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ZOOL 325 > Midterm 1 > Flashcards

Midterm 1 Flashcards

1
Q

why study vertebrate comparative anatomy?

A
  • provides context for human anatomy
  • fundamental basis for vet med
  • improves taxonomic classifications and adaptations
  • can reveal limits of anatomical modification
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2
Q

what are the 3 key ideas in comparative biology?

A
  1. monophyly
  2. adaptation
  3. homology
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3
Q

describe monophyly

A

taxonomic groups are defined by common ancestry

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4
Q

define adaptation

A

structure that evolved to serve its current function - “fit between form and function”

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5
Q

describe homology

A

structures in different taxa may be derived from a single ancestral structure

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6
Q

describe the 5 parts of a cladogram

A
  1. terminal taxon: real taxonomy that can be observes
  2. branches:
  3. sister taxa
  4. nodes: hypothetical ancestors that can be used to find monophyletic groups
  5. root: connects taxa in cladograms to other living things
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7
Q

describe monophyletic

A

clade that includes common ancestor and all its descendants

  • above genus level they have no associated ranks
  • every node defines a monophyletic group
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8
Q

describe paraphyletic

A

group that includes a common ancestor and some of the descendants

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9
Q

describe polyphyletic

A

group that includes only some descendants, no common ancestor

  • combines taxa that are not closely related at all
    ex: Haematothermia (group with only birds and mammals)
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10
Q

describe synapomorphy

A

a newly evolved feature shared by a taxonomic group that provides evidence of common ancestry

ex: four limbs is a synapomorphy of tetrapods

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11
Q

describe autapomorphy

A

derived feature seen in only 1 species

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12
Q

describe symplesiomorphy

A

ancestral feature shared by some members of a taxonomic group

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13
Q

describe exaptation

A

structure that evolved for one function and was alter modified to serve another

ex: tusk of an elephant is an enlarged incisor tooth that has been exapted for digging or fighting

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14
Q

explain owen’s homologous archetype

A
  • he considered homolgous body parts to be the one equivalent in different organisms
  • never accepted evolution and therefore believed in the “archetype” body plan as an explanation for homology
  • the body plan: fish-like with limbs or paired fins, four segments fused to form the skull and pairs of lateral spines across the body
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15
Q

describe homologous structures

A

structures that have a common evolutionary origin despite looking different/similar

ex: tiny bones in the mammalian middle ear and jaw joint bones in reptiles
tetrapod forelimbs

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16
Q

describe analogous structures

A

structures that have evolved independently but are similar in looks and function

ex: bird, insect, and bat wings

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17
Q

explain how to recognize homology (colin patterson)

A
  1. test of similarity: shape, composition, and development
    2: test of conjunction: if both structures occur together in the same organism, they are not homologous
    3: test of congruence: more likely homologous if they share many other homologous features
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18
Q

describe serial homology

A

repeated structures in one organism

ex: hindlimbs and forelimbs, teeth, ribs

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19
Q

describe metamerism

A

repetition of homologous body segments

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20
Q

what is the process of embryo development?

A
  1. zygote undergoes cleavage
  2. further division of cell leads to morula
  3. blastula becomes hollow for fluid filled cavity
  4. gastrulation leads to gastrula
  5. neurulation leads to neurula
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21
Q

what is the difference between the cleavage stage of a protostome and deuterostome?

A

protostome:
- spiral: planes between cells are not aligned
- determinate: cells fate are established

deuterostome:
- radial: plane between cells are aligned
- indeterminate: cells fate is established later

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22
Q

what is the difference between the coelom of a protostome and deuterostome?

A

protostome: schizocoelous (masses of mesoderm split to form coelom)

deuterostome: enterocoelous (folds of archenteron form coelom)

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23
Q

what is the difference between the blastopore stage of protostome and deuterostome?

A

protostome: mouth forms first (from blastopore)

deuterostome: anus forms first

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24
Q

what is an amphioxus?

A
  • lancelet
  • chordate, not a vertebrate
  • falls under cephalochordata
  • small marine suspension feeder
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25
Q

what is a lamprey?

A
  • primitive vertebrate
  • lacks jaws and paired fins
  • parasitic as adults
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26
Q

what are the plane positions?

A
  • frontal: horizontal
  • sagittal: vertical
  • transverse: cross section
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27
Q

explain amphioxus and lamprey coelom formation

A

anterior segments are enterocoely and posterior segments are schizocoely

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28
Q

explain jawed vertebrate coelom formation

A

it is only schizocoely

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29
Q

explain the 3 germ layers

A
  1. ectoderm: outer layer of skin (epithelium), nervous tissue
  2. mesoderm: bones, connective tissue, muscles, inner layer of skin, and some internal organs (kidneys, gonads)
    3: endoderm: inner lining of digestive tract, some internal organs (pancreas, liver)
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30
Q

explain organogenesis

A
  • the 3 germ layers are closer together after neurulation
  • differentiation of organs from tissues
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31
Q

explain the formation and function of neural crest cells

A
  • fold that come together to form the neural tube and ectoderm
  • specialised ectodermal cells
  • contribute to the formation of teeth, jaws, nervous system, and endocrine system
  • limited to vertebrates
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32
Q

what are the 4 major tissue types?

A
  1. epithelium - from ectoderm or endoderm
  2. nervous tissue - from ectoderm
  3. muscle tissue - from mesoderm
  4. connective tissue - from mesoderm
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33
Q

explain epithelial tissue

A
  • comprised of sheets (membranes) and secretory glands
  • forms outer layer of skin and inner lining of gut tube
  • functions: secretion, absorption, and protection
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34
Q

what is endothelium?

A
  • inner lining of blood vessels
  • specialised epithelium
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35
Q

describe nervous tissue

A
  • makes up brain, spinal cord, and nerves
  • contains neurons for transmitting impulses
  • receives sensory info and carries out a response
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36
Q

describe muscle tissue

A
  • made up of contractile fibres
  • generates tensile force - helps to produce or resist movement
  • can ONLY pull bones, NOT push
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37
Q

what is connective tissue?

A
  • supportive and structural framework of the body

ex: blood, adipose tissue, cartilage, and bone

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38
Q

what are the 4 body regions?

A
  1. head and throat
  2. trunk: coelom, ribs and muscles house the viscera
  3. tail: postanal structure
  4. appendages: pectoral and pelvic
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39
Q

explain metamerism

A
  • repetition of structures along the longitudinal axis
  • clear in embryos
  • metamerism in head is more ambiguous
    ex: vertebrae, ribs, spinal nerves
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40
Q

what are protochordates?

A
  • paraphyletic group
  • includes non-vertebrate chordates and hemichordata
  • use cilia and mucus to filter feed
  • undergo metamorphosis
  • larvae is planktonic and adults are benthic
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41
Q

what are chordate diagnostic characteristics?

A
  • notochord
  • dorsal hollow nerve cord
  • pharyngeal slits
  • postanal tail
  • subpharyngeal gland (thyroid gland endostyle)
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42
Q

explain notochord

A
  • stem from the mesoderm
  • spans from ventral to nerve cord
  • hydrostatic organ: stiffness due to internal pressure, but provides stability
  • vertebrae form around the notochord (in vertebrates)
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43
Q

explain dorsal hollow nerve cord

A
  • stems from neural tube of embryo
  • transmits information between brain and rest of the body
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44
Q

explain pharyngeal slits

A
  • vertical slits in lateral walls of pharynx
  • “gill slits” but used for filter feeding in primitive chordates
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45
Q

explain postanal tail

A

a tail extending posterior to the anal opening

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46
Q

explain subpharyngeal gland

A
  • non-vertebrates: endostyle
  • vertebrates: thyroid gland
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47
Q

define endostyle

A

mucus-secreting tract on the floor of the pharynx

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48
Q

what are enteropneusta?

A
  • hemichordata (acorn worms and kin)
  • acorn worms with proboscis, collar, and trunk
  • postanal tail is absent
  • their nerve network includes a longitudinal dorsal cord in the collar region
  • proboscis contains a stomochord, homologous to notochord
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49
Q

what are pterobranchia

A
  • hemichordata
  • colonial and bottom-dwelling
  • zooids live in tubes
  • pharyngeal slits in most species
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50
Q

explain cephalachordata

A
  • lancelets, amphioxus
  • planktonic as alrvae, burrowing suspension feeders as adults
  • dhnc, but no brain
  • notochord extends anteriorly
  • blood plasma in vessels, but no blood cells or heart
  • myomeres along sides of body
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51
Q

explain the circulation in cephalachordata

A
  • one way flow of blood plasma
  • sinus venosus doesn’t pump blood but vessels are contractile
  • cutaneous respiration requires large surface area
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52
Q

explain the feeding of cephalachordata

A
  1. buccal cirri filters large particles from mouth
  2. wheel organ (hair-like cilia) sweeps food in
  3. ends up in atrium of adults, where it is enclosed in a metapleural fold
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53
Q

explain urochordata: ascidiaceae

A
  • sea squirts, tunicates
  • larvae: motile
  • adult: sessile, hermaphroditic
  • “tunicate”: covered in “tunic” of cellulose, external to the skin
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54
Q

explain sea squirt metamorphosis

A
  1. adhesive papillae sticks to rock
  2. epidermal cells contract, and outer tunic, notochord, and trunk contract into body
  3. epidermal cells form an opening and presence of a fecal strand
  4. opening becomes branchial siphon, atrial siphon becomes exit, adult becomes sessile on the rock
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55
Q

explain urochordata: larvacea and thaliacea

A
  • laravacea resemble ascidian larvae where they are enclosed in an intricate capsule, tunic absent
  • thaliaceae resemble adult ascidians, siphons are used for jet propulsion
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56
Q

are primitive chordates inverted arthropods?

A
  • arthropods: solid ventral nc, schizocoely, spiral cleavage
  • chordate: hollow dorsal nc, enterocoely, radial cleavage
  • no, chordates did not evolve from arthropods
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57
Q

what do chordate fossils tell us?

A
  • there’s limited fossil records, but the most known is the “Pikaia” that resembles modern amphioxus
  • soft-bodied organisms, hard to preserve
  • ancestral chordates may have been cephalochordate-like
  • chordates evolved from ancestral deuterostome
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58
Q

what were the signs of transitioning from protochordates to vertebrates?

A
  • bone, brain, and sensory structures appeared
  • muscularisation of the mouth, pharynx, gut, heart, and vascular system
  • neural crest and ectodermal placodes contribute to structure formation
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59
Q

what is hypomere?

A
  • sheets of mesoderm surrounding coelom
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60
Q

what is splanchnic layer?

A

gives rise to muscle lining digestive tract in vertebrate - allows digestion to be more efficient

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61
Q

explain neural crest cells

A

cells that arise in neural folds in head, that eventually grow laterally

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62
Q

what do neural crests help form?

A
  • pigment cells
  • skin of facial region
  • skull, teeth, head muscles
  • heart
  • adrenal glands
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63
Q

explain ectodermal placodes

A

paired tissues that stem from the head and throat region and migrate elsewhere

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64
Q

what do ectodermal cells help form

A
  • olfactory epithelium
  • eyes
  • inner ear
  • cranial nerve ganglia
  • lateral line
  • pituitary gland
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65
Q

what are the 12 vertebrate characteristics?

A
  1. neural crest
  2. ectodermal placodes
  3. vertebrae
  4. skull
  5. integument with epidermal and dermal layers
  6. musculature sheathing digestive tract
  7. chambered, contractile heart
  8. tripartite brain
  9. cranial nerves
  10. spinal nerves
  11. nephrons: excretory cells
  12. thyroid
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66
Q

explain larval lamprey

A
  • ammocoete
  • suspension feeder
  • contraction of muscles that surround the pharynx aids movement of water
  • pharyngeal slits act as valves
  • adults are parasitic or non-feeding
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67
Q

vertebrate: explain agnathans

A
  • jawless fish
  • paraphyletic because they’re ancestral to gnathostomes
  • muscular pharyngeal pump
  • living: hagish and lampreys
  • single median nostril
  • lack bones
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68
Q

agnathans: explain myxiniformes

A
  • hagfish
  • burrowers and scavengers
  • slime glands
  • rough tongue
  • 1 semicircular canal in inner ear for orientation
  • notochord is associated with cartilaginous vertebrae in tail
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69
Q

agnathans: petromyzontiformes

A
  • lampreys
  • produce ammocoete larvae
  • oval mouth with keratinous teeth
  • notochord is associated with cartilaginous vertebral arches
  • 2 semicircular canals
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70
Q

explain conodonts

A
  • extinct agnathans
  • tooth-like microfossils
  • function was to trap and crush food particles
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71
Q

agnathans: ostracoderms

A
  • armoured agnathans
  • paraphyletic
  • bodies and head covered in bony plates
  • lateral line system and 2 semi-circular canals
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72
Q

vertebrates: explain gnathostomata

A
  • origin of jaws: upper jaw becomes part of the skull and lower jaw is mobile
  • bearing of teeth
  • complex endoskeleton
  • paired appendages
  • 3 semicircular canals
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73
Q

explain placoderms

A
  • paraphyletic because it is ancestral to gnathostomes
  • heavily armoured
  • Dunkleosteus
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74
Q

explain acanthodians

A
  • paraphyletic group of spiny sharks
  • ossified partial vertebrae associated with notochord
  • reduced armour, protective spines
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75
Q

explain chondrichthyes

A
  • cartilaginous skeleton, but calcified
  • oil-filled for buoyancy
  • males use claspers
  • elasmobranchs have placoid scales
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76
Q

explain osteichthyes

A
  • actinopterygians and sarcopterygians
  • endoskeleton made of bone
  • dermal scales
  • swim bladder or lung
    ossified gill cover
  • lepidotrichia
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77
Q

explain actinopterygii

A
  • ray-finned fishes
  • fins are supported by thin bony rays (lepidochtria)
  • fins are muscular closer to the body
78
Q

what are examples of primitive actinopterygii?

A
  • polypteridae (bichirs and reedfish)
  • acipenseriformes (sturgeons and paddlefish)
79
Q

what are characteristics of teleosts (derived actinopterygians)?

A
  • thin scales
  • homocercal tails
  • ossified vertebrae
  • jaw moves independently from the skull for better feeding
80
Q

explain sarcopterygii

A

lobe-finned fish

81
Q

what are groups of sarcopterygians?

A

coelacanths, lungfish, tetrapods, and osteolepiforms

82
Q

what are characteristics of sarcopterygians?

A
  • fin muscles and bones extend into fin for support
  • cosmoid scales contain cosmine
  • hinge across roof of skull, allowing for wider gape
  • disappearance from fossil record suggest they shifted into deeper habitats
83
Q

explain osteolepiforms

A
  • more closely related to tetrapods than coelacanths or lungfish
  • notochord is constricted by multi-part vertebrae
  • labyrinthodont teeth - bigger and sharper
  • predatory adaptations
84
Q

explain acanthostega

A
  • devonian sortapod
  • tail fin with developed rays
  • internal gills on branchial arches
  • lateral line system
  • limbs rather than fins
  • body plan suggest that the transition to terrestrial life
85
Q

explain tetrapods

A
  • “four-footed”
  • muscular limbs with joints and digits
  • earliest tetrapods were aquatic
86
Q

explain labyrinthodont amphibians

A
  • paraphyletic group with labyrinthodont teeth
  • each vertebrae had multiple ossifications
  • metamorphosis since juveniles are aquatic
87
Q

explain lepospondyli

A
  • monophyletic group of small amphibians
  • teeth are smooth
  • carboniferous and permian
  • closely related to amniotes
88
Q

explain lissamphibia

A
  • groups: frogs, salamanders, caecilians
  • pedicellate, bicuspid teeth
89
Q

what are 3 hypotheses of lissamphibian origins?

A
  1. lissamphibians evolved from temnospondyls (large, primtive)
  2. evolved from lepospondyls
  3. caecilians evolved from lepospondyls and others evolved from temnospondyls
90
Q

explain the parts of pedicellate teeth

A
  • crown
  • pedicel
  • bicuspid - 2 cusps on the crown
  • line of flexibility - allows crown to wiggle, suitable for predators
91
Q

lissamphibia: explain urodela

A
  • groups: salamanders and newts
  • least specialized clade
  • trunk musculature used for locomotion
  • larvae similar to adults but have gills
92
Q

lissamphibia: explain gymnophiona

A
  • caecilians
  • limbless
  • tropical habitat, aquatic and burrowing
  • limited vision
93
Q

lissamphibia: explain anura

A
  • frogs and toads
  • specialized skeleton: short vertebral column with urostyle, long hindlimbs
94
Q

define urostyle

A

rod-like fused tail vertebrae in anura

95
Q

explain amniota

A
  • reptiles, mammals, and their fossil relatives
  • amniotic egg prevents desiccation and increases egg size
  • calcified shell for protection
  • some are egg-laying, but membranes are retained
  • groups: sauropsids and synapsids
96
Q

explain saurposids

A

reptiles and birds

97
Q

explain synapsids

98
Q

explain temporal fenestrae

A
  • openings in the temporal region
  • accommodates jaw-closing muscles, allowing for wider gape
  • upper arch formed by squamosal and post-orbital bones
  • lower arch formed by jugal and quadratojugal
99
Q

explain anapsid skulls

A
  • no fenestrae or arches in the the temporal region
  • instead, they have emargination, which is an equivalent to fenestrae
  • turtles
100
Q

explain diapsid skulls

A
  • two fenestrae on each side: supratemporal fenestra (upper) and infratemporal fenestra (lower)
  • non-avian dinosaurs and birds
101
Q

explain synapsid skulls

A
  • “fused arch”
  • mammals
    infratemporal fenestra on each side, STF is absent
  • Po and Sq are integrated into skull roof
102
Q

explain euryapsid skulls

A
  • only STF on each side
  • ITF may have dissappeared, may have been converted into infratemporal embayment - connection betwen J and Qj are gone
103
Q

sauropsida: explain parareptilia

A
  • anapsid skull
  • small and terrestrial
  • BUT mesosaurs were marine and pareiasaurs were large
104
Q

sauropsida: explain sauropterygia

A
  • flappers for marine life
  • euryapsid skull - lower temporal bar lost
  • triassic-cretaceous reptiles
105
Q

suaropsida: lepidosauria

A
  • rynchocephalians: lizard-like, only left are tuatara
  • squamates: lizards, snakes, and amphisbaenians
106
Q

explain the difference in lepidosauria skulls

A
  • tuatara (rhynchocephalians): diapsid
  • iguana (squamates): euryapsid or modified diapsid
107
Q

why are turtle origins of interest?

A
  • modern turtles: anapsid skull, teeth absent, carapace, and plastron
  • primtive turtles: anapsid skull, teeth present, plastron present, carapace absent
  • did the plastron evolve before carapace to protect the underbelly in water
108
Q

explain archosauria (ruling reptiles

A
  • common ancestor of birds and crocodilians
  • pterosaurs
109
Q

archosauria: explain crocodylia

A
  • common ancestor of alligators, crocs, gharials
  • part of crocodylomorpha
110
Q

archosauria: explain pterosauria

A
  • triassic to cretaceous flying archosaurs
  • pneumatic bones
  • wings made of skin, supported by elongate 4th finger
111
Q

explain dinosauria

A
  • clades: ornithischia and saurischia
112
Q

dinosauria: explain ornisthischia

A
  • herbivores
  • ischium and pubis directed posteriorly, like birds - convergence
  • birds are NOT ornithischians, they are THEROPODS
113
Q

dinosauria: explain saurischian

A
  • long-necked herbivores (suaropodomorphs) and carnivores (theropods)
  • ischium is directed posteriorly and pubis is directed anteriorly
114
Q

explain avialae (birds)

A
  • theropod dinosaurs with feathers
  • modified diapsid skull by loss of STF and merging of ITF with orbit - anapsid condition, different from turtles
  • reduced weight: reduced limbs and digits, no teeth, no urinary bladder, shortened large intestine
115
Q

explain archaeopteryx

A
  • the first bird
  • from jurassic
  • plesiomorphies are absent in modern birds - long tail and teeth
116
Q

what are the clades of advanced birds?

A
  • palaeognathae: ratites and tinamous
  • neognathae: all other birds
  • the two have different palate arrangements
117
Q

synapsida: explain pelycosaurs

A
  • paraphyletic
  • retained plesiomorphies from ancestral amniotes
  • lower temporal fenestrae small
  • carboniferous and permian
118
Q

synapsida: explain therapsida

A
  • larger lower temporal fenestra
  • upright limb posture
  • non-mammalian existed from permian to jurassic
119
Q

explain the mammalian clade

A
  • first appeared: jurassic
  • skeletal features: secondary palate, 1 bone forming lower jaw, 3 bones in the middle ear
  • other features: hair, diaphragm, provision of milk, endothermy
120
Q

mammalian: explain monotremata

A
  • platypus and echidnas
  • lay yolked eggs
  • endothermic, but unstable body temps
121
Q

mammalia: explain marsupialia

A
  • born early then incubated in mother’s pouch
  • walls of pouch are supported by epipubic bones
122
Q

mammalia: explain placentalia

A
  • well-developed placenta
  • terrestrial, marine, and aerial
123
Q

placentalia: explain primates

A
  • arboreal
  • good eyesight
  • haplorhini: tarsiers, platyrrhines (new world monkeys), and caarrhini (old world monkeys
124
Q

what are the functions of the integument?

A
  • skin as a protective barrier: coloration, camouflage, and preventing desiccation
  • skin allows cutaneous respiration, excretion of wastes, and transfer of heat and moisture
125
Q

what are the derivatives of the integument?

A
  • defence: horns
  • insulation: hair, feathers
  • feeding: beaks, cheek pouches
  • sensory structures: whiskers, chemosensory buds
  • secretory glands
126
Q

what is the basic structure of integument

A
  • thick envelope that covers the body surface
  • epidermis
  • basement membrane that acts as a barrier
  • dermis
  • hypodermis
  • nerves, blood vessels, glands
127
Q

what are the layers of integument?

A

from top to bottom: epidermis, basement membrane, dermis, and hypodermis.

  • followed by muscle tissue
128
Q

explain the epidermis layer

A
  • derived from ectoderm
  • 2 layers of embryonic ectoderm: lower layer (stratum basale or stratum) produces new cells and upper layer is the periderm
  • upper part becomes keratinised in tetrapods, forming stratum corneum
129
Q

explain the dermis layer

A
  • deeper skin layer, containing capillary beds
  • function: stimulates cell division and differentiation in epidermis
  • derived from mesoderm
  • 2 layers: stratum spongiosum and stratum compactum
130
Q

what do mesoderms form?

A
  • somite or epimere
  • sclerotome: develops into vertebrata
  • myotome: develops into muscle
  • dermatome: develops into dermis, hypodermis, and lower basement membrane
131
Q

what do neural crest form?

A

pigment cells that contribute to dermis in facial region

132
Q

explain the epidermis in amphioxus

A
  • single, translucent sheet of columnar cells
  • larvae: ciliated
  • adult: epidermal glands secrete mucus
133
Q

explain the epidermis in larval lissamphibians

A
  • multiple stacked cells covered in mucous
  • non-keratinised, but with keratinous teeth
  • unicellular glands present
134
Q

explain the epidermis in adult lissamphibians

A
  • stratum corneum for cutaneous respiration
  • keratinised nuptial pads for reproduction
  • capillary beds that extend into lower epidermis
135
Q

epidermis of non-avian reptiles

A
  • 3 layers: stratum basale, stratum granulosum, and stratum corneum
  • shedding to prevent parasites on skin
136
Q

explain the epidermis in birds

A
  • keratinised stratum corneum
  • no mucus glands
  • 3 layers: basale, intermedium, corneum
137
Q

explain the epidermis in mammals

A
  • thick epidermis with 5 layers: stratum basale, s spinosum, s granulosum, s lucidum, s corneum
  • chromatophores, hair, scales are absent
138
Q

explain the dermis in aquatic vertebrates

A
  • stratum compactum: collagen fibres are in bundles and layers called plies
  • scales contain bony tissue
139
Q

explain the dermis in terrestrial vertebrates

A
  • contains collagen fibres but lacks clear layering
  • bony scales and multicellular glands present
140
Q

explain the dermis in mammals

A
  • thick, tough, and double-layered
  • upper layer contains collagen bundles and forms dermal papillae that intrude into epidermis
141
Q

what unicellular glands do fish have?

A
  • club cells that release warning substances
  • granular cells that contribute to the mucus layer
142
Q

what multicellular glands do hagfish have?

A

slime glands

143
Q

what multicellular glands do lissamphibia have?

A
  • larval: leydig cells that resist infection
  • mucus glands
  • poison glands
144
Q

what multicellular glands do non-avian reptiles have?

A
  • lizards: femoral glands
  • crocs, turtles: scent glands
  • for social signalling and predator defence
145
Q

what multicellular glands do birds have?

A
  • uropygial gland that secretes oily substance
  • nasal glands that excrete excess salt
146
Q

what multicellular glands do mammals have?

A
  • sebaceous: produces oil to lubricate skin and hair
  • sweat glands
  • mammary glands for milk
  • scent glands, pheromones
147
Q

what are some of keratinised structures in fish?

A
  • rasping teeth
  • breeding tubercles for courting and mating
148
Q

what are some of keratinised structures in reptiles?

A
  • epidermal scutes/scales
  • beaks and claws
  • feathers
149
Q

how do feathers develop?

A
  • from feather follicles
  • form in sheaths which unfurl
150
Q

what are the structures of a feather

A
  • vanes, barbs, and central rachis
  • not connected to vascular or nervous tissues
151
Q

define pterylae

A

arrangement of feathers on body

152
Q

what are the functions of feathers

A

flight, insulation, and display

153
Q

what are keratinised structure in mammals?

A

claws, nails, hooves, hair

154
Q

how does hair grow in mammals?

A
  • each hair grows form epidermal follicle rooted in dermis
  • arrector pili muscle causes hair to stand up straight
  • hair papilla stimulates hair growth
155
Q

what are the different hair arrangements?

A
  • pelage - fur with large guard hairs and small underfur
  • vibrissae
  • porcupine quills
  • rhino horn have hair-like keratin fibres
156
Q

how did hair evolve

A
  • pelycosaurs had keratinized epidermis and lacked hair
  • original function for insulation and tactile devices
157
Q

what are the parts of a horn?

A
  • bony core covered by keratin sheath
  • antlers are bare bones, no keratin sheath
158
Q

keratinized structure: explain baleen

A

filaments used to filter plankton from seawater

159
Q

keratinized structure: explain rattle

A
  • hollow segments that clash together when tail is shaken
160
Q

fish scales: explain placoid scales

A
  • elasmobranchii
  • tooth-like where it has enamel, dentine, and pulp cavity
161
Q

fish scales: explain cosmoid scales

A
  • sarcopterygii
  • enamel and a cosmine layer over bone
162
Q

fish scales: explain ganoid scales

A
  • basal actinopterygii
  • bone overlain by enamel
163
Q

fish scales: explain elasmoid scales

A
  • teleosts
  • cycloid (button-like) or ctenoid (fringe on edge)
164
Q

what are dermal bones proper?

A

superficial bones of the skull and lower jaw that is integrated into the rest of the skeleton

165
Q

what are the different kinds of pigment cells?

A
  • chromatophores from neural crest
  • epidermal in birds and mammals
  • dermal in other vertebrates
  • melanophores: melanin
  • iridophores: reflective
  • xanthophores: yellow
  • erythrophores: red
  • photphores: luminescent for communication and signals
166
Q

what are the functions of the skeleton?

A
  • internal framework and mechanical support
  • converts muscles contraction to body movement
  • protection
167
Q

what is the difference between endoskeleton and exoskeleton?

A
  • exo: bone formed within dermis
  • endo: forms deeper into the body
168
Q

where is cranial and post-cranial?

A
  • cranial: skull and lower jaw
  • postcranial: everything else
169
Q

examples of connective tissue

A
  • bone, cartilage, ligaments, tendons, adipose tissue, blood
170
Q

what materials do cartilage and bone have?

A
  • collagen fibres
  • cranial bones from neural crest due to mesoderm
171
Q

define calcification

A

deposition of calcium carbonate (invertebrates) or calcium phosphate in the form of hydroxyapatite (vertebrates)

172
Q

define ossification

A

form of calcification that produces bone tissue

173
Q

how do cartilage and bone mineralise?

A
  • bone is mineralised by ossification
  • cartilage may be mineralised by calcification
174
Q

what are the 3 categories of non-calcified cartilage?

A
  1. hyaline cartilage: coats limb bones, forming tracheal rings
  2. fibrocartilage: found in intervertebral discs that is resistant to tension
  3. elastic cartialge: found in the epiglottis and external ear, flexible
175
Q

what are the cell types associated with bone?

A
  • osteoblasts: produces bone
  • osteocytes: maintains bone
  • osteoclasts: destroys bone for modification
176
Q

what are the 2 structure classification of bone?

A

cancellous (spongy) and compact (cortical)

177
Q

what are the other classification of bone?

A
  • vascular vs avascular
  • cellular vs acellular
  • woven (fast-growing) vs lamellar (slow-growing vs haversian (lamellar bone forming osteons)
178
Q

explain the fibres of woven bones

A

collagen fibres are disorganised

179
Q

explain the fibres of lamellar bones

A

collagen fibres arranged in layers (lamellae)

180
Q

explain the fibres of haversian bones

A

fibres are arranged in concentric tubular shells, forming osteons that surround blood vessels

181
Q

what is line of arrested growth (LAG)

A

line that shows period of interruption in bone deposition

182
Q

what is endochondral bone?

A
  • develop from mesenchyme (mesoderm)
  • composed of hyaline cartilage, which later ossifies
  • deep parts of skull, most of postcranium
183
Q

what is intramembranous bone?

A
  • develop from mesenchyme (mesoderm)
  • direct formation of bone from mesenchyme
184
Q

what are the components of long bones?

A
  • diaphysis (shaft)
  • epiphyses (ends)
  • metaphyses (regions of growth)
185
Q

what are the 2 types of intramembranous bone?

A
  • dermal: forms integument
  • sesamoid: forms in tendon to provide support and improve mechanical properties
186
Q

what to intramembranous bone contribute to?

A

vertebrate in teleosts

187
Q

define diarthrosis

A
  • synovial joint that is mobile and is in contact with bone surfaces covered in hyaline cartilage
188
Q

synarthrosis: define syntosis

A

fusion between two bones

189
Q

synarthrosis: define synchondrosis

A

bones connected by fibrocartilage

190
Q

synarthrosis: define syndesmosis

A

bones connected by fibrous, non-cartilaginous tissue

ZOOL 325 (6 decks)

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