vertebrates Flashcards
chordates characteristics
notochord
dorsal hollow nerve chord
pharyngeal slits
post anal tail
notochord
flexible-rod-shaped structure
found in the embryonic stage of all chordates
located between the digestive tube and nerve cord
provides skeletal support throughout the length of the body
some species the notochords acs as the primary support structure throughout the animals life
in vertebrates, notochord is present during embryonic development, then it induces the development of the neural tube
not found in the postnatal stage in vertebrates, it is replaced by the vertebral column.
dorsal hallow nerve cord
lies within the ectoderm that rolls into a hollow tube during development
in chordates, it is located dorsal to the notochord
other animal phyla have solid nerve cords and are located either ventrally or laterally
in most chordates, the nerve cord eventually develops into the brain and spinal cord(the central nervous system)
pharyngeal slits
openings in the pharynx that extend to the outside environment
in aquatic organisms these slits allow for the exit of water that enters the mouth during feeding
invertebrate chordates use pharyngeal slits to filter food out of the water that enters the mouth
vertebrate fishes these slits are modified into gills, and in jawed fishes into jaws
in tetrapods the slits are modified into components of the ears and tonsils
post anal tail
posterior elongation of the body, extending beyond the anus
tail contains skeletal structures and muscles
n aquatic organisms the adult form maintains this structure to aid in locomotion
in some terrestrial vertebrates, tails can help with balance, courting, and signaling
in humans, the post anal tail is a vestigial structure
groups of chordates
urochordata
cephalochordata
craniata
vertebrata
Urochordata/tunicates
tunic or outer covering is composed of cellulose-like carbohydrate material
adult form does not possess a notochord, dorsal hollow nerve cord, or post-anal tail but the larval stage does. they do have pharyngeal slits in both larval and adult stages
cephalochordata
possess all of the chordate characteristics in the adult form as well as the embryonic form
the notochord extends in to the head (stands for the name)
extant members are the lancelets, named for their blade-like shape
small
sand at the bottom of warm temperate and tropical seas
filter feeders
craniata
no backbone
a group of organisms that have a cranium(bony, carilagious or fibrous structure surrounding the brain), and facial bones
most are bilaterally symmetrical
this group includes the hagfish, which have a cranium, but lack a backbone and all of the vertebrates
vertebrates
display all four characteristics of chordates but they also have a vertebral column composed of cartilage and bone and is derived from the notochord(only present in the embryonic stage) during development
molecular evidence and fossil evidence suggests that vertebrates are more closely related to lancelets than tunicates
vertebrate groups
fishes
amphibians
reptiles
birds
mammals-primates
chondrichthyes: cartilaginous fish
have skeleton made of cartilage
marine and some freshwater
sharks, rays, skates
most are oviparous(mother births a fertilized egg or viviparous(live birth)
Osteichthyes: bony fish
have skeletons made of bones
have a swim bladder to assist with buoyancy control
marine or freshwater
amphibians/the evolution of terrestrial animals require
had to deal with gravity and supporting weight during locomotion
had to evolve to be able to extract oxygen from air instead of water
tetrapod-evolved limbs for weight support
cutaneous respiration- oxygens/carbon dioxide exchange that can happen through the skin
reptiles
tetrapods
lay eggs enclosed in shells on land
some are ovoviviparous(mother incubates eggs internal, births eggs very close to hatching or viviparous (live birth)
crocodiles, turtles, snakes, lizards
