The Animal Kingdom The Chordates Nancy G. Morris Volunteer State Community College

Phylum Hemichordata Hemichordata (hemi = half; chordata= cord) acorn worm entirely marine adults show 3 of 4 basic characteristics: 1) pharyngial pouches 2) dorsal tubular nerve chord 3) tail evolutionary link between echinoderm and chordates ciliated larvum resembles tornaria larvum of echinoderms

Phylum Chordata Subphylum Urochordata (uro = tail; chordata= cord) Subphylum Cephalochordata (cephalo = head; chordata= cord) Subphylum Vertebrata (vertebrate = backbone)

Phylum Chordata All exhibit four chordata characteristics: –1) dorsal tubular nerve cord –2) notochord –3) pharyngial pouches –4) tail Deutrostomes – chordates & echinoderms

Anatomy of a Chordate

Subphylum Urochordata sea squirts or tunicates notochord present only in free-swimming larvum notochord does not extend into head larvum is free-swimming but non-feeding adult is sessile filter feeder

Subphylum Urochordata sea squirts or tunicate Campbell p 631 Settle after brief free-swimming larvum existence. Attaches at anterior end. Metamorphosis begins. Body turns Tail, notochord, dorsal nerve cord, disappear.

Subphylum Cephalochordata “head” cord lancelet or Amphioxus notochord present throughout life – extends into head region shallow marine waters chordate characteristics developed and apparent in adult tail has blocks of muscles called myotomes adults resemble tunicate larvum

Anatomy of a lancelet

Cephalochordata: lancelet

Subphylum Vertebrata General Characteristics: chordates with a backbone exhibit cephalization closed circulatory system neural crest (p. 633)

Subphylum Vertebrata Agnatha (without jaws) lamprey – parasitic bloodsuckers w/ rasping tongue hagfish – mainly scavengers no paired appendages larvum resembles lancelet

Agnatha: a sea lamprey

Lamprey mouth

Subphylum Vertebrata Chondrichthyes (cartilaginous fishes) flexible endoskeletons of cartilage strengthened by calcium granules sharks (internal fertilization) –oviparous – egg laying –ovoviviparous – retain fertilized eggs hatch within the uterus –viviparous – young develop in the uterus suspension-feeders (plankton)

Phylum Hemichordata Hemichordata (hemi = half; chordata= cord) acorn worm entirely marine adults show 3 of 4 basic characteristics: 1) pharyngial pouches 2) dorsal tubular nerve chord 3) tail evolutionary link between echinoderm and chordates ciliated larvum resembles tornaria larvum of echinoderms

Phylum Chordata Subphylum Urochordata (uro = tail; chordata= cord) Subphylum Cephalochordata (cephalo = head; chordata= cord) Subphylum Vertebrata (vertebrate = backbone)

Phylum Chordata All exhibit four chordata characteristics: –1) dorsal tubular nerve cord –2) notochord –3) pharyngial pouches –4) tail Deutrostomes – chordates & echinoderms

Anatomy of a Chordate

Subphylum Urochordata sea squirts or tunicates notochord present only in free-swimming larvum notochord does not extend into head larvum is free-swimming but non-feeding adult is sessile filter feeder

Subphylum Urochordata sea squirts or tunicate Campbell p 631 Settle after brief free-swimming larvum existence. Attaches at anterior end. Metamorphosis begins. Body turns Tail, notochord, dorsal nerve cord, disappear.

Subphylum Cephalochordata “head” cord lancelet or Amphioxus notochord present throughout life – extends into head region shallow marine waters chordate characteristics developed and apparent in adult tail has blocks of muscles called myotomes adults resemble tunicate larvum

Anatomy of a lancelet

Cephalochordata: lancelet

Subphylum Vertebrata General Characteristics: chordates with a backbone exhibit cephalization closed circulatory system neural crest (p. 633)

Subphylum Vertebrata Agnatha (without jaws) lamprey – parasitic bloodsuckers w/ rasping tongue hagfish – mainly scavengers no paired appendages larvum resembles lancelet

Subphylum Vertebrata Chondrichthyes (cartilaginous fishes) flexible endoskeletons of cartilage strengthened by calcium granules sharks (internal fertilization) –oviparous – egg laying –ovoviviparous – retain fertilized eggs hatch within the uterus –viviparous – young develop in the uterus suspension-feeders (plankton)

Subphylum Vertebrata Chondrichthyes (cartilaginous fishes) Rays & skates Bottom feeders – mollusks & crustaceans Whiplike tail w/ venomous barbs (defense)

Subphylum Vertebrata Chondrichthyes (cartilaginous fishes) Rays & skates Bottom feeders – mollusks & crustaceans Whiplike tail w/ venomous barbs (defense)

Subphylum Vertebrata Osteichthyes (bony fishes) Endoskeleton of hard calcium phosphate matrix Operculum- protective flap Swim bladder – controls buoyancy

Seahorse

Subphylum Vertebrata Amphibia (“two lives”) first tetrapods transition to land – still tied to water for respiration and reproduction Gills  lungs (metamorphosis) Frogs, toads, salamanders, newts

Subphylum Vertebrata Reptilia (Campbell, p. 644) (to creep) lizards, snakes, turtles, tortoises, Gila monsters, crocodiles, alligators first true land animal Scales, lungs, amniotic egg no feathers cold-blooded – ectotherms – (energy conservation)

Hatching reptile

Subphylum Vertebrata Fossil links………… Evolutionary link ?? between reptiles and birds: Archaeopteryx, a Jurassuc bird- reptile Clawed forelimbs Teeth Long tail w/ vertebrae

Archaeopteryx

Subphylum Vertebrata Aves (bird) feathered few flightless: ostrich, kiwi, emu breastbone with keel – carina – permitting flight jays, sparrows, warblers, etc

Subphylum Vertebrata Mammalia (breast) Hair or fur of keratin Active metabolism = endothermic Efficient respiration w/ diaphragm Efficient circulation w/ 4-chambered heart Layer of fat Mammary glands, tooth differentiation

Subphylum Vertebrata Mammalia (breast) Monotremes – egg-laying mammals (Platypuses & echidnas – spiny anteaters) Placental mammals Marsupial mammals – kangaroo, opossum

Marsupial & Placental Mammals Marsupial Placental