Vertebrate Biology - Introduction to Biology - Lecture Slides, Slides of Biology

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Classification

Phylum Chordata

Subphylum Urochordata

Subphylum Cephalochordata

Subphylum Vertebrata

tunicates lancets^ Agnathans Fish Sharks tetrapods

Class Agnatha , the jawless fishes Subclass (or order) Cyclostomata, the lampreys and hagfishes.

Class Chondrichthyes , the cartilaginous-skeleton fishes Subclass Holocephali, the chimaeras, or ratfishes Subclass Elasmobranchii, the sharks, skates, and rays

Class Placodermi

Class Acanthodii

Class Osteichthyes , the bony fishes Subclass Actinopterygii, the ray-finned fishes Superorder Chondrostei, the primitive ray-finned bony fishes: sturgeons, paddlefish, and bichirs Superorder Holostei or Neopterygii, the intermediate ray-finned fishes: gars and the bowfin Superorder Teleostei or Neopterygii, the advanced bony fishes: herring, salmon, perch. Subclass Crossopterygii, the coelacanth Subclass Dipnoi or Dipneusti, the lungfishes

• Lack jaws, paired fins, scales
• Possess medial nostril, medial fins,

notocord rather than vertebral column

Class Agnatha

Lamprey Characteristics

• Oral disc/buccal funnel, with epidermal denticles and rasping tongue; active "predatory parasites”
• No bone
• Nostril on top of head
• Well-developed vertebrate eyes
• Well-developed Lateral Line system
• Best developed pineal “eye” of any aquatic vertebrate;
• 2 pairs of semicircular canals;
• Uniformly 7 pairs of gills
• Cranium cartilaginous, open on top
• Opisthonephros
• Eggs deposited in freshwater; freshwater larva; many species have freshwater adult, but most migrate to sea and have marine adult stage (anadromous).

Characteristics

• Posses jaws with teeth, cartilaginous skeleton, paired fins
• Scales (denticles) have same origin and composition as teeth
• Possesses 5-7 gills
• Spiral valve intestine
• Ureoosmotic strategy
• Lateral line
• No swim bladder
• Heterocercal tail
• Relatively unchanged (480 mybp)

Sharks, skates, rays, chimera

Class Chondrichthyes

Ovipary - eggs enclosed in capsule; eggs are laid and hatched outside the mother

Ovovipary - give birth to young, eggs develop in uterus

Vivipary - give birth to young, placental connection

• Totally fossil, early jawed fishes;
• Bony armor usually present around head-trunk, generally flattened body, tend to be bottom-adapted with eyes rather dorsal (other various designs);
• No true teeth
• Notochord persistent, un-constricted.

Class Placodermi

• ganoid scales (don’t form rings as they grow)
• heterocercal tail
• persistent notochord; centra absent or cartilage rings
• large mouth, long maxilla attached at rear
• open spiracle

Superorder Chondrostei

• L.Permian-Recent, but mostly Juras. & Cretac.;
• Abbreviated heterocercal tail, often symmetric caudal fin;
• Ganoid or cycloid scales
• Single dorsal swim bladder, hydrostatic & respiratory; physostomous;
• No open spiracle
• Vertebral centra often at least partly ossified, constricting persistent notochord;
• More modernized jaws (than Chondrosteans) - maxilla shorter, free at rear; shorter mouth

Superorder Holostei

Acanthostega

• First complete tetrapod with free digits
  • eight digits on each hand
• Retained “fishy” characters:
  • gills
  • tail fin
  • Partial connection between skull and

pectoral girdle

• Labyrinthodont teeth
• Lateral line
• Ulna shorter than radius

Ichthyostega

Transition fossil from fw Crossopterygian to tetrapod

Class Amphibia

Characteristics

• Cold blooded
• Returns to water to breed
• Metamorphosis
• Some toxic
• Estivation-dry and hot
• Hibernation- cold

3,500 species

Class Amphibia

“Canaries in the coal mine”

• Habitat destruction
• Introduced species
• Pollution
• Pesticide use
• Diseases
• Over-harvesting
• Climate change
• Increased UV radiation