hollow sphere of cells formed during early stage of embryonic development in animals

-created when zygote undergoes cleavage

innermost germ cell layer; develops from gastrula

-consists of flattened cells that become columnar; forms epithelial lining of multiple systems

total cleavage, depending on amt. of yolk

-small cxn of yolk

outermost germ cell layer; emerges first & formed from outer layer of germ cells

-differentiates to form nervous system, tooth enamel,

epidermis, & lining of cavities

fluid-filled cavity formed w/in mesoderm; only present in triploblastic animals

-absorbs shock or provides hydrostatic skeleton; allows organs to grow independently off of body wall

type of mesoderm lying along central axis under neural tube

-gives rise to notochord

-induces formation of vertebral bodies

type of mesoderm found @ periphery of embryo

-will split into 2 layers: somatic mesoderm (future body wall) & splanchnic mesoderm (circulatory system & future gut wall)

membrane building amniotic sac that surrounds & protects embryo

-reptiles, birds, mammals

membranous sac attached to embryo providing early nourishment in bony fishes, reptiles, sharks, birds, primitive mammals

-developmental circulatory system of human embryo before internal circulation begins

fluid-filled central region of blastocyst

-forms during embryogenesis when zygote divides through mitosis

opening into archenteron during embryonic stages of organism

protostome: becomes mouth

deuterostome: becomes anus

formation of embryo development in deuterostomes:

mesoderm formed in which coelom forms from 'pinched off' pouches of digestive tract

division of body of animal; mainly discernible in embryonic stage (vertebrates)

'primitive segments'

group of tissues formed from somites that develop into body wall muscle

-each myotome divides into dorsal & ventral hypaxial parts

membrane that exists during pregnancy b/w fetus & mother

-formed by extraembryonic mesoderm & 2 layers of trophoblast; surrounds embryo & other membranes

process by which embryos develop in protostomes:

coelom is formed by splitting mesodermal embryonic tissue

part of developing animal conceptus; helps embryo exchange gases & handle liquid waste

-helps identify amniotes

protostomes: determinate

deuterostomes: indeterminate & radial

mammals: rotational

Spiralia: spiral

 monotremes & animals w/ telolecithal egg cells: discoidal

arthropods & animals w/ centrolecithal egg cells: superficial

type of undifferentiated loose connective tissue derived from mesoderm

-some mesenchyme derived from neural crest cells, thus originating from ectoderm

produce shelled egg, like reptilian ancestors

-only 4 species exist today: 3 species of echidna & platypus

many fish ventrally retain yolk sac after for period of time after hatching

-yolk sac: larval structure enclosing stored nutrients derived from egg

tetrapods w/ terrestrially-adapted eggs

-includes mammals, birds, & reptiles

-eggs protected by extensive membranes

stapes/columella

-function

stirrup-shaped bone of middle ear, lateral to incus & fenestra ovalis

-smallest, lightest bone in body

-transmits sound vibrations from incus to membrane of inner ear inside ovalis

group of reptiles w/ 2 holes in each side of skull

-crocodiles, lizards, snakes, tuatara

diverse range of early archosaurs built somewhat like crocodiles; w/ antorbital fenestra & teeth in sockets ('socket-tooth')

-includes ancestors of birds, dinosaurs, pterosaurs, & crocodiles

swim bladder: gas-filled internal organ contributing to ability of fish to control its buoyancy

lungs: respiration organ in air-breathing animals

-primitive fish had 2 lungs, but one disappeared & other migrated upward to become modern swim bladder

1 of 3 classes of actinopterygians

-have mobile maxilla & premaxilla & corresponding modifications in jaw architecture which make it possible for them to protrude jaw outward from mouth

-caudal fin is homocercal (upper & lower lobes are equal in size)

-spine ends @ caudal peduncle, which is distinguishing feature

-freshwater fish belonging to subclass Dipnoi

-Africa, S. America, Australia

-must come up for air

-burrow in mud & estivate during dry season

'spiny roof'

-extinct labyrinthodont genus, among first vertebrate animals to have recognizable limbs; intermediate b/w first tetrapods & lobe-finned fishes

-eight digits on each hand, proving 5 digits on hands is evolved trait

-axolotl (salamander)

-tiger salamander

-Rough-skinned newt

-flightless birds look like chicks of flighted birds

subclass of animals including all recent amphibians

-three orders: Anura, Caudata, & Apoda

frogs

-characterized by short bodies, bifid tongue, & absence of tail

salamanders

-superficial lizard-like appearance: slender bodies, short noses, long tails

paraphyletic group of early reptiles; share primitive features & resemble ancestors of all modern reptiles

-descended from Anapsids

extinct group of primitive, reptile-like birds

-evolutionary grade of transitional fossils, primitive birds b/w dinosaurs & derived modern birds

posterior opening that serves as only such opening for intestinal, reproductive, & urinary tracts of certain animals

-amphibians, birds, reptiles, monotremes

bastard wing; small projection on anterior edge of wing of modern birds

-freely moving first digit ('thumb'), typically covered w/ 3-5 small feathers

family of fibrous structural proteins

-makes up outer layer of human skin, hair, & nails, baleen of whales, parts of dinosaurs, horn coverings...

grouping w/ in class Mammalia

-synonymous w/ taxon Marsupialia

-produce yolk-sac placenta & give birth to larval-like offspring (marsupials)

anvil-shaped bone/ossicle in middle ear; connects malleus & stapes

-transmits sound vibrations from malleus to stapes

-only exists in mammals

forked bone found in birds & some other mammals; formed by fusion of 2 clavicles

-in birds, primary function is strengthening of thoracic skeleton to withstand rigors of flight

most animals in this group are extinct

-include monotremes

group of mammals consisting of placental mammals plus all extinct mammals that are more closely related to living placentals than living marsupials

-distinguishing feet, ankles, jaw, & teeth

hammer-shaped small bone of middle ear connecting incus & is attached to inner surface of eardrum

-transmits sound vibrations from eardrum to incus

synapsids: 1 opening

diapsids: 2 openings

anapsids: no openings

pigment-containing & light-reflecting cells found in amphibians, fish, reptiles, crustaceans, & cephalopods

-largely responsible for generating skin & eye colour in cold-blooded animals

cellular aggregation seen in histologic sections of developing teeth; lies above dental papilla

-forms enamel, initiates dentin formation, establishes shape of tooth's crown, & establishes dentogingivial junction

pigment that's found in most organisms

-protects against UV radiation

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

-found in many groups of extant & extinct reptiles

outermost layer of epidermis consisting of dead cells that lack nuclei & organelles

-forms barrier to protect underlying tissue from dehydration, infection, chemicals, & mechanical stress

small, nipple-like extensions of dermis into epidermis (make fingerprints)

-blood vessels in papillae nourish hair follicles & bring food & oxygen to lower layers of epidermal cells

1 of 4 major tissues making up teeth; hardest & most highly mineralized substance in human body

-part of tooth we see!

dermal bone found in ventral wall of crocodilian & Sphenodon species; found b/w sternum & pelvis & doesn't articulate w/ vertebrae

-in modern animals, it supports abdomen & provides attachment site for abdominal muscles

type of cell that synthesizes extracellular matrix & collagen, structural framework for animal tissues; plays critical role in wound healing

-most common cells of connective tissue in animals

lacuna

osteon

fundamental functional unit of compact bone; roughly cylindrical structures that are typically several millimeters long

-consists of concentric layers of compact bone tissue that surround central canal (Haversian canal), which contains bone's nerve & blood supplies

thick, horizontal process of maxilla forming anterior 3/4ths of hard palate

-roof of mouth

membrane lining outer surface of all bones except @ joints of long bones

-divided into outer 'fibrous' layer (contains fibroblasts) & inner 'cambium' layer (contains progenitor cells that develop into osteoblasts)

develops into branchial/gill arches in fish, & in humans, as outpockets on either side of developing pharynx

-are anlage for multitude of structures

small passageway

-channel found in ossified bone
-adaptation found on gastric parietal cells

-small ducts in eye

-blood supply w/ tooth

-where bile produced by hepatocytes is drained