post midterm notes Flashcards
1
Q
what is a muscle?
A
- Collection of modified cells that can generate force along the axis of their fibres
- Force can be used to produce movement or restrain movement
2
Q
what do muscle cells do that make them electrically excitable?
A
they respond to nervous stimulations
3
Q
how do muscles generate heat?/
A
shivering
4
Q
what generates electric shocks?
A
muscles or electric eels
5
Q
what generates electric fields?
A
muscles of electrosensory fishes
6
Q
what kind of fibres do muscles have?
A
contractile (extend and compress)
7
Q
how can muscles be classified?
A
- By location
- By method of nervous control
- By microscopic appearance
8
Q
what are the classifications by location of muscles?
A
somatic (skeletal) and visceral (gut)
9
Q
what are the classifications of muscles by method of nervous control
A
voluntary or involuntary
10
Q
what are the classifications of muscles by microscopic appearance?
A
skeletal, cardiac or smooth
11
Q
describe smooth muscles
A
muscles of blood vessels and many visceral organs
12
Q
describe skeletal muscles
A
associated with the skeleton
13
Q
describe cardiac muscles
A
muscle of the heart wall
14
Q
how do the 3 types of muscles differ?
A
striated shape (cylindrical or spindle shape) branched nucleus placement presence of disks voluntary or involuntary motion
15
Q
where did muscles derive from?
A
mesoderm
16
Q
what is included in the somites or epimere of the mesoderm?
A
dermatome
myotome
sclerotome
17
Q
what is the key part of the mesoderm for the skeletal muscle?
A
myotome
18
Q
what does the dermatome give rise to?
A
skin
19
Q
what does the sclerotome give rise to?
A
parts of skeleton
20
Q
what does the hypo mere give rise to?
A
heart and gut muscle
21
Q
dorsal part of myotomes
A
epaxial divison
22
Q
ventral part of myotomes
A
hypaxial division
23
Q
how do muscles usually work?
A
Usually two groups of muscles working opposite to each other for any one structure
24
Q
true or false:
A given muscle can be described by multiple terms
A
true
25
how is muscle attaches to skeleton?
with a tendon
26
what are the major muscle groups?
Postcranial muscles
Cranial muscles
Muscles of gut and heart
27
what are the 2 groups of post cranial muscles?
1. Trunk (axial) musculature: body wall, divided into epaxial and hypaxial divisions
2. Appendicular musculature: fins and limbs
28
what are the 3 major groups in the cranial muscles?
1. Branchiomeric muscles: jaw and pharynx muscles derived from somitomeres (innervated by cranial nerves)
2. Hypobranchial muscles: jaw and pharynx muscles derived from cervical somites (innervated by spinal nerves)
3. Extrinsic eye muscles
29
where are somitomeres found?
the cranial region
30
describe trunk muscles in fish
- Myotomes form distinct myomeres (segments) separated by connective tissue (myosepta)
- propulsive locomotion
- Dorsal (epaxial) and ventral (hypaxial) portions separated by the horizontal septum
- Major role in locomotion
31
what is critical for locomotion in fish?
trunk muscles (myotomes)
32
describe trunk muscles in tetrapods
- Decreased role in locomotion allows more specialized roles
- Flexion of the vertebral column
- Movement of the rib cage
- Support weight of body
- Movement of the head
33
what are the epitaxial musculature in amphibians (trunk muscles)
one segmented muscle mass
34
what are the hypaxial musculature in amphibians (trunk muscles)
differentiated into 3 bands of lateral muscle and a ventral muscle band
35
what is an amniote?
reptiles, birds, mammals
36
trunk muscles of amniotes: epaxial musculature
- differentiated further into three longitudinal bundles with no septa
- Attach to vertebrae and contribute to complex trunk and head movement
- no divisions
37
epaxial muscles in birds and turtles
reduced and some become many small specialized muscles for complex head movement
38
trunk muscles of amniotes: Hypaxial musculature
- differentiated further in more bands
| - Attach to rib cage but at varied levels –reduced in turtles but enhanced in snakes
39
what do other trunk muscles in amniotes facilitate?
- Ventroflex the spine
- Support the abdomen
- Support and compress the body wall
- Ventilation of lungs
40
what are appendicular muscles in fishes?
Usually arranged on opposing surfaces of fins or limbs
41
what are the 2 backs patterns of appendicular muscles in fishes?
posterodorsal to fin: anteroventral to fin:
42
what are posterodorsal to fin muscles in fish?
an abductor or extensor to pull fin dorsally and caudally
43
what are anteroventral to fin muscles in fish?
an adductor or flexor to pull fin ventrally and cranially
44
describe appendicular muscles in tetrapods?
Large muscle mass supports body weight and provides locomotion
45
what 3 sources are Pectoral girdle and forelimb muscles derive from?
- mostly from appendicular muscles of fishes
- fish branchial musculature
- fish axial musculature
46
where are Pelvic girdle and hindlimb muscles all derive from
appendicular muscles of fish ancestor
47
describe appendicular muscles in mammals
reduction of ventral muscles is seen in correlation with limb position
48
describe appendicular muscles in birds
muscles associated with flying and landing are greatly enlarged and posterior muscles are reduced
49
what kind of Limbs do reptiles have?
splayed limbs
50
what kind of limbs do birds and mammals have?
pendulous limbs
51
major muscle in birds
ventral pectoralis muscle (“turkey breast”)
52
describe Branchiomeric (branchial) muscles of fishes
- Many simple and serial muscles associated with pharyngeal arches (gills)
- Muscles of the first and second arches are dedicated to jaw suspension and jaw closure
- Involved in feeding and respiration
- Contraction reduces volume of mouth cavity and discharges water
53
describe Branchiomeric (branchial) muscles of tetrapods
- Large mandibular adductor is the dominant jaw muscle
- divides further in mammals
- Some muscles of the hyoid arch develop into the facial muscles in mammals
54
what do Branchiomeric (branchial) muscles of tetrapods include?
- jaw and throat muscles, muscle controlling the stapes and some shoulder muscle groups
55
what do hyoid arch develop into in some mammals?
facial muscles
56
what did the Mesenchyme give rise to?
various parts of the body
57
what was derived from the mesoderm?
- Somites or epimere
- Dermatome
- Myotome
- Sclerotome
- Hypomere
- Mesenchyme
58
what are the details of smooth muscle?
- not striated
- spindle shaped
- not branched
- nucleons central
- no disks
- relatively involuntary
59
what are the details of skeletal muscle?
- striated
- cylindrical
- not branched
- nuclei peripheral
- no disks
- voluntary
60
what are the details of cardiac muscle?
- striated
- cylindrical
- branched
- nuclei central
- intercalated disks
- relatively involuntary
61
describe hyobranchial muscles in fishes
- involved in feeding and respiration
| - Contraction opens mouth and expands pharyngeal cavity
62
describe hypobranchial muscles in tetrapods
- much more differentiated and contribute to catching, manipulating and swallowing food
- complex movement of the tongue, throat and larynx
63
what are extrinsic eye muscles?
Muscles involved in moving the eyeball within the orbit
64
true or false:
| The 6 extrinsic muscles present in fish are retained in tetrapods
true
65
what was the least affected group in he transition from water to land?
extrinsic eye muscles
66
what are intrinsic eye muscles?
Muscle responsible for changing the shape of the lens or pupil
67
what is diminished with terrestrial locomotion?
axial musculature
68
what does expanded pharyngeal cavity do?
creates negative pressure and sucks water in
69
examples of some new structures that come with new muscles
neck
| ribs
70
an example of where loss of muscle occurs
hypaxial muscles in turtles
71
what is the official name for amphibians?
lissamphibia
72
what are the 3 main groups of amphibians?
salamanders
frogs and toads
caecilians
73
describe the skin of amphibians
- Mucous glands secrete mucus to help with cutaneous respiration
- Granular glands secrete poisonous alkaloid compounds for defense
- Skin is thin
- More terrestrial forms have more keratin (fibrous protein).
- Some caecilians and toads have bone elements in the dermis
74
why is amphibian skin thin?
used for respiration
75
why do More terrestrial forms of amphibians have more keratin
defense
| drying out
76
indirect development
aquatic larva
| terrestrial adult
77
direct development
no aquatic stage
78
why do some species use direct development rather than indirect development?
adult doesn't have to be near water anymore
79
what kind of teeth do amphibians have?
pedicellate teeth
80
describe pedicellate teeth
Tooth has suture (uncalcified) dividing base (pedicel) from tip (crown) of calcified dentin
81
who has pedicellate teeth?
water amphibians and their ancestors
82
who has pedicellate teeth?
water amphibians and their ancestors
83
true of false:
| pedicellate teeth are homologous to our teeth
false
84
what is the scientific name for frogs and toads?
anura
85
describe anuras
- Paired limbs
- Absence of tail (adults)
- Jumpers
- Tympanum usually present to transmit sound to inner ear
- Fertilization external
86
describe skull of amphibians
- Flattened, open, with big jaws
- Palate is highly reduced
- Allows eyeballs to drop into oral cavity
- Hyomandibula becomes the stapes
87
what does reduced palate and eyes dropping down in amphibians allow for?
aids in swallowing
88
what is the functional significants of Hyomandibula becoming the stapes
sound transmission
89
describe frog axial Skeleton
- Shortened vertebral column with 9 or fewer vertebrae
- Atlas (cervical vertebrae) -skull junction forms a movable joint through two condyles
- improved mobility of head in dorsoventral axis
- Post sacral vertebrae fused into a rod-shaped urostyle lying between the two elongated illium bones of pelvic girdle
90
describe Anura appendicular skeleton
- Robust pectoral girdle and fused radius/ulna are used to absorb the shock of landing
- Tibia/fibula and ankle bones are also fused for sturdiness
- Increase in length of hind limbs, characteristic of jumpers
91
what is the scientific name for salamanders?
Caudata
92
describe the caudata
- Paired limbs and a long tail
- Suction feeding in water and projectile tongue on land
- No tympanum present
- Fertilization can be external or internal by means of spermatophore transfer
93
describe the skeleton of the caudata
- Flattened opened skull with large orbits
- Long back with 10-60 pre-sacral vertebrae
- Poor ossification
- Reduction and loss of bones is common
- more cartilage
94
describe caudata locomotion
- Walking and swimming are distinct modes of locomotion controlled by distinct sets if neurons in the brainstem
- Use short walking limbs and swimming tail
95
what is the scientific name of caecilians?
gymnophiona
96
describe gymnophiona
- No limbs or girdles, skull is often solid and compact
- burrowing
- Restricted to tropical habitats
- Internal fertilization
- Hatchlings are aquatic or terrestrial
- 60-285 trunk vertebrae, but tail is short or absent
97
what is the Caecilian fossorial way of life?
- Skull is often heavily ossified and used as a digging tool
- Eyes are reduced but compensated by paired tentacles in front of the head, which help with chemosensation in dark tunnels
98
what is the Gerobatrachus hottoni?
Has features found exclusively in living frogs (Anura) or salamanders (Caudata) but not in both•Links frogs and salamanders and affinity with Temnospondyii•Caecilians (Eocaecilla) appear to have affinity with Lepospondyi
99
what is the polyphyletic hypothesis?
Eocaecilia with Lepidospondyii
| - Anura and Caudata with Temnospondyii
100
what is the monophyletic hypothesis?
Affinity of Eocaecilia with Anura and Caudata (Temnospondyii origins)
101
what is heterochorony?
changes in the timing and rate of developmental events between ancestors and descendants
102
what is paedomorphosis?
larval characteristics of ancestors appear in adults of descendants
103
what are the 2 current hypotheses of where amphibians derived from?
polyphyletic hypothesis and monophyletic hypothesis
104
why can pedomorphosis mislead us?
- two unrelated groups with the same aquatic lifestyle could show loss of bones and reduction in ossification to help with buoyancy
105
what do Hypothesized ancestors of modern amphibians (temnospondyl and lepospondyl early tetrapods) show similar to paedomorphic salamanders?
loss of character and character modifications
106
what are amniotes?
reptiles
birds
mammals
107
when did early amniotes evolve?
early/mid-Carboniferous (360-330 mya)
108
how big were early amniotes?
often small (~20 cm long)
109
what kind of skeleton did early amniotes have?
slight but highly ossified skeleton.--“lizard like”
110
what are the 2 major groups of amniotes?
synapsids: mammals
sauropsids: reptiles and birds
111
what are the 2 major groups of diapsids?
lepidosaurs: lizards and snakes
archosaurs: dinosaurs, bird, crocs
112
what are the 2 major groups of the sauropsids?
anapsid and diapsids
113
what does an amniote egg have?
- a semi-permeable shell which allows gases to pass (O2, CO2), but keeps fluids inside
- Extra-embryonic membranes
114
what does the cleidoic egg do?
- Protection and gas transfer:
| - Respiration and waste storage:
115
what does the amnion in the cleidoic egg do?
surrounds the embryo with water
116
what does the chorion in the cleidoic egg do?
surrounds the embryo and yolk sac
117
what does the allantois in the cleidoic egg do?
fills with waste as yolk proteins are used
118
what does the cleidoic egg allow for?
- full development of the organism on land and loss of the larval stage
- Living on land led to more efficient respiration (gas exchange)
- Allowed embryo to become larger before hatching compared to amphibians
- More energy invested in each egg
119
why is it beneficial to be large when you hatch?
allows for higher rate of survival
120
why is low skin permeability important for survival on land?
- greater variation in skin (keratin)
| - presence of lipid
121
what does ventilation of lungs aided by ribs allow for?
- a long neck as now able draw air through a long tube
| - space for elaboration of the nerves that supply the forelimb
122
why do land species need good body support?
ncreased apparent weight (gravity) on land required stronger/stiffer skeletons
123
what do we see in amniote axial skeleton?
more types of vertebra
124
Why were lumbar ribs lost in some amniotes?
- No ribs in the way of hind limb forward movement
- Allowed vertical plane flexion of the column
- easier limb oscillation
- rapid locomotion
125
what do we see in amniote atlas and axis vertebra?
- Reduced centra and processes
- Skull-atlas joint
- vertical nodding and horizontal tilting of the head
- Atlanto-axial joint
- twisting movement
- maintains bony strength of neck while allowing cranial mobility
126
what changes in the vertebral column and body support of amniotes?
- Body is suspended between legs
- Vertebral column as a ‘bridge’ between support posts
- Makes use of arch designs
127
how are the trunk vertebrae held in amniotes?
an archer’s bow-like arch by abdominal muscles and sternum
128
how is the cervical vertebrae held in amniotes?
in a violin bow-like reversed arch by neck ligaments
129
how we dinosaur vertebrae likely held together?
by strong ligaments between neural spines
130
what did the hips act like in dinosaurs that were bipedal?
fulcrum
| vertebral column pivoting
131
what are some modifications 4 legged animals made when moving to land?
- Direction and height of vertebral neural spines are modified
- Spines are parallel with forces imposed by axial muscles
- Spine height is proportional to leverage needed to stabilize column
- Ligaments join shoulder neural spines to skull and neck vertebrate and help support a heavy head
132
what are some issues with 4 legged animals?
Need to deal with mechanical forces acting on vertebral column due to axial muscles
133
what is the Nuchal ligament of the horse
an antigravity mechanism
134
how was there a change in limb posture from water to land?
- In many mammals and dinosaurs, limbs are situated under the body for increased efficiency of limb swing during rapid locomotion
- Digit and limb position also rotated inward, allowing for a forward thrust better aligned with the direction of movement
135
true or false:
| Amniotes vary in the numbers of openings behind the orbit of the skull
true
136
why may have openings may have evolved in the skull?
reduce skull weight and provide attachment edges for jaw muscles
137
what does the orbit house?
the eye
138
what are the fenestrae?
openings in the back of the skull.
139
what is anapsid skull?
no temporal fenestrae (earliest amniotes and turtles)
140
what is a synapsid skull?
one lower temporal fenestra (extinct synapsids and mammals)
141
what is a diapsid skull?
two temporal fenestrae (reptiles, birds, dinsosaurs)
142
what have modern day mammals had happen to their skull over time?
lost bone between opening and orbit for 1 big space
143
what do snake skulls look like?
1 big opening, lost bone between openings
144
describe sauropsids (turtles)
- 341 species today with a wide range of habitats and diets
- Hard shell and solid toothless skull design has been stable over time
- Dorsal carapace and ventral plastron made up of fused bony elements covered by keratin scutes, attached on the sides
145
what are the 2 major components to consider when looking at How the turtle body plan evolve?
- Shell: [vertebrae + ribs + osteoderms] + scutes(keratin)
| - Position of scapula: inside of rib cage
146
what are the 2 hypotheses of how the turtle evolved?
- gradual transformation
| - rapid evolution via changes in developmental regulations
147
describe the tuatara
single extinct species
| lepidosaurs
148
describe lizards and snakes (lepidosaurs)
~6145 living species of lizards and ~3567 of snakes
- Lizards evolved earlier than snakes
- Relationship of snakes to lizards is uncertain
- Origin of snakes is hotly debated
149
what are the 3 main groups of lepidosaurs?
lizards, snakes, tuatara
150
what are the key morphological differences between tuatara and snake skulls?
snake: very detached
tuatara: everything connected
151
what are some Skull adaptation in lizards and snakes
- Loss of temporal bar(s) around fenestrae
- Lower absent in lizards
- Upper and lower absent in snakes
- Transcranial joint(s) across the top of the skull
- Ability of quadrate bone to rotate about dorsal connection with brain-case
152
what is opening in Cranial kinesis in lizards
snout tip up
153
what is closing in Cranial kinesis in lizards?
snout tip down
| - equal force of both jaws on food item
154
what are the 2 possibilities for transcranial joints across the top of the skull?
- Front of orbit in snakes (single)
| - Rear of orbit and back of skull in lizards (double)
155
what is importance of Equal perpendicular force of both jaws on food item
- easier to crush
| - none of the energy moves out (might lose it)
156
describe Cranial kinesis in snakes
- lower jaw is loosely hinged
- Two sides of mandible can come apart as only connected by muscle and skin
- Skull and upper jaws are moveable
- Moveable quadrate bone links jaw and skull
157
what is lateral undulation?
- Moving waves push sideways against contact points
| - Generates a reaction force with a forward component (lateral components cancel out)
158
what is concertina movement?
- costly
- used in narrow spaces such as tunnels
- involves stationary coils wedging the animal into place while free body parts move forward
159
what is sidewinding movement?
- used over sandy soil
- body contacts 2 or 3 straight tracks at a time with different segments in succession as they are released from previous track
- only segments between tracks are moving
160
what is rectilinear movement?
- slowest, but discreet
- used by many snakes
- Requires specialized muscles progressively lifting and bringing forward ventral scutes to peg them to the ground
- Body not in contact with ground is moved forward within very distensible skin
161
why is rectilinear movement slow but discreet?
stalking prey
| stealth
162
what kind of lifestyle do crocodilians live?
aquatic and predatory
163
describe the characteristics of crocodilians
- nostrils, eyes and ears on the head
- Eyelid is transparent
- Bony flaps in throat
- Ability to regulate body temperature by lying with its mouth open
- Four chambered heart
- Temperature of nest determines offspring sex
164
what was the 1st vertebrate group to evolve powered flight?
Archosaurs: Pterosaurs
165
how did early Archosaurs: Pterosaurs evolve for flight?
- Used membranous wings supported by elongated forelimb
- Early forms had long tails and elongated forelimb
- Later forms lost tail and teeth; had projection at back of head
166
what are the 2 main groups of dinosaurs?
Saurischia
| Ornithischia
167
how do we distinguish between Saurischia and Ornithischia?
- Distinguished by the structure of the pelvic girdle
- Saurischia: girdle bones radiate outward from the centre
- Ornithischia: ischium and part of pubis are parallel and project backwards
168
what kind of diet do Dinosaurs Saurischians have?
Herbivourous and carnivorous
169
what group did the birds likely evolve from?
Archaeopteryx
170
what kind of diet do Dinosaurs Ornithischians have?
all herbivores
171
what are the skeletal adaptations of giant dinosaurs?
- Shortened pillar-like limbs (weight support)
- Reduction/shortening of wrist/fingers and ankle/toes
- Elongated necks -more, longer, but lighter cervical vertebrae
172
true or false:
| bipedality evolved more than once in the dinosaur lineages
true
173
why were dinosaurs so successful?
- opportunistic
174
what was the main competitor of dinosaurs?
Crurotarsans
175
what happened after crurotarsans went extinct
dinosaurs prevailed because they were able to take over their empty niches
176
who was the better competitor; dinosaurs or crurotarsans?
crurotarsans
177
when did birds evolve?
jurassic (170 mya)
178
why are birds so successful?
- Basic avian design is highly adaptable and their distinguishing characteristic is feathers
- Flyers can gain access to flying prey, escape from non-flying predators, and have unrivaled migratory abilities
179
older ideas about the origin of flight
arboreal hypothesis
| cursorial hypothesis
180
what is the arboreal hypothesis?
gliding from tree to tree
181
what is the cursorial hypothesis
running start and lifted off the ground for insect foraging
182
what is the new idea about the origin of flight?
Use wings to scale inclined objects and trees
183
what are the skull adaptations in birds?
reduced number of bones and thinner bones; no teeth (beak). Light weight
184
what are the neck adaptations in birds?
exceptional flexibility -compensate for the loss of fore limbs. heterocoelous cervical vertebrae
185
what are the backbone adaptations in birds?
very rigid to minimize the number of muscles needed to maintain the streamlined body during flight, thereby reducing the energy consumption
186
what are the pelvic girdle adaptations in birds?
fused with synsacrum: bipedal; no symphysis (pelvic bones not fused) so large outlet for massive eggs
187
what kind of vertebrates do most mammals have?
acoelous
188
what kind of vertebrates do most fishes, some salamanders, and some lizards have?
amphicoeloous
189
what kind of vertebrates do anurans, most living reptile have?
procoelous
190
what kind of vertebrates do most living salamanders have?
opisthocoelous
191
what kind of vertebrates do birds have?
heterocoelous
192
describe the sternum in the birds?
ossified and wellpronounced keel (carina) to provide attachmentfor flight muscles
193
describe the integument of reptiles
- Relatively few glands –dry integument
- Glands produce poisons, pheromones as signals for sex, identity, navigation
- well developed epidermal keratinized (horny) scales (scute)
- continuous folds of epidermis
- shed regularly in lizards and snakes
- protection from desiccation
- locomotion (snakes)
194
describe the integument of birds
- Single large gland -uropygial gland produces oily secretion for transfer to feathers
- Waterproofing, well developed in aquatic birds
- EPIDERMAL DERIVATIVES
- Scales in places without feathers
- Claws at the ends of digits
- Beaks often include tooth like protuberances (not true dermal teeth)
- Feathers for thermoregulation, locomotion and attract mates
195
what is the order of evolution to get to mammals?
Pelycosaurs--> Therapsids--> Cynodonts--> Mammals
196
what are Basal Synapsids: “Pelycosaurs”?
- reptiles that arose in Carboniferous before lineage that led (eventually) to modern reptiles
- Single temporal opening!
- describe versus ancestor to reptile lineage that had two
197
describe Pelycosaurs
- Still had a sprawling posture
- Some had a broad ‘sail’ along the back made of extended neural spines and skin
- hindlimbis modified to a semi-erect position closer to the body --> greater stride length
198
describe cynodonts
- Mammal-like reptiles
- Changes in jaw muscles that allowed chewing in multiple directions
- Adductor differentiates into masseter and temporalis muscles
- Muscles expand and invade larger areas of the skull roof bones
evolved mammal-like double condyles
- Greater mobility of neck
- Nasal turbinates for regulation of heat and water exchange
- Division of food and air passages by secondary palate
199
when did the first mammals arrive?
late triassici (~210 mya)
200
describe the first mammals
- Small insectivores displaying agile, rapid movements
| - Endothermy with enlarged brain for better hearing and smell
201
what are mammalian characters?
- Feed young milk from mammary glands
- Extended parental care of young
- Large brain relative to body size
- Hair
202
features of modern mammalian sebaceous glands
- alveolar glands
- oily/waxy secretion often with hair
- waterproof hair and protect skin from drying
203
features of modern mammalian sweat glands
- tubular
- secrete water, salts, urea
- some important for thermoregulation
204
what did specialized glands arise from?
sebaceous and/or sweat glands
205
describe mammary glands
- Develop along the milk line during embryonic development
- Number and location of nipples varies across species
- Provide nutrition for young offspring
206
describe scent glands
Defense, sexual recognition
207
what are some derivatives of integument?
- Claws, hoofs and nails at the end of digits
- Horns (most not shed; keratin over bony core)
- Antlers (shed; mostly bone)
- Hair –thermoregulation and sensory organ
208
describe jaw support to sound transmission pre mammals
- Hyomandibula bone (second branchial arch) supports jaws in fishes
- Hyomandibula becomes stapes in amphibians –sound transmission in middle ear
- Jaw articulation between quadrate (upper)and articular (lower) in bony fishes, amphibians, reptiles and birds
209
describe the jaw support to sound transmission from reptiles to mammals
- Lower jaw now made up of a single bone, the dentary
- Jaw joint is now between dentary and squamosal
- Quadrate and articular are now part of middle ear
- Middle ear is now made of three bones
- Stapes: was hyomandibula in fish
- Incus: was quadrate
- Malleus: was articular
210
describe the evolution of dentition
- Mammals have teeth with specialized functions (incisors, canines, premolars and molars)
- Dentition is described by the dental formula –varies widely between species
211
what is the traditional view of dinosaurs and mammals?
- Early mammals were small shrew-like animals
- A few lineages persisted in specialized ecological niches amongst the dominant dinosaurs
- Evolved into many diverse lineages after extinction of the dinosaurs when their niches became available
212
what is the more recent view on dinosaurs and mammals?
Mammals started to diverge beforethe K-T extinction
213
true or false:
| there was in increased diversification of mammals after the loss of dinosaurs
true
214
describe monotremes
- Mammalian characteristics of hair, endothermy and suckling of young
- Lack nipples and external ears
- Embryos develop in leathery eggs (primitive amniote character); suggests earlier mammals also laid eggs
- Limited diversity: duck-billed platypus and four species of echidnas (spiny anteaters) in Australia/New Guinea
215
describe marsupials (metatheria)
- Found predominantly in Oceania (~200 species)
~100 species in the Americas, only one in North America (Virginia opossum)- Give birth to tiny young who suckle until they grow much larger, often in a specialized pouch of the mother
216
describe Placentals(Eutheria)
- Most diverse and widespread group of mammals
- Radiated extensively after the KT extinction but limited diversification during last 50 my!
- Prolonged gestation of embryo in uterus with placenta
- Distributions correlate with isolation of continents as they drifted away from the earlier supercontinent (Pangea)
217
where is it thought that marsupials arose?
likely arose in what would become North America
218
describe marsupial diversity
- South American and Australian groups are distinct as became isolated after continent breakup
- Australian groups occupy various niches as placentals elsewhere: convergent evolution
219
where did placentals likely arise?
Asia
220
what is convergent evolution?
- independent evolution of similar features in species of different periods or ephos in time line
- creates analogous structures that have similar form or function but were not present in the last common ancestor of those groups
221
describe placental diversity
- Early placentals moved into Africa from Asia
222
what happened to the Afrotheria group?
- evolved in Africa after breakup from other land masses (~105 mya)
- Species filled a diversity of ecological niches over ~70 MY in relative isolation
- Africa collided with Europe/Asia ~ 30 myaso some species became located on those continents
223
what species are included in the Afrotheria group?
```
golden moles,
elephant shrews,
tenrecs,
aardvarks,
hyraxes,
elephants
sea cows
```
224
what are the primate characters that lead to their success?
- Agile in trees
- Grasping hands/feet, opposable thumbs/toes
- Sensitive finger pads and flat nails
- Large brain-body size ratio
- Long period of development and enhanced parental care
- Only one offspring (usually)
- Delayed sexual maturity
- Long life-span
225
what are some possible things that drove the extensive adaptive radiation of mammals?
- Extended parental care
- Greater intelligence
- Versatile feeding mechanisms (dentition)
- Locomotory adaptations
- One or a combination of key adaptations promoted radiation into newterrestrial (and some marine) niches more quickly than reptiles, birds or amphibians
226
what was synapse evolutions characterized by?
key adaptations in the skeleton, physiology (endothermy), life history and parental care
227
what is cutaneous respiration important in?
amphibians
228
what is needed for cutaneous respiration?
- Low keratinization of the skin is required for efficient gas exchange, but low keratinization = water loss in air
- Water or moisture needed to maintain integument
- Need blood capillaries close to surface of exchange and increased surface area
229
describe tetrapod lungs
- Generally:paired, high surface-to-volume ratio, joined to gut by trachea
- Trend toward increased compartmentalization associated with increased body size and metabolic rate
230
what amphibians have external gills?
- Salamander larvae and some adults (paedomorphosis)
- Typical anuran larvae have external gills briefly after hatching
- Resorbed/ internalized
231
how does buccal pump of amphibians work?
2 stoke pump
- inspiration: buccal cavity expands, air is drawn into buccal cavity from outside lungs
- expiration: buccal cavity contacts, air is forces out of nostrils, air is forced into lungs (some mixing)
232
how is air forced into lungs with buccal pump?
with positive pressure
233
how is air sucked into lungs through aspiration pump of amniotes?
using negative pressure
234
describe aspiration pump of amniotes
- Ribs and intercostal muscles power the pump in most reptiles
- Diaphragm muscle and rib cage participate in lung ventilation in mammals
235
what kind of air flow do bird lungs have?
unidirectional air flow
236
describe bird lungs
- Aspiration pump, lungs coupled with air sac system
- Air flow in the lung is dorsobronchus -->parabronchus -->ventrobronchus, but complex network of air sacs is involved
- Gas exchange occurs in small capillaries in the walls of the parabronchi
237
how does bird lung ventilation work?
- Two-cycle breathing --> inhaled air is divided into lungs and posterior air sacs
- Air sacs perfuse the lungs during the first exhalation
238
describe mammal gas transfer at respiratory surface
Blood encounters relatively constant gas concentrations (uniform pool)
239
describe bird gas transfer at respiratory surface
Blood encounters increasing gas concentrations allowing progressive loading of oxygen in a cross-currentexchange system
240
describe fish gas transfer at respiratory surface
Blood first encounters lower gas concentrations and is fully equilibrated with oxygenated water in a countercurrent system
241
what are some special adaptations in bird lungs?
- Unidirectional airflow: two cycles of inspiration and expiration to move the air mass through the system
- Cross-current exchange
- Large exchange surface: 10 times more than mammals per volume
- Relatively fixed lung volume, using air sacs to ventilate air
242
true or false:
| Faveolar lung = unidirectional flow
false
243
how does tetrapod circulation work?
Blood passes through the heart twiceduring each circuit
244
in tetrapods what kind of circulation is used to get blood to/from body?
systemic circulation
245
in tetrapods what kind of circulation is used to get blood to/from lungs?
pulmonary circulation
246
who has the least efficient gas transfer at respiratory surface?
mammals (uniform pool)
247
who has the most efficient gas transfer at respiratory surface?
fish (countercurrent)
248
what is the set up of the anuran heart?
Two atria, one ventricle
249
what fish has a double circuit heart?
lungfish
250
blood flow through the anuran heart
- Oxygen poor blood from the body enters the right atrium, enters ventricle, to lungs and skin via pulmocutaneous artery
- Pulmonary veins carry oxygen-rich blood from the lungs to the left atrium
- Oxygen-rich blood enters the ventricle and goes to body (systemic)
- Conus partially divided by spiral value guiding blood flow towards systemic and pulmocutaneous routes
251
describe the facultative heart of reptiles
- two atria partially divided ventricle
| - Two aortic (systemic) vessels from left side to body and head
252
how does the facultative heart of reptiles work under water?
- Most blood bypasses lungs
| - Gap between ventricles allows deoxygenated blood to leave heart via left aorta rather than pulmonary artery
253
what is blood shunt mediated by?
pulmonary resistance
254
how does the hear of birds and mammals work?
- Four-chambered hearts with similar design
| - Systemic arch to body and head on left side in mammal and right side in bird
255
how does fetal circulation in mammals work?
- Uptake of oxygen and nutrients occurs at placenta
| - Need to shunt most of blood away from developing lungs and into systemic circulation
256
how does bypass 1 of fetal circulation work?
Blood enters right atrium and exits through foramen ovaleto left atrium and left ventricle then to head and upper body
257
how does bypass 2 of fetal circulation work?
Remaining blood enters right ventricle and enters pulmonary artery, travels through ductus arteriousto lower body and placenta to be oxygenated
258
how many pairs of aortic arches do lamprey have?
8 pairs
259
how many pairs of aortic arches do hagfish have?
15 pairs
260
how many pairs of aortic arches do Chondrichtyans and Sarcopterygias have?
5 pairs
261
how many pairs of aortic arches do Actinopterygians have?
normally 4 pairs
262
how many aortic arches do embryo have?
6 arches
263
how many aortic arches do teleosts have?
4 arches (3-6)
264
how many aortic arches do lungfish have?
five arches (2-6)
265
describe amphibian aortic arches
- three arches*
- 3 = carotids to head
- 4 = systemic on both sides; single vessel from heart splits in two
- 5= pulmonary to lungs
266
describe reptile aortic arches
- 3 arches (3-5)
| - 4 found on both sides with separate vessels from heart
267
describe bird aortic arches
```
3 arches (3-5)
- 4 only on right side
```
268
describe mammal aortic arches
- three arches (3-5)
| - 4 only on left side
269
why is there 2 bypasses in the fetal circulation?
if only ductus arteriosus: all blood would go to lower body
270
where are both fetal circulation bypasses closed off?
at birth
271
what are the 2 fetal bypasses?
foramen ovale
| ductus arteriosus
272
what does the digestive system do?
- Receives, stores, breaks down (physically and chemically) and absorbs food
- Stores and discharges undigested waste
- Vertebrates have a complete digestive tract from mouth to anus (or cloaca) –two openings
273
what are the components of the digestive tract?
- mouth
- pharynx
- tubular parts (alimentary canal): esophagus, stomach, intestine (small and large)
- cloaca or rectum
- Accessory organs and glands: tongue, teeth, salivary glands, pancreas, live
274
describe the mouth portion of the digestive tract
entrance to the digestive tract
275
history of the mouth
- Ancestral vertebrates were likely filter feeders with small mouths
- Agnathans have no jaws or true teeth and a small buccal cavity
- Fishes have highly specialized mouths with firm tongues
- In tetrapods, trend toward increased physical and chemical aspects of digestion
276
what are teeth derived from?
bony dermal armor/ similar structure to placoid scale
277
what are teeth composed of?
dentin, covered by a crown of enamel
278
what is acrodont dentition? (TEETH)
teeth attached to the outer surfaceor to the summit of the jawbone; many teleosts
279
what is pleurodont dentition? (teeth)
attached inner side; anurans, salamanders, many lizards
280
what is hecodont dentition? (teeth)
teeth occupy bone sockets or alveoli; some fishes, crocodilians, fossil birds, mammals
281
what its homodont tooth variation?
teeth all the same size and shape
282
what is heterodoxy tooth variation?
teeth vary morphologically
283
describe mammalian teeth
- Heterodont dentition with species-specific number of teeth
| - evolved along with ability to chew
284
where are multicellular glands with ducts found?
only in tetrapods: not fishes
285
what is the functions of oral (salivary) glands?
- Primary is to moisten the food for lubrication
- Allows tongue to be sticky to assist prey capture –frogs and anteaters
- Allows start of starch digestion –some mammals- Modified into poison glands in some snakes and lizards
- Moved to near orbits in marine reptiles and birds and functions for salt excretion
286
how do birds mechanically break down for?
using the gizzard
287
what is the esophagus?
- Muscular tube between pharynx and stomach
- Greatly folded and distensible lining
- Rich in mucous glands
- Conducts food to the stomach
288
what is the stomach?
- Muscular chamber that begins at the end of the esophagus and terminates at the pylorus: an opening surrounded by the pyloric sphincter (ring of smooth muscle)
- Contains gastric glands that produce hydrochloric acid
- May have evolved as a storage sac
- Digestive function involves mostly breaking down of food with little absorption
289
what adaptations of the stomach are seeing birds?
- Glandular proventriculus: secretes digestive enzymes
| - Muscular gizzard (ventriculus): tough horny layer for grinding and mixing food with gastric secretions
290
what are the 4 modifications in some mammals stomachs (ruminants)?
1. rumen
2. reticulum
3. omasum
4. abomasum
291
what does the rumen do?
stores and churns; residence for bacteria, which produce cellulase to breakdown cellulose (no vertebrates can produce the enzyme themselves)
292
what does the reticulum do?
receive food from rumen and form cud, then regurgitate for further chews
293
what does the omasum do?
temporary holding site
294
what is unique about the abomasum?
the only place with gastric gland
295
what is the intestine?
- Long tubular part with highly folded surface
- Secretion of mucus and digestive enzymes, other enzymes secreted into intestine from liver and pancreas
- Selective absorption of nutrients and water
- Movement by peristalsis
296
what is the small intestine the site of?
digestion and absorption of nutrients
297
what is the large intestine's job?
mostly recovers water, but can be used for fermentation
298
where do Major digestive glands (liver, pancreas) empty their secretory product?
into the section adjacent to the stomach: the duodenum
299
what do herbivores long guts with intestine specializations promote?
fermentation
300
what are the 4 layers of the gut wall outside to in?
1. serosa
2. muscular externa
3. submucosa
4. mucosa
301
what is in the serosa?
connective tissue and mesentery
302
what is in the muscular externa?
two layers of smooth muscle: longitudinal and circular
303
what is in the submucosa?
connective tissue, autonomic nerves
304
what is in the mucosa?
epithelial lining, smooth muscle fibres, connective tissue
305
what are the 3 strategies for increased surface area of the digestives tract?
caeca
spiral valve
folding
306
what is the caeca?
blind-ended extensions of gut, can come out in various places (pyloric caeca, colic caeca, etc)
307
what is the function of the caeca?
digestion/absorption in fishes, fermentation in some mammals
308
what animals do spiral valves present themselves?
chondrichthyans, lungfish
309
what is the function of the spiral valve?
Forces passing food through a spiral route, increasing path length
310
what is the function of foldings?
Large surface area is achieved by coils of the canal, folds, villi, and microvilli on the internal surface
311
what is the function of the excretory system?
- remove nitrogenous wastes and other harmful substances
- control osmosis to achieve water and salt balance
salt glands
312
what is the function of the reproductive system?
produce and release gametes, bring them together, provide nourishment to young,
313
what are the organs involved in the excretory system?
kidney, gills, skin, part of the digestive system,
314
what organs are involved in the reproductive system?
gonads, ducts, cloaca, copulatory organs
315
how does the kidney develop?
- moves from anterior to posterior in three sections with breaks in between them
- More anterior regions usually degenerate as posterior regions become functional
- More posterior break may not form so that two instead of three pairs of kidneys are formed in sequence
316
what is the pronephros portion of the kidney and how does it develop?
- most anterior
- Segmented usually the first 4 segments
- Appears in all vertebrates (rudimentary form) but degenerates quickly
- Functional in fish larvae and adults of hagfish and some teleosts
- Degenerates into ‘head kidney’ in other species
- Has hemopoietic, lymphoid and endocrine functions
317
what is the Opisthonephros and mesonephros portion of the kidney?
- Reduced segmentation
- Adult fishes and amphibians have an opisthonephric kidney
- Developing amniotes develop a mesonephros that degenerates
318
what is the metanephros?
- Kidney of amniotes
- Unsegmented•Forms from most posterior part of nephrogenic cord
- Replaces mesonephros that arose earlier in development
- Old mesonephric duct degenerates in females but persists in males to carry sperm
319
how is the metanephric kidney drained?
by a new duct the ureter
320
what is the nephron?
- functional unit of the kidney
| - renal corpuscle + nephrite (renal) tubule
321
what is the glomerulus?
cluster of cappillaries (internal or external)
322
what is the renal or bowman's capsule?
cup like sac that collects urine
323
what is the pronephric functional in?
fish larvae, adult hagfish and some teleost
324
what is the opisthonephric functional in?
most fish and amphibians
325
what is the metanephric functional in?
amniotes
326
what are the 2 sources that the gonads develop from?
- Mesomere genital ridges
| - Primordial germ cells
327
what part of the gonads develop from the mesomere genital ridge?
become supporting tissues of gonads (sex cords
328
what part of the gonads develop from the Primordial germ cells?
- become gametes
| - arise from endoderm and migrate to genital ridge early in development
329
what are the principle urogenital ducts?
- nephric ducts (pro, meso, opistho)
- Müellerian ducts
- ureter
- accessory ducts
330
what ducts do all vertebrates other that cyclostomes have?
- a pair of nephric and Muellerianducts and possibly other
331
true or false:
| cyclostomes have sexual ducts
false:
| Eggs and sperms released into coelom, exit into cloaca by way of genital pore
332
what is variations in urogenital ducts the result of?
retention, loss or modification of the basic structure
333
what do efferent ducts do?
carry sperm from testis to nephrite duct
334
what does the nephrite duct do?
carry sperm or urine or both depending upon the organism
335
describe urogenital ducts in more sharks and amphibians
nephric duct carries sperm; accessory urinary duct for urine;
336
in mudpuppy, how are sperm and urine carried?
both by nephrite duct
337
describe urogenital ducts in teleost
nephric ducts for urine; new sperm duct
338
describe urogenital ducts in amniotes
nephric duct for sperm; ureter for urine
339
what do Müellerian ducts become?
oviduct to carry ova
340
where do teleosts oviducts derive from?
ovarian folding
| not homologous to Mullarian ducts
341
describe female urogenital ducts in Sharks, teleosts and amphibians
opisthonephric ducts carry urine
342
describe urogenital ducts in amniotes
- Mesonephric duct degenerates
| - Ureter carries urine
343
what is the function of the nervous system?
(along with endocrinesystem) determines response of the body to changes in its environment
344
how can neutrons be classified?
according to function or morphology
345
what does the cell body of a neutron usually bear?
one or more dendrites to receive information and usually one axon to transmit impulses
346
what are dendrites and axons called?
fibers
347
what are glia?
type of cell, many types for protection and support
348
what are Schwann cells?
type of glia
| - insulate axons with myelin
349
what are Astrocytes?
- type of glia
| - pass nutrients between capillaries and neurons
350
what are Microglia?
type of glia
| - engulf foreign material
351
what is the synapse?
an axon of one neurons with a dendrite or nerve cell body of another neurons
- directional transmission of signal from one neuron to another
352
what does the brain do?
- Organ that coordinates all activities of the organism
| - Master control centre
353
what is the function of the spinal cord?
receive incoming impulses, integrate and coordinate them, transmit them wherever they should go within the CNS, and send responses to the PNS as appropriate
354
somatic
skeletal muscle and skin (voluntary)
355
visceral
involuntary muscles and glands (autonomic)
356
afferent (sensory)
tissues to CNS
357
efferent (motor)
CNS to tissue
358
what are spinal nerves?
Nerves associated with spinal cord segments
359
what does the dorsal root contain?
- sensory neuron fibres (somatic and visceral)
| - cell bodies clustered in ganglia
360
what does the ventral root contain?
- motor neuron fibres (somatic and visceral)
| - Cell bodies of motor neurons are in spinal cord (clustered in nuclei)
361
what is grey matter?
cell bodies of motor neurons and unmyelinated fibers (this is wherethe synapses are)
362
what is white matter?
myelinated fibers (axons)
363
how did the lamprey's spinal nerves work?
- visceral motor fibre exits from cord on dorsal nerve
| - separate dorsal and ventral nerve
364
where are the cranial nerves and what do they do?
- Nerves that emerge directly from the brain (including the brainstem) rather than spinal cord
- Relay information between the brain and parts of the body
365
describe the visceral nervous system
Division of PNS that controls visceral organs, monitors their internal environment and activity
366
what components of the body are controlled by the visceral nervous system?
Cardiac and smooth muscles, urogenital system, pigment cells, some respiratory organs, intrinsic eye muscles and glands
367
what 2 sets are the visceral motor fibres divided into in amniotes?
sympathetic and parasympathetic
368
how many motor neurons carry out the efferent (motor) signals in autonomic (visceral) system?
2
369
how many motor neurons carry out the somatic signals in spinal nerves?
1
370
which set of visceral motor fibres in amniotes has a shorter preganglionic fiber?
sympathetic
371
which set of visceral motor fibres in amniotes has a shorter postganglionic fiber?
parasympathetic
372
what does the sympathetic set do?
- Prepares body for stressful situation, expands energy: alertness, excitement, alarm, the ‘fight or flight response’
- Ganglia in a chain
- Thoracolumbar outflow
373
what does the parasympathetic set do?
Slow down: ‘rest/digest’
- ganglia close to organ
- Craniosacral outflow
- Often more postganglionic neurons than preganglionic
374
what has happened with the evolution of the brain?
Enlargement of the cerebrum (higher functions) and cerebellum (regulates motor movements)
375
how does impulse flow work?
dendrite to nerve cell body to axon
376
true or false:
| a nerve cell can be both sympathetic and parasympathetic
false:
| anatomically distinct
377
what do sense organs do?
perceive and integrate sensation, and initiate action
378
what is a sensory receptor?
usually composed of dendrites of a neuron & can include tissue that amplifies the stimulus
- transducer that transforms a stimulus into an electrical impulse
- usually in CNS
379
describe olfactory organs
- ectodermal origin
•Olfactory epithelium located in the nasal pit or respiratory passage
•Filaments serve to increase surface are
- Olfaction used for discrimination of chemicals in the environment
380
describe fish olfactory organs
- water into nasal pit
| - lamellae made up of olfactory epithelium and support tissue
381
describe air breathing vertebrates olfactory organs
add mucous cells to dissolve the particle and wash away old samples
382
describe tetrapods olfactory organs
size and complexity of nasal chamber increased
383
describe mammals olfactory organs
- complex turbinate (scrolls of bone); distinguish trillions of odours!
- dogs: 40x humans
384
describe taste organs
- detect similar molecules with similar structure as the olfactory organs but differ in:
•less sensitive
•receptor cells aggregated into taste buds
•associated with afferent sensory fibers from cranial nerves rather than having their own axons (not hard wired)
•exposure -worn and replaced
385
what are the 2 types of chemoreceptors?
olfactory organs
| taste organs
386
what are photoreceptors?
Cells capable of phototransduction, i.e., generate electrical potential with photon absorption
387
where are photoreceptors found?
retina
388
how does the retina work?
- Photoreceptor cells (rods and cones) detect light
•Converted to electrical signal and relayed to brain via optic nerve
•Brain translates the electrical signals into an image
389
how is the eye accommodated in water?
- index of refraction of water is the same as inside eye and cornea, but index of refraction of lens is above that of water
•Need to focus change in lens position by contraction of the retractor lentis muscle
•Cornea is flat so not involved in focusing light
390
how is the eye accommodated on land?
- index of refraction of air differs from inside the eye and cornea
•Focusing change in lens shape by relaxation of ciliary muscle which attaches suspensory ligaments between eye and lens
•Cornea is rounded so also involved in focusing light
391
how does the eye adapt to dim light?
Large eyes: large pupil, large lens close to retina
•Few cones or none, slender rod cells are closely packed
•Tapetumlucidum(mirror) can be present (e.g. deer in the headlights)
392
describe the mechanoreceptor proprioception
- Muscle spindles and Golgi tendon organs monitor muscle contraction and limb flexion
- Enable the brain to keep track of body position
393
how does the lateral line system work as a mechanoreceptor?
- detects water movement
- in all fishes and larval (some adult) amphibians
- Consists of thousands of neuromasts dispersed on the body surface or inside lateral line canals
394
how does the lateral line system work as an electroreceptor?
- present in many fishes and the platypus
| - detects weak electric stimuli using electroreceptors made up of jelly-filled canals leading to the skin surface
395
how is water movement measures?
- by displacement of the gelatinous cupula
- bends the stereocilia towards kinocilium increasing firing rate of sensory neuron
- Neuromasts collectively provide both spatial and temporal information
396
what are the 2 functions of the ear?
equilibrium and hearing
397
what do the functions of the ear depend on?
hair cell movement by for transduction of mechanical information
398
describe ear equilibrium
- vestibular system in inner ear
- Similar structure, function and development to lateral line system
- Register head position
- Detect angular acceleration of head
399
what parts of the ear aid in hearing?
middle ear and cochlea
400
what is the ear made up of?
Three semicircular canals and two chambers, utricle and saccule.
401
what is an extension of the saccule called?
lagena (cochlea in mammals)
402
what do the semicircular canals of the ear do?
- Respond to rotational movements
•Angular acceleration,
•Position of head in 3 dimensions
403
what do the chambers of the ear do?
- Response to head position relative to gravity
| •Linear acceleration
404
what may the cupola be modified into?
solid crystal mass: otolith
405
how does hearing work?
- Tympanum (eardrum) receives airborne sound wave
•Middle ear bones mechanically transmit the vibration to the oval window -the opening of the bony housing of inner ear
•Motion of waves in fluid translate into shearing force over the hair cells
406
what mechanisms increase the force in the ear of mammals?
- small oval window
| •lever system of three ear bones
407
what are infrared receptors?
- Cells capable of detecting infrared radiation emanating from the surface of warm objects
•Most developed in snakes to detect warm prey in the dark (e.g. pit vipers)
•Facial pits (or pit organ) have a high density of free nerve endings organized in a membrane
