BIS 2C: Chordates Flashcards
lancelets (cephalochordates)
small filter feeding animals
chordate features present in adults
segmented body muscles
tunicates (urochordates)
sea squirts are bag-like with enlarged perforated pharynx for filter feeding
vertebrates
water to land and back again
trends in vertebrate evolution
increased cephalization
increased agility of movement
new feeding modes
“physiological upgrading”
hagfish
no bones, jaw or vertebrae
tongue with rasping teeth
scavengers on dead animal carcasses
tie themselves in knots
produce copious amounts of slime
lamprey
no bone or jaw/larvae are mud dwelling filter feeders
ostracoderms
heavily armored (bony), extinct jawless
placoderms
armor plated predators with jaws and teeth like structures
cartilaginous fish (sharks, rays)
skeleton made of flexible cartilage
largest predatory shark
great white
largest shark but filter feeder
whale shark
feeding in fish
efficient unidirectional flow
water in mouth, out in pharyngeal slits
colonization of land involved
lobed fins to limbs and use of lungs
amphibians
caecilians, frogs and toads and salamanders
thoughts of amphibian decline
possibility of pathogenic chytrid fungus
amniotes
impermeable skin, efficient kidneys, amniote egg (with shell and membrane that resist desiccation)
clades of reptiles
birds, crocodiles, lepidosaurs, turtles
clades of mammals
prototherians, marsupials, eutherians
prototherians
egg laying mammals
marsupials
pouched mammals
eutherians
placental mammals
old view of position of turtles
sister to lepidosaurs
recent view of position of turtles
sister to archosaurs
evolution of snake-like reptiles
snakes evolved once from lizard like ancestors
case of ratite birds
traditional view: sister to tinamous
recent view: tinamous embedded phylogenetically within ratites
canine convergence in mammals
marsupials/ eutherian convergence in mammals
amphibian features
require moist environments
lose water rapidly through skin and early stages often require water
