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Flashcards in Chordates Deck (469):
1

Chordate zoology is what type of biology

whole-organism biology (not just cell, function, form,.. everything)

2

organismal biology

research at the level of the whole organism, integrated over structure, function, ecology, and evolution

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organism structure

anatomy, morphology

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organism function

physiology, behaviour

5

evolution

phylogeny

6

functional morphology

focuses on the link between form (morphology) and performance

7

ecological morphology

focuses on the link between performance and ecology (ecomorphs, ecomorphotypes)

8

ecomorph

species with the same structural habitat/niche, similar in morphology and behavior, but not necessarily close phyletically

9

ecomorphotype

Any morphological modification caused by, or related to, specific ecological conditions

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integrative biology

near synonym for organismal biology; brings different aspects of organisms and their environment together

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comparative biology

an area of research that attempts to explain biodiversity and its adaptive radiation in a phylogenetic (historical) framework (comparative method)
how phylogeny tests/explains hypotheses

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natural history

scientific study of the organism in its natural surroundings

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kinds of chordates

Tunicata
Cephalochordata
Vertebrata

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Tunicata includes

tunicates and sea squirts

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Tunicata was formerly called

Urochordata (also protochordates- not valid taxonomic name)

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Cephalochordata includes

lancelets (amphioxus)

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Numbers of chordate species

Tunicata - 2150
Cephalochorddata - 25
Vertebrata - 63 600
*numbers are always changing

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tunicates

free-living larva, sessile adult

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shared characteristics of chordates

notochord
dorsal hollow nerve cord
pharyngeal gill slits
endostyle
muscular postanal tail

20

notochord

incorporated in vertebral column in vertebrates
stiff, flexible rod, runs length of back, provides connections for body muscles, and support

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dorsal hollow nerve cord

spinal cord with brain at anterior end in vertebrates

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pharyngeal gill slits

slits in pharynx/throat region through which water passes and food particles are filtered out, involved in filter-feeding and gas exchange
retained in fish- gas exchange
tetrapods- gill slits disappear in adults
gill arches become jaws and other structures in vertebrates

23

endostyle

ciliated groove before larynx
secretes mucus to trap food
homologous with thyroid gland in vertebrates

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muscular postanal tail

extension of the body that runs past the anal opening
only present in embryonic stage of humans

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paedomorphosis

retaining juvenile characteristics into adult hood

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sister group to vertebrates

urochordata (most current theory)
vertebrates and urochordates are sister group to cephalochordates

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pattern vs. process

phylogeny vs. scenario
current phylogenetic theory (pattern), process (scenario) yet to be determined

28

myomeres

blocks of skeletal muscle tissue found commonly in chordates. commonly zig-zag, "W" or "V"-shaped muscle fibers

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possible first chordate

Pikaia

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aspects of morphology (anatomy)

comparative
functional
transitional

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comparative morphology

similarities/differences between groups
ex. heart

32

functional morphology

how organisms are equipped to deal with different situations

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transitional morphology

macroevolutionary change- how we go from one form to another

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why study chordates

intrinsic interest
vertebrates are us
diversity
evolutionary record
model organisms

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chordate diversity

masses range from 10^-4 - 10^5 kg! (larva to blue whale)
altitudes range 58km- deep ocean - over himalayans

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why evolutionary record is important for studying chordates

they have the best preservation of all organisms

37

model organisms

amphibians- developmental biology
birds- population biology

38

vertebrates characteristics

internal skeleton
vertebral column with cranium at anterior
spinal nerve cord with brain at anterior
neural crest
HOX genes

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vertebrate internal skeleton

bone and/or cartilage

40

vertebral column

individual vertebra, skull at end
rudimentary in lampreys
lacking in hagfish
full formed in gnathostomes

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gnathostomes

jawed vertebrates

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neural crest

cells/tissue- formed during embryonic development and migrate to head

43

HOX genes

do exist in inverts but more important in vertebrates
vertebrates have the most HOX genes

44

"grades" of vertebrates

"fishes"
Tetrapods

45

paraphyletic

composed of some but not all members descending from a common ancestor

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fishes

paraphyletic- would be monophyletic if we include all groups that have come from fishes (including us)
31,000 species
mainly Osteichthyes

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groups in fishes

Agnathans
Chondrichthyes
Osteichthyes

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Agnathans

jawless vertebrates- hagfish and lampreys, Ostracoderms

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Chondrichthyes

cartilaginous fish- sharks, rays, ratfish

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Osteichthyes

bony fish
Crossopterygii, Actinopterygii

51

Cossopterygii

Actinistia + Dipnoi (lobe-finned fish- coelacanth + lungfish)

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Actinopterygii

ray-finned fish (most fish)

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Tetrapods

all the rest of the vertebrates
4 feet, lots of secondary loss examples

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Tetrapod examples

Amphibia
Amniota
Aves
Mammalia

55

Amphibia

7000 species
lissamphibians- apodans salamanders, anurans

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Amniota

amniotes-- Reptilia

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Reptilia

10,000 species- turtles, crocodiles, tuataras, lizards, snakes, amphisbaenians

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Aves

10,000 species
directly derived from reptiles, make reptiles a non-taxonomic group

59

Mammalia

5500 species- mammals
mostly placentals, some monotremes and marsupials

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Ectotherms

"fishes"
amphibians
"reptiles"

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endotherms

generate own body heat metabolically
birds
mammals

62

Amniotes

"reptiles"
birds
mammals
(taxonomic group)

63

Anamniotes

"Fishes"
Amphibians
(not a taxonomic group)

64

Sauropsids

"reptiles"
birds

65

synapsids

mammals

66

lampreys

Agnathan- parasitize other fish

67

Fossil Agnathans

Ostracoderms- coats of bone armour, very different from living fish

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Gnathostomata

defined by presence of jaws with teeth
usually have limbs

69

thought to be closest living relative of tetrapods

lungfish (3 species)

70

tetrapoda

limbs with digits for terrestrial locomotion
internal nostrils
tympanic membrane and stapes
strong skeleton

71

internal nostrils

breathing through nose
fish do not breath through nose (except lungfish)

72

tetrapod tympanic membrane and stapes

to detect airborne sounds- ear drum
in fish stapes supports skull, in tetrapod it is main bone by which sound is transported into inner ear

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tetrapod strong skeleton

support against gravity (adaptation to terrestrial life)

74

Lissamphibia

3 major, distinct morphological groups
thin skin
complex life cycle
numerous departures from theme

75

Lissamphibia thin skin

highly permeable
respiratory gas exchange- skin covered in mucus to facilitate exchange
water exchange- drink by skin, lose water through skin-- restricted to moist habitats

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Lissamphibia complex life cycle

includes metamorphosis
aquatic egg-- aquatic larva-- aquatic/terrestrial juvenile and adult

77

Amphibian groups

salamanders
anurans
apodans

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Salamanders

mostly north temperate zone
mostly elongate body
mostly limbed- some highly reduced
some permanently aquatic retain larval form, some bipass larval form- direct development, lay eggs on ground, hatch into full formed adult
some pedomorphosis, have gills

79

Anurans

hyper developed back legs
aquatic/terrestrial/arboreal (ex. tree frogs climb w/ suction cups)
no paedomorphic frogs
some cut out larval stage
larval/adult generally radically different

80

unique Anuran forms

one species- female swallows eggs and they develop in her stomach

81

Apodans

(Caecilians)
superficially resemble earthworms/snakes
mostly live hidden in the ground, least familiar order of amphibians, smallest group, carnivores, large mouth
aquatic/burrowing/nocturnal/terrestrial
some have complex lifestyle, some direct development
live bearing- no placenta, hyper developed gills, mostly viviporous

82

Amniota

amniotic egg- amniote surrounds embryo
exclusively internal fertilization

83

allantois

waste dump, highly vascularized (blood vessels)
develops to line membrane surrounding the egg- transport system for gas exchange

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amniote shell

holds eggs together, has mating consequences- necessitates internal fertilization, must develop on land (oviparity)

85

oviparity

Oviparous animals are animals that lay eggs, with little or no other embryonic development within the mother

86

Reptilia

not a taxon group
thicker skin, covered with epidural scutes (keratin)
much more terrestrially adapted, lose water slower

87

scutes

scales
keratin provides mechanical protection, defense against water loss, protection of lipids

88

"reptile" groups

turtles
tuataras
lizards
amphisbaenians
snakes
crocodilians

89

turtles

only vertebrate in which ribs are outside
lots of aquatic, some marine, some terrestrial

90

Tuataras

endemic to New Zealand, highly restricted, resemble most lizards, part of a distinct lineage
long, slow life style, last remaining species of diverse group

91

"lizards"

biggest group of "reptiles"
very diverse, worldwide, terrestrial, arboreal
lots of long slender bodies w/o limbs

92

Amphisbaenians

derived from lizards, sometimes called worm lizards
burrowing species, swim, mostly tropic, some subtropic, mostly lack limbs, different head shapes for specialization of burrowing

93

head types of Amphisbaenians

round head- soft sediment
wedge shaped head- hard substrate

94

snakes

mostly have no trace of limbs
many arboreal- long and slender to spread weight out over branches

95

rain snake

oval cross section
tail flattened to propel through water

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Crocodilians

~22 species
living forms all fairly similar
body covered with osteoderms
long, elongate skull
extant are only aquatic
tropical/subtropical

97

osteoderms

bony deposits forming scales, plates or other structures in the dermal layers of the skin

98

crocodile snout specialization

long, skinny snout- fish eating- quicker swiping through water

99

Aves

highly modified reptiles
endothermic
body covered with feathers (keratin)
legs covered with epidermal scutes
wings and other modifications for flight
modified jaw with beak (keratin) and no teeth

100

bird feet/beak

tell a lot about overall life ecology
ex. flightless - marine

101

bird feathers

aid endothermy
major flight surface of wing

102

Mammalia

endothermic
body covered with hair/fur (keratin, insolation)
highly differentiated dentition
numerous derived traits in skeleton
pinna

103

derived traits in mammal skeleton

squamosal-dentary jaw joint
7 cervical vertebrae (neck vertebrae)- almost all mammals have 7

104

Pinna

the visible part of the ear that resides outside of the head

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main groups of mammals

monotremes
marsupials
placentals

106

monotremes

lay eggs- platypus, echidna
only a few species
basically same as reptile eggs- hatch then female feeds milk via ducts (not nipples)

107

marsupials

wide diversity of form, mostly in Australia, bears, rodents, carnivores, koala, kangaroo, opossum, wombat
have placenta but not well developed
embryo develops in uterus for short period of time
born at early embryonic stage, crawls up to pouch and attaches until ready to be born

108

marsupial embryo pouch

marsupion

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placentals

development until birth is in uterus
intimate connection between embryo and mother (nutrients, gas exchange)

110

important parts of evolution

genes, chromosomes, alleles, mutation (many neutral, some lethal), proteins (structural, hormones, enzymes), recombination, dominance, pleiotropy, polygenic traits, epistasis, regulatory genes

111

pleiotropy

single genes code for multiple parts of the body

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epistasis

interactions between genes
effect of gene depends on presence/expression of other genes

113

regulatory genes

govern expression of genes

114

phenotype =

genotype * environment

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phenotypic plasticity

ability of an organism to change its phenotype in response to changes in the environment

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heritability

the proportion of observed variation in a particular trait (as height) that can be attributed to inherited genetic factors in contrast to environmental ones

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reaction norms

expression of the phenotype of a particular genotype in different environments

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no genotype environment interaction, reaction norm

phenotype vs. environment graph
variation is constant, parallel for 2 genotypes among different environments

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genotype environment interaction, reaction norm

genotypes are not parallel or constant (lines may cross)
one genotype may produce multiple phenotypes

120

phenotypic flexibility

reversible changes within individuals
ex. plumage variation with season- changeable/reversible phenotype

121

types of selection

artificial selection
(natural) selection
adaptation
directional selection
balancing selection
disruptive selection

122

natural selection

variation, heritability, differential survival/reproduction
variation has to be heritable for evolution to occur

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adaptation

a trait that has arisen from natural selection

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three modes of selection

stabilizing
directional
disruptive

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stabilizing selection

balancing
extreme values are a disadvantage and are 'pruned'
keep population at certain 'optimum'

126

directional selection

one extreme is disadvantageous
leeds to a shift away from one extreme

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disruptive selection

intermediates are disadvantageous
selection is for the extreme- split down the 'middle'

128

example of directional selection

high proportion of unbounded snakes- selection against banding- population pushed primarily to unbounded
banded snakes remain in population due to migrations from mainland
balance between migration and selection

129

example of balancing selection

UK birth weights- low mortality in mid weight babies
small babies underdeveloped, large babies died during birth
selection for optimal birth size- med size babies were commonest, had best chance of survival, most likely to pass on their characteristics

130

selection isn't the only factor that determines change

genetic drift
founder effect

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genetic drift

genes that wouldn't normally be passed on are passed due to small population- selection goes in different direction that it normally would

132

founder effect

small founding colony of individuals will have more limited make-up than the population they came from, depends on founding colony being small

133

species/speciation concepts

multiple species concepts
discontinuities
morphospecies
biological species
hybridization
asexual reproduction

134

discontinuities

breaks between species (ex. morphology)

135

multiple species concepts

many definitions of species
the 2 we will focus on are biological species concept (BSC), morphological species concept

136

BSC

depends on sexual breeding, must be able to interbreed, hard to test, depends on species exhibiting sympatry
discontinuity- reproductive isolation

137

sympatry

species that occur in same geographic area

138

why species concept can be hard to test

if they don't come together naturally there is no way of knowing if they naturally mate- bringing them together in the lab is artificial

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morphospecies

different species should look different
domestic dogs- haven't speciated

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sibling species

different species that look identical

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sibling species example

Hyla versicolor- tetraploid (gray tree frog)
Hyla chrysoscelis- diploid (Cope's gray tree frog)

142

tetraploid

Triploid/tetraploid chromosomes are polyploidy
Polyploid organisms are those containing more than two paired (homologous) sets of chromosomes. Most species whose cells have nuclei (Eukaryotes) are diploid, one set inherited from each parent.

143

polyphyletic

does not include the common ancestor of all members of the taxon

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paraphyletic

includes the most recent common ancestor, but not all of its descendents

145

species is used to

describe groups that we recognize
describe what the animals themselves recognize

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stable hybrid zone

ranges of 2 species come together, where they meet there is a zone that consists of hybrids
hybrids usually not sterile but may be less fit

147

hybrid example

manitoba toads- meet in East manitoba, zone where there are hybrids (separate species)
yellow-rumped warbler (sub-species)
gray wolf/eastern wolf/coyote/red wolf/dogs
European water frogs

148

incipient speciation

evolutionary process in which new species form but are still capable of interbreeding; can be the first part of the larger process of speciation

149

yellow-dumped warbler hybrids

Audubon's warbler / Myrtle warbler
100km hybrid zone
graphs show different traits within/outside of hybrid zone

150

introgression

(introgressive hybridization), movement of a gene (gene flow) from one species into the gene pool of another by repeated backcrossing of an interspecific hybrid with one of its parent species

151

3 known categories of asexual reproduction in vertebrates

recall that BSC requires sexual breeding
hybridogenesis
gynogenesis
parthogenesis

152

hemiclonal

half of females genome is passed on clonally

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clonal

all of females genome is passed on clonally

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hybridogenesis

male mates with female but males genetic contribution is discarded at mitosis
egg is fertilized but genetic info. not passed on in next generation

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gynogenesis

mates with male but sperm are not used (salamanders, some fish)
diploid egg, sperm stimulates reproduction but doesn't fertilize
female relies on sperm from heterospecific males to initiate embryogenesis

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parthenogenesis

males not used at all, diploid, unfertilized egg (clonal)

157

most vertebrates are

bisexual- normal sexual reproduction

158

European water frogs hemiclonal hybridogenesis

Rana ridibunda x R. lessonae = R. esculenta
R. esculenta x R. lessonae = R. esculenta
R. esculenta x R. esculenta = R. ridibunda
R. esculenta x R. ridibunda = R. ridibunda
R. esculenta maintains itself by mating with parent species- at meiosis discards lessonae part of genome and reconstitutes itself

159

usually inviable offspring

R. esculenta x R. esculenta = R. ridibunda

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origin of R. esculenta

R. ridibunda x R. lessonae = R.esculenta

161

why do males mate with female gynogens (gynogenesis)

selection should favor males that gynogenesis
sexual females increase their preference for males whom they observe consorting with female gynogens

162

elements of speciation

occur in variable orders/rates/ranges/time, process of species formation, multiplication of species, complex process that involves multiple phenomena
elements: reproductive isolation, genetic divergence, phenotypic divergence

163

Bulloch's Oriole and Blatimore Oriole

two morphologically distinct species, but they are interfertile
two morphospecies, but one or two biological species?

164

interfertile

capable of interbreeding

165

cryptic species

morphologically similar, genetically distinct, incapable of interbreeding

166

cryptic species example

African Savanna Elephant, African Forest Elephant

167

speciation can occur

allopatrically, parapatrically/peripatrically, or sympatrically

168

allopatric speciation

geographically separate

169

parapatric speciation

geographically adjacent

170

sympatric speciation

geographically coincident (same area)

171

non-selective speciation

'by accident'- random drift in small founding populations

172

natural selection speciation

mutation-order speciation
ecological speciation

173

ecological speciation

evolution of reproductive isolation between populations by divergent natural selection arising from differences between ecological environments
indirect or direct

174

indirect ecological speciation

by-product speciation
reproductive isolation occurs as an incidental by-product of adaptation to different environments

175

direct ecological speciation

selection directly favours reproductive isolation
ex. if hybrids are less viable

176

allopatric (geographic) speciation

vicariant event- splitting events/barriers cause species to adapt independently to conditions (ex. glaciation)
dispersal- disperse to new area (ex. island), may lead to founder effect (ex. galapagos finches)

177

Possible outcomes of secondary contact after long periods of separation

partial/complete reproductive isolation- basically separate species
hybrid zones
complete introgression- interbreed as if never separated
selection for reproductive isolation- behavioural differences

178

lentic

standing water

179

lotic

running water

180

ecological speciation changes in fishes

marine-freshwater
physio-chemical transitions
lotic-lentic transitions
discrete river habitat
water depth
benthic-open water
benthic substrate shifts
piscivory
durophagy
intrinsic incompatibilities
divergent sexual selection

181

piscivory

eating of fish

182

durophagy

eating behavior of animals that consume hard-shelled or exoskeleton bearing organisms, such as corals, shelled mollusks, or crabs

183

increasing potential for gene flow in absence of differentiation

decreasing spatial scale
allopatric-- parapatric-- sympatric

184

ecological speciation example

repeated parallel speciation in endependent populations of sticklebacks, regulation in gene due to reproductive isolation
deep water- prominent spine, predator protection
shallow water- absence of fin, harder for insect larvae to attach

185

Replicated (parallel) ecological speciation in lizards

habitat matching- different species show the same coloration changes to match light/dark soil habitats

186

punctuated equilibrium

little net evolutionary change for most of geological history, remaining in an extended state called stasis, disrupted by abrupt change

187

phyletic gradualism

speciation is slow, uniform and gradual
When evolution occurs it is usually by the steady transformation of a whole species into a new one

188

microevolution

microphylogeny, microecology
change over short time and small spatial scale
ex. population genetics, shifts in color patterns, polumorphisms

189

macroevolution

historical ecology, macroecology
change over long time scales and large spatial scales
taxonomic and transformational implications- major changes in body form

190

Historical Ecology

taxic-- speciation, cospeciation
transformational- adaptation, coadaptation

191

macroevolutionary phenomena

origin of new structures
discontinuities in 'adaptive space'
rates of evolution
causes and natures of radiations
causes and natures of mass extinctions

192

fundamental to biology

phylogeny, taxonomy, systematics

193

why phylogeny/taxonomy/systematics are important in a world with decreasing biodiversity

different conservational issue depending on whether or not separate species

194

BC spotted frog

found to be 2 species; 1 restricted to coastal Oregon, BC; new species is very restricted and need immediate conservation help

195

Tuatara Sphenodon (lizard) endemic to NZ

one species found to be two, separate conservation plans had to be made

196

folk taxonomy

local and simple
classifying animals based on known plants, local
used in everyday language- 'bugs' 'shrubs'

197

world exploration

disruption to local order

198

Linnaeus

1700s, Systema Naturae binominal system
subjective, based on intuition, experience, 'umwelt', mix of art and science
species names have 2 parts, first subjective system

199

evolutionary taxonomists

1800s, influenced by Darwin
classification should reflect evolutionary relationships
shift in point of view but not methods
a species is what a good taxonomist says it is

200

making taxonomy a science

1950s, injecting objectivity

201

numerical taxonomy

unweighted characters, quantitative
take as many characters as can, try to find similarities to make unbiased connections

202

molecular taxonomy

proteins, RNA, DNA, comparison of apples and oranges
differences between species in relation to proteins and DNA
first time characters could be compared in vastly different organisms

203

Cladistic taxonomy

phylogenetic taxonomy
shared evolutionary novelties
not all traits are useful, some are more important than others- shared derived traits

204

fungi are closely related

to animals (more than to plants)

205

classification

ordering of organisms into sets based on relationships
relationships defined in various ways- phylogeny, resemblance

206

identification

allocation of previously unidentified specimens to the correct sets, as in 'keying'

207

taxonomy

the theoretical study of classification, including principles and procedures (rules)

208

taxon

general term for any taxonomic group of any rank

209

systematics

study of diversity and interrelationships of organisms, causes and origins of relationships including zoogeography
broader than taxonomy

210

nomenclature

very narrow term, having to do with actual naming

211

types of classification

cross-tabulation
linearly ordered list- alphabetical, numerical (not a good classification, just a list)
hierarchy- by some criterion of similarity

212

cross-tabulation

take 2 traits and compare them in 2x2 grid
ex. endothermy/ectothermy, eyes/no eyes

213

biological classifications

hierarchical - groups nested within groups
based on similarity- morphological, genetic
usually reflect evolutionary relationships

214

taxon ranks in Linnean classification system

Kingdom- Phylum- Subphylum- Class- Subclass- Order- Suborder- Family- Genus- Species (binomen)- Subspecies (trainmen)

215

plural of taxon

taxa

216

order names end in

a
Order Squamata - not the Squamata order
or we can talk about squamates, or squamate reptiles

217

family names end in

idea
Family Viparidae- not the Viperidae family
or "viperirds" or "viperid snakes"

218

subfamily names end in

inae
Subfamily Viperinae
or "viperines" or "viperine snakes"

219

nomenclature rules are found

in International Code of Zoological Nomenclature

220

kinds of similarity

similar origin (developmental or evolutionary)
similar function
similar structure

221

similarity in origin example

articulation of jaw in mammals- squamosal and dentary
in all tetrapods except mammals- articular and quadrate

222

articular and quadrate in mammals

middle ear- different fn and structure but similar origin
articular = malleus
quadrate = incus

223

middle ear ossicles

3 in mammals- incus, malleus, stapes
1 in other tetrapods- stapes (trace back to fish)

224

similarity in structure example

3 different kinds of wings- bird, pterosaur, bat
forelimbs of tetrapods- similar features; ulna, radius, humerus
parts shaped differently with same basic elements

225

similarity in function example

noise-making in snakes- rattling, tail-vibrating, hissing, stridulation, cloacal popping

226

rattling in snakes

Crotalus: series of interlocking segments make up rattle, special shaker muscle vibrates at rapid rate for long time,
add segments to rattle every time they shed their skin, babies only have one segment and can't rattle

227

tail-vibrating and hissing in snakes

Pituophis: shake tail to make noise in dry leaves (confused with rattlers)
specialized keel increases loudness of hissing (~10 decibels higher with keel- decibels are log scale)

228

stridulation in snakes

Echis: (scale-rubbing) specialized scale on side of body, move body segments against each other to make noise

229

cloacal popping

Micruroides, Gyalopion: force air out of cloacal (opening for intestine, reproductive, urinary tract) and make a popping noise

230

kinds of similarity

homology
homoplasy
analogy

231

homoplasy

"false" evolutionary resemblance
parallelism, convergence, reversal, loss, mimicry
can confound construction of phylogenies
but can be used to make inferences about adaptation

232

"false" evolutionary resemblance

phenotypic similarities mislead us to relationship

233

reversal

loss of trait back to original state

234

confound construction of phylogenies

sorting out homoplasies from other similarities is key

235

Convergent evolution (this is the term we will use)

convergence- evolution of similar phenotypic features independently in different lineages, usually from different features and developmental pathways

236

Parallel evolution

parallelism- evolution of similar/identical features independently in related lineages, usually based on similar modification of the same developmental pathways

237

convergence in African Cichlids

fish in two different lakes look similar- mimic each other
fish in same lake look different but are more similar to each other than to fish in other lake

238

convergence in mammals

similar body forms through time
many marsupials look similar to eutherians (placentals)
mole-- marsupial mole
flying squirrel-- sugar glider
woodchuck-- wombat

239

convergence of echolocation

different kinds of echolocation arise independently multiple times (bats, dolphins)

240

homology

"true" evolutionary resemblance, a relative term
similarity of origin is important, to some extent
taxic or transformational

241

homology is determined from

comparative anatomy, fossil record, developmental biology, distribution of character states among taxa (using parsimony)

242

reptile to mammal transformation homology

jaw joint to middle ear ossicle
polarity of the trait = direction of change over time

243

taxic homology

shared evolutionary novelties that help define taxa

244

tetrapod wings

show how the level of analysis changes the definition, relative terms
homologous as tetrapod limbs
homoplasious as wings (bird, pterosaur, bat all independently derived wings)

245

cladistics

phylogenetic systematics
grouped based on 1+ shared unique characteristics from the group's LCA

246

monophyletic group

ancestor plus all descendants

247

paraphyletic group

monophyletic group with some descendants missing
ex. "reptiles" birds missing, would be a correct taxonomic group if we included birds

248

polyphyletic group

group composed of members separated by two or more ancestors
usually constructed by homoplasies

249

homoplasy

character shared by a set of species but not present in their common ancestor

250

plesiomorphies

ancestral, 'primitive' traits

251

apomorphies

derived, 'advanced' traits

252

symplesiomorphy

shared ancestral trait

253

synapomorphy

shared derived trait

254

we want to construct phylogenies with only

synapomorphies (shared derived traits), only clades
ex. all vertebrates have hearts does not set them apart from other taxon

255

grade vs clade

grade- group of species united by morphological/ physiological traits, gives rise to another group differing from ancestral condition- not considered part of the ancestral group, same grade can be in different clades
ancestral group- not phylogenetically complete, doesn't form a clade, represents a paraphyletic taxon

256

Linnaean classification of Vertebrates

Class Chondrichthyes- sharks, rays
Class Osteichthyes*- bony fish
Class Amphibia- lissamphibians
Class Reptilia*- reptiles
Class Aves- birds
Class Mammalia- mammals
* paraphyletic groups

257

anagenesis

change in form within a lineage

258

cladogenesis

splitting events

259

grades =

paraphyly, group which does not include all its descendents
"fish" and "birds" are paraphyletic

260

clades =

monophyly, taxon (group of organisms) which forms a clade, meaning that it consists of an ancestral species and all its descendants

261

grades can be attributable to

synapomorphy- monophyletic groups (grade = clade, mammals are a grade and a clade)
symplesiomorphy- paraphyletic groups (reptile, fish)
convergence- polyphyletic

262

symplesiomorphies

characters shared by everybody, everybody's got these traits so they don't help characterize one group

263

synapomorphies

unique traits that maybe can be used to categorize one group vs. another

264

autapomorphies

derived traits that are unique to a particular taxon

265

each person is, in certain respects like all other people, like some other people, and like no other person

all other people- symplesiomorphies
some other people- synapomorphies
no other people- autapomorphies

266

in phylogeny we are trying to recognize sister taxa

a synapomorphy is present only in 2 sister-taxa and is the inherited autapomorphky from their LCA. ID'ing a character as a synapomorphy is essential for recognizing sister taxa

267

phylogenetic systematics

taxa (clades) defined by shared derived traits only
evolutionary relationship (phylogeny) among taxa represented by a branching diagram (cladogram)
sister clades receive equal rank (no taxon labels)
all taxa are monophyletic
groups defined by shared ancestral traits have no taxonomic value (may be important in other ways)

268

dichotomous branching

each branch is a sister group

269

fully resolved phylogeny

each point has only two branches
>2 - polytomy

270

phylogenetically defined taxa are always

monophyletic
taxon = monophyletic group = lineage = clade

271

groups defined by shared ancestral traits have no taxonomic value (may be important in other ways)

ectotherms- not a natural grouping, has eco-physiological meaning

272

fossil problem

incomplete specimens
incomplete record through time
mostly hard parts, few soft tissues
no molecular data
maybe unique derived traits that we can not see

273

types of clades

node-based
stem-based
apomorphy-based

274

node-based

crown group
based on extant forms (more information)
just below node of sister group

275

stem-based

total group
consists of crown group + extinct forms (stem) that are part of the ancestral lineage of crown group
just above node below sister group

276

apomorphy based

based on first known appearance of a particular derived trait
ex. first appearance of limbs in fossil record
somewhere in between sister group node and node below

277

crown group defined

by extant groups but can contain extinct groups

278

why phylogeny is more useful than Linnean system

more complete and informative classification
phylogeny recoverable from taxonomy and vice versa
can use a list to create cladogram (isomorphic, equal rank get equal indentation)

279

phylogeny limitations

polarity and/or homology of many traits is not unambiguously established (whats the direction of change)
evidence is evidence not proof, many disagreements on 'correct' phylogeny (still much debate, where do turtles go)
molecules vs. morphology
everything is provisional

280

molecules vs. morphology

modern phylogenies usually derived from molecular data
we then can map other traits onto the phylogeny and interpret them (ex. convergences)
mostly, now, start with molecular phylogeny and then map morphological

281

ingroup

group of taxa whose relationships we want to resolve

282

outgroup

comparison taxon closely related to the taxa of interest
sometimes 2 or more outgroup taxa are used, one more closely related and one more distantly related

283

outgroups used to determine

how the cladogram should be rooted
ex. help determine polarity (direction) of changes in traits

284

calibrating phylogeny so branch lengths give estimate of time since separation

fossil record
base phylogeny on genes and calibrate via molecular clock
use ancient DNA

285

ghost lineage

incomplete history, missing fossil record implied by sister group

286

NGS

next-generation DNA sequencing (paleogenomics)
some contamination problems
can bring evidence on questions such as time since divergence
can sequence hundreds of thousands of years back
can give an idea of process rather than just pattern

287

Phylogeny

evolutionary chronicle
branched chronological series of character state changes along lineages (what)
clear methodology (cladistics)

288

Genealogy

historical narrative
casual statements, explanation, interpretations, evolutionary scenarios (how and why)
no clear methodology- gaps between taxa filled by fossils, extant taxa, imagination, intuition

289

the comparative method

using comparisons across species that have evolved independently

290

why should we care about systematics

systematics are fundamental to biology and can tell us alot

291

problems comparing characteristics

shared history- lineage specific effects (non independence)
phylogenetic effects/differences- history matters

292

independent comparison method for 2 characters in a single phylogeny

sister taxa are averaged to give node value
differences are taken between sister taxa for d1 and d2
differences are taken between nodes d3
differences compared for characters and then the 2 characters differences are plotted against each other

293

number of rooted, bifurcating, labeled trees for n species

(2n-3)! / (2^n-2)(n-2)!

294

problems constructing phylogenies

large number of possible tree topologies (15 trees for n=4)
different analytical methods give different answers
numerous different trees for same group
fossil forms incomplete

295

analytical methods of phylogeny

parsimony and variants
compatibility (character "cliques")
distance matrix methods
likelihood methods
others, all quantitative

296

consensus tree

constructed when we have 2 or more different trees for the same group

297

parsimony

Occam's Razor
the simplest, most plausible hypothesis is the obvious place to start
if you hear hoofbeats, think horses not zebras
cladogram w/ fewest evolutionary steps is best starting hypothesis

298

inferring characters in poorly known taxa

modern analogues
extant phylogenetic bracket

299

extant phylogenetic bracket

if a character is exhibited by bracketing extant species, then most likely exhibited by internal branches (extinct species)
ex. parental care seen in crocodilians and birds, so probably in the dinosaurs 'in between'
may have evolved independently but less parsimonious- more evolutionary steps

300

endothermy in dinosaurs?

crocodilians- 4 different dinosaurs- birds
we know that crocodilians are not endothermic, birds are
there are 5 equally parsimonious trees to explain the evolution of endothermy in to birds, so we can't infer where it evolved

301

non-therian synapsids

all synapsids other than mammals

302

nocturnality in non-therian synapsids

study finds synapsids were nocturnal ancestrally
carnivores are predominantly nocturnal or cathemeral

303

cathemeral

irregularly active at any time of night or day, according to prevailing circumstances

304

myrmecophagy

feeding behavior defined by the consumption of termites or ants

305

convergence example

myrmecophagy in Dendrobatids (frogs)
echolocation in bats and dolphins
flightlessness in birds
endothermy in Scombroidean Fishes

306

species that overlap geographically are sister taxa

sympatric speciation

307

sister species do not overlap geographically

allopatric speciation

308

sister species do not overlap and the range of one is smaller than the range of the other

peripatric speciation

309

polymorphism

occurrence together in same habitat of 2 or more discontinuous forms, or "phases", of a species in proportions that the rarest of them cannot be maintained merely by recurrent mutation (genetically determined variants)

310

polyphenism

phenomenon where two or more distinct phenotypes are produced by the same genotype
Multiple phenotypes in population (polymorphic), not based on genotype
phenotypic variation induced by an environmental cue
form of phenotypic plasticity

311

example of polyphenism

amphibian larvae – shifts in morphological phenotype
due to predators, competitors, and prey
cannibalism is induced when high density of conspecifics- leads to larger mouth and teeth

312

why nervous system is useful in phylogenetic research

lots of data to compare
lots of genetic markers

313

origin of chordates, old system and new system

old- vertebrates sister group to Amphioxus
new system- Vertebrates sister group to Tunicates

314

why were tunicates 'moved' in the phylogeny?

found to have a number of fast-evolving genes
very derived, even though they appear basal
no longer a kew organism in understanding

315

mosaic development

something happened early in tunicate development that allowed them to rapidly evolve in a different direction

316

serial mesoderm (segmented) evolution

'hairy' gene in Arthropods and Annelids
homolog of 'hairy' in chordates
~same gene, evolved once

317

chordate characters

pharyngeal gill slits
dorsal nerve cord
segmental muscles/mesoderm
notochord
postanal tail

318

pharyngeal gill slits

probably first to evolve, seen in hemichordates and maybe echinoderms
amphioxus doesn't use as gills- filters food
large surface area for gas exchange

319

segmental muscles/mesoderm

serial myotoes/somites
other inverts. typically circular/longitudinal muscles
in vertebrates only around guts

320

postanal tail

anus not terminal, body extends over primary anus to form tail, new anus is formed (non-terminally)

321

dorsal nerve cord

ventral in proterostome
evolves separately in new place OR inversion, mouth migration (moves down in chordates)

322

mouth formation

delayed, area btw mouth and nerve cord expands
ventral mouth is a derived character-- lead to face evolution
as mouth 'moves' pituatary 'chases' it- moves to oral cavity, then up to underside of nerve cord

323

model organisms for developmental biology of vertebrates

zebrafish, mouse, chick, frog

324

why frog?

easy to obtain large # of eggs, embryogenesis occurs outside body- eggs can be manipulated

325

frog cell cycle

rapid cell cycle- no G1, G2-- increases # of cells in embryo (large cell #)
no zygotic transcription

326

blastula parts

animal pole (AP)- top, blastocoel, superficial cells
Vegetal pole- cells more dense, comprise gut structures

327

gastrulation

series of coordinated cell rearrangements leading to germ layers
equatorial region forms dorsal blastopore lip- bottle cells 'crawl' and involute- displaces blastoceal

328

germ layers

ectoderm
mesoderm
endoderm

329

ectoderm

skin, nervous system

330

mesoderm

muscle, bone

331

endoderm

gut

332

results of gastrulation

endoderm cells were on outside before gastrulation
archenteron formed
AP moved equatorial
blastopore formed (future anus)

333

protostome gastrulation

starts at mouth

334

deuterostome gastrulation

starts at anus

335

upon completion of gastrulation

3 germ layers are evident and layered (endo, meso, ecto)
A-P and dorsal-ventral poles established
preliminary notochord present, terminating in dorsal blastopore lip

336

next stage after gastrulation

neurulation - dorsal ectoderm becomes CNS (central nervous system)

337

mammalian, chick embryo proper

flat sheet of cells, epiblast, prior to gastrulation
cells migrate through primitive groove to give rise to 3 germ layers

338

neural plate stage

neural tube formation
neuroectoderm-- neural groove formation-- neural fold-- neural tube pinches off-- neural crest cells disperse and notochord forms-- epidermis on top
gives rise to brain and spinal cord

339

neural crest

one of defining features of vertebrates- novel
migrate to different regions- even non neural cells

340

neural crest derivatives

PNS- peripheral nervous system
Endocrine and paraendocrine derivatives
pigment cells
facial cartilage and bone
connective tissue

341

sometimes referred to as the 4th germ layer

neural crest
distinguishes vertebrates from other chordates

342

a9.49 cell

always gives rise to pigment- overexpression of 'twist' = loss of melanocyte-- migration is similar to neural crest cell (may be a precursor)

343

closure of neural tube

---neurula stage- formation of somites, tailed, expansion of forebrain, gill area
failure of closure = spina bifida (.7/1000 births, folic acid deficiency)

344

notochord remnants

retained in lancelet, larval tunicate
supports vertebrae in mammals

345

notochord implicated in different cell type generation

signals ectoderm to form CNS
implicated in different cell type generation
move/remove notochord- induce cell diversity in dorsal part of neural tube, in a graded manner (1 22 1)

346

shh

sonic hedgehog secreting cells- gradient directs TF expression- 3TF = 5 domains
gradient of morphogen- cells respond to density = expression of different genes
one signalling factor gives rise to multiple factors

347

tadpole with yellow in head

remnants of yolk, starts feeding after thats gone

348

coqui

'direct developers'
hatch as live frogs- no larval stage
much larger embryo and yolk, quicker maturation, nutritional endoderm, less reliant on water (eggs can be laid on land)
parallel evolution with amniotes

349

frog metamorphosis controlled by

thyroid hormone, T3 tri-iodothyrodine

350

nutritional endoderm

novel cell type, single cell containing yolk, doesn't integrate into frog, connected for feeding, similar to amniote

351

allantois

stores waste
gas exchange

352

chorion

outer most membrane
gas exchange
mammals = placenta

353

polyembryony

more than one embryo from one egg
armadillos always give rise to 4 identical twins, all share same amnion and chorion (very rare in humans- 1% of human twins)

354

to make a phylogenetic tree start with

homologous DNA sequences that you have collected in the lab or downloaded from a database search
align sequences

355

BLAST

basic local alignment search tool - takes query, finds pairwise match, 'hit'

356

Clustal W

gives multiple sequence alignments- doesn't discriminate between non-homologous sequences- this is up to the biologist

357

correctly aligned, non-homologous

ACCTCATC
_C____T_

358

used to manipulate Clustal W results

BioEdit

359

distance matrix

how many differences between sequences
start with columns = sites, rows = sequences, count how many differences between sequences
make new grid, ex. sequences 234 vs. 123 with # differences

360

distance tree

tree branches add up to differences, sized based on differences
works best if you have same amount of data for each sequence- less similarities if comparing a short sequence- (not b/c the similarities don't exist)

361

if you don't have same amount of data for each sequence

use p-distances (proportions)

362

problems with number of differences/p-distances

unobserved mutations
A--G--T = 2 substitutions but only 1 is observed
A--G--A = 2 substitutions, none are observed
what we see is not always the whole story

363

attempt to correct for unobserved mutations

Jukes and Cantor formula

364

Jukes and Cantor

distantly related sequences likely to have experienced more substitutions than visible
mutations are more likely to occur at the same place given a large number of mutations

365

without Jukes and Cantor correction p-distance over time graph

asymptotes

366

Jukes and Cantor formula

gets rid of asymptote
distance = -(3/4)ln(1-(4/3)p)
p = proportion of changed sites, p-distance

367

if p= 0.18, JC distance =

0.206

368

influence of JC formula

distance btw similar sequences increases very little
distance btw distant sequences increases more
increases branch lengths in distant sequences

369

Actinopterygii

almost all fish

370

Sarcopterygii

lungfish, coelocanth
forgs, reptiles, mammals,..

371

relationship btw lungfish, lobe-fin, tetrapod, ray-fin

LF and Coelocanth (lobe fin) sister taxa
LF, C and T sister taxa
LF, C, T and RFF sister taxa

372

exons and introns

exons encode a.a.'s, introns dont
changes in interns less likely to have effect on proteins
we compare exons- more likely to be similar

373

exon vs. intron graph

more distance between families than within
more distance in introns (x-axis) then exons (y-axis)

374

red pandas

sister group of raccoons, badger, otter
more closely related to seals and sea lions than other bears

375

giants panda

at the base of the bear tree
other bears are more closely related to one another than to giant pandas

376

heyenas

are much more closely related to cats than to dogs

377

OLD convergence and parallelism

C- evolution of similar traits in unrelated taxa
P- evolution of similar traits in closely related taxa

378

NEW convergence and parallelism

C- evolution of similar traits in different lineages, involving different developmental pathways
P- evolution of similar traits in related lineages, involving same developmental pathways

379

new convergence and parallelism definitions based on

closeness of relatedness and molecular pathway
but don't really need to say anything about relationship
C- results from different genetic mechanisms

380

toothlessness evolution

same genes are involved- parallelism
if we look at the relationships it would be convergence

381

evolution of body elongation

in sister taxa- same mechanism (increasing size of vertebrae) - parallelism
in more distantly related species- different mechanism (increasing # of vertebrae) - convergence

382

Pattern

the "what"?
ex. phylogeny
simple description of what we see

383

Process

the "how"?
genetic development/mechanism
process by which pattern arose
ex. giraffes have long necks b/c they expand size of vertebrae
and the "why"?
adaptive/selective scenario
assumed to be for feeding at higher levels

384

The integrated organism

diverse physiological processes all affect each other (ability, rate) one imposes trade-off on another
ex. water absorption through skin affects gas loss through skin, heat exchange, etc.

385

fluxes of mass

respiratory gases, organic and inorganic substances, water

386

fluxes of energy

heat, charge, potential energy

387

physiologic trade-off in Darwin's finches

negative trade-off btw velocity and bite force- 2 separate muscles, can't maximize both at the same time

388

endothermy trade-off

can live in cold parts of the world
must eat all the time to conserve thermoregulation processes

389

interacting organ systems of vertebrates

skin, skeleto-muscular, nervous, endocrine, respiratory, digestive, excretory, circulatory
all interacting

390

major transitions in evolutionary history of vertebrates

water to land (origin of tetrapods)
land to water (origin of whales)
origin of amniotes
ectothermy-endothermy
evolution of flight (origin of birds)
origin of mammals
origin of turtles
origin of snakes
all involve multiple systems at once

391

adaptations in the transition between land and water

density/viscosity changes - locomotion and support
O2/CO2 content - gas exchange
thermal capacity - thermoregulation
refractive index - visual system
velocity of sound - hearing apparatus'

392

evolution of endothermy

insulation - controlling heat loss/gain
circulatory system
respiratory system (endo. high O2 demand)
metabolic rate
musculoskeletal system

393

evolution of birds

endothermy
flight
wings
pneumatic bones (air filled bones)
feathers
rhamphotheca (bill)

394

evolution of snakes

elongation of body
reduction/loss of limbs
repackaging of internal anatomy (long and skinny)
modified locomotion
modified feeding apparatus

395

correlated progression assumptions

incremental changes
natural selection
systems evolve in parallel
--traits can only change by one unit at a time, can be no more than one unit different than connecting traits, no obvious starting point

396

incremental changes in correlated progression

characters are highly integrated with each other, no one can evolve by more than a small amount at a time, without losing functional integration within organism as a whole
ex. can't just grow a leg and become terrestrial

397

natural selection in correlated progression

natural selection tests the fitness of an organism as a whole, not any individual characteristics
ex. fitness of leg is not the issue, fitness of the organism is

398

systems evolve in parallel, correlated progression

all structures and functions evolve by respective sequences of small steps in loose correlation with each other to maintain continuous functional integration

399

your inner fish

all the parts mammals have are modified parts from fish ancestors
no parts are new parts, history matters

400

co-option

new use for old parts

401

gill arches

co-opted for other functions
arches 1-4 --- jaws, ears, larynx, throat
bones, muscles, nerves, arteries develop inside these gill arches

402

every bone in our head can be traced to

plates, blocks, and rods (from fish)
plates- dermatocranium
blocks- chondrocranium
rods- splanchonocranium (jaws)

403

distinguishing feature of mammals (bone)

lower jaw only one bone- dentary

404

macroevolution

changes above or at a species level (speciation)
organisms are highly integrated
constrained by ancestral history- if we could build a new one it would be much different

405

linking micro and macroevolution

phenotypic plasticity- variation within individual species raw material for evolution of new species
developmental biology (evo-devo)

406

graph of phenotypic plasticity in reaction norm

phenotype vs. environment is a linear graph where phenotype is able to vary with different environments

407

genetic assimilation

occupying on enviro.---unexpressed capacity for plasticity-- enviro. changes-- rxn norm allows population to persist-- novel phenotype, no initial genetic change-- phenotype becomes fixed-- rxn norm loses plasticity

408

why reaction norm may lose plasticity

drift, cost associated w/ maintaining plasticity when it is not favoured by natural selection- old environment no longer favoured

409

macroevolutionary phenomena

origin of new structures
discontinuities in "adaptive space"
rates of evolution
causes and natures of radiation
causes and natures of mass extinctions

410

therapsids

mammal like reptiles

411

cause and nature of radiation example, therapsids

different lineages, showing increasingly mammalian characteristics, parallel changes in lineages

412

phylogenetic baggage

we are constrained by our evolution

413

exaptation

and the related term co-option describe a shift in function of a traits evolution
ex. trait can evolve because it served 1 function, but comes to serve another

414

preadaptation

large change in function is accomplished with little change in structure

415

mammals and vertebrae

7 cervical vertebrae almost always in mammals
exception- manatees have 6/7; sloths have recruited thoracic vertebrae to lengthen neck

416

why are mammals constricted to 7 cervical vertebrae?

morphological integration with other body parts, evo-devo- environmental biology evolved along with neck
each vertebra is restricted by a somite that produces myoblasts
C3-C5 migrated further back in body, responsible for formation of diaphragm
C6-C7 associated with muscles in shoulder area

417

largest known mammal necks

increase size of vertebrae not number (giraffe)

418

Annolis inovations

lizard- 'pave the way' for future evolutions
feet w/ hooks for climbing vertical surfaces- success of the species
key innovations can only really be determined to be key in hind sight

419

adaptation

feature that performs a specific function, arises as a result of selection

420

exaptation

one function taking over old function
new use will arise for a structure

421

in trade-offs be aware of

other variables that affect trade-offs
do simple correlation value and semipartial correlation values change

422

scaling relationships

how different characteristics are related to body size

423

allometry

statistical shape analysis in biology for differential growth rates of the parts of a living organism's body
morphometrics, multivariate stats, homologous landmarks

424

morphometrics

quantitative study of shape, heavily statistical

425

landmarks

changes in position give change in shape
knowing distances between points to determine shape and convert it to data

426

example of landmarks as a beneficial study

determining landmarks in endangered species to determine sex (M/F) for rearing eggs

427

PCA

principle component analysis

428

using landmarks in salamanders

2 salamanders with overlapping ranges, occurring in allopatry and sympatry
IDing landmarks on heads to determine how they differ in allopatry and sympatry

429

isometric vs. allometric growth

Iso- no change in shape proportions of body parts- stay the same
Allo- body proportions change

430

ontogenetic change in shape

change in shape during growth, through life

431

cohort

born at the same time

432

longitudinal study

following a cohort, following a group through life

433

cross-sectional study

slice in time, harder to determine age

434

measuring and testing allometry, bivariate case H_o

H_o : isometry, b = 1

435

testing bivariate allometry, equation

Y = aX^b
ln(Y) = ln(a) + b*ln(X)

436

testing for area

H_o: b = 2

437

testing for volume or mass

H_o: b = 3

438

results of Natrix natrix allometry regression

M have longer tails in absolute measurements, not in relative = isometry (M are smaller than F)
2 sexes are different but that is established right at birth, no change during life time- isometric
longer for copulation, reproductive organs

439

growth rate of head in humans

negatively allometric to body size in early life before head reaches full size
brain growth declines with age, relatively speaking

440

growth rate of heart in humans

about isometric to body size

441

proportionate difference in skull shapes of dogs and cats

dogs undergo greater shape changes than do cats
greater diversity of skull shapes in different breeds of dogs
dogs are tremendously allometric in skull growth
cats are close to isometric in skull growth

442

chameleon characteristics

highly derived- lots of apomorphves
zygodactyly (2 fingers opposing other 2)
highly projectile tongue
independently moving eyes
prehensile tail (to anchor)

443

slope of log(mass) vs. log(length)

mass = volumetric = 3 if isometric
< 3 is negatively allometric
>3 is positively allometric

444

allometric tail growth in chameleons

negatively allometric at posterior end, positively allometric at anterior end- prehensile tail- able to curl tightly at end because vertebrae are very small

445

adaptive significance of allometry in hatchling sea turtles

highly vulnerable to predation, swallowed whole by dolphinfish (mahimahi)- grow wider shell (positive allometry)
after week 5, probability of lethal encounter decreases quicker with wider shells
turtles- caretta caretta, chelonia mydas, lepidochelys kempii

446

intraspecific

same species

447

interspecific

different species

448

phylogenetic studies require

interspecific comparisons, representative measurements from different species

449

most important evolutionary force of overall color

camoflauge

450

patches of color

intraspecific signalling

451

types of concealment

crypsis, disruptive coloration/obliterative shading, irregular marks to break up bodies outline, lighter ventral surface

452

spotted species are generally found

arboreal (forests)

453

striped species are generally found

grasslands (blend in to blades of grass)

454

aposematism

prey advertise noxiousness/pugnacity
ex. skunk

455

discontinuous color variation

white or black
albinism- likely no adaptive significance, rare
melanism- common in tropical forests (black panther)

456

sexual dichromatism

rare in most mammals, common in primates

457

physiological coloration

reflet/absorb sunlight for thermoregulation, enhance/reduce evaporation, reduce glare (dark eyes)

458

thermoregulation coloration

pale species found in deserts- reflect sunlight
dark species found in tropics- enhance H2O evaporation, protect against UV

459

If plasticity was acting on lizard field experiment

would expect immediate difference in hindlimb length
not what was seen

460

problems inferring behaviour of extinct species

underlying assumption have to be made
have to rely on modern analogues when there may not be
behaviours exhibited were documented in crown groups, little know of stem taxa

461

wing skeleton and migration

migratory, semi-migratory taxa have proportionally longer wing skeleton than non migratory taxa

462

large crushing force with bill

exceeds force needed for herbivory-- likely predation, scavenging

463

fossilized footprints

many found oriented in same direction along shoreline-- moving in parallel, gregarious behaviour

464

modern avian behaviours exhibited by ancestor of crown birds

vegetative nests, extensive pre and post-hatching parental care, egg brooding

465

loss of hearing represents

regressive evolution

466

reduction of hair cell density indicates

involvement in high-freq hearing loss
fewer hair cells = fewer sites for signal transduction

467

how selection against production of unfit hybrids can lead to differentiation

ex. female choice selecting for a divergence in male secondary sexual traits that facilitates species recognition

468

reinforcement hypothesis

the ultimate explanation for a sympatric character divergence is that it reduces the probability of hybridization

469

selection against hybridization in sympatry

overrides sexual selection for elaborate traits