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.
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)
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.
Subphylum Vertebrata Approximately 50,000 species. Vertebrates arose in the marine enviro.
SYNAPOMORPHIES
Dorsal Fin with skeletal supports Vertebrae – complete neural arches
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”
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
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
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
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
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.
Subclass ArchosauriaCrocodilians
Alligators, crocodiles, caimans, and gavials
about approx. 40 species