristics (ex: loss of eyelids) are consistent with fossorial lifestyle
82
how do crocodilians use organs to help with movement
move lungs and liver to shift centre of gravity
83
why do crocodilians have yes and nostrils on their dorsal surface
so they can conceal themselves in water
84
what allow crocodiles to feed underwater
valve at back of throat to prevent water from entering trachea
85
what are gastroliths and what is the function
stones that crocodilian consume that end up in stomach
mechnnical breakdown of food and increased weight for diving
86
is there a difference between oxygen in blood in two halves of heart during apnea
no
87
how do crocodilians breathe
moving their livers like a piston
88
what kind of respiration do crocodilians use
unidirectional and controlled by valves
more efficient than tidal air flow
89
what was first vertebrate capable of flight
pterosaurs
90
why are dinosaurs so big (factors that allowed them to)
- indeterminate growth
- efficient respiration (unidirectional air flow)
- lighter skeletons
- efficient reproduction
- for sauropods - long neck gave access to more food
91
why are dinosaurs so big (factors that caused them)
- more vegetation
- predator-prey relationship selected for bigger
92
what are skeletal modifications that birds have for flight
- loss/reduction of bones
- fusion of bones in the trunk (increase strength)
- some bones are pnematisized (with internal struts for strength)
93
what powers downstroke of wing
pectorals major contracting, which is attached to keel and humerus
94
wat powrs upstroke of flight
superacoracoideus muscle contracting
which is attached to sternum and humerus (by tendon)
95
is up or down stroke more powerful
downstroke
96
what does the furcula (wishbone) do
helps stabilize scapula
functions as spring (stores energy generated by downstroke and releases it during upstroke)
97
what are feathers homologous with
reptilian scales and synapsid hair
98
what do feathers form from and made from
from follicles in skin and are composed primarily of beta keratin
99
are bird lungs static or moving
static
volume is conrsant
100
how does air move through bird lung
air sacs expand and contract to move air through lungs
101
how do birds gain respiratory efficiency
by separating respirator surface (lungs) from ventilatory mechanism (air sac)
102
what is the syrinx `
organ used by birds to vocalize
103
what was the path of the evolution of feathers (3 terms
protofeather -> plummaceus feather -> pennaceous feather
104
what are the 3 hypotheses for the origin of feathers
- thermoregulation
- sexual selection
- tactile (played sensory role like whiskers)
105
what are bird-like characteristics that archaeopteryx
- feathers
- beak
- 3 digits on forelimbs
- wishbone
- flexible wrist joint
106
what are reptile-like characteristics that archaeopteryx had
- teeth
- forelimb digits had claws
- long vestigial tail
- flat sternum
107
what species is the transitional fossil between birds and dinosaurs
archaeopteryx
108
what Is difference between gliding and flying
gliding is controlled falling
flying involves powered flight
109
how many times has flying evolved in vertebrates
3
110
what are the 3 times that flying evolved
birds
pterosaurs
bats
111
what is the evidence that archaeopteryx could fly
- presence of wishbone
- long asymmetrical flight feathers
- feathers tails/legs may have provided additional flying surface
- wing bones were capable of withstanding the stresses of flight
112
evidence against archaeopteryx flight
- small flat sternum without ossified keel
- lacked trios seal foramen (no powerful upstroke)
- shoulder joint may not have been able to lift above head
- short rounded wings
113
what are the hypotheses for the evolution of flight in birds
- arboreal hypothesis (tree down): early birds lined in trees and would use wings to glide down from them
- cursorial hypothesis (ground up): early birds were fast bipedal runners that used wings for lift
- wing assisted incline running (modified ground up): used wings for lift as they ran up steep inclines e
114
what are the benefits of endothermy
- can live in cooler environments
- can be active at night
- always alert and capable of activity
- embryos can develop faster
115
what are the correlates of endothermy
- retaining heat (insulation)
- high metabolic rate
- large brains
- more upright posture
116
how can mammals/birds use fur/feathers to adjust insulation
raise or lower them (changes amount of trapped air)
117
what are nasal turbinates and what is function
thin sheets of bone/cartilage lined with epitheliium
warm/humidify air
reclaim moisture and heat from exhaled air
118
do all amniotes have a multichambered lung
yes
119
do birds/mammals have more or less complex/effiecient lungs than other amniotes
more
120
why don't mammal RBCs have nuclei, what is benefit
RBCs are small and also have have more capillaries = more SA for gas exchange = greater oxygen transport capacity
so small they dont have nuclei
121
what other group (apart from mammals) have really small RBCs
birds
122
what is the problem that more capillaries creates and what is the solution
problem: as number of capillaries increases, more BP is needed to maintain blood flow
BUT high BP causes fluid to leak out of alveoli
solution: provide high BP to body and low BP to lungs by separating these 2 circuits
123
what kind of circulatory system do both mammals and birds have
fully divided 4 chamber heart with complete separate pulmonary and systemic circuits
124
what are the advantages of having fully divided heart with 2 different circuits
- prevents mixing of oxygenated and deoxygenated blood
- can maintain different BP in different circuits
125
why transition from land to sea
- end-permian extinctions included extinctions of many marine predators
- separation of continents in Mesozoic created lots of coast and shallow seas
- marine nutrients increased at start of the Mesozoic. This led to productive habitats that supported more diversity and higher trophic levels
126
what were the 2 body plans of sauropterygians
- short neck - fast swimming
- long neck - slower movement
127
what are the 2 groups of cetaceans
- toothed cetaceans (ex: orcas)
- baleen whales
128
