Vertebrate Anatomy Exam I

Front 1

What is microevolution?

Back 1

change in the genetic structure of population(s) over a “short” period of time

Front 2

What are the necessary conditions for microevolution?

Back 2

existing genetic variation for the existing trait (via mutations, recombinant, etc.)

Front 3

Name three mechanisms of microevolution.

Back 3

1. natural selection – the differential reproductive success of an organism within a population based on some genetic allele
2. bottleneck – very small population size causes loss of rare alleles; nonselective, just random – not related to genetically based trait
3. genetic drift – “founder effect” – only a few individuals move to separate location, limiting genetic variation

Front 4

What is macroevolution?

Back 4

evolution above the species level

Front 5

How does macroevolution differ from microevolution?

Back 5

1. More pronounced differences among organisms
2. Novel structures – things that don’t have obvious homology
3. Historically – long time

Front 6

What are four mechanisms of macroevolution?

Back 6

1. Gradualism – gradual accumulation of small changes
2. “hopeful monsters” – big mutation that occasionally results in an advantage
3. Novel structures
4. Selection at species level (i.e. extinction and rapiad speciation)

Front 7

What is gradualism?

Back 7

gradual accumulation of small changes

Front 8

What are novel structures?

Back 8

Gene duplication- allows additional sets to mutate w/o loss of original function
Changes in genes that regulate other genes

Front 9

What is homology?

Back 9

features in two or more organisms derived from a common ancestors

Front 10

Analogy

Back 10

features of two or more organisms that perform similar function not derived from a common ancestor

Front 11

Phylogeny

Back 11

evolutionary history of a group/groups of organisms; based on ancestor descendant relationships

Front 12

Phylocode

Back 12

summarize lineages by giving names that don’t necessarily have taxonomic rank – assign names to lineages based on phylogeny that constructs monophyletic groups

Front 13

taxon

Back 13

group of organisms

Front 14

Homoplasy

Back 14

similarity that is related to function

Front 15

node

Back 15

represent the common ancestor

Front 16

lineage

Back 16

line of descent from an ancestor from any node

Front 17

sister group

Back 17

two lineages from a single node or common ancestor

Front 18

What are the criterion of relatedness in a phylogeny?

Back 18

recency of common ancestor; based on best available evidence about common ancestry of different taxa

Front 19

Apomorphy

Back 19

derived character state

Front 20

Plesiomorphy

Back 20

ancestral character state

Front 21

Synapomorphy

Back 21

shared, derived characteristics

Front 22

Synplesiomorphy

Back 22

shared unmodified character; unmodified ancestral state so all forms should retain ancestral form unless there is modification

Front 23

Are synapomorphies informative for looking at relationships within that group? Why?

Back 23

NO, because all members within that group should have that characteristic; need other characteristics to resolve relationships within that group

Front 24

monophyletic

Back 24

group with one evolutionary history/lineage; groups contain ALL and ONLY members of a lineage from a common ancestor

Front 25

polyphyletic

Back 25

group has members from a different lineage (non-linear lineage)

Front 26

paraphyletic

Back 26

group is missing some of its members

Front 27

eukaryote

Back 27

membrane-bound nucleus and organelles

Front 28

heterotrophic

Back 28

must eat; no photo or chemasynthesis

Front 29

bilateral symmetry

Back 29

one plant that divides into mirror images; one head and one tail

Front 30

radial symmetry

Back 30

more than one plane of symmetry

Front 31

eucoelomate

Back 31

true tissue

Front 32

deuterostome

Back 32

blastopore becomes anus; radial, indeterminate cleavage

Front 33

notochord

Back 33

axial rod situated on long axis of the body

Front 34

what are some characteristics of a notochord?

Back 34

- flexible – can bend but incompressible – “skeleton”
- not a huge part in all chordates, but in most adults there is remnants of its presence
- expressed at some stage of development
- bend side to side but cannot compress end-to-end; allows lateral motion

Front 35

pharyngeal gill slits

Back 35

occur at some stage in development in every chordate but don’t necessarily pierce the wall; originally used for filter feeding

Front 36

post-anal tail

Back 36

structure supported by the notochord or vertebrae past the anus

Front 37

dorsal hollow nerve cord

Back 37

located dorsal to notochord; brain and spinal chord; hollow space is fluid filled

Front 38

stomochord

Back 38

notochord-like structure; more hydrostatic than notochord

Front 39

endostyle

Back 39

homologous in form and function to the thyroid; iodine based organ

Front 40

fertilization

Back 40

all cells in multicellular body derived from fertilized egg; haploid sperm and haploid egg

Front 41

zygote

Back 41

fertilized egg; diploid

Front 42

cleavage

Back 42

mitotic divisions of the zygote

Front 43

Describe the first 2 divisions of cleavage in deuterostomes.

Back 43

longitudinal

Front 44

Describe the 3rd division of cleavage in deuterostomes.

Back 44

equatorial

Front 45

Describe cell division during the cleavage stage

Back 45

cells divide without growing

Front 46

blastula

Back 46

ball of cells at the end of cleavage

Front 47

blastocoel

Back 47

hollow, fluid-filled space of blastula

Front 48

blastodisc

Back 48

forms when cells are so dense that only cytoplasm cleaves

Front 49

gastrulation

Back 49

rearrangement of cells in the blastula

Front 50

What forms during the gastrulation stage?

Back 50

- Formation of the archenteron – “primitive gut” – will become the digestive tract and associated structures
- Establishes germ layers – ectoderm, mesoderm, and endoderm

Front 51

How are the steps of gastrulation achieved?

Back 51

- Cell shape changes
- Cell surface contacts with extracellular matrix and with other cells
- Cell movements using pseudopodia

Front 52

Describe the steps of gastrulation.

Back 52

1. Displacement of blastoceol toward animal plane
2. Cells move inward over the dorsal lip of the blastopore
3. Cavity formed by invaginating cells = archenteron
4. Blastopore is retained – becomes anus
5. Blastoceol shrinks; ultimately lost
6. By end of gastrolation, embryo has three germ layers

Front 53

archenteron

Back 53

cavity formed by invaginating cells (primitive gut)

Front 54

What derives from ectoderm?

Back 54

epidermis of skin, nervous system, neural crest and its derivatives

Front 55

What derives from mesoderm?

Back 55

notochord, dermis of skin, muscle, urogenital systems, components of skeleton, lining of coelom, heart and blood vessels

Front 56

endoderm

Back 56

lining of gut, digestive glands, lungs

Front 57

neural crest

Back 57

a paired strip of tissue that separates from the dorsal edges of the nueral groove as it forms the neural tube

Front 58

neuralation

Back 58

formation of the nerve cord; ectoderm is beginning to change, cells that become dorsal hollow nerve cord begin to form

Front 59

What are the steps of nueralation?

Back 59

1. invagination of neural plates – neural fold
2. neural tube detaches from overlying ectoderm
3. neural crest tissue adjacent to neural tube
4. neural crest cells migrate

Front 60

somite

Back 60

more distinct clusters posterior to the head

Front 61

What are the three regions of the somite

Back 61

dermatome, myotome, and sclerotome

Front 62

dermatome

Back 62

musculature of dermis of the skin of somite

Front 63

myotome

Back 63

paraxial muscles of somite

Front 64

sclerotome

Back 64

vertebrae of somite

Front 65

epimere

Back 65

region of the development of mesoderm – “paraxial mesoderm” – extends along the long axis of the embryo notochord

Front 66

What are the regions of the epimere? Describe them.

Back 66

- somatomers – clusters of mesoderm cells in the head
- somites – more distinct clusters posterior to head divided into dermatome, myotome, and sclerotome

Front 67

mesomere

Back 67

gives rise to kidney structures

Front 68

hypomere

Back 68

gives rise to the gonads

Front 69

induction

Back 69

interactions among tissues to determine cell fate

Front 70

What are some synapomorphies of vertebrates?

Back 70

neural crest, placodes, “head”, muscular derivative hypomere, calcium phosphate, pronephros, eucoelomate, bilateral symmetry, eumetazoan

Front 71

What characteristics define vertabrates?

Back 71

eukaryotic, heterotrophic, multicellular, deuterostomes, notochord does not extend beyond brain, epidermal layer of skin is stratified (2+ layers of skin), bone (calcium phosphate) and/or cartilage, vertebral elements, cranium, nephron function of kidney, brain well developed, 10-12 pairs of cranial nerves, embryonic tissue – neural crest

Front 72

What characteristics define Myxini?

Back 72

jawless, no trace of vertebrae on or around their notochord, body fluid composition is similar to surrounding seawater

Front 73

What major group constitutes myxini?

Back 73

Hagfishes

Front 74

What synapomorphy defines gnathostomes?

Back 74

jawed vertabrates

Front 75

What characteristics define gnathostomes?

Back 75

bony jaw, bones – calcium phosphate

Front 76

Name the groups that constitute Gnathostomes.

Back 76

placoderms, chondrichtyes, ancanthodii, osteichthyes, amphibia, lepospondyii, reptilia, aves, mammalia

Front 77

What are the major characteristics that define chondrichthyans?

Back 77

similar fin structures, cartilaginous skeleton, and pelvic claspers in males, placoid scales

Front 78

What major groups constitute chondrichthyans?

Back 78

Elasmobranches and holocephalans

Front 79

What are the characteristics that define elasmobranches?

Back 79

tooth replacement in most sharks, electric organs in some rays

Front 80

What groups comprise elasmobranches?

Back 80

sharks and rays

Front 81

What are characteristics of holocephalans?

Back 81

body does not end in an enlarged propulsive caudal fin; instead it is long and tapered to a point, operculum covers gill slits, scales are absent, males have cephalic clasper in addition to pelvic clasper

Front 82

What is the major group that comprises holocephalans?

Back 82

chimaera (ratfish)

Front 83

What are some synapomorphies of teleostomes?

Back 83

mouth terminal, narrow-based braincase, three otoliths in ear

Front 84

What are the characteristics that define teleostomes?

Back 84

jaw opening, gill cover (ossified), and gill flap (branchistegal rays)

Front 85

What major grups constitute teleostomes?

Back 85

bony fishes and tetrapods

Front 86

What characteristics define acanthodians?

Back 86

spiny on top and sides of body, each fin except the caudal fin was defined on its leading edge by a prominent spine that probably supported a thin web of skin, notochord served as major mechanical strength for the body, nonoverlapping scales, extinct

Front 87

What are the synapomorphies of the group actinopterygians?

Back 87

air bladder, vertebral development, brain development

Front 88

What characteristics define actinopterygians?

Back 88

ossified bone, most have swim bladder that provides neutral buoyancy, lepidotrichia (slender rods that provide internal support to fins), ray-finned fishes, fins supported by lepidotrichia, muscles that control fins are located within body wall, fins rays attached directly to limb girdles

Front 89

What are the synapomorphies of sarcopterygians?

Back 89

stylopodium: proximal element of limbs (humerus or femur or homologues)

Front 90

What characteristics define sarcopterygians?

Back 90

ossified bone, most have swim bladder that provides neutral buoyancy, lepidotrichia (slender rods that provide internal support to fins), paired fins rest at the ends of short, projecting appendages with internal bony elements and soft muscles; “fleshy-finned fishes” or “lobe-finned fishes” (lobe between fin rays and limb girdles; lobe is supported by stylopodium

Front 91

What major groups comprise sacropterhgians?

Back 91

coelocanth, lungfishes, rhipidistians (extinct)

Front 92

What characteristics define temnospondyls?

Back 92

extinct sister group to amphibians

Front 93

What characteristics define lissamphibians?

Back 93

sister group to temnospondyls, eggs lack shells and extraembryonic membranes are laid in water or moist locations, paired lungs, mucous glands of the skin keep them moist, and granular glands produce toxic or unpleasant chemicals, respire through their skin, have pedicellate teeth with a suture dividing the tooth base fro the tip and have auricular operculum (extra bone in ear)

Front 94

What groups constitute lissamphibians?

Back 94

frogs and toads (anurans), salamanders (urodeles), Caecilians

Front 95

What are the characteristics of amniotes?

Back 95

presence of membrane surrounding embryo (embryo enclosed inside an amniotic egg

Front 96

What are the characteristics of sauropsids?

Back 96

braincase

Front 97

What groups constitute sauropsids?

Back 97

– birds, dinosaurs, modern reptiles

Front 98

What are the characteristics of parareptilia?

Back 98

distinctive ear region where the eardrum is supported by the sqamosal and retroarticular process, the digits of the foot articulate with the ankle bones

Front 99

What groups constitue parareptilia?

Back 99

only extant are turtles (testudinata)

Front 100

What characteristics define the group testudinates?

Back 100

shell made up of a dorsal carapace of expanded ribs and surface skin plates and a connected ventral plastron of fused boney pieces

Front 101

What characteristics define the group Eureptilia

Back 101

two openings in temporal region of skull

Front 102

What groups constitue Eureptilia

Back 102

diapsida (archosaurs (includes birds) and lepidosaurs)

Front 103

What characteristics define Archosaurs?

Back 103

anteorbital foramen, trend towards bipedalism (two foot locomotion)

Front 104

What groups constitue Archosaurs?

Back 104

dinosaurs, birds, crocodiles and related groups

Front 105

What groups constitute lepidosaurs?

Back 105

snakes, lizards, and tuatara

Front 106

What are the characteristics of birds?

Back 106

members of archosaurs, lay eggs encased in shells, amniotes, capacity for flight, feathers, talons

Front 107

What are the synapomorphies of synapsids?

Back 107

features of skull and pectoral girdle

Front 108

What are the characteristics of synapsids?

Back 108

amnioties with a single temporal bar, transition from ectothermic to endothermic amniotes

Front 109

What groups comprise synapsids?

Back 109

Pelycosaurs, therapsids

Front 110

What characters define the group pelycosaurs?

Back 110

sail-backed reptiles supported by neural spines, extinct

Front 111

What characteristics define the group therapsids?

Back 111

most terrestrial group, greater diversity in ody design, quadrupedal and had five digits on feet, legs positioned directly under body, specialized teeth, became endothermic

Front 112

What are the characteristics of mammals?

Back 112

– hair, mammary glands, endothermic, nourished from birth from milk secreted by mothers, sebaceous and sweat glands, anucleate red blood cells, large brain in comparison to body size, maintenance of high body temperature

Front 113

What are the characteristics of montremes?

Back 113

hair, suckle their young, are endotherms, embryos are developed in shelled eggs

Front 114

What are the characteristics of marsupials?

Back 114

tiny young are born at an early developmental stage, pull themselves into their mother’s pouch, and suckle there until considerable larger

Front 115

What are the characteristics that define placental mammals?

Back 115

nutritional and respiratory needs of young are provided through placenta

Front 116

What are the characteristics of deuterostomes?

Back 116

indeterminate/radial cleavage, blastopore becomes anus (1st opening is anus, 2nd opening is mouth)

Front 117

What groups constitute deuterostomes?

Back 117

echinoderms, hemichordates, chordates

Front 118

What are the characteristics of echinoderms?

Back 118

body symmetry is radial, adults have no head and are relatively sessile, larva have head and are free swimming

Front 119

What groups constitute echinoderms?

Back 119

sea stars, sea cucumbers

Front 120

What are the characteristics that define protosomes?

Back 120

determinate cleavage, blastopore is mouth

Front 121

What are the characteristics that define cephalochordates?

Back 121

notochord extends entire length, gill slits, dorsal nerve cord, post anal tail, endostyle, circulation (but no heart), midgut cecum (precursor to liver and pancreas)

Front 122

What are the characteristics that define urochordates?

Back 122

sessile as adults, more like other chordates as larva, , filter feeders as adults; AS LARVA: notochord, dorsal hollow nerve cord, post anal tail, endostyle, pharyngeal gill slits; AS ADULTS: pharyngeal slits and endostyle

Front 123

What groups constitute urochordates?

Back 123

sea squirts, larvacea, thaliacea

Front 124

What are the characteristics of hemichordates?

Back 124

gill slits, nerve cord region – dorsal hollow only in part, but no notochord, no post anal tail, and no endostyle; larval form very similar to echinoderm larval form (molecular evidence suggest a strong relationship)

Front 125

What group constitutes hemichordates?

Back 125

acorn worm