test 1 Flashcards
study of structure and function and how that structure plays a role in evolution of new forms
morphology
suggest descent from a common ancestor, inherited similarities, relates to origin
homologous structures
solutions to a common challenge, relates to function; similar function in similar habitats can produce convergent forms; lead to convergent evolution
analogous structures
any similarity between characters that is due to their shared ancestry, common historical ancestry can carry forward shared structures
homology
occurs when characters are similar, but are not derived from a common ancestor; accidents and incidental events can make parts look alike
homoplasy
a structure or behavior possesses the necessary form and function before the biological role arises that it eventually serves, adaptive traits serve the roles of the moment if there is not an immediate role selections eliminates the trait, traits do not anticipate a later need or role
preadaptation (exaptation)
homologous characters that already exist in a common ancestor
primitive condition/plesiomorphic trait
homologous characters that have evolved more recently and therefore only occur among certain species in the cladogram
derived condition/synaptomorphic trait
a group of organisms that is given a name
taxon
a group of organisms that exists as a result of evolutionary process: a species is a lineage, a collection of organisms that share a unique evolutionary history and are held together by the cohesive forces of reproduction; a monophyletic group or clade is a group of taxa encompassing an ancestral species and all its descendents
natural taxon
represents an incomplete or invalid evolutionary unit: paraphyletic group and polyphyletic group
artificial taxon
a taxon that includes an ancestor but not all of the descendants of that ancestor
paraphyletic group
artificial because its members are derived from 2 or more ancestral forms not common to all members
polyphyletic group
clade of animals characterized by the formation of the organism’s mouth before its anus during embryonic development; blastopore (mouth), spiral cleavage, schizocoelic coelom, ectodermal skeleton
protostome
animals characterized by their anus forming before their mouth during embryonic development; blastopore (anus), radial cleavage, enterocoelic coelom, mesodermal skeleton
deuterostome
notochord, pharyngeal slits, endostyle/thyroid gland, dorsal hollow nerve cord, postanal tail
what cephalo- and urochordates and vertebrates have in comon
cephalo- and urochordates: lack a bony or cartilaginous skeleton, all marine, suspension feeders; vertebrates: possess endoskeleton, terrestrial or marine, most use jaws to feed
differences between cephalo- and urochordates and vertebrates
notochord, pharyngeal slits, endostyle/thyroid gland, dorsal hollow nerve cord, postanal tail
5 fundamental features of chordates
develops from mesoderm, ventral to nerve cord, mechanical properties of a rod but biomechanically a hydrostatic skeleton
notochord
all chordates have had these, functions: suspension feeding-via mucus, respiratory exchange; evolution of a muscular pharyngeal pump, superior fluid movement compared to cilia
pharyngeal slits
derived from ectoderm in embryonic origin, formed through invagination of a neural plate, sinks to reside dorsally from notochord
dorsal hollow nerve cord
share some or all 5 features of the fundamental chordate body plan; larval-pelagic/planktonic (limited locomotor capability), metamorphosis, adult-benthic/burrowing/sessile; marine animals that feed by means of cilia and mucus
protochordates
first appearance of chordate body plan components, sister taxa with echinoderms, features=pharyngeal slits, dorsal collar cord, epibranchial ridge; burrow or suspension feeders: cilia and mucus food capture, in mouth to pharynx out pharyngeal slits to brachial pouch and out brachial pores; show traits that link chordates and echinoderms
hemichordates
primarily water exit during filter feeding, secondarily respiratory exchange through vascularized tongue bar, branches from the dorsal and ventral blood vessels supply each tongue bar suggesting that respiratory exchange also occurs in the pharyngeal slits of the hemichordate
function of the pharyngeal slits
deuterostome; ciliated, simple gut, planktonic larva: resembles the auricularia larva of echinoderms, molecular and morphological agreement therefore single taxa; some species of hemichordata whose larval metamorphosis results in a circulatory and excretory system with probable vertebrate homology
tornaria larva
muscular contractions cause contraction of notochord muscle cells via the nerve cord resulting in stiffening, possible for burrowing or bursts of speed
unique amphioxus notochord
only the larva exhibits all 5 chordate features
urochordate ascidian larva
nervous system: sensory vesicles (ocellus/otolith), cerebral ganglion, visceral ganglia, dorsal hollow nerve cord
amphioxus cephalochordate
vertebral column: defines the body axis, incrementally replaced the notochord to meet the mechanical demands of the organism; head: defined by cranium/skull, cephalization clustered sensory organs (the enlarged anterior part of the neural tube), vertebrate sensory organs of the head are derived from vertebrate-unique neural crest cells and epidermal placodes (unique neurogenic ectoderm)
vertebrate innovation
mechanical changes to the pharynx: encircling bands of muscle, cartilage replaced collagen in pharyngeal bars, muscular pump incrementally replaced cilliary pumps, removed overall organisms size limits, drove gill evolution to satisfy respiratory demands; muscular suspension feeding and respiration currents: increasingly active lifestyle and cephalization; raptorial feeding: selective feeding/forceful capture of larger particles, expansion and closure of the pharyngeal pump, anterior pharyngeal bars become grasping jaws, active predation of large prey
evolutionary features of gnathostome (jawed vertebrates)
five common chordate features, cephalized brain and vertebrae, dermal skeleton and lateral line, pectoral fins, jaws and pelvic fins
early fish evolution synapomorphies
early vertebrate lacking jaws with a biting apparatus derived from pharyngeal bars (muscular pump to produce food-bearing water current), larval benthic, suspension feeder, showing much similarity to amphioxus
agnathans
product of the cambrian explosion; amphioxus-like pharynx, atrium, and atriopore; lacked skull and ear capsule, straight myomers; vertebrate-like gill filaments large brain with putative eyes and vertebrae; agnathan chordate
haikouella
skull elements with sensory organs, gill bars, v-shaped myomeres, heart; agnathan vertebrate
haikouichthys
mysterious mineralized fossil teeth finally connected to a jawless but very motile vertebrate, modification on pharyngeal basket suspension feeding into moving plates that caught and shredded food, recent analysis had shown evidence of convergent tooth evolution; extinct group of agnathan (jawless) vertebrates
conodonts
“shell-skins”, agnathan, complex eyes, dentin: neural crest derived tooth component, few appendages, sensory lateral line, evolution of bone: dermal bone body armor covering cartilage vertebral skeleton
ostracoderms
“fleshy-finned fish”-pivoting in shallow water (lungfish) or holding on to bottom (coelacanths); gave rise to tetrapods via rhidipstians: cosmoid scale, no link between skull and pectoral girdle, robust pectoral digit bones, flattened skull with dorsal spiracle for air breathing, loss of bony gill covers, large ribs for torso support on land
sarcopterygii
shows clearly chordate features and similar overall body plan to vertebrate lamprey
amphioxus
parietal and postparietal bones in dermal skull roof meet in a dermal intracranial joint, the external manifestation of the endocranial hinge; intracranial joint allows the snout to flex ventrally when feeding, strap-like basicranial muscle spans this joint, connecting the cranial and caudal ends of the skull and its powerful contractions drive the teeth of the upper jaw bones deep into prey; intracranial joint is lost in later tetrapods
in sarcoptygerians and tiktaalik
gave rise to land vertebrates, tetrapod design: paired appendages, jaws, vertebrae, lungs
lobe-finned fishes
chiridium: a muscular limb with well-defined joints and digits
primary tetrapod characteristic
specific tooth structure, dermal skull bones, limbs with polydactyl digits (8), weight-bearing girdles, lacked airborne auditory system, retained fish brachial arches, mobile neck region, aquatic reproduction, lateral line in juveniles only
labyrinthodont features
primarily aquatic vertebrates (cyclostomes, fish, and amphibians have these mechanoreceptors that are sensitive to minute, local water displacements so approaching organisms are detected and localized to perceive and locate prey, approaching enemies or members of the animals own species; found in young but not adult labyrinthodonts
lateral line organs
the second phase of development, a migration of blastocyst cells inward leading to multiple distinct layers of tissue called germ layers-ectoderm: outer layer of skin, hair, lining of the nose and mouth and nervous system; endoderm: digestive tract, respiratory tract, liver, and pancreas; mesoderm: muscles and skeleton
gastrulation
allows passage of materials by diffusion and filtration, found in kidney glomeruli, air sacs of the lungs, lining of blood vessels; flat nucleus
simple squamous epithelium
single layered cube shaped cells, role in absorption and secretion
simple cuboidal
single layer of tall cells, absorption, secretion of mucus, ciliated type propels mucus; microvilli, noncilliated
simple columnar
single layer of cells of varying heights, nuclei at different levels, cilliated
pseudostratified columnar epithelium
pseudostratified and only in the bladder and ducts of urinary system, resembles both stratified squamous and stratified cuboidal, stretches readily permits distension
transitional epithelium
more than one layer of cells, flat surface cells, protects underlying tissues in areas subjected to abrasion, non-keratinized found in esophagus, keratinized found in epidermis
stratified squamous
more than one layer of cells, cube shaped, plays a role in protection in large ducts of mammary, sweat, and salivary glands
stratified cuboidal
more than one layer of tall cells, plays a role in protection and secretion, rare cell type found in male urethra and large ducts
stratified columnar
endocrine glands and exocrine glands
glandular epithelium
secretions (hormones) pass into blood after passing through interstitial fluid; produce hormones that regulate various body activities; examples include pituitary gland, pineal gland, thyroid and parathyroid glands, adrenal glands, pancreas, ovaries and testes
endocrine glands
secretions released into ducts; produce mucus, perspiration, oil, earwax, milk, saliva, digestive enzymes
exocrine glands
variety of functions in diverse context, all except adipose have significant interactions with extracellular matrix-determines the physical properties of the connective tissue and its functional role (protein fibers, ground substances); general: widely dispersed, ligaments and tendons and dermis…; special: hemopoietic (makes blood cell types), mineralization (cartilage), calcification (bone)
connective tissues
firm but flexible; ground tissue-chondroitin sulfate, polysaccharides, salts; fibers-collagenous or elastic; chondrocytes within lacunae; hyaline-ends of bones, tips of ribs, trachea, precursor to bone; fibrocartilage-collagen fibers to resist warping, intervertebral discs, discs in knee; elastic-ear and nose, flexible and springy
cartilage
osteocyte connective tissue with calcium phosphate added to the matrix; vascular and innervated
bone
endochondrial ossification: formation of cartilage from collagen and formation of bone from cartilage; intermembranous ossification: formed directly from mesenchyme with no cartilage intermediate
patterns of embryonic bone development
from within cartilage; formation of a cartilage model of future bone from mesenchymal tissue and the subsequent replacement of this cartilage model by bone tissue, occurs in three regions of the bone: diaphysis (middle shaft), epiphysis (each end), epiphyseal plate/metaphysis (between epiphysis and diaphysis)
endochondral bone development
- hyaline cartilage template 2. diaphysis bone collar formation 3. calcification and vascularization of the diaphysis 4. ossification by osteoblasts 5. secondary ossification of the epiphysis 6. continued length growth by cartilage growth in epiphysis and ossification of the diaphysis 7. loss of epiphyseal plate with maturity
endochondral bone development steps
bone forms directly from mesenchyme cells, no cartilage precursor; mesenchyme cells produce osteoid tissue, blood vessels invade and tissue become calcium enriched, true bone is formed and expands; three types of specialized development: dermal bones-skull (dermatocranium), integument (dermal plates); sesamoid bones-form with tendons, patella of the knee
intermembranous ossification
composes most of the fibrous connective tissue of the dermis, regularly patterned, alternating layers give shape and structure and material properties
collagen “plies”
flexible, allows lateral bending, resists distortion, stretched without wrinkling, allows smooth water flow
dermal material properties of shark skin
accumulation of various protein products as new epidermal cells push superficial ones to the surface creating a nonliving layer that serves to reduce water loss, more often in terrestrial organisms; avoids: drying, abrasive damage
keratinization
nonliving layer that serves to reduce water loss, dead cells that have produced and accumulated keratin, increases with friction (callus), can differentiate into specialized structures, ex: claws, hooves…
stratum corneum
integument folds; if dermal ossification in origin, then dermal scales; if epidermal keritinization in origin, then epidermal scales
scales
covered with mucus (mucous cuticle); resists infection, increases laminar flow, evasion of predators, toxic components
fish skin is “alive” and usually not keratinized
raised dentin and enamel mushroom-shaped tubercles over dermal bone
ostracoderm scales
pointed or cone shaped and show no signs of growth develop in the dermis, projects through the dermis gaining an enamel cap
chondrichthyes placoid scales
do not pierce the epidermis, covered by mucus forming, stratified epidermis
bony fish scales
enamel and dentin, double layer of bone, found on sarcopterigians
cosmoid scales
thick enamel without dentin over bone, found on gars
ganoid scales
only non-calcified lamellar bone-lacks enamel, dentin, and vascular bone; two varieties: cycloid and ctenoid
teleost scales
loss of dermal scales, little keratinization but stratum corneum protects from abrasion and retains moisture, cutaneous respiration; two types of glands: mucous gland-smaller, poison gland: larger, conspicuous secretory product
amphibians
extensive keratinization (stratum corneum), lipid barrier (multicellular glands)
tetrapods must resist desiccation
extensive keritinization, epidermal scales-lack underlying support, fold in the epidermis
reptile skin
modified reptile scales-homologous skin specializations, reptilian ancestors had to adapt to significant differences between land and the aquatic environment-production of a barrier in the skin that limited the loss of water by transpiration or evaporation, protected against UV light and provide mechanical protection; development of soft alpha-keratin and hard beta-keratin, only bird and reptiles possess hard beta-keratin along with soft alpha-keratin for flexibility
bird feathers=modified reptile scales
non vascular, noninnervated; epidermal keratinization, found on specific tracts (pterylae), molted, like reptile scales, “a mature dead keratinocytes that is full of slits”
feathers
proliferation: interaction between dermis and follicle produced keratinocytes, patterning: varying morphogenic signals create keratin structures and spacing with the sheath, unfurling: preening removes the sheath and results in interlocking of barbules, dermal core regression: calamus formation
feather regeneration
rapid expansion of the buccal cavity, hyoid apparatus forms a strut
suction feeding apparatus
study of structure and its function and how that structure plays a role in evolution of new forms
morphology
natural selection acts on existing parts to affect the whole
emergent properties
animals that can be divided into several identical halves when cut along the central axis
radiata
animals that can be divided into two identical halves along a single axis
bilateria
suspension feeders
hemichordates feeding mechanism
filter feeders
urochordates feeding mechanism
hypothesis that during the course of animal evolution, the structures along the dorsoventral have taken on an orientation opposite of that of the ancestral form
dorsal ventral inversion
suspension feeding based on pharyngeal filtering apparatus surrounded by an atrium
cephalochordates feeding mechanism
the anterior clustering of specialized sensory organs such as paired eyes, ears, nose, and other sensory receptors forming a head and brain during evolution and embryonic development
cephalization
a special group of early embryonic cells that depart from the neural tube, migrate through defined pathways, and differentiate into a vast array of cell types
neural crest cells
asymmetric vane=flight feather, symmetric vane=contour feather
types of feathers
composite organ including the epidermis (produces hair, feathers, claws, nails, horn beaks) and dermis (gives rise to dermal bones and osteoderms of reptiles)
integument
