TAXONOMIC GROUP OF SELECTED ANIMALS Flashcards
uniting trait of echinoderms, hemichordate, chordate
Deuterostomes
Chordata subphylums
Urochordata, cephalochordate, vertebrata
subphylum
half of chordate characteristics
hemichordate
subphylum
Most have an endoskeleton
vertebrates
subphylum
resemble the earliest chordates, all lack bones
Cephalochordate
all marine, all lack bones
Urochordates
All three taxa share a common body design, 5 fundamental features:
Notochord
Pharyngeal slits
Endostyle or Thyroid gland
Dorsal hollow nerve cord
Post – anal tail
Protochordates
Subphylum Urochordata
Subphylum Cephalochordata
Jawless vertebrates (agnathans)
Superclass Cyclostoma
Jawed vertebrates
Superclass Gnathostoma
Cartilaginous fishes
Class Chondrichthyes
ray-finned fishes
Class Actinopterygii
lobe-finned fishes
Class Sarcopterygii
lowest 4 legged vertebrates, naked and slimy skin, and living near or in water
Class Amphibia
air breathing vertebrate, horny scales
Class Reptilia
vertebrate with feathers
Class Aves
vertebrate with hair and mammary glands
Class Mammalia
Phylum Hemichordata example
acorn worm
3 body regions of acorn worm
proboscis
collar
body trunk
Marine worm, related to echinoderms and chordates
acorn worm
3 regions of acorn worm
branchiogenital or thoracic
hepatic
abdominal
hollow cavity, spans the organisms
coelom
Within the proboscis
extension of digestive tract in acorn worm
stomochord
Food enters the mouth
together with the water
Pharynx to gut
Water exists to the _____ in acorn worms
pharyngeal slits
Salient points of the internal anatomy in acorn worm
❖ Collar nerve cord
❖ Pharyngeal gill slits
❖ Stomochord
pharyngeal slits open into each ___________ a common compartment of the branchial pore that opens up to the environment
branchial pouch
arises from the embryo as an outpocketing roof of the embryonic gut anterior to the pharynx
retains a connection to what will become the buccal cavity
They usually enlarge towards the cavity of the proboscis to form the pre oral diverticulum
Stomochord
Lower Chordates
unicates / sea squirts
Subphylum Urochordata
Subphylum Urochordata
Free-swimming larva
Sessile adult stage and tail is reabsorbed
Larva exhibits all 5 characteristics of chordates
Class Ascidiacea
Subphylum Urochordata
Tiny marine animals
resided in planktonic communities
Class Larvacea
Subphylum Urochordata
Free-living
Derivatives of adult Ascidiaceans
Class Thaliacea
example Subphylum Urochordata
Molgula, pandocia
Oval sac like creature, scarcely resemble and animal
Rough irregular form, food and debris adhere to it
Urochordata
2 opening siphons in Urochordata
Oral siphon – incurrent, upper
Atrial siphon – excurrent, lower