Exam 1 Lab Flashcards
What are protochordates?
all aquatic with larval life vs. adult life larval-pelagic/planktonic, metamorphosis and the adult is benthic as burrowing or sessile. They are considered the hemichordate, cephalochordate, urochordate.
What are hemichordates?
first appearance of chordte body plan components but not a chordate, sister taxa with echinoderms (ambulachrania)[Stylophora is a hemichordate fossil that shows calcium carbonate plates similar to many echinoderms, but without radial symmetry], chordate features. it has pharyngeal slits, a dorsal collar cord homologous to DNC and Epibranchial ridge- in pharyngeal slits and stomochord- similar to endostyle. no notochord so uses cilia to move.
What is a tornaria larva?
species of hemichordates that is deuterostome, ciliated, simple gut, planktonic: resembles the aurivularia larva of echinocderms, and it has molecular and morphological agreement with sinle monophyletic clade.
What are echinoderms?
starfish creature thingies
What do the adult hemichordates do?
The adult is a burrower or suspension feeders using cilia and mucus to capture food in mouth to pharynx using cilia out pharyngeal slits to brachial pouch and out brachial pores. Bad water into collar and rest into body. Nerve ring sorting out what is or isn’t edible.
• In pharynx water comes in thorugh secondary tongues and then in thorugh primary bars with skeletal rods keeping tight structure. Tongues highly vascularized allowing these structures used for respiration.
What is the function of pharyngeal slits in hemichordates?
primarily water exit during filter feedings, secondarily respiratory exchange through vascularized tongue bar
What are the similarities in metamorphosis in hemichordates?
metamorphosis results in a circulatory and excretory system with probable vertebrate homology. the nephridial duct in larva that becomes glomerulus to eliminate waste. It has unpigmented plasma, with two ventral blood vessels go into heart vesicle continuing circulation going into glomerulus and goes back to ventral blood vesicle. Have pulsatile vesicle becoming heart vesicle.
What are cephalochordates?
they are a chordate species thats last ancestor was related to echinoderms and hemichordates.
Cephalochordates: increased specialization, all suspension feeders using ciliated structure in mouth to bring in food and partilces into feeding, extending notochord into head but no brain. having all of the structures of a chordate as well as a midgut cecum which was a secretory forward extension of the guut and the liver and pancreas forerunner. The endostyle is placed laterally and the notochord going to the head suggesting homology with pituitary gland.
What is circulation in cephalochordates like?
similar to vertebrate circulation pattern as blood flow does not reverse but has afferent and efferent veins with respiration happening through simple diffusion and the nephridium consisting of podocytes similar to those in kidneys. and it is heart like but does not pulse and instead the vessels contract form the hepatic portal and vein
ventral aorta- blood flowing towards head and upwards with close association with glomerulus up and back through the dorsal aorta on top of pharyngeal complexes becoming single tube and gut come into sinus venosus pulling, not heart or contractin but the vessels themselves are.
What is afferent?
going to
what is efferent?
coming out of
What is special about the notochord in hemichordates?
notochord connected through system of muscles and connected to dorsal nerve cord connecting into notochord causing the muscles to contract and dependenmt on muscles from myomeres. Unique amphioxus notochord.. muscular contractions cause contraction of notochord muscle cells via the nerve cord resulting in stiffening, possible for burrowing or bursts of speed.
How does the cephalochordate eat?
oral hood of worm cilia pushing out big particles of food. Water goes in on Hatschek’s pit or groove only on right side below notochord (homologous to pituitary gland secreting mucous) passing by wheel organ with a bunch of ciliated structure when move look like its rotating pushing water in towards the velum (diaphragm with more tentacles separating food particles) everything then goes into pharynx from ventral part to dorsal and accumulates then pushed back towards duct.
o function of blood to transport nutrients, clear blood to transfer it to all cells and organ systems.
o muscle fibers of segmental myomeres highly integrated with notochord making them contract. notochord cant compress axially but only laterally.
What are urochordates?
tunicates sister taxa to vertebrates that have all 5 chordate features in their larva they also have a bronchial basket housing the pharyngal slits. hermaphoditic life cycle of sexual and asexual but can’t fertilize themselves.
What are ascidian larva
urochordate lava with all five chordate features. , the tail backstring or reffering to tunic or felexible outer body larva free swimming that don’t feed but attach to ground
