Lab 6 - Echinodermata, Protochordates, Fishes Flashcards
Deuterostome characteristics
Radial cleavage
Anus develops from blastopore
Enterocoelous eucelomate
What type of symmetry do Echinoderms have
Pentaradial symmetry (groups or multiples of fives)
Water Vascular System Function
Gas exchange, locomotion, feeding
Structural support of Echinoderms (what makes it up? what are the subunits called?)
Calcareous endoskeleton made of ossicles
Parts of the water vascular system
Ring canal, radial canals, tube feet, ampulla, madreporite
Where does water enter within echinoderms
Madreporite
Ampulla
pumps water thru tube feet, causes them to extend or retract
Five major taxa of Echinodermata
Crinoidea (sea lilies) - rare
Asteroidea - Sea stars
Ophiuroidea - Brittle Stars
Holothuroidea - Sea Cucumbers
Echinoidea - Sea Urchins and Sand Dollars
Asteroidea
sea stars, feed on clams and bivalves, use tube feet to open up bivalve then everts stomach to digest, slow movement
Ophiuroidea
Lack tube feet, no digestive glands in arms, arms more distinctly offset, rapid movement
Echinoidea
Use movable spines for protection and locomotion (irregular only), possess aristotle’s lantern
Holothuroidea
Tentacles which are modified tube feet, ossicles largely reduced, defense mechanism everts internal organs thru anus which are later regenerated
Protochordates
First marine life to have basic chordate characteristics. Two taxa
Two taxa of Protochordates
Urochordata and Cephalochordata
Basic Chordate Characteristics
Dorsal hollow nerve cord, notochord, pharyngeal pouches, post-anal tail, endostyle/thyroid gland
Urochordata
AKA Tunicates, TAIL has well developed notochord (tail-chordate), dorsal hollow nerve cord, pharnyx has slits in larva
Tunicate larva
Larva of urochordata, becomes less vertabrate-like as it matures by attaching to a solid structure and losing its tail/notochord/nerve cord
Cephalochordata
AKA Branchiostoma/amphioxus, small ish that lie partially in the sand, filter feed using pharyngeal gill slits. Notochord goes into the head (head-chordate). Retain all 5 chordate synapomorphies unlike urochordates
Craniata
AKA Vertebrata, distinguished by cartilaginous or bony skull enclosing the brain
Craniata chracteriscs
skull (cartilage or bone), olfactory organs, eyes, inner ear
Two taxa within Craniata
Agnatha, Gnathostoma
Agnatha
without jaws, hagfish and lampreys
Gnathostoma synapomorphy
with jaws
Name for agnatha larvae
Ammocoetes
Ammocoete characteristics
vertebrate kidneys, liver, fully formed brain, gill structures for filter feeding
Differences between Ammocete and Amphioxus
Amphioxus does not have a brain, does not have heart or liver, has an anus instead of a cloaa, possesses an atriopore for excretion of water, has no circulatory system, and a caudal fin and wheel organ. Ammocete has oral hood WITHOUT tentacles and no wheel organ. More developed digestive system
Gnasthostomata taxa
Chondricthyes and Osteichthyes
Chondrichthyes synapomorphy
Cartilagionous endoskeleton (chond=cartilage, ichthys = fish), sharks, rays, skates,
Osteichthyes synapomorphy
bony endoskeleton (oste = bone)
Taxa within Osteichthyes
Actinopterygii and Sarcopterygii
Actinopterygii
Diverse ray-finned fishes, also contains Telosts which have disarticulated mouth structures forming “lips” (maxilla, premaxilla) allowing them to extend mouth to suck in prey
Sarcopterygii
Lobe finned fishes
Pedicellaria
features around spines of sea stars and urchins which are used for defense and cleaning the gills around the spines
Types of muscles in sea cucumber
Longitudinal and Circular
Function of muscles in sea cucumber
longitudinal are retractors to pull tentacles in, circular contract body
Ambularcal tracts
In sea cucumbers, five of them line the sides of the body and are filled with tube feet
Digestive system of the sea cucumber
Tentacles to mouth to intestines to cloaca
Cuverian tubules
In sea cucumbers, extend off respiratory tree and are used for defense. Expelled during evisceration, some are toxic or entrap predators
Caudal fin
Cirri function amphioxus
prevent large particles from blocking chamber of mouth
Wheel organ function
in amphioxus, draw water into mouth
Endostyle function in amphioxus
Secretes mucous for food particle entrapment within the pharengial region
Fins in gnathostomes
Two paired fins (Anterior pectoral, posterior pelvic), Dorsal, Caudal, Anal fins
Movement in Gnathostomes
Larger, broader caudal fins with larger caudal penducles associated with burst speed, smaller and narrower more for sustained swimming
Three sections/body regions of Osteichtyes
Head, trunk, tail
What are pectoral and pelvic fins homomologous to?
Tetrapod limbs
Gnathostome mouth types and functions
Terminal mouth - anterior end facing directly forward, feed on insects and larger prey. Downturned ventral mouths - feeding off of substrate. Elongated mouth - long reach and quick movmeent, helps catch prey as it swims by
