Chordates and Vertebrates Flashcards

Vocabulary flashcards for Chordates and Vertebrates lecture.

Ecdysozoa

A clade within Bilateria that includes Nematodes and Arthropods.

Deuterostomes

A clade within Bilateria that includes Echinoderms, Hemichordates, and Chordates.

Chordate Characteristics

Notochord, Dorsal hollow nerve cord, Pharyngeal clefts/slits, Muscular post-anal tail

Notochord

A cartilaginous rod that is a key characteristic of chordates.

Cephalochordates

Lancelets; most basal living chordates; larvae develop 4 chordate qualities; 'swollen tip' of nerve cord for brain

Urochordates

Tunicates (sea squirts); chordate qualities occur as larva; larva use muscular tail and notochord to find suitable substrate to settle

Vertebrates

Chordates with a jointed dorsal vertebral column surrounding the dorsal nerve cord and an anterior cranium (skull) with a large brain.

Hox Genes in Vertebrates

Duplicated at least once (vertebrates have at least two copies of each Hox gene, usually more)

Myxini

Hagfishes, jawless vertebrates with rudimentary vertebrae and a cartilaginous skull that secrete slime for defense.

Petromyzontida

Lamprey (jawless) mostly parasitic with cartilaginous skeleton (w/o collagen). Catilage wraps & projects from notochord

Conodonts

Extinct soft-bodied, jawless vertebrates with cartilage skeletons, large eyes, and mineralized dental tissue.

Gnathostomes

Jawed vertebrates.

Derived Characters of Gnathostomes

Jaws (with teeth), Enlarged forebrain, Lateral line system (aquatic)

Chondrichthyans

Cartilaginous Fishes; Sharks, rays & relatives; Cartilage-skeleton, often fortified w/ calcium; Continuous swimming (gas exchange in gills); Pectoral, Pelvic & Dorsal Fins

Actinopterygii

Ray-Finned Fishes; 'Bony rays that support fins;' Bony scales, unlike teeth-like scales of sharks; Operculum – bony plate over gills

Sarcopterygii

Lobe-Finned Fishes; Coelocanths & Lungfishes; Also have bony scales & operculum; Rod-shaped bones, & muscles in pectoral & pelvic fins (becoming limb-like); Lungs likely evolved to help oxygen diffuse into blood

Tetrapods

Gnathostomes that have limbs which allowed for support and propulsion on land; have a neck, ribs, and fused girdles; Key transition from fish to tetrapods is Tiktaalik roseae

Amphibians

Urodeles, Anura, and Apodans that inhabit damp habitats rely on moist skin for gas exchange and lay eggs in water or a moist environment.

Urodeles

Salamanders, terrestrial ones walk side to side.

Anura

Frogs and toads with body form specialized for jumping: elongated hind legs, short forelegs, and a short trunk.

Apodans

Caecilians, legless, nearly blind found in the tropics.

Amniotes

Major derived character: Amniotic egg Reproduction no longer tied to water

Amnion

Encloses fluid around embryo

Chorion

Gas exchange

Yolk sac

Stores nutrients

Allantois

Waste storage

Reptiles

Scales made out of keratin, Ectothermic – “cold-blooded” (i.e., absorb external heat as main source of body heat)

Diapsids

Changes in skull (i.e., pair of holes on each side of the skull behind the eye sockets)Allows muscles to pass through and attach to jaw à helps control jaw movement

Archosaurs

Pterosaurs, Ornithischian dinosaurs, Crocodilians, Birds

Birds

Wings and feathers (made of beta-keratin), keeled sternum, honeycombed bones requires Large brain for sight and motor control High aerobic demand (4-chamber heart and efficient lungs)

Lepidosaurs

Tuataras, Squamates (lizards + snakes)

Mammals

Mammary gland, Hair, Endothermic, Diaphragm à helps ventilate the lungs, Larger brain to body size than other vertebrates, Differential teeth

Monotremes

Found only in Australia and New Guinea,Lay eggs,Hair, produce milk, but lack nipples,Milk secreted from glands – baby sucks milk from hair

Marsupials

Higher metabolic rates, Nipples, Placenta, and complete development in maternal pouch – marsupium

Eutherians

Placental mammals” – placenta is more complex -Longer pregnancy – young complete development in the uterus

ectotherm

An animal that absorbs external heat as its main source of body heat; cold-blooded.

endotherm

An animal that maintains its body temperature through metabolic activity; warm-blooded.

Operculum

A bony plate that covers the gills in ray-finned fishes.