Exam 1 Flashcards
1
Q
Monophyletic group
A
A clade, all organisms in a lineage plus the ancestor they have in common, therefore a natural group
can be separated from root with single cut and includes ancestral taxon and all of its descendants
2
Q
paraphyletic group
A
an incomplete clade resulting from removal of one or more component lineages. clade originating from a single common ancestor but does not contain all descendants from this ancestor
2
Q
polyphyletic group
A
an artificial group characterized by features that are not homologous. organisms that are grouped together despite not being closely related, often include organisms that have similar traits or appearances but do not share an evolutionary history
3
Q
Taphonomy
A
the study of how organisms decay and become fossils
4
Q
absolute (radiometric) dating
A
Where radioactive isotopes decay at a constant rate (half life) comparison of relative amounts of parent and daughter isotopes in igneous rocks ex) argon accumulates from decay of potassium
5
Q
Relative (stratigraphic dating)
A
uses stratigraphy and law of superposition, stratigraphy is the branch of geology that studies the succession of rock layers (strata) as well as the origin, composition, and distribution of these geological strata
6
Q
index fossil
A
hard bodied fossils that we know are constrained to a particular time horizon
7
Q
taxonomy
A
principles and practice of naming organisms and groups of organisms
8
Q
classification
A
principles and practice of ordering diversity for information storage and retrieval
9
Q
Law of Superposition
A
in undeformed strata, the oldest rocks will be at the bottom and the youngest at the top, used to reconstruct chronology of events one location at a time
10
Q
principle of fossil correlation
A
biostratigraphy, similar assemblages of fossils assumed to be the same age, therefore, the rock layers in which they are deposited must also be the same age. Uses index fossils
11
Q
How does Linnaean classification work?
A
Animal taxonomy, binomial system of biological nomenclature, hierarchy is nested, based on similarities in obvious physical traits, puts groups in taxa (a group of organisms that are classified as a unit, subjective, relies on physical traits, ranks are not meaningful
12
Q
How do we write Linnean classification
A
Homo sapiens (itallicized)
Homo->genus
sapiens-> species
13
Q
order of geologic periods
A
cambrian->ordovician->silurian->devonian-> carboniferous-> permian-> MESOZOIC ERA (triassic, jurassic, crestaceous)-> CENOZOIC ERA
14
Q
cambrian period
A
warm, lots of water, oxygen=large multicellular life, cambrian explosion
15
Q
ordovician period
A
very high sea level, cold at end, mass extinction at end, vertebrates with bony skeletons
16
Q
silurian period
A
first terrestrial ecosystems (swamps with plants, arthropods) lots of mountain building, fish, reefs
17
Q
Devonian period
A
shallow tropical habitat, continents start to converge, ends with mass extinction (40%), many fish groups diversify (tetrapods), trees originate and begin to diversify
18
Q
Carboniferous period
A
lots of trees (creates massive coal deposits) swampy and lots of early tetrapods diversify
19
Q
permian period
A
large early tetrapods, amphibious, split between amphibians and amniotes (amniotes further diverge into reptiles and synapsids)
20
Q
Mesozoic Era
A
Triassic, Jurassic, Cretaceous periods
pangea breaks up, high sea level by cretaceous and very warm, mass extinction at end of cretaceous, new groups cynodonts (early mammal relatives), mammals, lepidosaurs, archosaurs
21
Q
Cenozoic Era
A
Eocene epoch to present
diversification of modern groups, tetonic movement created land bridges, ocean circulation patterns, in Pleistocene period there were megafuna (which then went extinct)
22
Q
Geologic periods anagram
A
Can Oprah Sell Dented Cars Please Mom Check
cambrian, ordovician, silurian, devonian, carboniferous, permian, mesozic, cenozoic
23
Q
How does radiometric dating work
A
radioactive isotopes decay at a constant rate (half life) comparison of relative amounts of parent and daughter isotopes in igneous rocks (formed by crystallization at higher temps) comparison to known have live to establish absolute ages of rock formation
ex)argon is a chemically unreactive gas, rocks form without argon content, argon contant accumulates overtime with the decay of potassium, measure ratio K:Ar and use half life to date
24
How do we use synapomorphies and plesiomorphies to refer to characters on a cladogram
Synapomorphies: a shared derived characteristic that unites two or more taxa into a monophyletic group, phylogenies are inferred using synapomorphies
Plesiomorphies: an apomorphy of a more inclusive hierarchal level than those being considered. an ancestral or primitive characteristic
* a synapomorphy is a recent shared trait, a pleisiomorphy is more ancestral trait
25
Crown group
a clade that contains all living members of a group adn any fossils within it
26
stem group
extinct taxa that are more closely related to the crown group than any other group, but fall outside of it
27
Total Group
the group including both stem and crown group
28
what are some characteristics that make an animal more likely to fossilize?
species with hard parts and living near water are most likely to fossilize (bones and teeth, aquatic organisms) soft tissues only preserved under exceptional circumstances such as rapid burial, fine grained sediments, and anoxic conditions
29
What processes of taphonomy is fossilization working against
Taphonomy is the study of how decay and tissue disintegration affect fossilization. fossilization has to happen because of rapid burial, freezing, embedding in amber, and desiccation (all of these protect from decay, weathering, scavenging).
30
Discuss the difference between homology and analogy, give an example of each
homology: two or more features that share a common ancestor
analogy: features with similar functions but no common ancestor, evidence of convergent evolution (distantly related organisms independently evolve similar traits to adapt to similar necessities)
An example of an
31
What are the different parts of a cladogram? What relationship tells you how closely two taxa related to one another?
root (start of tree) nodes(where two branches split off) tips (top of tree) branches (each split group) **just look at picture** phylogenetic trees are built using characters (genes, development, behavior) and can show us how closely related two taxa are. The most closely related taxa are known as sister taxa
32
Describe the major innovations that characterize vertebrates. What were the anatomical changes and why were they beneficial?
A cranium is present- skeletal container and support for brain and sensory capsules this houses and protects the brain and neural crest cells migrate from CNS and give craniofacial skeleton, brain with tripartite organization (forms distinct brain which includes forebrain, midbrain, and hindbrain), vertebral elements surrounded the notochord (separated by intervertebral disks, neural and hemal arches, centrum replaces notochord)
33
What are neural crest cells and why are these cells so important to vertebrates?
Neural crest cells migrate down the head and trunk in streams from the central nervous system,
and give rise to most of the craniofacial skeleton in
vertebrates, also pigment cells, parts of nervous system. These cells are so important because they readily proliferate and migrate to give rise to a diverse variety of craniofacial structures
34
What are major character transformations that occured during the transition from fishes to tetrapods? How were they useful for adapting to a terrestrial lifestyle
skull changes (pectoral girdle disconnects from skull to form neck which gives more movement, rounded head becomes flatter head which allows for better sight out of water, loss of opercular and temporal skull bones) pelvic girdle forms (specialzed sacral vertebrae to connect hind limbs) and fins become limbs with digits (7-8) instead of fin rays. Also, lungs become more developed to breathe air and scales are reduced or absent
35
Embryonic germ layers
ectoderm (outer), endoderm (inner), mesoderm (middle)
36
Ectoderm
gives rise to cells that become the CNS, PNS, sensory organs, epidermis, hair, and nails
37
Endoderm
gives rise to mucous membrane lining digestive and respiratory tracts, digestive glands, other things
38
mesoderm
becomes gelatinous tissue called mesenchyme, gives rise to cartilage, bone, blood, muscles, connective tissue, heart, blood vessel, and kidney
39
what are the differences between protostomes and deuterostomes
Protostomes: spiral cleavage, blastopore forms mouth, mesoderm splits to form coelom
Deuterostomes: Radial cleavage, blastopore forms anus, coelom forms from gut outpocket
40
What are the major chordate synapomorphies and which are present in each group of protochordates we talked about
the 5 chordate characters are pharyngeal slits, notochord, nerve chord, endostyle and post anal tail
hemichordates have pharyngeal slits and a nerve chord
cephalochordates and urochordates have all 5
Urochordates are sister group to vertebrates
41
Jawless fishes -> gnathostomes
Jaws, paired pectoral and
pelvic fins, segmented
pharyngeal arches, paired
nasal openings
42
Actinopteygians (ray fins) vs sarcopterygians (lobe fins)
Musculature on body wall vs
fin, shoulder girdle connects
to many rays (radials and
lepidotrichia) vs to single basal
element
43
actinopterygians-> teolosts
Homocercal tail, circular scales
without ganoine, kinetic skull
44
Early amphibians -> amniotes
Egg with amniotic membrane, specialized
ankle bone (astragalus)
45
Dinosaurs -> birds
Character transformations leading to birds: feathers further developed for flight, hollow bones, fused clavicles (furcula = wishbone)
46
Characters present only in birds
pygostyle, synsacrum, carina/keel for flight
muscle attachment (lots of fusions)
47
amniotes->mammals
Sprawling to upright posture, jaw bones
move to ear, hair and milk glands
48
Hemichordates
share deuterostome pattern of cleavage and coelom formation, have pharyngeal slits and a nerve chord, terminal anus, three part body plan, enteropneusts and pterobranchs
49
Cephalochordates
rate marine environments Dorsoventrally inverted compared to hemichordates Characters: pharyngeal slits, hollow nerve chord, notochord,
postanal tail Relatively simple anatomy - headless wonder?
suspension feeders with oral hood and cirri, closed circulation but no heart just contractile vessels
50
urochordates
Have all five chordate characters: pharyngeal slits,
notochord (hollow), endostyle, hollow nerve cord, postanal
tail
* Have flexible outer body cover, a tunic and branchial basket
for filter feeding
* All species are marine
* Ascidians = swimming larvae, sessile adults
* Larvacians and thaliaceans = permanently pelagic
51
Notochord
Mesodermal
Rigid but flexible rod of cells and fluid, encased in a fibrous
sheath
Allows lateral flexion but prevents collapse during
locomotion
Ventral to nerve chord; dorsal to body cavity
52
pharyngeal slits
endodermal
* Pouches in the anterior end of the gut (pharynx)
* Mucus production
* Supported by a basket or other skeletal apparatus
* Functions in respiration and feeding
53
endostyle/thyroid gland
endoderm
* Likely homologous structures between chordates and
vertebrates
* Endostyle - glandular groove in floor of pharynx
* Involved in filter feeding
* Thyroid gland – endocrine gland that produces hormones
* Arises embryologically from groove in pharynx
* Both involved in iodine metabolism
* Example: lamprey with endostyle in juvenile and thyroid in
adult
54
Nerve cord
ectoderm
* Formed from folding/invagination of the neural plate
* Dorsal to the gut and notochord
* Hollow throughout its length
55
Postanal tail
ectoderm and mesoderm
Body extension beyond the level of the anus/posterior limit
of the gut
* Includes muscles, skeleton, notochord
* Functions in aiding locomotion
56
proboscis
found in enteropneusts, fleshy structure protruding anterodorsally over the dorsal surface of the snout in front of the nostrils.
57
Collar
found in enteropneusts (acorn worms), short fleshy collar that is used to bury in mud
58
Trunk
the body without the limbs
59
Oral/buccal cirri
feeding structures found in the oral hood of primitive jawless organisms called amphioxus
the first filter during feeding by eliminating unwanted large or noxious particulate
60
Tunic
firm but flexible body covering of tunicate
61
branchial/pharyngeal basket
the cartilaginous structure supporting the gills in protochordates and lower vertebrates plays an important role in food chewing, processing, and transport. found in urochordates and cephalochordates
62
Cranium
Structure made of bone and/or cartilage that houses and protects the brain, vertebrate innovation
63
Tripartite brain
vertebrate innovation
neural tube enlarged to form distinct brain (forebrain, midbrain, hindbrain)
64
Vertebral column
vertebrate innovation
Skeletal elements that surround
notochord
* Separated by intervertebral discs
or fibrous rings
* Neural and hemal arches
* Can include centrum that replaces
notochord
* Notochord reduced to
intervertebral space – nucleus
pulposus
65
Ostracoderms
Fossil jawless fishes
Bony shields, complex eye muscles, lateral line system
first appearance of paired fins with endoskeleton
66
Placoderms
fossil ganthostomes, encased in dermal armor, jaws with gnathal plates
67
pelvic claspers
elongated modifications of the pelvic fins, allows for facilitation of sperm transfer, originates as a chondrichthyan character
68
acanthostega and ichthyostega
Oldest known tetrapods: many digits,
sensory canals on skull, rudimentary
sacrum, notochord present in adult part of labyrinthodonts
69
Describe the different categories of skull fenestration, and the major groups they are found in
Diapsids – two skull fenestrae
* Early reptile relatives, Lepidosaurs (modern reptiles), Archosaurs (crocodiles & birds), and Turtles
* Synapsids – a single skull fenestra
Early mammal relatives, Modern mammals (Monotremes, Marsupials, Placentals)
70
turtles
Phylogenetic position uncertain, Ribs and bony scutes modified into dorsal carapace and ventral plastron, Pleurodires (lateral neck flexion) vs cryptodires (vertical neck retraction
71
Archosaur
Crocodiles + birds and all their ancestors, Includes dinosaurs, pterosaurs, other extinct groups
72
Monotremes
egg laying, platypus and echidna
73
Marsupials
pouch to house altricial young, lots of convergence with eutherians
74
Eutharians
placenta (most mammals)
75
rhynchoecephalians (tuatara)
lepidosaurs that ARENT squamates
transverse cloacal slit, paired hemipenes, intravertebral divisions for tail autonomy
76
skeletal muscular tissue
Contains multiple nuclei, Striations — alternating dark and light
bands, Voluntary — under conscious control
77
Cardiac muscle
limited to the heart wall
Short and branched with one centrally located nucleus, Intercalated discs join cardiomyocytes end
to end to provide electrical and
mechanical connection, Striated and involuntary
78
Smooth muscle
fusiform cells lacking striations, Cells are shorter and have one nucleus, Involuntary, Most is visceral muscle — walls of hollow
organ
79
Epithelia cells
sheets of closely adhering cells, one+ cells thick, Covers body surfaces and lines body cavities, Upper surface usually exposed to the environment or an internal space in the body, Avascular (does not have blood vessels), Epithelial cells are very close together; have a high rate of mitosis
80
simple epithelia
contain one layer of cells, all cells touch the basement membrane
81
stratified epithelia
contain more than one layer, named by shape of cells, some cells rest on top of others and do not touch basement membrane
82
simple squamous
simple epithelia, thin, scaly cells
83
simple cuboidal
simple epithelia, square/round cells
84
simple columnar
simple epithelia, tall, narrow cells
85
pseudostratified cilliated columnar
simple epithelia, every cell reaches the basement membrane (but not all cells reach the free surface)
86
keratinized stratified squamous
stratified epithelia, think callouses
87
non keratinized stratified squamous
stratified epithelia, eyes, lips, vagina
88
stratified cuboidal
stratified epithelia, cube shaped
89
urothelium/transitional
stratified epithelia, stomach lining
90
Connective tissue
Most have lots of
extracellular matrix (ECM)
(adipose is exception)
* General: consist of
fibroblasts
* Loose – mesenchyme,
adipose, areolar
* Fibrous – dense regular and
irregular
* Special : cartilage, bone,
blood, lymph
91
Areolar
loose connective tissue
loosely organized
fibers, abundant blood
vessels, and a lot of
seemingly empty space
* Fibers run in random
directions; mostly collagenous,
but elastic and reticular also
present
* Nearly every epithelium rests
on areolar tissue
92
reticular
loose connective tissue
mesh of reticular
fibers and fibroblasts
* Forms supportive stroma
(framework) for lymphatic
organs
* Found in lymph nodes, spleen,
thymus, and bone marrow
93
dense fibrous regular
connective tissue
densely packed,
parallel collagen fibers
* Compressed fibroblast
nuclei
* Elastic tissue forms wavy
sheets
94
dense irregular tissue
connective tissue
randomly arranged
collagen fibers and few
visible cells
* Withstands unpredictable
stresses
* In deeper layers of skin,
capsules around organs
95
adipose tissue
connective tissue (fat)
Tissue in which adipocytes are the dominant cell type
Fat is the body’s primary energy reservoir (triglyceride, recycled continuously)
White – main type, provides thermal insulation and cushions organs
Brown – in fetuses, infants, and children only; functions to generate heat
96
cartilage
connective tissue
chondroblasts produce matrice, chondrocytes are trapped cells, perricardium is dense irregular connective tissue surrounding elastic and hyaline cartilage
97
bone
osseous connective tissue
Bone cells: osteoblasts – build new bone, osteoclasts – remove existing bone,osteocytes – maintain bone
Also endochondral (preformed in
cartilage) vs intramembranous
(direct ossification)
98
spongey bone
porous appearance
* Delicate struts of bone:
trabeculae
* Found in heads of long bones
and middle of flat bones
99
lamellar bone
bone is deposited in
layers
* Typically slow-growing
* LAGs = lines of arrested growth
100
compact bone
denser, calcified
tissue with no visible spaces
* Found in shafts of long bones
(called cortical bone) and in
outer edges of flat bones
101
Non lamellar bone
collagen fibers
arranged irregularly in bone matrix
* Typically fast-growing
102
haversian bone
subtype of lamellar
* Arranged in cylinders that surround central canal
= osteons
* Blood vessels and nerves travel through central
canal, bone matrix is deposited in concentric rings
103
Hyaline cartilage
most common, not much collagen found in joins, respiratory tract, immature skeleton
104
fibrocartilage
reinforced with collagen fibers, exposed to tensile forces found in intervertebral discs, pubic sympysis, acetabular , foot and ankle
105
elastic cartilage
flexible, elastic fibers in matrix, ear larynx and epiglottis
106
neuroglia
glial cells, protect and assist neurons "housekeepers" of the nervous system
107
neurons
nerve cells, detect stimuli, respond quickly, and transmit coded
information rapidly to other cells
108
Neurosoma
part of neuron, cell body, houses
nucleus and other organelles;
controls protein synthesis
109
dendrites
part of neuron, short, branched
processes that receive signals from
other cells and transmit messages to the neurosoma
110
axon
part of neuron, nerve fiber, sends outgoing
signals to other cells;
111
epidermis
part of integument, ectoderm, Forms mucus in many vertebrates
* Stratum corneum for desiccation
protection
* Keratinized layer of dead cells
112
basement membranes
part of integument, ectoderm Layer between an epithelium and
underlying connective tissue
113
dermis
part of integument, Produces dermal bone w/ no cartilage precursor, Contains fibrous connective tissue and collagen, also contains pigment cells,Thicker than epidermis (usually), mesoderm
114
dermal scales
If scales are mostly formed from dermis (esp. ossified
dermal bone), fish scales
115
epidermal scales
Epidermal folds, esp. with thick keratin layer, lizard and bird scales
116
femoral glands
inside thighs of lizards, release pheromones
117
uropygial gland
birds, base of tail, secretes lipid and protein for preen
118
salt gland
birds, on the head, excretes excess salt from diet
119
sebaceous gland
mammals, oily secretion called sebum, globular in shape, Associated often with hair, but also other body parts, Outer ear canal, Meibomian glands of eyelid
120
eccrine gland
mammals, long, coiled invaginations of epidermis, produce thin and watery fluids On soles of feet, prehensile tails, areas that contact abrasive surfaces
121
apocrine gland
mammals, sweat, produce viscous,
lipid-like fluid at hair follicles
* Chemical signaling - scent
* Evaporation dissipates heat
* Example – mammary glands
122
Cosmoid
scales thick layer of dentin
beneath a layer of enamel
* Australian lungfish
123
Ganoid
shiny, overlapping,
interlocking with surface enamel
layer. No dentin
* Gars
124
Teleost scales
lack enamel, dentin,
and vascular bone layer. Retain
lamellar bone
* Cycloid – concentric rings (circuli)
* Ctenoid –margin has jagged edge
* New circuli are deposited as fish grows
(like tree rings), can be used to age fish
125
fish glands
Unicellular glands
Single specialized and interspersed (club
cell, goblet cell, sacciform cell)
* Thread cells of hagfish
126
Amphibians
Mucus glands - small clusters of cells -> one duct, Poison glands – larger and contain stored secretions
127
Reptile glands
femoral glands and scent gland in crocodiles and turtles (open into cloaca and/or mouth
128
bird glands
femoral, scent, uropygial, salt
129
mammal glands
sebaceous, eccrine, apocrine (mammary)
130
Feather structures
rachis (middle stalk)
vane (main feather soft part), Spathe (vane+rachis) Barb (each individual piece of feathery part), barbule (smaller fluffy pieces off each feather, interlocking detail), calamus (quill/base)
131
Flight feathers
Asymmetrical vanes
* On wings = remiges, on
tail = rectrices
132
Contour feathers
Symmetrical, aka
pennaceous, small feathers which form outline of bird's plumage
133
Down feathers
Aka plumulaceous, lack a
rachis, lots of fluffy barbs
134
filoplume
specialized feathers for display
135
dermal papilla
zone of proliferation, invaginates to form follicle
* Shh (sonic hedgehog) and BMP2 (bone morphogenetic protein 2) are turned
on in feather buds and direct development of barbs as epidermal ridges
136
feather follicles
develop embryologically, cells proliferate at base, protective sheath shields feather, successive pulp caps protect dermis, spathe slowly unfurls
137
placoid scales
no dermal bone, but enamel and dentin present (feel rough to touch) develop in dermis, project through epidermis to surface
138
Nuptial pads
on amphibians/frogs, found on digits or limbs, raised calluses of cornified epidermis that help male hold female
139
What are some examples of bony exoskeletons in tetrapods
armadillos/alligators have dermal amour made of dermal bone
140
arrector pili
muscle causes hairs to stand on end
141
nails
keratin plates to protect fingers
and toes (primates only)
142
Claws/talons
curved and laterally
compressed projections from tips of digits
143
Hooves
enlarged keratin plates on tips
of ungulate digits
144
Baleen
Keratinized plates originating
from dermal papillae
* Papillae extend and take
epidermis with them
* Epidermis forms cornified layer
of keratin
145
Melanophores
contain melanin, Melanosomes in cell house melanin
granules, Dermal – broad, flat cells that change color rapidly, only in ectotherms, Epidermal – thin, elongate cells prominent in endotherms – gives color to
hair and feathers
146
iridophore
contains light-reflecting,
crystalline guanine platelets – mostly
in ectotherms
147
Xanthophore
yellow pigments
148
Erythrophore
red pigments
149
How to vertebrates use melanophores to change their color?
Darker skin - Melanocytes produce greater quantities of melanin, Melanin breaks down more slowly, melanin granules more spread out in keratinocytes -> melanized cells seen throughout the epidermis
Lighter skin - melanin
clumped near keratinocyte
nucleus
* Little melanin seen
beyond stratum basale;
what is there breaks down
quickly
150
How is skin color determined in humans (both evolutionary and at a cellular level)
Evolutionary: Melanin in skin evolved as an adaptation to high levels of UV radiation, hemoglobin adds pinkish tint to skin
* Melanin blocks Vitamin D absorption
Cellular:UV exposure stimulates melanin secretion and darkens skin
* Color fades as melanin is degraded and old cells are exfoliated
151
Aposematism
Colors can warm predators
152
Chondrichthyans
no dermatocranium, cartilage braincase, two-point jaw articulation,
spiracle
153
Actinopterygians
highly kinetic skulls in teleosts, less so in earlier forms, skull rotates
to open mouth, pharyngeal teeth in many species
154
Sarcopterygians(lungfish)
many small dermal bones in fossil, lots of cartilage in living species, tooth plates
155
Sarcopterygians (coelacanth)
joint separating skull into two parts
156
Early tetrapods
heavy dermal bone nares
157
modern amphibians
reduction of dermal bones (orbital series and opercular series)
158
turtles
edentulous (no teeth), anapsid (lacks temporal opening)
159
Sphenodon
classic diapsid, not much kinesis, tooth specialization
160
Lizards
modified diapsid condition, most lizards and snakes have a quadrate with independent rotation known as streptosyly
161
lingual feeding in lizards
Hyoid apparatus (ceratohyal, basihyal,
ceratobranchials) has elongated lingual
process (Lp)
* A circular accelerator muscle wraps
around Lp
* Muscle contracts and squeezes the Lp as
it slides down, shoots the tongue out
162
snakes
highly kinetic skulls
163
Crocodillians
dominated by dermatocranium, secondary palate
164
birds
loss of some orbital and temporal bones, endentulous, rotational hinge in beak
165
monotremes
no lacrimal bone, edentulous
166
Eutherians/placentals
lots of fusions in skull bones, tympanic bulla, secondary palate
166
Enamal
hardest substance in the body
Only on crown
Deposited after tooth erupts
Epidermal (ectoderm)
166
Dentin
resembles bone but is harder
Distinguished by microscopic channels
Underlies enamel
Forms walls of the pulp cavity
Grows by daily apposition
Neural crest derived
166
Compare and contrast the two hypotheses of the origin of teeth. What does each say and what are the issues with each
Outside in: Teeth are derived from the bony scales of primitive fishes
As jaws evolved, scales along the margins moved inside the mouth to form teeth Similar developmental process but no transitional scale fossils have been found
Inside out: Teeth originated in the pharynx (endodermal) and progressed forward in the mouth
Many fish have pharyngeal teeth but there is tooth structures in placoderms which don't have pharynx
167
Cementum
bone-like
Rests upon dentin and grows layers on top of the annuli
168
pulp
inner layer of teeth, Supports blood vessels and nerves entering the tooth through the apical foramen.
169
apical foramen
tooth's natural opening, found at the root's very tip—that is, the root's apex—whereby an artery, vein, and nerve enter the tooth and commingle with the tooth's internal soft tissue, called pulp
170
Homodont
all teeth are the same
171
Heterodont
different tooth shapes in one animal, more common, humans
172
Polyphyodont
teeth continuously replaced, ex sharks
173
Diphydont
most mammals, teeth replaced once Deciduous/milk teeth are first set, permanent teeth are second set
174
Thecodont
deeply sunken into bone sockets (mammals and archosaurs)
175
Acrodont
shallow sockets on edge of jaw (snakes)
176
Pleurodont
teeth attached to medial side of dentary (lizards)
177
Bunodont
rounded peaks, generalized
178
lophodont
cusps draw out into ridges (rodents and perissodactyls)
179
selenodont
crescent shaped cusps (artiodactyls), deer cows camels hippos
180
Mammal tooth types
incisors, canines, premolars, molars can write formula as fractions with top being upper teeth and bottom being lower teeth and then I, C, P, or M
181
Edentulous
no teeth at all, turtles birds and whales
182
Describe the difference in development of endochondral bone and intramembranous ossification
Intramembranous ossification occurs "within a membrane," specifically within mesenchyme, which are connective tissue stem cells; mesenchyme is directly replaced with bone tissue. Endochondral ossification occurs inside cartilage; mesenchyme differentiates into cartilage, which is then replaced with bone tissue.
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what components make up cranial skeleton and what make up post cranial skeleton?
Cranial: skull
postcranial: vertebrae, limbs, all parts of skeleton that are not skull
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Paleostyly
Jaw suspension, none of the arches
attach to cranium = agnathan
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Euatostyly
jaw suspension,mandibular arch is
suspended by itself = extinct
placoderms (primitive autostyly)
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Amphistyly
two attachments: an
anterior ligament connecting
palatoquadrate to braincase, and
hyomandibula = early fishes
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Hyostyly
jaw suspension, jaws attached primarily through hyomandibula =
chondrichthyans & actinopterygians
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Metautostyly
jaws are attached
directly through quadrate =
tetrapods, lungfish, holocephalans
(secondary autostyly
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Craniostyly
upper jaw incorporated
into braincase = mammals
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hyoid arch evolution from fish to tetrapods
fish: Hyoid arch consists of hyomandibula and ceratohyal – helps to connect the jaw to the braincase
tetrapods: The hyomandibula separated from the
ceratohyal and was reduced
**The function changes from jaw
suspension to hearing, and the
hyomandibula becomes the stapes
(aka columella) in tetrapods
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Hyoid arch evolution in mammals
The bones of the hyoid arch and lower jaw have been further modified form the bones of the middle ear (quadrate = incus, articular =malleus, hyomandibula = stapes)
* The dentary takes over and becomes the only
lower jaw bone in mammals
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Synovial joints
permits considerable movement
* Capsule with walls of dense fibrous
tissue
* Lined by a membrane that secretes a
lubricant = synovial fluid
* Knee, elbow, jaw etc.
* Most structurally complex type of
joint
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Synathrosis
restricts movement, synotosis (bone fusion), synchondrosis (cartilage, symphyses), syndesmosis (fibrous, sutures)
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Chondrocranium
underlies and
supports the brain, is formed of
endochondral bone and/or
cartilage Four regions: ethmoid (nasal capsules), orbital (eyes), otic
(semicircular canals and inner ear), occipital (posterior brain)
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Splanchnocranium
visceral cranium) – most ancient part, first arose to support pharyngeal slits in protochordates
Mandibular arch (palatoquadrate +
quadrate/epipterygoid + articular in teleosts), Hyoid arch (hyomandibula + ceratohyal + basihyal, sometimes), Branchial (gill) arches
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Dermatocranium
dermal bones
making up the outer casing of the
skull
197
Spiracle
reduction of first gill slit, found in chondrichthyans, brings water into gills
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Metakinesis
hinge is at back of skull (lizards)
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Mesokinesis
hinge is behind orbit (burrowers)
200
Prokinesis
hinge is in front of orbit (snakes and brids)
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Streptostyly
quadrate with independent rotation, in most lizards and snakes
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Nuchal crest
back of skull on either side for muscle attachments, placental
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sagittal crest
center of skull for muscle attachment, placental
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Secondary palate
Includes hard palate of bone and posterior continuation, a soft palate
Separates food chamber from respiratory chamber
Important for chewing since food stays in mouth for longer
Mastication doesn’t
impede breathing
Precise tooth occlusion= loss of kinesis
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5 vertebral regions
cervical (neck) thoracic (chest) lumbar (no ribs) sacral (pelvic girdle) caudal (tail)
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Monospondyly
one centrum/body segment (cat)
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diplospondyly
two centra/body segment (bowfin)
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Acoelous
cavity, centra with flat ends (mammals)
Receive and distribute compressive forces within the vertebral column
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Amphicoelus
each surface is concave (fish, salamanders)
Limited motion in most directions
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Procoleus
concave anteriorly and convex posteriorly (frogs, some reptiles)
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Opisthocoelous
concave posteriorly and convex anteriorly (gar)
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Heterocoelous
saddle-shaped articular surfaces at both ends (cryptodire turtles and bird cervicals)
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Intervertebral discs
(mammals only): fibrocartilage disc with nucleus pulpous center
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transverse processes
general term for lateral projection from the vertebrae
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Diapopyses
lateral projections of vertebrae for attachment of upper rib head (tuberculum)
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Parapophyses
lateral projections of vertebrae for attachment of lower rib head (capitulum)
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Basapophyses
paired ventrolateral projections that are remnants from the hemal arch bases
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Zygapophyses
articulations between successive vertebrae, divided into pre- and post-
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True ribs
meet ventrally with sternum
Sometimes include vertebral/costal segment and sternal segment
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False ribs
articulate with each other and not sternum
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Floating ribs
false ribs that articulate with nothing
222
Rhachitomous vertebrae
centra separated into two parts (in early tetrapods)
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Gastralia
abdominal ribs, posterior to sternum, found in some lizards, crocodilians, Sphenodon
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Plastron
lower ventral part of shell
in turtles – includes clavicles, interclavicle, dermal ventral elements
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Major variations in vertebrae across vertebrates
Early fossil fishes had no centra, just arches
- Lack of centra persists in a handful of living fish groups (jawless fishes, sarcopterygians,
non-teleost actinopterygians like sturgeon)
- Most fish have amphicoelous vertebrae, fused into one unit
- Modern tetrapods – atlas (in all) and axis (in amniotes) – what do they do?
- Snakes – extra articulations (zygosphene and zygantrum)
- Birds have lots of fusion – synsacrum, pygostyle
- Mammals have 7 cervical vertebrae (except for sloths and manatees/dugongs)
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Heteroceral
caudal fin type, vertebral column (VC) turns upward and into dorsal lobe of caudal fin
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Diphyceral
caudal fin type, VC extends straight back, fin is symmetrical around it
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Homoceral
equal lobes and appears symmetrical, but narrow VC slants up to form dorsal edge
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Stylopod
upper arm and thigh
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zeugopod
forearm and shank
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autopod
wrist and digits
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manus
autopos of forelimb
233
pes
autopod of hind limb
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What are the two major hypotheses of paired fin origins, and what do they say? What are the major issues with each?
Gill-arch hypothesis: gill rays on posterior gill arch expanded and grew out to give rise to fin, Lots of developmental evidence, Not many living fishes have gill rays (just sharks/skates/rays), What about pelvic fins?
Fin-fold hypothesis: continuous ventrolateral folds grew out and later subdivided to form paired fins
Some fossil fishes show fin flaps
Not much developmental evidence for this, unless median fins are used as a proxy for lateral fin folds
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How are the pectoral and pelvic fins/girdles different in actinopterygian fishes?
**postemporal bone connects girdle to skull which limits movement of head without vertebral movement
**pelvic girdle is not fixed in place in actinopterygians
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Feathers and hair are both keratin based integumentary structures. How are feather development and hair development similar? different?
Hairs originate from epidermal follicles that grow down into the dermis, the middle layer of the skin. Unlike hair, Feathers grow from an outgrowth of the epidermis. Follicles develop as raised papilla filled with dermal cells, feathers remain attached until they are pushed out by new feathers
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What is a major trend in pectoral girdle arrangement from fish to tetrapods?
Paired fins or limbs + girdles (attach them to vertebral column) in fish
Early tetrapods have lost skull articulation and have lost bones connecting girdle to skull
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What trends in digit morphology can be seen in tetrapods
Early tetrapods are polydactyly (more than 5 digits) but then reduced by the time of vertebrates to mostly be pentadactyly (5 digits), ungulates, and 3/4 in birds
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Ceratotrichia
Fin rays in chondrichthyans, cartilage
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Lepidotrichia
fin rays in osteichthyans, bone
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Pterygiophores
part of fin that articulates fin rays to girdle or other part of body (can be median too)
Basals = proximal
Radials = distal
242
Archipterygial
axis runs through center fin
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Metapterygial
axis is located posteriorly in fin, most radials project towards preaxial side
244
Aquatic
swimming
245
Cursorial
running
246
salatorial
hopping
247
Aerial/volant
flying
248
Arboreal
tree dwelling
249
brachiation
using arms to swing from tree to tree
250
Scansorial
climbing using claws
251
Fossorial
burrowing
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How did limb posture in amphibians vs mammals affect locomotion and transmission of ground forces on skeleton
Sprawled posture: lateral undulations of the vertebral column with overarm swing
Adductor muscles (which run from girdle to limb) are massive to lift and hold body in pushup position
Upright posture: mammal limbs adducted under their body, increases the ease and efficiency of limb swing during rapid locomotion (like a pendulum)
Dorsoventral instead of lateral undulations
Reduced adductor musculature
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Unguligrade
only hoof touches ground (tip of one or two digits; deer, horses)
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Digitigrade
Only digits bear weight (cats) just phalanges
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Plantigrade
entire sole of foot contacts ground (humans)
ankle bones to toe bones
256
Asymmetrical gait
when footfalls are unevenly spaced
cantor: leading and trailing pattern
trot: diagonal limbs are moved together
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Symmetrical
footfalls spaced evenly
pronk: all four feet strike in unison
bound: hindfeet launch and animal lands on forefeet in unison
258
Primary wings
attach to manus, provide forward thrust
(more distal attachment)
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Secondary wings
attach to forearm, provide lift (closer to body) passive like airplane
260
what morphological changes are often seen in the limbs of secondarily aquatic tetrapods?
Reduction of limbs or modification of limbs into fin-like structures
Webbing
Elongation and thickening of propulsive limbs
261
How do skeletons of running vertebrates change their speed?
Stride length, Stride rate, Reduce amount of time limb contacts ground
can lengthen distal limbs, extensive flexion of vertebral column
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Gliding
minimizing drag and using lift
263
Parachuting
maximum drag (biggest surface area to slow fall)
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What are the three hypothesis for origin of flight?
arboreal hypothesis (dinos climb in trees and use feathers to parachute which then learn to fly)
Insect-net hypothesis (feathers for capturing prey which then grew and allowed for flight)
Wing assisted incline running (WAIR) birds flap wings while running up trees
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What adaptions are useful for burrowing/fossoriality?
Stout and robust bones
Short forearm and hand, long elbow to maximize mechanical advantage
Mole forelimbs
Heavily fortified skulls
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How did forces on vertebrae and limbs change with the transition from water to land? How did this affect digit orientation
Direction of digits changed to accompany limb position and enable more efficient terrestrial locomotion
Femur/humerus twisted anteriorly
Seen in early tetrapods
this leads to digits shifting form being at side to swinging forward
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What morphological adaptations are advantageous for quick bursts of speed vs substained running? give an example of a vertebrate that uses teach type of running
Crocodiles: run at upright posture because of crurotarsal joint
Cheetas: short speed Extensive flexion of vertebral column increases speed Body mass is displaced vertically, takes a lot of energy (very muscular limbs)
Horses: long speed Less vertebral flexion; keeps mass more linear
Uses much less energy (muscles closer towards body)
