2007-2008

DomainBacteria

DomainArchaea

DomainEukarya

Common ancestor

Kingdom: Animals

Domain Eukarya

VERTEBRATES!!!

postanaltail notochord

hollow dorsalnerve cord

pharyngealpouches

PHYLUM = CHORDATA

becomes brain & spinal cord

becomes vertebrae

becomes gills or Eustachian tube

becomes tail or tailbone

CHARACTERISTICS: NOTOCHORD PHARYNGEAL POUCHES POST ANAL TAIL DORSAL NERVE CORD

SUBPHYLUM = VERTEBRATA

VERTEBRATE CHARACTERISTICS:ALL CHORDATE CHARACTERISTICS PLUS:

• Bones or cartilage around a dorsal nerve cord

• Cranium (skull) to protect brain• Endoskeleton made of bone or cartilage• Closed circulatory system

fish, amphibians, reptiles, birds, mammals

NOTOCHORDNotochord: flexible rod

Helps organize developing cells in embryo

Replaced by spinal cord in most vertebrates

Becomes the vertebrae

DORSAL NERVE CORD VENTRAL HEARTSPINAL CORD FORMS ALONG DORSAL SIDE

PHARYNGEAL POUCHES

Become gills in some vertebrates

Become back of throat and inner ears in humans

POST ANAL TAIL

HUMAN EMBRYO32 DAYS OLD

Pharyngeal arches appear during 4th week

Tail disappears at approximately 8 weeks

VERTEBRATES: FISH Characteristics

body structure bony OR cartilaginous skeleton Scales, fins Lungs/swim bladder

body function gills for gas exchange two-chambered heart;

single loop blood circulation ectotherms

reproduction external fertilization external development in

aquatic egg

salmon, trout, sharks450 mya450 mya

gills

body

TRANSITION TO LANDEvolution of

tetrapods

Tibia

Femur

Fibula

Humerus Shoulder

RadiusUlna

Tibia

FemurPelvis

Fibula Lobe-finned fish

Humerus

Shoulder

Radius

Ulna

Pelvis

Early amphibian

Evidence suggestslobe finned fish are

ancestors of amphibians

TIK-TAALIKIntermediate between fish and early tetrapods

Fins have basic wrist bones and simple fingers Earliest fish with a neck

Discovered by Neil Shubin and Ted Daeschler in 2004

http://evolution.berkeley.edu/evolibrary/images/news/tiktaalik_reconstruction.jpg

lung

buccalcavity

glottisclosed

VERTEBRATES: AMPHIBIAN Characteristics

body structure legs (tetrapods) Thin, moist skin

body function lungs (positive pressure) &

diffusion through skin for gas exchange three-chambered heart/2 loops Ectotherms Excrete UREA

reproduction external fertilization external development in aquatic egg metamorphosis (tadpole to adult)

frogssalamanders toads

350 mya350 mya

VERTEBRATES: REPTILES Characteristics

Dry, scaly skin body function

lungs for gas exchange three-chambered heart/2 loops (except

crocodilians) ectotherms excrete URIC ACID

reproduction INTERNAL fertilization external development- AMNIOTIC egg

250 mya250 myadinosaurs, turtles lizards, snakesalligators, crocodile

embryoleatheryshell

chorion

allantoisyolk sac

amnion

amnion -bag of waters; the extraembryonic membrane of birds, reptiles, and mammals, which lines the chorion and contains the fetus and the amniotic fluid

http://medical-dictionary.thefreedictionary.com/amnions http://media-2.web.britannica.com/eb-media/27/117227-050-E1C9ABEE.jpg

IMPORTANT DEVELOPMENTAMNIOTIC EGG- reptiles didn’t have to return to water to lay eggs

VERTEBRATES: BIRDS Characteristics

body structure feathers & wings thin, hollow bone;

flight skeleton body function

very efficient lungs & air sacs four-chambered heart/2 loops endotherms excrete URIC ACID

reproduction INTERNAL fertilization external development in AMNIOTIC egg

150 mya150 myafinches, hawk ostrich, turkey

trachea

anteriorair sacs

lung

posteriorair sacs

VERTEBRATES: MAMMALS Characteristics

body structure hair specialized teeth

body function lungs, diaphragm; negative pressure four-chambered heart/2 loops endotherms

reproduction internal fertilization internal development in uterus

nourishment through placenta birth live young mammary glands make milk

220 mya / 65 mya220 mya / 65 myamice, ferret elephants, batswhales, humans

musclescontract

diaphragmcontracts

VERTEBRATES: MAMMALS Sub-groups

monotremes egg-laying mammals duckbilled platypus, echidna

marsupials pouched mammals short-lived placenta koala, kangaroo, opossum

placental true placenta shrews, bats, whales, humans

VERTEBRATE QUICK CHECK… Which vertebrates lay eggs with shells? Which vertebrates are covered with scales? What adaptations do birds have for flying? What kind of symmetry do all vertebrates have? Which vertebrates are ectothermic and which

are endothermic? Why must amphibians live near water? What reproductive adaptations made mammals

very successful? What characteristics distinguish the 3 sub-

groups of mammals?