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49 Cards in this Set
- Front
- Back
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Gnathostome synapomorphies
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1) Jaws
2) 2 pairs of paired appendages 3) A 3rd (“horizontal”) semicircular duct in vestibular system of ear (aids 3D orientation) |
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PLACODERMS
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• HEAVILY ARMORED
• Distinct joint between head & trunk shield (so could raise head high) • True jaws but with bony cutting edges, no teeth • 2 pairs paired fins (arrows) • Heterocercal tail |
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ANTIARCHS
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• PLACODERMS
• Pectoral fin enclosed in bone to produce spine (punting bottom feeders) • Spine originally short and unjointed; becomes longer and jointed in later species • Often found in aggregations of several individuals |
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ARTHRODIRES
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• PLACODERMS
• Most diverse placoderm clade (~60% all species); often huge (20+ ft long) • Large NUCHAL GAP allows greater head movement, more forceful bite • Note sclerotic ring in eye; jaw edges can show tooth-like projections • Evidence of both healed and unhealed bite wounds |
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Why did Placoderms go extinct?
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- Decline in sea level in Late Devonian may have eliminated shallow water,
high-oxygen habitats, forcing competition with other lineages (osteichthyes, chondrichthyes) |
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• Bony gill covering
(operculum) |
• Acanthodians (extinct)
• Actinopterygii • Sarcopterygii |
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• Optic pedicel
(golf tee supports eyeball) |
• Placoderms
• Condrichthyes |
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CHONDRICHTHYAN SYNAPOMORPHIES
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(1) CARTILAGINOUS SKELETON
(2) CLASPERS (modified pelvic fin in males, conducts sperm during internal fertilization) (3) PLACOID SCALES (tooth-like structure with pulp cavity, enamel) (4) VERTEBRAL CENTRA (BODY) ELABORATED (reduced notochord) (5) CONTINUOUS PROLIFIC TOOTH REPLACEMENT (TOOTH WHORL) |
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CLADE CHONDRICHTHYES (Cartilaginous “fishes”)
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CHIMERAS & RATFISH
(Clade Holocephali) SHARKS + BATOIDS (SKATES & RAYS) (Clade Elasmobranchi) (Sharks are a GRADE unless batoids are included) |
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EVOLUTIONARY TRENDS IN SHARK MORPHOLOGY
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1) More mobile pectoral fins, improves steering
• Narrow attachment, flexible CERATOTRICHIA 2) More heterocercal tail (top lobe bigger than bottom) 3) Mouth position. (Terminal to Ventral) |
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EVOLUTIONARY TRENDS IN SHARK MORPHOLOGY
Pt 2 |
4) Tooth shape & diversity
• CLADODONT - big middle cusp, lots side cusps (catch prey whole) • Diverse modern shapes & behaviors, fewer side cusps (some have multiple types = HETERODONT) 5) Jaw attachment to skull AMPHISTYLIC-->HYOSTYLIC |
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HYOSTYLIC
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• Ancestral, 2 jaw-skull connections:
(1) Upper jaw (palatoquadrate)-braincase (2) Jaw-hyomandibula-braincase • Connection 1 replaced with LIGAMENT |
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ORDER OF SENSE USE IN PREY DETECTION
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1) OLFACTION (smell - chemoreception)
• Locate prey at distance (1 part in 10 billion) 2) LATERAL LINE (mechanoreception) • Slightly closer distance, thrashing water 3) VISION - also well developed (even low light) 4) TACTILE - may bump unfamiliar prey for close appraisal 5) ELECTRORECEPTION - very close, after eyes closed during strike |
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Sharks have BIG BRAINS for their size, helps process complex sensory info
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True
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BATOIDS!
SYNAPOMORPHIES |
(Rays, skates, sawfish, guitarfish)
1) FLAT BODIES (often enlarge pectoral fins, too) • Originally related to bottom dwelling, some now open water 2) VENTRAL (belly-side) GILLS • SPIRACLE still big, faces up (dorsal) 3) DUROPHAGY - eat hard (shelled) prey • Crushing tooth plates |
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BATOID DIVERSITY
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MAIN POINTS
1) Pect fins get bigger, tail shorter 2) Electric & sting rays different groups 3) Reduce tail to whip (not used for swimming) 4) Eagle/manta rays FLAP pectoral fins to swim, other pass waves along |
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BATOID SWIMMING STYLES
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STINGRAY: pass waves along pectoral fins
(UNDULATION) COWNOSE RAY: flap pectoral fins (OSCILLATION) |
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HOLOCEPHALANS
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Chimeras, ratfish, rabbitfish
• Adaptations for durophagy (hard prey) - AUTOSTYLY = upper jaw fused to braincase - Big crushing tooth plates • Fleshy “operculum” covering gills (not same as later one in bony fish) • Diphycercal tail (vert column between equal-sized lobes) • Swim by flapping pectoral fins |
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osteichthyes
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†ACANTHODIANS
CLADE ACTINOPTERYGII (Ray-finned “fishes”) • Fins supported only by rays CLADE SARCOPTERYGII (Lobe-finned “fishes”, includes TETRAPODS) • Fins supported by robust internal skeleton |
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CLADE OSTEICHTHYES
• SYNAPOMORPHIES: |
1) LEPIDOTRICHIA (bony ray-supports in fins)
2) LUNGS (or swim bladder that evolved from them) |
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CLADE ACTINOPTERYGII
• SYNAPOMORPHIES: |
• SYNAPOMORPHIES:
1) Single dorsal fin |
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CLADE ACTINOPTERYGII
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1 most basal)Polypteriformes
(bichirs) 2)Chondrostei (sturgeon, paddlefish) 3)Lepisosteidae (gars) 4)Amiidae (bowfin) 5)Teleostei (teleosts) |
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Monophyletic group
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another name for clade (= Greek “one tribe”)
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Paraphyletic group
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does not include all descendants of a common ancestor (NOT CLADES)
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Grade
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paraphyletic taxa grouped together for convenience, often because they share similar features (e.g., non-avian reptiles); NOT A CLADE
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Outgroup
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clade outside clade being considered, helps determine primitive features
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Sister taxa
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adjacent branches on cladogram that form clade together
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What does it mean when a character is in 2 groups that don’t form a clade?
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Character was lost in intervening taxa
CONVERGENT EVOLUTION (feature evolved independently in both taxa) |
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Eons
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Phanerozoic (current)
Proterozoic (middle) Archean (oldest) |
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Phanerozoic
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Cenozoic era (65.5 - 0 mya)
Mesozoic era (251 - 65.5 mya) Paleozoic era (542 - 251 mya) |
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Cenozoic
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Quaternary (2nd- humans)
Tertiary(1st) |
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Mesozoic
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Cretaceous (3rd, flowering pants, extinction)
Jurassic (2nd, birds mammals) Triassic (1st, dinosaurs appear) |
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Paleozoic
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Permian (extinction)
Carboniferous (big primative trees, reptiles) Devonian (tetrapods) Silurian (first land plant fossils) Ordovician (first vertebrates) Cambrian (first shells) |
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UROCHORDATES
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tunicates/sea squirts
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CEPHALOCHORDATES
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lancelets/amphioxus
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Craniates
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Hagfish, vertebrates
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CHORDATE SYNAPOMORPHIES
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1) Notochord
(fibrous rod along body axis) 2) Dorsal hollow nerve cord (dorsal = toward the back) 3) Postanal tail 4) Iodine binding structure (endostyle, thyroid) 5) Pharyngeal pouches / slits (pouches from gut that may open to outside as slits in throat) |
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How in course of evolution do animals go from active larva to bag of goo to larva to active adult.
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Paedomorphasis- Hypotheses states that adult change doesn’t immediately go away, but metamorphosis is delayed, eventually after sexual maturity.
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CRANIATE SYNAPOMORPHIES
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• Cranium (=braincase, cartilage or bony skull surrounding brain)
• Complex sense organs • Large, three-part brain (forebrain, midbrain, hindbrain) • Neural crest cells (Important! More later…) • Heart, gills, hemoglobin, etc… |
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VERTEBRATE SYNAPOMORPHIES
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vertebrae
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CLADE MYXINIFORMES
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Hagfish
• Have basic Craniate features (neural crest, etc.) • Lack vertebrae (so, NOT vertebrates), notochord persists through life • Notice what’s lacking: jaws, paired fins |
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• ECTODERM
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outer body surface, nervous system, neural crest
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ENDODERM
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gut lining & organs from it (liver, pancreas, lungs)
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MESODERM
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– SOMITES: myomeres, vertebrae, dermis
– INTERMEDIATE MESODERM: kidneys, gonads – LATERAL PLATE MESODERM: blood vessels, heart, mesenteries, more… – NOTOCHORD |
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2 types of Bone
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– ENDOCHONDRAL: cartilage precursor, deep structures (limbs, deep skull)
– DERMAL: grows in dermis, no cartilage precursor • Flat, superficial: skull roof, armor plates in crocs, early verts |
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3 REGIONS OF THE SKULL
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1) Chondrocranium (braincase)
• Deep bones of skull, cartilage precursors • Surrounds sides, back, & underneath brain (occipital condyle, foramen magnum) (2) Splanchnocranium • Arches that support gills and jaws • Derived from neural crest • Cartilage precursor (3) Dermatocranium • Dermal (no cartilage precursor) • Superficial: skull roof, palate,lower jaw |
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EXCRETORY SYSTEM
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Develops from INTERMEDIATE MESODERM
(close assoc. with reproductive system) Removes metabolic (nitrogenous) wastes, excess salts & water via anatomical structures called NEPHRONS (collected into KIDNEYS) |
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• Kidney development & evolution
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-PRONEPHROS
Far toward head Only in embryos -OPISTHONEPHROS Further toward tail Fishes, amphibians -METANEPHROS Rearmost part of opisthonephros Reptiles (+birds), mammals Kidney develops from intermediate mesoderm that ran the length of the embryonic body |
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CLADE PETROMYZONTIFORMES
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(Lampreys)
• SIMPLE GUT TUBE: no stomach, mostly absorptive intestine • Secondarily lost bone (skeleton cartilaginous) • Notice what’s lacking: paired fins |
