Lecture 1 Flashcards
3 subphyla of Chordata
Cephalochordata
Urochordata
Vertebrata
CEphalochordata
Notochord extends to the head [lancelets]
Urochordata
Notochord in tail [sea squirts]
Vertebrata
Has a vertebral column
Subphyla of Vertebrata
Pisces and Tetrapods
Pisces characteristics
first Fishes: Agnatha, Acanthodii, placodermi, chondrichthyes, osteichthyes ……p/t tetrapods…progression is from no jaws to jaws ->appendages->then to internal bony skeletons
Tetrapods characteristics
Paired appendages.. More terrestrial…after Pisces…progression includes the movement from water to land… More terrestrial
Pisces subgroup Agnatha
W/o jaws and paired appendages…hagfishes/lampreys…
Pisces subgroup Acanthodii
Spiny fish- gnathostomes: first vertebrates w/ jaws (W/ placodmeri)
Pisces subgroup Placodermi
Gnathostomes: (w/ Acanthodii)….have paired fins and w/ jaws
Pisces subgroup Chondrichthyes
Cartilaginous fishes- lacking ability to form bone-sharks, skates, Rays)
Pisces subgroup Osteichthyes
Bony fish- largest number of species
Tetrapod subgroup Amphibia
“Water/land”-frogs, toads, salamanders, caecillians.
Tetrapod subgroup Reptilla
Lizards, crocodillians, dinosaurs, pterosaurs, and plesiosaurs
Tetrapod subgroup Aves
All birds; characteristic is possesses feathers
Tetrapod subgroup Mammalia
All mammals. Characteristics : presence of hair and mammary glands
Chordata characteristics shared w/ invertebrates
Cephalization Complete digestive tract Symmetry Metamerism Triploblasty Eucoelomate body cavity Closed circulatory system Deuterostomy
Four big characteristics of chordata:
Dorsal hollow nerve cord
Pharygeal gill or slits
Notochord
Post-anal tail
MAjor characteristics of vertebrata
Vertebral column !! Head-sense organ Trunk-viscera and support Tail-begins at anus Appendages- typically 2 pairs
Basic differences among the 3 chordate subphyla
Cephalochordata: notochord extends to head
URochordata: notochord in tail
Vertebrata: Vertebral Column
Cranial/caudal axis
Coronal axis
Anterior/posterior
Dorsal/ventral
Dorsal/ventral axis
anterior/posterior axis
Left and right axis
L and R
Sagittal plane is defined by:
Cranial/caudal and; anterior/posterior axis
Frontal (coronal) defined by:
Left/right and cranial/caudal axis
Transverse plane defined by:
Anterior/posterior &; left/ right axis
Flexion/extension occurs in which plane?
Sagittal about L/R axis
Abduction and Adduction occur in:
frontal (coronal)plane about sagittal axis
Rotation occurs:
In transverse plane about a cranial/caudal axis
Dorsal hollow nerve cord
Future brain and spinal cord…ventricles of brain
Pharyngeal gill slits-arches-pouches
Cranial portion of gut tube…connect interior of pharynx to external environment…cranial nerve branches for ppl..mandibular/hyoid/tonsils…gas exchange is another use for organisms
Notochord
Primitive (hydrostatic)axial skeleton…support system…remnants are intervertebral discs…responsible for formation of the nervous system
Acoelomates:
Lack a body cavity separating somatic tube from the visceral tube (flatworms)
Pseudocoelomates
Posses a body cavity but it is only partly dervied from embryonic mesoderm
Eucoelomates
Most animals;possess a body cavity that is lined w/ embryonic mesoderm.
Eucoelomate vertebral column
Consists of outer somatic tube and inner splanchnic tube
Eucoelomate outer somatic tube
INteracts w/ external environment–SKin and skeletal muscle…allows organism to detect changes in its external environment and to respond to those changes.
Eucoelomate inner splanchic tube
Involved w/ gut function-metabolism. Processing nutrients..anabolism/catabolism
Vertebrates paired appendages
Pectoral (towards cranial end) and pelvic (closer to caudal….only Cyclostomes don’t have 2 paired appendages
Vertebrates Internal mesodermal skeleton
Unique in possessing an internal mesodermal skeleton..cartilage or bone..ppl have cartilage replaced by bone
Vertebrates epaxial/hypaxial musculature
Epaxial- segmentally arranged blocks of skeletal muscle [fish uses for locmotion]
Hypaxial- muscle that forms walls of body cavity and fins /limbs
Vertebrates subdivided coelom
2 subdivisions in vertebrates; 3 subdivisions in mammals.
2 coelom divisions in vertebrates:
Pericardial and PLEUROPERIOTONEAL
3 divisions of coelom in mammals:
Pericardial, pleural, and peritoneal
What separates cavities of coelom in fishes/amphibians reptiles
Fibrous transverse septum
Cavities are lined w/ what in coelom of Vertebrates?
serous membranes-thin, watery lubricating fluid. These are called parietal layers.
Membranes covering organs are called:
visceral layers
______ are where the visceral and parietal peritoneum join forming double layers
Mesenteries
Dorsal mesenteries
Suspends gut tube from Dorsal roof of coelom
Ventral mesentery
Connects the gut tube to the floor of the coelom
Falciparum ligament (VM-2)
Ventral mesentery: connects liver to floor of peritoneal cavity
Lesser omentum
connects Between the liver and the ventral gut
Where do the kidneys lie? What cavity?
Retroperitoneal
Vertebral metamerism
Segmentation- repeating body units on either side of midline…cranial to caudal..epaxial musculature in relating blocks, another ex: vertebral column
Vertebral triploblasty
body plan is from 3 germ layers: endoderm, ectoderm, mesoderm
Endoderm
Innermost layer; makes gut tube and derivatives
Ectoderm
Outermost layer; makes integument and CNS
MEsoderm
Middle germ layer; makes connective tissue, cartilage, muscle, GU
Vertebral deuterostomy
Not unique to chordates. “first opening becomes anus”…blastopore becomes the anus
Vertebral cephalization
Not unique to chordate…development of definite head…accumulation of sense organs.
