Chapter 3 Flashcards
vertebral column
derived from notochord
series of bone/cartilage blocks
defines central axis of body
vertebrae
series of bone/cartilage blocks
neural spine and neural arch
covering the nerve cord (spinal cord)
centrum
body of vertebrae with a cushioning intervertebral disc
hemal spine and hemal arch
covers blood vessels
cranium
cartilage/bone plates protects the brain and sensory organs
neural crest cells (found only in vertebrates) are used to help build the cranium
neural crest cells
only vertebrates have these and the things that they give rise to
they are embryonic and build features that distinguish vertebrates from others
cephalochordate
peaceful protochordates
amphioxus-like, filter feeding, sinu venosus, hepatic cecum, myomeres… most resemble vertebrates
agnathan
first vertebrates. first fish. muscular pumping pharynx, cartilage replaces collagen in pharynx
-bigger appetite
gnathostome
powerful jaw for biting prey. body grows larger. predatory nature. powerful pharyngeal pump
agnathans
diverse jawless fish
conodonts
dentin (bone like) rasping mechanism in mouth. relationship to later species unclear
endoskeleton
cartilage, strengthens the notochord
exoskeleton
bony plates to protect soft bodies, head shields, first bone
ostracoderms
elaborate skeletons, ancestors to gnathostomes, ostracoderms extinct now
myxini (hagfish)
found today at bottom of oceans
feeding on dead fish
no vertebrae
but have cranium
eat dead stuff
burrow into carcasses of dead fish
pteraspidomorphi
extinct ostracoderms with head shields
cephalaspidomorpha (includes lamprey)
unusual single nasal opening
lamprey
mostly marine- all return to freshwater to spawn
most are parasitic: sucking the blood of other fishes
anatomical features:
brain present, encased in full cranium
cartilage endoskeleton strengthens notochord
primitive vertebrae
complex gills
heart (sinus venosus, atrium, ventricle)
paired fins, jaws, bones are absent)
gnathostome diversity, developments during the silurian period
jaws, paired fins (pectoral and pelvic), cartilage/ bone endoskeleton for fin articulation, agile swimming
placoderms
looked like ostracoderms, but they jaws
heavy bony plates protected body
all extinct
chondrichthyes
very successful
cartilaginous fish
trace of bone is present on teeth and scales
radiation during carboniferous period caused placoderms to go belly up
constant swimming, and hydrodynamic shape keeps fish afloat
bone, as a tissue, has been around since the cambrian
elasmobranchs
sharks, skates, rays (700 species), most successful group of cartilaginous fish, most predatory with replaceable rows of teeth
unusual features:
rays have a flattened body and large pectoral fins
first gill slit modified (spiracle)
spiracle for breathing water into pharynx
mating is internal fertilization (clasper present)
fertilized eggs can be kept up until hatching
whale shark
largest, 20 m long whale shark
osteicthyes
most vertebrates (past or present) are bony fish
appearance of bone not gradual- was present from the start
air-filled swimm bladders aid buoyancy
gill openings are covered by a flap (operculum)
some use lungs to supplement / replace gills
surface covered in hard scales (some containing enamel = ganoid scales)
actinopterygians
largest division of bony fish
fins supported by “rays” (lepidotrichia)
sturgeon (largest freshwater fish) is one of the last remaining examples of early forms (chondrostei)
include most common fish: salmon, trout, pike, herring, catfish
teleost = common name for majority
sarcopterygians
small but important group
fleshy-finned fish
lungfish (dipnoi) are able to breathe air
lobe-finned fish (crossopterygians):
coelacanth is only survivor
rhipidistians were the ancestors of amphibians
complex teeth = labryinthodont teeth
rhipidistians
pattern of small bones in cranium shared with amphibians
labryinthodont teeth shared with amphibians
fleshy fins with same bones as tetrapods
tetrapods
four legged animals
derived from rhipidistians during devonian period
first four legged animals were amphibians
amphibians
frogs, toads, salamanders, caecilians
ADULTS AND LARVAE
-scales and labyrinthodont teeth (primitive characteristics in some)
- larvae with lateral lines and gills
-adults: limbs with digits, appendicular skeleton/ muscle well developed, lungs, able to hear in air
NOT FULLY TERRESTRIAL
-external fertilization: eggs laid in water
-eggs protected only by a jelly layer
-metamorphosis in water: larval to adult
-moist adult
amniotes
-eggs protected with membranes (amnion) and shell
-internal fertilization
-eggs hatch outside body (except mammals)
-adapting to life away from water
-first amniotes from carboniferous period (300 mya) =cotylosaurs (stem reptiles
anapsids
amphibians, no temporal fenestrae, turtles only remaining members, carapace dorsal, plastron ventral
synapsids
early and late mammals, one pair of temporal fenestrae
diapsids
dinosaurs, birds, lizards, two pairs of temporal fenestrae (holes in head)
sauropsid
everything but synapsid, usually considered reptile group
sauropsids (reptiles)
thick keratinized skin, lungs only
diapsid
GROUP ONE
into water: ichthyosaur, plesiosaur
lepidosaurs on land:
-snakes, lizards, sphenodon
GROUP TWO
archosaurs “ruling reptile”
-crocodilians, birds (survive)
-pterosaurs (powered flight)
-dinosaurs
do modern birds have two pairs of temporal fenestrae, even though they are diapsid?
no! crocodilians are the only ones that still
birds
-not only animal to fly, but only one with feathers
-body modified for a large number of different lifestyles
archaeopteryx
transition reptile with feathers, front claws, tail, teeth
pelycosaurs
early synapsid-reptiles successful, sail-backed reps, dominated permian for 40 million years
therapsid
mammal-like reps, first in late permian, shrew to hippo
mammals
appeared in triassic 225 mya (from therapsids)
-endotherm, hair, legs beneath body, mammary glands, large brain
monotremes
duckbill platypus, egg-laying
marsupials
kangaroos, live-birth, but no placenta
placental
all other mammals, live-birth using a placenta, numerous specialized species, some returned to water: cetaceans, some got smart in the trees: primates
