ch. 34 phylum cordata Flashcards
subphylum of phylum cordata
- subphylum vertebrata
- subphylum eurochordata
- subphylum cephalochordata
4 main characteristics of chordates
- notochord
- dorsal, hollow nerve cord
- pharyngeal slits/clefts
- muscular, post-anal tail
notochord
longitudinal, flexible rod between digestive tube and nerve cord
- provides skeletal support
dorsal, hollow nerve chord
- nerve chord of embryo develops from plate of ectoderm that rolls into tube dorsal to notochord
- develops into central nervous system
pharyngeal slits/clefts
- grooves form along outer surface of pharynx
- clefts develop into slits that then open to outside of the body
function of pharyngeal slits
- suspension feeding for invertebrate chordates
- gas exchange in vertebrates (except tetrapods)
tetrapods
vertebrates with limbs
tetra
four
pod
foot
where do pharyngeal slits develop for tetrapods
parts of the ear, head, and neck
muscular, post-anal tail
- tail can be greatly reduced during embryonic development
- contains skeletal/muscular elements
- provides propelling force in aquatic species
ex. of subphylum cephalochordata
lancelets
- blade-like shape
ex. of subphylum urochordata
tunicates
characteristics of subphylum cephalocordata
- marine
- filter/suspension feeders
- sessile but can burrow and swim
- gas exchange across body surface
subphylum Urochordata characteristics
- filter feeds (incurrent/excurrent siphons)
- adults sessile w/ only pharyngeal slits
- tadpoles/larvae have all 4 characteristics
- complete gut
- open/rudimentary circulatory system
what are subphylum Urochordata animals enclosed in
tunic
subphylum Urochordata sexuality
hermaphroditic
feeding of subphylum Urochordata
draws water in through incurrent siphon, filters out food particles, shoots water through excurrent siphon when attacked
classes of subphylum vertebrata
- petromyzontid
- myxini
- chondrichthye
- aetinopterygii
- actinistia
- dipnoi
- amphibia
- reptilia
- aves
- mammalia
ex. of petromyzontid
lamprey
ex. of myxini
hagfish
ex. of chondrichthye
sharks, rays
ex. of actinopterygii
ray-finned
ex. of actinistia
lobed-finned
ex. of dipnoi
lungfish
ex. of amphibia
frogs
ex. of reptilia
lizards
ex. of aves
birds
ex. of mammalia
humans
how many sets of Hox genes do vertebrata have
2+ sets
how many sets of Hox genes do lancelets and tunicates have
1
vertebrae
enclose spinal cord and take over mechanical roles of notochord
neural crest
cell that appear along edges of closing neural tube of embryo
what does the neural crest give rise to?
anatomical structures unique to vertebrates
endoskeleton of vertebrates
cartilage or bone - most also have 2 pairs of appendages
internal organs of vertebrates
liver, kidneys, endocrine glands, heart w/ at least 2 chambers
what organ is unique to vertebrates
liver
what organs are more complex than analogous structures in other taxa
heart, kidneys, endocrine system
hagfishes and lampreys common trait
- lack backbone, but have rudimentary vertebrae
class petromyzontida characteristic
- jawless vertebrates
- marine/freshwater
- some parasites, some free-living
- notochord and cartilaginous skeleton
class myxini characteristics
- jawless vertebrates
- cartilaginous skull and flexible rod of cartilage derived from notochord
- small brain, eyes, ears, nasal opening, tooth-like formations
- marine and bottom dwellers
- produce slime
why do hagfishes produce slime
to repel competitors and predators