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
ex. of class chondricthyes
sharks, skates, rays
skeleton in chondricthyes
composed of flexible cartilage
characteristics of chondricthyes
- streamlined body and swift swimmer
- continual swimming
- short digestive tract
- acute senses
- internal fertilization of eggs
dorsal fins function in chondricthyes
stabilizers
pectoral and pelvic fins function in chondricthyes
maneuvering
why must sharks always be swimming
- to maintain continuous flow of water over gills
- will sink when they stop
- maintain buoyancy and breathing
feeding of sharks
largest are suspension feeders, but most carnivores
digestive tract of sharks
short with spiral valve that increases surface area and slows the passage of food
how are shark eggs fertilized?
internally, but embryos can develop in different ways
oviparous
eggs hatch outside the mother’s body
ovoviviparous
eggs are retained within oviduct, young are born after hatching within uterus
viviparous
embryo develops within uterus and is nourished from the mother’s blood through a yolk sac placenta
cloaca in sharks
reproductive tract, excretory system, and digestive tract empty into the cloaca
- common chamber with opening to the outside
circulatory system of sharks
2 chambered heart - single circulation
lateral line
pressure wave detection
- like an ear
rays
- bottom dwellers
- feed on molluscs and crustaceans
- flattened, have enlarged pectoral fins (water wings)
- whiplike tails, some with venomous barbs
how do most fish breathe
by drawing water over gills protected by an operculum
how do fish control buoyancy
with air sac called swim bladder
do fish have a lateral line system?
yes
reproduction of most fish
oviparous, some have internal fertilization and birthing
ex. of actinopterygii
ray-finned fish
actinopterygii characteristics
- long, flexible rays modified for maneuvering, defense, and other functions
- have been harvested for years by humans
- negatively impacted by dams
how are ray-finned fish negatively impacted by dams
change water flow patterns, affect prey capture, migration, and spawning
ex. of class actinistia
lobed-finned fish - coelacanths
what species of fish was thought to have become extinct 75 million years ago?
coelacanths - but then one was caught
characteristics of actinisita
- special joint in skull gives powerful bite
- swim bladder filled with oil instead of gas
ex. of class dipnoi
lungfish
characteristics of class dipnoi
- live in oxygen-poor freshwater
- gills/lungs
- will suffocate if unable to breath air
- can aestivate in mud
tetrapod charcteristics
- 4 limbs and feet w/ digits
- neck for movement of head
- fusion of pelvic girdle to backbone
- no gills (mostly)
- ears for airborne sounds
how many species of amphibians
6,150 species in 3 clades
3 clades of class amphibia
- caudata
- anura
- apoda
clade caudata
- tailed ones
- salamanders
- some aquatic, some land
- pedomorphosis
clade anura
- tail-less ones
- frogs
- powerful hind legs for locomotion on land
- carnivorous adults, herbivorous larva
clade apoda
- legless ones
- gymnophiona
- nearly blind
- uterine milk nourishes young inside mother’s body
buccal pumping in amphibians
forces air into lungs
how many chambers are in the heart of an amphibian
3
what is metamorphosis regulated by in amphibians?
thyroid hormones
what type of birth do amphibians have
all 3
paedomorphosis
alternative process to metamorphosis in which adults retain larval traits at adult stage
- newts and salamanders
- larvae reach sexual maturity without losing their gills
toads
frogs with leathery skin
what does amphibian mean?
both ways of life
- metamorphosis of aquatic larva to terrestrial adult
why do most amphibians have moist skin
to complement lungs in gas exchange
fertilization of most amphibians
- external
- eggs require moist environment
amniotes
group of tetrapods whose living members are the reptiles (including birds and mammals)
characteristics of amniotes
- 4 extraembryonic membranes
- eggs have shell
- impermeable skin
- water-conserving kidneys
- thoracic breathing
4 extraembryonic membranes
- amnion
- yolk sac
- allantois
- chorion
amnion
protects embryo in amniotic cavity
yolk sac
yolk
allantois
disposal of wastes
chorion
with allantois for gas exchange
thoracic breathing in amniotes
negative pressure sucks air in
ex. of reptiles
tuataras, lizards, snakes, turtles, crocodilians, birds, some extinct groups
characteristics of reptiles
- scales that create waterproof barrier
- lay shelled eggs on land
- internal fertilization
- ectothermic
ectothermic
absorb external head as main source of body heat
- regulate body temp through behavioral adaptations
orders of class reptilia
- crocodilia
- chelonia
- squamata
- rynocheocephalia
order rynocheocephalia characteristics
- tuataras- small islands off coast of New Zealand
- threatened by introduced rats that consume their eggs
- 2 species
- beak/snout head
- no external ears like lizards
- active at cooler temperatures
order squamata
- lizards and snakes
- lizards have moveable eyelids and external ears
- snakes have kinetic skull, chemical sensors, heat-detecting organs, venom
order chelonia
- turtles, tortoises, terrapins
- lack of holes in skull behind eye socket
- hard protective shell
- vertebrae/ribs fused to shell
- lack teeth but have sharp beak
order crocodilia
- alligators/crocodiles
- restricted to warm regions
- 4 chambered heart
- teeth in sockets
- care for young
class aves characteristics
- feathers
- air sacs - efficient breathing
- reduction of organs
- lightweight skeleton
- internal fertilization (oviparous)
- warm body temp
- double circulation
- active vision
- most carnivores
- eggs brooded
- complex courtship
feathers
modified scales to keep birds warm and enable flight
reduction of organs in birds
single ovary, no urinary bladder
lightweight skeleton in birds
thin, hollow, honeycombed
- sternum to anchor flight muscles, no teeth
mammalia characteristics
- mammary glands
- hair and subdermal fat
- kidneys
- endothermy
- efficient cardiovascular/respiratory
- parental care
- differentiated teeth
