Phylum Chordata
SubphylumUrochordata
SubphylumCephalochordata
SubphylumVertebrata
tunicates lancets AgnathansFishSharkstetrapods
Characteristics of Chordates
1st fish
Proto-vertebrate
Tunicate larvae Adult tunicate
lancelet
Possible evolution of 1st fish
PikaiaBurgess Shale FaunaCambrian540-500 mya
Early Chordate ancestor may have given rise to 1st vertebrate
General Features Shared by Chordates:
1. Eukaryote2. Multicellular3. Bilateral- deuterstomes4. Heterotrophic
Phylum Chordata Subphylum Urochordata - Tunicates
Class Ascidiacea - Sea SquirtsSolitary e.g. Styela montereyensisColonial - in groups but with own tunicCompound Colonial - colonial with sharedtunic
Class Thaliacea - Salps (free swimming),planktonic
Class Larvacea - Gelatinous house, planktonic
SubphylumUrochordataSubphylumUrochordata
tunicate
Subphylum Urochordata = tunicate
Tunicate - also called 'sea squirt' • notochord is confined to the tail • notochord is lost during
metamorphosis into sessile adult • possess pharyngeal slits • Repro- sexual (hermaphroditic)
& asexual (budding)
Tunicate Adult Anatomy
Tunicates:
Free swimming larva:• 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
Settled larva:• Settle after brief free-swimming larvum existence. • Attaches at anterior end. • Metamorphosis begins. • Body turns 1800. • Tail, notochord, dorsal nerve cord, disappear.
Class Larvacea - planktonic
Oikopleura
Oikopleura
Jelly-like house
Marine snow
Class Larvacea - Gelatinous house, planktonic
Pyrosoma- bioluminescentColonial salp
Class Thaliacea - Salps (free swimming), planktonic
Class Ascidiacea - Sea Squirts
SubphylumCephalochordata
SubphylumCephalochordata
lancet
• Strictly marine• Live buried in sand with head sticking out• Filter feeders
Lancet Anatomy
Vertebrate Higher Classification Superclass Agnatha - without jaws
Class Myxini – hagfishes Class Cephalaspidomorphi – lampreys
Superclass Gnathostomata – with jaws Class Chondrichthyes – sharks, rays, chimaeras Class Actinopterygii – ray-finned fishes Class Sarcopterygii – lobe-fin fishes Class Amphibia – frogs, salamanders Class Reptilia – snakes, lizards, crocodiles Class Aves - birds Class Mammalia - mammals
Agnatha (jawless fishes)• Lack: paired fins, scales,
& well developed vertebrae
• Hagfish (slime eels)– Mucus for protection– Feed on decaying flesh
• Lampreys– Parasitic– Anadromous
• Marine adults, breed in freshwater
Class ChondrichthyesSharks, skates, rays,chimera
SubphylumVertebrata
• Heterocercal tail
• Two dorsal fins
• Paired pectorals
• 5-7 gill slits
• ureoosmotic
Chondrichthyes (cartilagenous fishes)
Osteichthyes (bony fishes)
• Swim bladder
• Operculum (gill cover)
• Homocercal tail
• Scales of bony origin– Smooth cycloid– Spiny ctenoid
Intestine
Adipose fin(characteristicof trout)
Cut edgeof operculum
Swimbladder Caudal
fin
Lateralline
UrinarybladderPelvic
fin
Anus
Dorsal finSpinal cord
Brain
Nostril
Gills
Kidney
Heart
Liver
Gonad
Anal fin
Stomach
Class AmphibiaClass Amphibia
Characteristics
• Cold blooded• Returns to water to breed• Metamorphosis• Some toxic• Estivation-dry and hot• Hibernation- cold
3,500 species
Class AmphibiaClass Amphibia
Rana cancrivora
salamander
Poison arrow frog
newt Mudpuppy (salamander)
Coqui
Class ReptiliaClass Reptilia
Characteristics
• Cold blooded• Have scales• Amniotic egg• Dry skin• 3 chambered heart (except crocks)
6,500 species
Class ReptiliaClass Reptilia
Sea snakeMarine turtle
Saltwater crocodile
Marine iguana
Class AvesClass Aves
Characteristics
• Warm blooded• Feathers and wings• Hollow bones• Horny bill• Lungs have air sacks• Hard egg shell
Class Aves
Class MammaliaClass Mammalia
Characteristics
• Warm blooded• Have fur or hair• Suckle young• 3 middle ear bones
Class MammaliaClass Mammalia
Subclasses• Protheria- echidna & platypus• Metatheria- marsupial• Eutheria- true mammals