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38 Cards in this Set
- Front
- Back
Generalized
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structural complexes that, in some (or all) descendants, have undergone subsequent adaptation to a variety of conditions
ex: an insectivore hand is generalized compared to a bat wing or seal flipper |
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Preadaptation
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structure has necessary form & function before "new" biological role arises
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Homologous Traits (Between taxa)
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# two or more taxa share a feature that is derived from a common ancestry; structures may not look alike & may not function in same way
criteria: similar position, ontogeny, fossil intermediates, genetics? |
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endostyle of Protochordates & thyroid gland of vertebrates
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# share same position
# share same development or ontogeny # share a similar "special" reaction to iodine Structural homologs |
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Analogous Traits (between taxa)
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# features on > 2 or more taxa have a common function
# features do NOT have to look alike to perform same function # features may or may not have a shared ancestry |
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Serial Homology (within taxon)Sexual Homology (within taxon, between sexes)
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* segmented (metameric) structures share common development, design & function
* e.g. vertebrae, branchiomeric muscles in gills# ome reproductive organs share a common embryonic tissue origin& development during indifferent (undifferentiated stage) # e.g. gonads (testes & ovaries) |
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Shared, Derived trait
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* Define - absent in ancestor but shared by some of the related descendants, but not other descendants
* Use - forms subsets within descendants; key role in tracing phylogeny |
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Metazoa
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# Taxa - all Animalia
# Shared, Derived Traits * multicellular * heterotrophic - can't use sunlight to get energy * lack cellulose cell walls outside of cellular membrane * early embryo forms a hollow ball called a blastula * sperm have flagella |
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Bilateria
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# Taxa - Nematoda, Platyhelminthes, Annelida, Arthropoda, Mollusca, Echinodermata, Hemichordata, Chordata +
# Shared, Derived Traits * Triploblastic o 3 germ (embryonic tissue) layers of ectoderm, mesoderm, endoderm * Bilateral Symmetry o body shows cephalization, a head end o body has 3 principal body axes; longitudinal (anterior-posterior), dorsal-ventral, & lateral (left-right) |
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Coelomata
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# Taxa - e.g. Annelida, Arthropoda, Mollusca & others + Echinodermata, Hemichordata, Chordata
# Shared, Derived Traits * Complete Gut o digestive system continuous from a mouth to anus * Coelom present o cavity lined by mesodermal membranes that produce fluid to reduce friction during organ movement o body forms a tube (gut) within a tube to isolate trunk & gut movement o examples - pleural, pericardial, peritoneal membranes |
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Deuterostomata
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# Taxa - Echinodermata, Hemichordata, Chordata
# Shared, Derived Traits * Indeterminate Cleavage o first few cell divisions of fertilized egg are not yet "programmed" to develop into specific tissues o early on, each cell can produce a complete individual * Radial Cleavage o cell divisions occur in same planes through animal to vegetal pole o divisions extend out from a central axis & line up on top of each other * Deuterostome o embryonic blastopore (first opening) becomes anus o i.e. true mouth forms later at opposite end of embryo * Enterocoelous coelom o coelomic mesoderm folds inward as pockets off of endoderm; varies in some descendants * Mesodermal internal skeleton |
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Phylum Chordata
Living Taxa? |
Urochordata, Cephalochordata, "Vertebrata"
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Chordate Shared, Derived Traits
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# Notochord [noto = back]
* long rod forms above dorsal wall of gut; 1st skeletal support system * flexible, "gel-filled" cells covered with fibrous & elastic tissue layers # Dorsal hollow nerve cord * forms from ectoderm - described in embryology chapter # Pharyngeal gill arches * expanded anterior portion of gut * shares dual functions - digestive & respiratory * earliest taxa - small filter feeders o trapped small particles of food in mucus o used cilia to move water over gill arches o some gas exchange occurs across gill arches, but most gas exchange in skin # Endostyle * ciliated groove in floor of pharynx used to track food particles into the gut * attracts iodine & is in same location & shares iodine function with thyroid of vertebrates * homologs to endostyle = subpharyngeal gland of lamprey larva = thyroid gland of adult craniates # Post-anal tail * locomotory device "behind" body, more efficient position * has v-shaped muscle segments (myomeres) to provide force |
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Influence of Paedomorphosis in Craniata/Vertebrae
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* Urochordate Life Cycle
o juveniles are free-swimming larvae with long tails & obvious notochord o adults are sessile/attached to substrate & have lost notochord & tail * Hypothesized "Vertebrate" Origins o alternation of developmental stages or life history of ancestor like Urochordata o "vertebrates" retained some larval Urochordate characteristics into adult stage o paedomorphosis - refers to special type of alteration in life cycle - next lecture |
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Clade Craniata
Shared, Derived Traits? |
axa - Myxini, Cephalaspidomorphi, all gnathostomes
Cranium, INcreased Brain size, Muscular Pharynx for feeding/gas exchange, debated:True Bone |
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Clade Vertebrata
Shared, Derived Traits? |
Taxa - Cephalaspidomorphi, & all gnathostomata
Vertebrae, 2 pair of semi circular ear canals, Large Eyes |
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Clade Gnathostomata
Shared, Derived Traits? |
Taxa - Placodermi, Acanthodii, Chondrichthyes, Actinopterygii, Sarcopterygii & all Tetrapoda
Gnathostome * cartilage or bony support for mouth - more food intake Paired appendages * presence of both pectoral & pelvic paired fins * improved control over locomotion & aided prey capture 3 pairs of semi-circular ear canals * added 1 pair of horizontal semi-circular canals * 3 canals allow detection of acceleration in all 3 body planes |
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OSTEICHTHYES [oste = bone, ichthy = fish = bony fishes]
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# Taxa - Actinopterygii (ray-finned fishes), Sarcopterygii (lobe-finned fishes) & all Tetrapoda
# Trait - presence of lung or swim bladder (in most; may be lost in some Actinopterygii) |
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SARCOPTERYGII [sarco = flesh, pteryg = fin]
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* Taxa - Sarcopterygii (lobe-finned fishes) & all Tetrapoda
* Trait - serial arrangement of bones/cartilages extending far into fin or limbs |
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TETRAPODA [tetra - four, podo- foot]
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# Taxa - Batrachomorpha, Lissamphibians (living amphibians - frogs, salamanders..), & all Amniota
# Traits * 4 limbs (on most) * digits or true separate toes/fingers on limbs, if limbs are present |
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AMNIOTA [amni = fetal lamb; embryonic membrane]
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# Taxa - all Sauropsida (Testudines & all Diapsida) & all Synapsida
# Traits * unique, new extra-embryonic membranes present - the amnion, chorion & allantois * epidermal scales or hardened stratum corneum covers entire body; skin is dry * true claws (or claw derivatives) present on digits |
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Myxini [myx = mucous]
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# Taxa - hagfish
# Traits * eyes primitive, simple & very small * lacks true vertebral elements |
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Cephalaspidomorphi [cephal = head, aspid = shield]
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# Taxa - lamprey & some fossil taxa
# Traits * simple vertebral elements - cartilaginous * larger eyes, more complex ear |
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Placodermi* [placo = a plate, derm = skin]
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Traits
* "armored" fishes, many have large dermal plates over head * unique "teeth" - dermal bones form long cutting edges or "blades" & sharp points |
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Chondrichthyes [chondr = cartilage, ichthy = fish]
taxa, traits, kind of scales? |
# Taxa: shark, skates, rays, ratfish
# Traits * completely cartilaginous skeleton (may have calcium deposits to harden cartilage) * placoid scales or tiny "denticles" with projecting tips that feel like sandpaper * teeth are enlarged placoid scales that are attached to skin & not jaws * 5-7 pairs of long gill slits usually visible in most (ratfish have a fleshy operculum covering the gills) * broad, thick, flat paired fins |
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Actinopterygii [actino = ray, pteryg = fin; ray-finned fishes]
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# Taxa - "bony fishes; a misnomer because some of these have partly cartilaginous skeletons
* e.g. salmon, sturgeon, gar, bowfin (Amia), perch, flounder, etc. # Traits * bony operculum covers gills * flexible fin rays made of tiny overlapping bony scales * a few small bones support base of fin |
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Sarcopterygii [ sarco - fleshy or lobe finned fishes]
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# Taxa - lung fishes & coelacanth; most species are extinct
# Traits * bony operculum covers gills * fins contain series of long, "jointed" bones that extend vertically into fin * muscle associated with these fin bones extends into distal areas |
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Stegocephali or "Labyrinthodontia" [labyrinth = maze, folded, dontia = teeth]
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Traits
* some had specialized highly grooved teeth (labyrinthine) * high otic notch ("ear" opening) in skull angles downward toward brain |
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Lissamphibia [liss = smooth, amphi - double - refers to dual water & terrestrial adaptations]
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# Taxa - frogs, salamanders, caecilians = apodans or legless amphibian
# Traits - most lack dermal or epidermal scales, skin is smooth & moist |
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Anapsida*
* [an = without, apsi = juncture] |
Trait - no openings in temporal regions of skull; ear canal in typical "low" postion
NOTE: paraphyletic group!!! |
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Testudines or Testudomorpha
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# grouping uncertain, not closely related to stem amniotes; perhaps related to either lepidosaurs or archosaurs??
# Taxa - turtles, tortoises # Trait - bony armor around trunk forming a solid dorsal & ventral shell |
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Lepidosauria or Squamates [lepido = scale, sauri = lizard]
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# Taxa - lizards & snakes, tuatara
# Traits - * modified diapsid skull with 1 or 2 of the arches of bone lost to make skull kinetic * specialized epidermal scales (see skin lab) * transverse cloacal slit & hemipenis in males |
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Archosauria [archo = ruler, chief, sauri = lizard]
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# Taxa - alligator, crocodile, caiman & gavial
# Traits * diapsid skull that retains 2 distinct temporal arches of bone * anteorbital fenestra is shaped like an inverted triangle |
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Aves [avi = bird]
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* Taxa - birds
* Traits o feathers?? possibly in some fossil dinosaurs?? o arms modified into wings o modified diapsid skull - retained lower arch of bone, lost upper arch & opened fossa to the eye socket |
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Synapsida* [syn = together, apsi = juncture]
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* Trait - synapsid skull (1 temporal opening)
includes synapsida and mammalia |
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Prototheria [proto = first]
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* Taxa - monotremes & spiny anteaters
* Trait - egg-laying mammal; epipubic bones Metatheria |
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Metatheria [meta = boundary]
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* Taxa - opossum & all other marsupials
* Traits - mammal with very short gestation placenta; epipubic bones |
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Eutheria [eu = good, true ]
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# Taxa - "placental mammals"
# Traits - longer gestation placenta than marsupials; single vagina |