Fishes :/ Flashcards
major advances in the subphylum Vertebrata
flexible and adaptable integument, endoskeleton of cartilage and bone, muscular pharynx
integument
outer epidermis derived from ectoderm, inner dermis derived from mesoderm, modifies to become hair/scales/horns/feathers/etc.
endoskeleton in basal vertebrates
notochord/vertebrae made from cartilage
endoskeleton in bony fishes/tetrapods
true bone
function of muscular pharynx in vertebrates
originally for passive filter-feeding, becomes muscular in vertebrates and can be used in respiration
3 major “groups” of extant fishes
Superclass Cyclostomata, Class Chondrichthyes, and Superclass Osteichthyes
superclass known as “jawless fishes”
Superclass Cyclostomata
classes contained within superclass Cyclostomata
class Myxini and class Petromyzontida
commonalities of superclass Cyclostomata
lack of a bony jaw, no scales, cartilaginous skeletons, round mouths with rasping teeth
class of Cyclostomata known as hagfishes
class Myxini
characters of class Myxini
marine scavengers, live on the ocean floor, feed with keratinized teeth on dead animals, produce slime when threatened
class of Cyclostomata known as lampreys
class Petromyzontida
general characters of class Petromyzontida
38 species, half are parasitic, feed via oral disk with keratinized teeth, no distinct stomach
general life cycle of class Petromyzontida
spend majority of life as an ammocoete in freshwater streams, migrate to adult habitat following metamorphosis, die right after breeding
key groups of extinct fishes
Ostracoderms and Placoderms
characters of Ostracoderms
paraphyletic group, covered with bony dermal armor, jawless, likely filter-feeders
major advances seen in Ostracoderms
first group of fishes with pectoral fins and to use their pharynx for respiration
characters of Placoderms
paraphyletic group, first jawed fishes, head covered in bony armor
major advances seen in Placoderms
first fishes with pelvic fins
class of fishes known as cartilaginous fishes
class Chondrichthyes
subclasses contained within class Chondrichthyes
subclass Elasmobranchii and subclass Holocephali
subclass of Chondrichthyes containing sharks, skates, and rays
subclass Elasmobranchii
subclass of Chondrichthyes containing chimaeras
subclass Holocephali
general characters of class Chondrichthyes
almost entirely marine, skeleton completely cartilaginous, mostly predatory
method for maintaining buoyancy in Chondrichthyans
HUGE oil-filled liver (not as effective as a swim bladder, keeps Chondrichthyans limited to a small range of depth)
morphological traits of Chondrichthyans
heterocercal tail (vertebrae extend into upper lobe), placoid scales (homologous to vertebrate teeth), paired pectoral and pelvic fins
respiration in Chondrichthyans
spiracle pumps water into gills for breathing; sharks must constantly swim to breathe
reproduction in Chondrichthyans
internal fertilization using claspers to transfer sperm, most have oviparity
reproduction in sharks specifically
can be oviparous, ovoviviparous, or viviparous
sensory systems in Chondrichthyans
olfactory system (long distance), lateral line to detect vibrations (medium distance), vision (close distance), and ampullae of lorenzini (very close distance)
superclass known as bony fishes
superclass Osteichthyes
classes included within superclass Osteichthyes
class Sarcopterygii and class Actinopterygii
general characters of superclass Osteichthyes
pectoral, pelvic, and caudal fins, lateral line to detect movement, muscular operculum covers gills
method of respiration in Osteichthyans
water flows in through mouth and over 4 paired gills, each gill has gill makers, gill arch, and gill filaments, counter-current exchange maximizes oxygen uptake
method of regulating buoyancy in Osteichthyans
swim bladder
two types of swim bladders in Osteichthyans
physostomes and physoclists
swim bladder in physostome fish
esophagus connects directly to swim bladder, which is filled/drained via the mouth –> constrained to shallow waters
swim bladder in physoclist fish
swim bladder regulated via bloodstream, gas gland adds oxygen to bladder and ovale removes oxygen –> more common, allows for greater depth range
methods for detecting sound waves in Osteichthyans
inner-ear with otolith and weberian ossicles
structure of otolith
3 semi-circular ear canals made from dense calcium carbonate to detect vibrations
structure of weberian ossicles
only 1/3 of Osteichthyans have this, modified vertebrae that connect to swim bladder
vision in Osteichthyans
hard round lens, eyes focus by moving physically closer or farther from retina
class of Osteichthyes known as ray-finned fishes
class Actinopterygii
subclasses contained within Actinopterygii
subclass Chondrostei and subclass Neopterygii
characters of subclass Chondrostei
bony fishes with cartilaginous skeletons, heavy ganoid scales (like armor), can have either heterocercal tails or diphycercal tails, spiral valve intestine
intestine in Chondrichthyans
has a spiral valve to maximize surface area
characters of early Neopterygians
heterocercal tail, bony skeleton, ganoid or cycloid scales (cycloid scales much lighter), some have remnants of a spiral valve intestine
characters of “teleosts” in Neopterygii
contains over half of all vertebrates, incredibly diverse, about half marine and half freshwater (1% live in both)
reproduction in teleost Neopterygians
most have external fertilization, and some have parental care (most do not)
structure of scales in teleost Neopterygians
scales derive from mesodermal skin (like hair!), overlap for flexibility, thin layer of mucus covers scales to reduce drag, most have ctenoid scales (scales have small bumpy teeth to aid in drag reduction)
tails of teleost Neopterygians
homocercal; symmetrical with upper and lower lobes, makes tail the strongest muscle for swimming
method of feeding for teleost Neopterygians
use suction feeding where buccal cavity rapidly expands, creating a vacuum to suck in prey
class of Osteichthyes known as lobe-finned fishes
class Sarcopterygii
common traits of Sarcopterygians
muscular lobed fins, diphycercal tails
subclasses of class Sarcopterygii
subclass Sipnoi and subclass Actinistia
subclass of Sarcopterygii containing lungfishes
subclass Dipnoi
characters of Dipnoids
swim bladder functions as a lung, can live out of water for a while (uses limbs to crawl onto land)
subclass of Sarcopterygii containing coelacanths
subclass Actinistia
characters of Actinistians
only 2 species, live in deep marine waters, huge, poorly understood
