Anatomic Diversity Human anatomy is a typical anatomy

of a member of Phylum Chordata. Human anatomy understood

biologically within its comparative and developmental contexts.

Understanding the development of vertebrate (in this case human) anatomy is necessary to understand the adult anatomy across vertebrates.

Phylum Chordata Notochord = stiff connective tissue rod Dorsal hollow nerve cord (neural

tube) = hollow nerve cord dorsal to notochord (spinal cord + brain in us)

Endostyle/thyroid = gland involved in iodine metabolism

Pharyngeal Openings (gill openings) = openings into “throat,” behind mouth

Post-anal tail

Phylum Chordata Subphylum

Urochordata Subphylum

Cephalochordata Subphylum

Myxini Subphylum

Vertebrata

Phylum Chordata

Uroch

ordat

a

Cephal

ochord

ata

(la

ncele

ts)

Verte

brata

(ver

tebra

tes)

pharyngeal openings

notochord,neural tube,

post-anal tail,endostyle/thyroid,

Myx

ini (

hagfis

hes)

Subphylum Urochordata Sea Squirts, Salps, & Larvaceans Suspension feeders Tadpole larva with

notochord in tail.

Sea Squirt Metamorphosis

Subphylum Cephalochordata Lancelets (Amphioxus, Branchiostoma)

Suspension feeders Notochord extends into head & includes

skeletal muscle cells. Chordate derived characteristics obvious.

Chordate Synapomorphies

notochorddorsal

nerve tube

pharyngealbasket (slits)

post-analtail

anusintestine

hepaticdiverticulum

Phylum Chordata

Uroch

ordat

a

Cephal

ochord

ata

(la

ncele

ts)

Verte

brata

(ver

tebra

tes)

pharyngeal openings

notochord,neural tube,

post-anal tail,endostyle/thyroid,

Myx

ini (

hagfis

hes)

notochordextends

into head

tadpolelarva

segmentalmuscles

Lancelet Musculature

MusculatureLancelets, hagfishes, & vertebrates have segmental muscles (myotomal muscles).

segmental muscles(myotomal muscles)

Lancelet Tail Section

notochord

nerve tube

myotomalmuscles

Lancelet Structure

Sketch on board.

Craniata Hagfishes and vertebrates.

SYNAPOMORPHIES

Cranium (cartilage or bone) Liver Calcium phosphate in skeleton Neural crest tissue (Developmental)

Neurogenic placodes (Developmental)

Phylum Chordata

Uroch

ordat

a

Cephal

ochord

ata

(la

ncele

ts)

Verte

brata

(ver

tebra

tes)

pharyngeal openings

notochord,neural tube,

post-anal tail,endostyle/thyroid,

Myx

ini (

hagfis

hes)

notochordextends

into headsegmental

muscles

Craniate Phylogeny

Myx

ini (

hagf

ishes

)

lam

preys

shar

ks, r

ays,

etc

.

Actin

optery

gii

coel

acan

ths

lungfis

hes

amphib

ians

Mam

mal

ia

Reptil

ia

liver, CaPO4, neural crest, neuro. placodes

Hagfishes, Subphylum Myxini 43 species; marine

scavengers no jaws lack functional eyes,

tentacles, & one naris serially

hermaphroditic lack bone (cartilage) secrete slime

Hagfish Anatomy Cartilage under brain and in

mouth apparatus. Keratinous tooth plates. No real vertebrae.

Hagfishes, Subphylum Myxinitentacles

caudalfin

pharyngealopenings

mouth

Hagfishes, Class Myxini

Hagfish Slime

Subphylum Vertebrata Approximately 50,000 species. Vertebrates arose in the marine enviro.

SYNAPOMORPHIES

Dorsal Fin with skeletal supports Vertebrae – complete neural arches

Vertebrae

Craniate Phylogeny

Myx

ini (

hagf

ishes

)

lam

preys

shar

ks, r

ays,

etc

.

Actin

optery

gii

coel

acan

ths

lungfis

hes

amphib

ians

Mam

mal

ia

Reptil

ia

dorsal fin,complete neural arches

Lampreys Class Petromyzontida 41 species Oral disc with “teeth” & rasping “tongue” Ammocoete larva - VERY similar to

cephalochordates in way of life Larvae undergo metamorphosis. Marine and freshwater ectoparasites

(adults) and suspension feeders (larvae)

Lampreys, Class Petromyzontida

pharyngealopenings

eye

oraldisc

dorsalfins

1 narial opening

keratinous“teeth”

Lampreys, Class Petromyzontida

adult

ammocoetelarva

Lamprey, ammocoete

notochord

neural tube

pharyngealbasket

(slits & bars)

post-analtail

endostyle Sketch on board.

anusintestine

liverheart

brain – spinal cord

Lab Activity Obtain a slide of a lamprey ammocoete

and a dissection microscope. Examine the slide on the microscope. If appropriate, date the page in your lab

notebook and sketch the ammocoete. Label all the parts you labeled on the previous slide.

Ask your instructor if you have difficulty. Examine the whole preserved lampreys.

Lab Activity Obtain a slide of a cross sectioned

ammocoete larva and a compound microscope.

Find the section through the post-anal tail and examine the slide on the microscope.

Sketch the tail section. Label the notochord, myotomal muscles, & neural tube.

Ask your instructor if you have difficulty.

Gnathostomata gnatho- = jaws; stoma = mouth jawed vertebrates pectoral & pelvic fins Myelinated nerves

Craniate Phylogeny

Myx

ini (

hagf

ishes

)

lam

preys

shar

ks, r

ays,

etc

.

Actin

optery

gii

coel

acan

ths

lungfis

hes

amphib

ians

Mam

mal

ia

Reptil

ia

jaws, myelin,paired limbs Gnat

hostom

ata

Sharks, Rays, Chimaeras, etc. chondro- = cartilage; ichthys = fish Sharks, rays, sawfishes, & chimaeras Males have pelvic claspers. marine (and freshwater) carnivores Approx. 850 species

Class Chondrichthys

Osteichthys osteo- = bone; ichthys = fish “bony” vertebrates, NOT just FISHES bony endoskeleton, lung(s) ray-finned fishes, lungfishes, the coelacanth, &

terrestrial vertebrates

Craniate Phylogeny

Myx

ini (

hagf

ishes

)

lam

preys

shar

ks, r

ays,

etc

.

Actin

optery

gii

coel

acan

ths

lungfis

hes

amphib

ians

Mam

mal

ia

Reptil

ia

bony endoskeleton,lung(s)

Ostei

chth

ys

Class Actinopterygii actino- = ray; ptery = fin or wing ray-finned fishes marine and freshwater 24,500+ species

(= the number of species of all other vertebrates put together)

Very diverse in habits and body form.

24,000 species+

sturg

eons

& pad

dlefis

h

gars bowfin

Amia

cal

va

TELEOSTS

reed

fishes

Class Actinopterygii

single, dorsallung

Sarcopterygii

sarco- = flesh; ptery = fin or wing fleshy & bony pectoral and pelvic axis lobe “fins” (NOT just FISHES) lungfishes, coelacanths, & terrestrial

vertebrates

Craniate Phylogeny

Myx

ini (

hagf

ishes

)

lam

preys

shar

ks, r

ays,

etc

.

Actin

optery

gii

coel

acan

ths

lungfis

hes

amphib

ians

Mam

mal

ia

Reptil

ia

“lobes” Sar

copte

rygii

Coelacanths

2 species deepwater marine

(East Africa & Indonesia)

Lungfishes

6-9 species, Tropical freshwaters

unique morphology Paired ventral lungs

Tetrapoda tetra- = four; poda = foot “terrestrial” vertebrates pectoral and pelvic limbs with digits

1

1

2

2

3 4

Craniate Phylogeny

Myx

ini (

hagf

ishes

)

lam

preys

shar

ks, r

ays,

etc

.

Actin

optery

gii

coel

acan

ths

lungfis

hes

amphib

ians

Mam

mal

ia

Reptil

ia

Tetr

apod

a

limbs with digits

Amphibians amphi = both/double, bios = life

frogs, toads, salamanders, caecilians Usually distinct metamorphosis Approx. 5,000 species freshwater and terrestrial (none marine) mucus covering skin

Amphibians

Amniota Amnion = amniotic membrane Amniotic membrane surrounds

embryo (in egg or in uterus)

amniotes = reptiles & mammals Very distinct from other vertebrates

Craniate Phylogeny

Myx

ini (

hagf

ishes

)

lam

preys

shar

ks, r

ays,

etc

.

Actin

optery

gii

coel

acan

ths

lungfis

hes

amphib

ians

Mam

mal

ia

Reptil

ia

amnion

Amnio

ta

Class Mammalia Mammals Named for

mammary glands

Hair (no exceptions)

Approx. 4000 species

Most diverse = rodents and bats.

monotre

mes

mar

supia

ls

euth

eria

ns

hair,mammary glands

nipples

Theria

Monotremes Platypus & Echidnas Australia & New Guinea. Lay eggs Young lap up milk from nipple-less

mammary glands

Baby Platypus

Echidnas

Marsupials Metatherians Australia, New Guinea, & S. America Morphologically diverse in Australia Do not lay eggs, young develop in an

external pouch. Milk from nipples

Eutherians “Placental” mammals Worldwide, Very diverse morphologically Do not lay eggs; young do not develop

in an external pouch. Milk from nipples.

Class Reptilia Turtles, lizards,

snakes, tuataras, crocodylians, & birds

Birds ARE reptiles Thick keratin

scales Approx. 15,000

species Many extinct

turtl

es

lizar

ds & s

nakes

croco

dilian

s

birds

epidermal scalesof beta keratin

Turtles Turtles, tortoises, & terrapins Worldwide, <1000 species Ribs and vertebrae form a

“shell” (test). No teeth, keratinous “beak” Lay eggs.

Lepidosaurs: Lizards & Snakes Lizards, snakes, & tuataras Worldwide 5000+ species

Subclass ArchosauriaCrocodilians

Alligators, crocodiles, caimans, and gavials

about approx. 40 species

Subclass ArchosauriaBirds

Aves 9,000 species Feathers, no teeth, keratin beak