chordates BIOL 230 UWRF

what makes up class chondricythes

cartilaginous fishes

true or false - in class chondricythes, the boneless condition is secondary

true, ancestors did have bony structures so the loss of bone is a secondary adaption

what is unique about the teeth of class chondricythes

mature teeth are routinely shed so replacement teeth are constantly growing and moving out from inside of the mouth

what does the endoskeleton of cartilaginous fishes look like

persistent notochord and distinct vertebrae present

what does the skeleto-muscular system of cartilaginous fishes look like

consists of axial and appenducular skeleton

true or false- standard fin arrangement is common only in class chondricythes

false, it is common in most extant fishes

true or false - the paired fins of fish ancestors are the beginning of the four limb arrangement of vertebrates

true

how did jawed animals evolve in class chondricythes

through modification of the first pharyngeal arch into lower jaw

how do sharks stay aloft in the water

larger liver containing oil reduces density; heterocercal tail and pectoral fins like ailerons

what does the sensory system of cartilaginous fishes look like

well developed; complex eyes; extremely sensitive olfactory system; lateral line system; ampullae of lorenzini (electroreceptors in head)

what does the digestive system of cartilaginous fishes look like

short intestine is typical of carnivores; spiral valve in intestine increases surface area for nutrient absorption

what does osmoregulation in cartilaginous fishes look like

rectal gland secretes salt into rectum; relatively high concentration of urea maintained in bloodstream to keep blood hypertonic

what does the circulatory system of cartilaginous fishes look like

two chambered heart and hepatic portal system

what does the reproduction of cartilaginous fishes look like

dioecious; internal fertilization; oviparous, ovoviviparous and viviparous species

what does oviparous mean

egg laying

what does ovoviviparous mean

offpsring develop inside mothers body but nourished by nutrient-rich yolk stored in egg

what does viviparous mean

give birth to live young

what makes up class actinopterygii

ray finned fishes

what does the endoskeleton of class actinopterygii look like

bony skeleton including cranium, veterbrae, etc

true of false- fishes in the class actinopterygii have an operculum

true

what purpose does the operculum serve in class actinopterygii

it greatly increases respiratoty and feeding efficiency

what is the fin form in class actinopterygii

much greater diveristy in fin form; homocercal Tain in the most modern fishes

how does class actinopterygii generate thrust in a viscous medium

fusiform bidy to reduce drag; reduced undulation; undulation limited only to tail in fastest fishes

what does fusiform mean

streamlined body; not many sticky outy parts; smooth shape

what is used for bouyancy in class actinopterygii

swim bladder; derived from primitive lung; sac like outgrowth of esophagus

what adaptions help increase gas exchange efficiency in class actinopterygii

muscular pharynx; fine gill filaments; operculum; ram ventilation; countercurrent flow

what does reproduction in class actinopterygii look like

dioecious with external fertilization; oviparity is the rule but ovoviparity is not uncommon; varying degrees of parental care from none to lots

true or false - disruptive selection created 3 male forms in one species

true

what is diadromy

diadromous fish species migrate between marine and freshwater habitats for spawning purposes

what is anadromy

a form of diadromy in which fishes live in saltwater then migrate up freshwater rivers to spawn (and die)

what is catadromy

a form of diadromy in which fishes live in freshwater then migrate downstream to ocean to spawn (and die)

what makes up class sarcopterygii

lobe finned fishes; very few extant species

what is the probable ancestor of all tetrapods

ancestor of modern sarcopterygii

what is the fossil sequence

fish → fishpond → tetrapod

what are the 5 key characteristics for the phylum chordata

notochord, dorsal hollow nerve cord, pharyngeal pouches and slits, endostyle or thyroid gland, post-anal (true) tail

what is the first supporting structure of the chordate body

the notochord

what is the notochord replaced by during development in more derived chordates

vertebral column

what where pharyngeal pouches and slits originally used as

part of filter feeding apparatus

what is a common name for urochordata

tunicates or sea squirts

what is a common name for cephalochordata

lancelets, amphioxus

what is a common name for vertebrata

fish, amphibians, reptiles, birds, mammals

why are urochordata called tunicates

because of their outer skin which contains cellulose, also called sea squirts because they forcefully discharge water when handled

why are cephalochordata called lacelets

because of their shape but usually called amphioxus

what is another term for the jawless fishes

class agnatha

what are the only two extant representatives of class agnatha

hagfish and lampreys

what do lampreys do unlike most other vertebrates

undergo metamorphosis

how do vertebrates differ from most other animals

generally larger in size, generally more active, organ systems are adapted to accommodate these characteristics

what are the muscle-skeleta adaptations of vertebrates

endoskeleton of cartilage and bone, dermal bone including cranium, W-shaped myomeres (segmented muscle), larger locomotory muscle mass, paired limbs

what did pharyngeal function shift from over time

from feeding function toward gas-exchange

what do echinodermata and chordata have in common

both are deuterostomes

the term tunicate is a name used for

urochordata

what is the name of the first supporting structure of the chordate body

notochord

what two adjectives must be included to properly describe the chordate nerve cord

dorsal, hollow nerve cord

the endostyle in primitive chordates is homologous with what in derived chordates

thyroid gland

what is gnathostomes a term for

jawed fishes

what are some examples of class chondricythes

sharks, rays, ratfishes