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85 Cards in this Set
- Front
- Back
taxonomy |
-naming and classifying species into hierarchical groups (taxa) -developed in 18th century by Linnaeus |
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systematics |
-classification system of groups linked by shared common descent -developed in 20th century by Willi Hennig |
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phylogeny |
hypothesis for evolutionary relationships of taxa |
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apomorphies |
derived characters, not from ancestral characters |
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node |
common ancestor of two descendant taxa |
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root |
base of phylogeny |
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synapomorphies |
shared derived characters by two or more taxa |
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plesiomorphies |
ancestral characters |
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symplesiomorphies |
characters shared by a group of organisms found in their common ancestor |
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monophyletic lineage |
includes common ancestor and all descendants |
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paraphyletic |
includes a common ancestor and only some of its descendants |
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polyphyletic |
taxon that does not include most recent common ancestor of all its members |
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clade |
a phylogenetic lineage originating from a common ancestral taxon and including all descendants |
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parsimonious |
the evolutionary relationship requiring the fewest number of changes from ancestral to derived character states |
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parallel evolution |
species that diverged relatively recently develop similar specializations (not common ancestry) |
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sister group |
monophyletic lineage most closely related to the monophyletic lineage being discussed |
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reversal |
produces similar structures in distantly related organisms (not common ancestry) |
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monophyletic |
having a single evolutionary origin |
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chordate notochord |
-rigid dorsal rod -site of attachment for muscles to permit body propulsion from myomeres contraction -vertebral column surrounds it |
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chordate dorsal nerve cord |
-precursor to central nervous system -concentrated sensory apparatus in the front of the body |
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chordate postanal tail |
muscular, segmented tail expanding beyond the anus |
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chordate endostyle |
-ventral longitudinal groove along pharnyx -secretes mucus to trap food particles -homologous to vertebrate thyroid gland which regulates body's metabolic rate |
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chordate pharyngeal slits |
-present along pharynx -used for filter feeding -used for respiration O2 uptake and CO2 released by diffusion |
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chordates |
classification of all vertebrates |
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cephalochordata (27 spp.) |
-small filter feeders of coastal marine environments -large surface to volume ratio because lack of large organs -sequential contraction bends body in S shape |
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urochordata (tunicata) (3000 sp) |
-marine filter feeders -free swimming larvae -sessile adults have highly derived body plan incurrent siphon brings water in and excurrent releases -similar look to cephalochordata |
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cephalization |
-higher rates of activity increase tendency to explore new environments -required specialization of head region -protection for anterior head region |
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embryonic development |
-endoderm is the inner lining of digestive tract -ectoderm is the epidermis and nervous system -mesoderm is the muscles, bones, cartilage, blood, notochord, vessels, and urogential tract |
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neural crest |
-4th germ layer only found in vertebrates -gives rise to structures in the head (cranial bones and muscles, peripheral nervous system, pigment cells) |
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hox genes |
-control other genes regulating longitudinal body development and segmentation -larger sets increase ways they can interact generating new phenotypes -1st duplication of all genes following divergence from vertebrates -2nd duplication before evolution of gnathostomes |
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vertebrae |
-cartilaginous or bony skeleton elements that surround nerve chord and notochord -provide protection and stability |
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cranium |
-protective enclosure for brain -protects body parts exposed to new environment first -supports complex sense organs to navigate environment -major components include chondrocranium, splanchrocranium, and dermatocranium |
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branchiomeric muscles |
-expand and contract visceral skeleton -permits suction feeding -moves water over gills for O2 absorption |
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extended head |
-cephalic region extends beyond notochord -provides physical space for brain, sense organs, and modified branchial architecture |
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tripartite brain |
-larger brain with distinct 3 part arrangement -allows detection and integration of wide range |
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circulatory system |
-blood contained within vessels until they reach target tissues in which then they diffuse out -O2 and CO2 transported into bloodstream -oxygen is bound to hemoglobin, increasing efficiency of O2 uptake and circulation -3 chambered heart used to efficiently pump blood in unidirectional fashion -sinus venosus- atrium- ventricle |
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myomere arrangement |
-W shape permits greater overlapping of adjacent myomeres -greater range of body movement when muscles contract -modified from V shape seen in cephalochordates |
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gut activity |
-movement of digestive tract by penstasis -extracellular digestion has food particles broken down first by secretion in the liver and pancreas, they are then absorbed |
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kidney |
-organ specialized to remove nitrogenous waste and maintain water/ion balance -basic unit is nephron |
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photoreception and vision |
-adaptions for detection of light -pineal gland -well developed eyes with retina, cones, and rods |
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chemoreception |
-specializations for detection of dissolved molecules (low chemicals in water) |
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lateral line system |
-sensory system that detects water movement by pressure changes |
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electroreception |
ability to detect electrical impulses generated in biological tissues |
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vestibular apparatus |
-organ of balance -indicates position in space by fluid movement in tubes connected to organ -secondarily modified in land vertebrates and some fishes to detect our displacement |
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cambrian vertebrates |
->500mya -small, soft bodied fish shaped animals -cranium with sensory structures indicates presence of neural crest -W-shaped myomeres and notochords |
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myxinoidea (hagfishes) |
-75sp -most primitive living vertebrates with mix of ancestral and uniquely derived traits -evolved 500 mya -jawless fishes with eel like body form -15 gill slits -one semicircular canal -accessory hearts in liver and tail -only rudiments of vertebrae |
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hagfishes head |
-3 pairs of head tentacles are tactile organs (barbels) -used in pray search -mouth has 2 rows of teeth like structures made of keratin (not avg vertebrate teeth) |
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hagfishes feeding behavior |
-deep sea cold water scavengers of carcasses but can pursue live prey in sediment -can tie body in knot to gain leverage when shearing off flesh |
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hagfishes defensive strategy |
-secretes massive amounts of mucus and protein from unique slime glands when disturbed -causes prey to let go because they are unable to properly breathe |
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petromyzontoidea (lampreys) |
-40 sp -jawless fishes considered closest living relative of gnathostomes -mix of primitive and highly derived adaptations -possesses arcualia (cartilagenous elements of dorsal neural arches) -large eyes -7 external gill slits -2 semicircular canals -heart innervated by CNX (vagus nerve) |
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larval lamprey (ammocoete) |
-use pharynx for filter feeding and respiration -they show key transition in function of pharnyx |
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adult lamprey |
-specialized for parasitic lifestyle -simple digestive tract linked to fluid diet - oral hood with teeth like spines provide suction and abrasion -spiky tongues used as rasp to scrape off skin -oral gland secretes anticoegulant |
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flow-through respiration in lampreys |
-water passes through mouth into respiratory tube where it exchanges O2 with gill filaments -pumped out through external gill slits |
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tidal respiration in lampreys |
-water pumped into pharynx via external gill slits by suction created by elastic recoil of branchail basket -velum prevents water from entering esophagus |
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invasion ecology |
-P. marinus invaded Great Lakes in early 1900s- led to decline of economically important fishes -this is examples of species declination from exotic species introduction |
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conodonts |
-evolved in late cambrian (500 to 200 mya) -soft bodied jawless vertebrates with unique paryngeal morphology -tooth-like structures composed of apatite -s teeth for grasping, p teeth for crushing |
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ostracoderms |
-multiple lineages of jawless vertebrates -more derived then living agnathans -arrived (460-360 mya), declined with extinction of small soft bodied prey at end of devorian -first verts with bony tissue -lacked true jaws, but some had moveable mouth plates that's not seen today |
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original functions of bone |
-protection from predators -insulation of electroreceptor organs -regulation of key minerals (calcium & phosphorus) |
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odontodes |
-skin elements homologous with true vertebrate teeth -placoid scales of living sharks closely resemble odontodes of ostracoderms |
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gnathostomes |
-larger size, greater activity, and increased complexity -2nd hox gene duplication -evolved true jaws (modified branchial apparatus) -expanded into new ecological niches |
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derived features of gnathostomes |
-jaws (usually with teeth) -gill rakers (block food from entering gills) -hypobranchial muscles permits suction feeding -2 sets of paired fins helps improve locomotory performance -2 olfactory tracts for 2 distinct nostrils increases sensitivity to dissolved chemicals -first gill slit is spiracle -3 semicircular canals -centrum with ribs -horizontal septum -myelin sheaths on neurons -conus ateriosus on heart |
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gnathostome fins |
-enlarged caudal fins produce thrust -unpaired dorsal and anal fins control roll (rotation around long axis) and yaw (left and right swing) -paired pectoral and pelvic fins control pitch (up and down tilt) and braking/accessory thrust |
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evolution of jaws |
-jaws evolved from branchial gill arches -first gill arch became upper and lower jaw -mandibular arch: pelatoquadrate cartilage and mandibular cartilage -first gill slit became spiracle (allows water to enter pharynx during feeding) -second gill arch became hyoid arch -new branchial muscles evolved for respiration -strong suction brings in more water -selection for larger muscles required larger gill arch |
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mallatt hypothesis |
mobile jaws are by product of selection for gill ventilation |
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secondary functions of jaws |
-grasping and manipulation of food items -non food object can be manipulated for other purposes |
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placoderms |
-diverse group of extinct primitive gnathostomes (early silurian 440-360 mya) -mostly bottom dwellers (benthic) -thick bony shield over anterior half of body -joint between head and truck allowed head to lift when feeding -some had truth teeth others had fake made of bone -earliest known verts with live birth (shown by fossils) |
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acanthodians |
-early ordovician (450-280 mya) -extinct group closely related to true bony fishes -evolved in oceans but diversified in freshwater habitats -up to 6 pairs of ventrolateral fins in addition to pelvic and pectoral fins -fusiform bodies and heterocercal tail suggest active midwater (pelagic) lifestyle |
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density and viscosity |
water is denser and more viscous than air |
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oxygen content |
-water has lower oxygen content than air -requires efficient mechanisms to extract it -saltwater has lower O2 than freshwater |
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heat conductivity |
-water has higher heat conductivity than air -heat readily transferred to water -hard to maintain body temp above background water temp |
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obtaining O2 with gills |
-gills are major gas exchange organs of aquatic vertebrates derived from pharynx -usually receive water unidirectional from mouth, covered by operculum in bony fishes |
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gill structure |
-gill arch is the skeletal structure derived from pharyngeal bars of chordate pharynx, support gill filaments -gill filaments are thin vascularized structures attached to gill arches |
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capillaries (secondary lamellae) |
blood vessels linking the afferent and efferent arterioles within each gill filaments |
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counter-current exchange |
-O2 in water diffuses into blood capillaries of the secondary lamellae -ensures diffusion gradient maintained along secondary lamellae -always higher concentration of oxygen in water relative to secondary lamellae |
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sequence of blood flow through the gills starting at conus arteriosus |
afferent branchial artery, afferent arteriole, capillary, efferent arteriole, efferent artery |
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labryinth |
-this organ is in the back of the mouth -rich in the blood vessels -allows O2 to move into gills |
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buccal pumping |
-water pumping through gills by opening and closing mouth -suction moves water into mouth -positive pressure forces it across gills |
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ram ventilation |
-O2 intake by swimming with mouth open -many sharks and predatory bony fishes |
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adjusting buoyancy |
-ordinarily most fish are neutrally buoyant -water pressure changes with depth |
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swim bladder |
-air filled sacs to regulate buoyancy -to change depth in water column they must change air volume in the bladder |
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buoyancy |
-when descending outside water pressure increases and bladder compresses -must add gas to bladder to prevent bladder from collapsing -when ascending hydrostatic pressure decreases and bladder expands -must release gas to prevent bladder from over expanding |
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physostomous fish |
-retain connection (pneumatic duct) between gut and swim bladder -add air to bladder by gulping air at surface which then enters via digestive tract -burping allows fish to rise |
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physoclistous fish |
-lack pneumatic duct-causes the swim bladder is disconnected from digestive tract -cannot add air bladder by gulping at surface -derived condition -ventral part of swim bladder linked to special capillaries (rete mirabile) -gas gland secretes lactic acid and CO2 increasing blood pH -as blood acidifies, hemoglobin releases O2 into blood -when O2 pressure in rete mirabile > swim bladder, O2 diffuses into swim bladder -excess O2 released through muscular valve (ovale) back into blood |
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bohr effect |
hemoglobin reduces affinity for O2 |
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root effect |
hemoglobin cannot bind as much O2 |