Chordata: Chordata: Urochordata and Urochordata and CephalochordataCephalochordata

Joycelin LucJoycelin Luc

Michelle ChenMichelle Chen

http://www.glaucus.org.uk/diazona0.JPGhttp://research.myfwc.com/images/gallery/20060309_140447_23656.jpg

Intro to Chordata Intro to Chordata

Have a Have a notochordnotochord Have a Have a dorsal nerve corddorsal nerve cord => develops into => develops into

central nervous system (brain and spinal central nervous system (brain and spinal cord)cord)

Most have Most have pharyngeal cleftspharyngeal clefts and and pharyngeal slitspharyngeal slits

Usually have a Usually have a post-anal tailpost-anal tail

Michelle Chen

Common NamesCommon NamesUrochordataUrochordata

TunicateTunicate sea squirts sea squirts sea porksea pork

Cephalochordata Cephalochordata LanceletsLancelets amphioxus amphioxus

(means “both (means “both ends pointed”)ends pointed”)

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http://www.ucmp.berkeley.edu/chordata/urochordata.html (left pic)

http://www.biologycorner.com/resources/Lancelet.JPG (right pic)

UrochordataUrochordata

http://www.mun.ca/biology/scarr/Ascidian_metamorphosis_2.gif

Michelle Chen

CephalochordataCephalochordata

http://kentsimmons.uwinnipeg.ca/16cm05/16labman05/lb7pg1_files/amphioxsis.jpg

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Body Cavity and Body Body Cavity and Body symmetrysymmetry

Coelom Coelom presentpresent in both the Urochordata in both the Urochordata and Cephalochordata subphlya and Cephalochordata subphlya

bilaterianbilaterian (bilaterally symmetrical) (bilaterally symmetrical) Body consists of myoepithelial and Body consists of myoepithelial and

Epithelial cells Epithelial cells

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Nervous System & Nervous System & Sensory FeaturesSensory Features PresentPresent consisting of brain and consisting of brain and

spinal cordspinal cord in Urochordata, nervous system in Urochordata, nervous system

disintegrates when it reaches adult disintegrates when it reaches adult stage stage

Michelle Chenhttp://www.mun.ca/biology/scarr/142007_Urochordata.jpg

Circulatory SystemCirculatory SystemUrochordataUrochordata

Blood contains high Blood contains high concentration of concentration of vandium and lithiumvandium and lithium

Open circulatory Open circulatory systemsystem

Ventral heartVentral heart

CephalochordataCephalochordata Closed blood systemClosed blood system Main ventral and Main ventral and

paired dorsal aorta paired dorsal aorta No central heart, but No central heart, but

consists of branchesconsists of branches lacks hemoglobin lacks hemoglobin

and is colorless and is colorless Has Atria cavityHas Atria cavity

http://faculty.vassar.edu/mehaffey/academic/animalstructure/outlines/chordata.html

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Digestive & Excretory Digestive & Excretory SystemSystem

UrochordataUrochordata Draws food through Draws food through

siphon into atrium from siphon into atrium from pharyngeal slitspharyngeal slits

Food filtered by mucous Food filtered by mucous netnet

Moves to esophagus Moves to esophagus through cilia through cilia

Exits excurrent siphon Exits excurrent siphon

CephalochordataCephalochordata Uses Uses cilia pumpingcilia pumping

to move food to move food particles from slitparticles from slit

Trap food in pharynxTrap food in pharynx

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Locomotion/ Musculature Locomotion/ Musculature

UrochordataUrochordata Juvenile: tail Juvenile: tail

muscles; gravity and muscles; gravity and light sensitive cellslight sensitive cells

Adult: attach to a Adult: attach to a substrate substrate sessilesessile

CephalochordataCephalochordata Contraction of Contraction of

muscles arranged in muscles arranged in a <<<< structure -> a a <<<< structure -> a side to side side to side undulation to move undulation to move forwardforward

SomitesSomites

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UrochordataUrochordata Juvenile: tail Juvenile: tail

muscles; gravity and muscles; gravity and light sensitive cellslight sensitive cells

Adult: attach to a Adult: attach to a substrate substrate sessilesessile

Skeletal TypeSkeletal Type

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UrochordataUrochordata Notochord (some Notochord (some

have spicule when have spicule when young)young)

adult: attach to adult: attach to rock rock

CephalochordataCephalochordata Develops dorsal, Develops dorsal,

hollow never cord hollow never cord Post-anal tail Post-anal tail

ReproductionReproduction

UrochordataUrochordata HermaphroditesHermaphrodites Eggs kept inside until Eggs kept inside until

hatchhatch Sperm released into Sperm released into

H2OH2O

CephalochordataCephalochordata Gonochoristic: sex Gonochoristic: sex

separateseparate Sperm and eggs Sperm and eggs

released into waterreleased into water Fertilization is Fertilization is

externalexternal

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Gas ExchangeGas Exchange

Uses cilia to regulate the gasesUses cilia to regulate the gases Pharynx and pharyngeal slits regulate the Pharynx and pharyngeal slits regulate the

gas exchange (across external body gas exchange (across external body surface)surface)

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Other unique featuresOther unique features

Urochordata = very few natural predatorsUrochordata = very few natural predators Invasive speciesInvasive species Form coloniesForm colonies

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QuizQuiz

1. What are the four basic features that 1. What are the four basic features that separate Chordata from other phyla?separate Chordata from other phyla?

2. Name one difference between Urochordata 2. Name one difference between Urochordata and Cephalochordata.and Cephalochordata.

3. How do adult sea squirts move? What about 3. How do adult sea squirts move? What about adult lancelets?adult lancelets?

4. How are the reproductive methods for 4. How are the reproductive methods for Urochordata and Cephalochordata Urochordata and Cephalochordata different? different?

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THE END!!!THE END!!!