Invertebrates and the Origin and Evolution of Vertebrates

Flashcards about Invertebrates, Echinodermata, Chordates, and Vertebrates

Echinodermata

Animals that are pentaradial symmetry as adults, have oral/aboral sides, have a central mouth, have no head and no brain.

Endoskeleton

Internal CaCO3 plates and spines working with muscles to move arms.

Coelom

Distributes nutrients and helps gas exchange.

Water-vascular system

Fluid-filled canals and tube feet function for locomotion and feeding.

Notochord

Flexible dorsal rod that works with muscles for locomotion.

Dorsal, hollow nerve cord

Tube that forms from the fold of ectoderm dorsal to the notochord.

Pharyngeal slits or clefts

Ancestral use for filter-feeding & gas exchange.

Muscular, post-anal tail

Multiple muscle segments for undulating locomotion.

Endostyle

Ciliated groove.

Cephalochordata: Lancelets

All key chordate features in adult, burrows tail-in & filter-feeds, cilia in pharynx creating currents

Urochordata: Tunicates

Highly derived sessile adult that suspension-feeds with pharyngeal slits

Vertebrae

Enclose spinal cord.

Cranium

Skull of cartilage or bone, holds brain.

Vertebrate Heart

Heart with 2-4 chambers with valves, closed circulatory system, with hemoglobin within blood cells.

Extant Jawless Vertebrates

Eel-like bodies and no lateral fins, notochord, but spinal cartilages present, cartilage skull; no jaws, keratinous teeth aid feeding.

Myxini: Hagfish

Marine scavengers with reduced eyes and keratin teeth, famous for defensive slime.

Petromyzontida: Lampreys

Jawless parasite on fish