Lecture 3: what is a vertebrate? (pt.1)

Isosmotic

having the same osmotic pressure as surrounding environment

Hyperosmotic

having higher osmotic pressure as surrounding environment

Cephalization

concentration of sense organs at the anterior (i.e., head) of the body

Cranium

part of the skull that encases and protects the brain

Hermaphroditic

a sexually reproducing organism that produces both male and female gametes

Hemal + neural arches

ventral + dorsal spinous projections of the vertebrae

Vertebral centra

the ossified central section of the vertebrae

Arcualia

primordial or rudimentary vertebrae, made of cartilage

Synarcual

fused series of vertebral elements

Heterocercal tail

tail in which the vertebral column extends into one lobe (usually the upper)

Myomeres

blocks of skeletal muscle arranged in sequence along the flanks

Semicircular canals

interconnected tubes located in the inner ear, used to sense movement and orientation

Ammocoete larvae

juvenile stage of lamprey, resembles a cephalochordate

Gill (branchial) arches

the cartilaginous or bony skeleton supporting the gill filaments

Mandibular cartilage

the lower 1st branchial (gill) arch, becomes the lower jaw

Palatoquadrate cartilage

the upper 1st branchial (gill) arch, becomes the upper jaw

Spiracle

remnants of the 1st gill slit, used for ventilation in benthic fishes like rays

Operculum

bony or cartilaginous plate which covers the gills in ratfishes, acanthodians, and bony fishes

Placoid scales

tooth-like odontodes that cover the body surfaces of cartilaginous fishes

Ceratotrichia

stiff collagenous filaments which support the fins of cartilaginous fishes

Lepidotrichia

the bone-reinforced collagenous fin filaments which comprise the fins in bony fishes

Oviparous

egg-laying

Viviparous

live-bearing, having live young

Ovoviviparous

embryos that develop inside eggs that remain in the mother's body until they are ready to hatch