AD unit 4 Flashcards
synapomorphies of Echinodermata
Pentaradial symmetry, Larvae bilaterally symmetrical; Calcium carbonate endoskeleton; WVS
Common deuterostome characteristics?
blastopore doesn’t become mouth, enterocoelous development, radial indeterminate cleavage
Echinodermata characteristics
Marine; benthic predators, detritivores, herbivores or suspension feeders
what are Asteroidea?
sea stars
Major Echinoderm Subgroups
Asteroidea, Ophiuroidea, Echinoidea, Holothuroidea, Crinoidea
what are Ophiuroidea?
brittle and serpent stars
what are Holothuroidea?
sea cucumbers
what are Echinoidea?
urchins, sand dollars
what is the skeleton of articulated plates made of in Asteroids?
calcium carbonate
what are Crinoidea?
sea lillies
what are the key features of the external anatomy of an Asteroid?
interambulacral + ambulacral regions; pper surface w pedicellariae (pincers on stalks); Mouth faces down, anus on top (aboral surface)
what is the internal anatomy of an Asteroid?
body filled w perivisceral coelom (PVC)
how does the WVS work?
Ends are tube feet; Radial canals run down arms in ambulacral grooves, Along radial canals are ampullae, 1 above each tube foot, Contract, tube feet expand/attach; relax and muscles contract, it moves; Ring canal (RC) encircles mouth; Stone canal connects RC to madreporite (sieve plate) on aboral surface
what is the Water Vascular System?
coelomic tube system filled w seawater
what are tube feet?
tentacles used for locomotion/prey capture
what do asteroids eat?
How do asteroids eat?
evert stomach thru mouth, no/small anus
nervous system characteristics of Asteroids
nerve net w ring nerve under RC; radial nerve extends into each arm
gas/waste characteristics of Asteroids?
occurs across tube feet; papullae aid respiration; PVC transports O2
what is the hemal system in Asteroids?
Ophiuroidea (brittle/serpent stars) general anatomy
5 slender arms w round central disk; Mouth w 5 jaws, madreporite on oral surface; no anus; Radial nerves covered by plates (closed ambulacral groove)
what are Holothuroidea’s?
elongated, soft echinoids
Echinoidea (urchins and sand dollars) general anatomy
Round/flattened _____ w spines, pedicellariae (small wrench/claw-shaped appendage w movable jaws (valves); Gonopores, madreporite, terminal tube feet open thru 5 apical plates; closed ambulacral groove
what are Cuvierian tubules?
modified parts of respiratory trees; stick threadsd
What other animals have tripartite coeloms?
lophophorates, echinoderms
general anatomy of Holothuroidea’s?
stone canal leads to internal madreporic bodies; respiratory trees for gas exchange
how are Cuvierian tubules used and what for?
what is Evisceration?
when harassed/stressed sea stars dump their guts
what are the 3 body regions of Hemichordata?
proboscis, collar, trunk - each w coelom
what are Pterobranchia?
marine colonial tube dwellers; deep sea
what are Enteropneusta?
marine benthic worms; solitary, acorn worms
how do Enteropneusta eat?
eat particles that stick to proboscis; water flows into mouth, out thru pharyngeal slits
where does gas exchange occur in Enteropneusta?
pharyngeal slits
Major synapomorphies of Chordata include:
notochord, postanal tail, endostyle, DHNC, pharyngeal slits/pouches
what is a notochord?
flexible dorsal skeletal rod, replaced by vertebrae in most verts
what are the major subgroups of Chordata?
Cephalochordata, Urochordata, vertebrata
what is a postanal tail?
vestigial, lost in few verts
where in the endostyle in humans?
thyroid gland
what are lancelets?
suspension feeders in shallow, warm marine habitats
what is Cephalochordata?
lancelets
what diagnostic chordate features are found in Cephalochordate adults?
V-shaped myomeres
how do Ascidiacea reproduce?
cloning - form colonies; sexual - Hermaphroditic, occasional self fertilization; Tadpole larva w dorsal hollow nerve cord, tail, notochord
what are myomeres?
segmented trunk muscles
what are Ascidiacea’s?
Tunicates
what are 3 subgroups of Urochordata?
Ascidiacea, Thaliacea, Appendicularia (Larvacea)
Ascidiacea anatomy
covered by tough tunic; 2 siphons; water pumped into pharynx by oral siphon cilia; endostyle secretes mucus - water passes thru mucus, trapping food; Dorsally, mucus rope moved to esophagus; gas exchange in pharynx
what are the 2 siphons in Ascidiacea?
oral/incurrent, atrial/excurrent
what are the holes in tunicates?
stigmata
Vertebrate synapomorphies:
Distinct head w tripartite brain (fore/mid/hindbrain), cranium (skull); Neural crest; Neurogenic ectodermal placodes;
W-shaped myomeres
what are Thaliacea?
salps, pelagic urochordates that form large colonies
3 major extant subgroups of vertebrates?
lampreys, hagfish, gnathostomes
what are Appendicularia/Larvacea?
larvaceans; Pelagic, retain tadpole-like form as adults; Secrete large mucus “house” for filtering device, protection
what is a Neural crest?
mass of cells lying along neural tube
what are Neurogenic ectodermal placodes?
series of “plates” (thickenings) along neural tube
who were the earliest verts?
Haikouichthys, Myllokunmingia
when did Haikouichthys, Myllokunmingia live?
~530 myo
Haikouichthys, Myllokunmingia characteristics
cranium, heart, W-shaped myomeres, but no bone
what are Cyclostomata?
Agnatha
what groups are in Osteichthyes?
Actinopterygii; Actinistia, Dipnoi; Tetrapoda
What animals are in Cyclostomata?
hagfish, lampreys
what does Gnathostomata mean?
“jaw mouths”
what groups are in Gnathostomata?
Placodermi, Chondrichthyes, Osteichthyes
what are Placodermi?
extinct, heavily armored jawed fish
what are Chondrichthyes?
sharks, skates, rays
what are Actinopterygii?
ray-finned fish
what are Osteichthyes?
Euteleostomi; bony fish, tetrapods
what are Actinistia, Dipnoid?
coelacanths, lungfish
what do Hox genes do?
control segment identity along body (critical in placement and number of limbs, vertebrae)
how many Hox clusters do Cephalochordates have?
1
how many Hox clusters do Hagfish and Lampreys have?
2
how many Hox clusters do Gnathostomes have?
4
what are the neural crest and placodes and what do they do?
Form peripheral nervous system, cranium, adrenal glands, sense organs (nose, eyes, inner ear)
what are Ostracoderms?
paraphyletic group of jawless fish - covered w body carapace or plates, many lack paired fins
what are Conodonts known from?
small, hard comblike “elements”
what are the early Gnathostomes?
Placoderms, Acanthodians
what are placoderms?
armored, large (10 m)
what are acanthodians?
most closely related to Chondrichthyes
what are the living fish?
Cyclostomata, Gnathostomata
What are ”fish”? How would you define them?
aquatic vertebrates w gills, fins, dermal scales; w/o legs
what are Myxini?
hagfish “slime eels”
how many species are there of Myxini?
~70
Myxini characteristics
marine scavenger/predators; Rasp off bits of food w tooth-covered tongue; no scale/vertebrae; fished to make eel skin leather
what are Petromyzontoidea?
lampreys
Petromyzontoidea characteristics
~40, half are blood parasites of fish; No scales, have small cartilaginous vertebral structures; Many spawn in FW – have filter-feeding ammocoete larvae
What is cartilage?
connective tissue made of collagen, elastin
what are the 2 groups of Chondrichthyes?
Holocephali, Elasmobranchii
what are Holocephali?
chimaeras, ratfish; 1 gill opening on head
Elasmobranchii characteristics
multiple gill openings on head; 5-7 gill slit pairs, no swim bladder
what are Elasmobranchii?
sharks, rays
shark characteristics
several groups, predators; placoid scales; include largest “fish”
what are placoid scales?
cellular pulp covered by dentin, enamel
Characteristics of bony fishes include:
Endochondral bone, swim bladder/lungs, most have gills covered w operculum
Rays, skates characteristics
Dorsoventrally flattened, w large pectoral fins; Some w venomous tail barbs
what is an Endochondral bone?
bone that replaces cartilage
what are Osteichthyes?
Clade comprising bony fish and tetrapods; Includes Actinopterygii, Sarcopterygii
what is bone made of?
calcium hydroxylapatite, Ca10(PO4)6(OH)2
Actinopterygii Diversity
Cladistia, Chondrostie, Neopterygii