Evolution of Animals 2 Flashcards
state and identify the four main features of a chordate
- pharyngeal slits
- post anal tail
- notochord
- dorsal hollow nerve cord
notochord
provides skeletal support and develops into the vertebral column in vertebrates
dorsal hollow nerve cord
develops into the central nervous system: the brain and spine
post anal tail
skeletal extension of the posterior end of the body
pharyngeal slits
openings in the pharynx that develop into gill arches in bony fish and into the jaw and inner ear in terrestrial animals.
what are the 3 subphyla that comprise the phylum chordata?
- cephalochordata (lancelets)
- urochordata (tunicates and sea squirts)
- vertebrata (hagfish, lempreys, cartilagenous/bony fish, amphibians, reptiles, birds, mammals)
what was the first true vertebrae?
lampreys (petromyzontidea)
who had the first true skeletal cartilage?
hagfish (myxini)
who had the first true skeletal bone?
ray finned fishes (actinopterygii)
who had the first hinged jaws?
sharks/rays/skates (chondrichthyes)
who had the first cranium?
hagfish (myxini)
who had the first paired appendages?
sharks/skates/rays (chondrichthyes)
who had the first two pairs of limbs?
amphibians (frogs/salamanders)
lancelets
cephalochordata
- notochord
- dorsal hollow nerve chord
- post anal tail
- pharyngeal slits (solely for feeding here)
small, marine
tunicates
urochordata (“sea squirts”)
- notochord
- dorsal hollow nerve chord
- post anal tail
- pharyngeal slits (feeding, only characteristic which is retained through to the adult form)
myxini
vertebrata
hagfish
- true cartilage
- cranium
- gills for gas exchange
-no eyes/fins/jaw/vertebrae
petromyzontidae
vertebrata
lampreys
- true vertebrae
- cartilage (fake teeth)
- cranium
- gills for gas exchange
-no jaw, no true teeth
chondrichthyes
vertebrata cartilagenous fishes (sharks/skates/rays)
- true vertebrae
- cartilage
- cranium
- jaws and teeth
- paired appendages (paired pectoral fins)
- scales
- gills for gas exchange
osteichthyes (what 2 groups make up these fishes?)
vertebrata - bony fishes
- ray finned fishes
- lobe finned fishes
actinopterygii
osteichthyes - bony fishes
ray finned fishes
- most common fishes
- swim bladder
- true skeletal bones
- jaw
- cranium
- teeth
- scales
- gills for gas exchange
sarcopterygii
lobe-finned fishes - bony fish
(actinistia) coelocanths and (dipnoi) lungfish
- muscular appendages extensions of skeleton
- bony skeleton
- swim bladder
- scales
lungfish has first true lungs
amphibia
vertebrata - tetrapoda
amphibians
- two pairs of limbs
- gills in young, lungs in adults
- go through metamorphosis
- semi-aquatic
- no scales (susceptible to desiccation)
- first chordates to be somewhat terrestrial
reptilia (what groups comprise reptiles?)
amniota
snakes, lizards, crocodiles, turtles, birds
- scales
- lungs for gas exchange
- eggs covered with a shell
- amnion (now independent of water)
lepidosauria
reptilia
lizards, snakes, tuatara
- true teeth
- skeletons
- lungs
