Fishes Flashcards
What are the 3 first subphylums of the phylum Chordata?
Cephalochordata - lancelets; Urochordata - tunicates; and Vertebrata - vertebrates
What are 5 characteristics of the phylum Cephalochordata?
Lancelets have a brain, gill slits, dorsal nerve cord, notochord and a post-anal tail
What are 6 characteristics of the subphylum Vertebrata?
- Notochord, dorsal nerve cord, pharyngeal pouches, post-anal tail
- Cartilaginous or bony exoskeleton with backbone (one expection)
- Pronounced cephalization: a well developed nervous system with anterior brain and specialized receptors (nose, eyes, ears)
- Closed circulatory system with a 2-4 chambered heart and blood w/ hemoglobin
- Excretory system of paired kidneys
- Endocrine system of ductless glands (adrenal, pituitary, thyroid, etc.)
Osteichthyes - bony fishes refers to which 2 classes of fishes?
Actinopterygii - ray-finned fishes and Sacopterygii - Lobe-finned fishes
Superclass Gnathostomata means what? And how what are the 3 classes in this superclass?
Jawed
- Chondrichthyes - cartilaginous fishes
- Actinopterygii - ray-finned fishes
- Sarcopterygii - lobe-finned fishes
Name 6 types of fins with respect to location
1st dorsal, 2nd dorsal, adipose, pelvic, anal, caudal
Name 4 types of fish tails
Heterocercal, homocercal, protocercal (pointed), diphycercal (expanded pointed with abrupt point)
Name 4 types of fish scales and what kind of fish they are often found on
- Placoid or Denticles - sharks and rays
- Cosmoid - Lungfish
- Ganoid - Sturgeon, bowfins, gars
- Leptoid (cycloid and ctenoid) - most other fish
Name a few fish that lack scales and one that appears to lack scales but has a coating of deeply embedded scales
Ratfish, mackerel, swordfish, eel, catfish, and blue-fin tuna has embedded scales
What is the Superclass for jawless fishes?
Agnatha (part of subphylum vertebrata)
What does the Class Myxini, Order Myxiniformes, Family Myxinidae refer to?
Hagfish
Do Hagfish have vertebrae?
No. They have a cartilaginous skeleton with a notochord that persists in the adult as a cartilage rod
How do hagfish remove their slime?
They squeeze it off by tying their bodies in a knot and working the knot down their body to the tail removing slime along the way
What are the 2 species of hagfish in BC?
Pacific and black hagfish
What kind of environment are hagfish found in?
Marine
If hagfish don’t have jaws, what are their mouths modified for?
Mouths are modified for sucking and have two rows of teeth on the tongue
What function do hagfish barbels have?
Sensing
List 5 features of hagfish
no eyes no paired fins (caudal only) Cartilagenous skeleton a notochord but no vertebrae slime glands to ward of predators
What do hagfish eat?
scavenge and prey on invertebrates and dead or dying fish
What does the class petromyzontida, order petromyzoniformes, family petromyzontidae refer to?
Lampreys
What are the 2 species of Lamprey in BC?
Pacific (Tooth at top of mouth with 3 points?) and River Lamprey
List 5 characteristics of Lampreys
Notochord that persists as an adult surrounded by a cartilagenous pile with rudimentary vertebrae jawless sucking disc with many teeth no barbels prominent eyes dorsal and caudal fins
What do Lampreys eat?
They are parasites that feed on fish and other creatures
What kind of life cycle to Lamreys have?
Anadromous – spend part or all of adult life in salt water and return to freshwater streams to spawn (like salmon)
What is does class chondrichthyes refer to?
Cartilagenous fishes
What are 2 subclasses in class chondrichthyes?
Subclasses:
Elasmobranchii (sharks, skates, rays)
Holocephali (ratfish/chimaeras)
How many dorsal fins do sharks have?
2
What is a shark’s skeleton made of?
Cartilage
What does a shark have in excess of in it’s liver and what is the function?
Oil for buoyancy because they don’t have a swim bladder
Why must most sharks swim continuously?
to keep water moving over their gills for oxygen and maintain buoyancy
What kind of tail fin does a shark have?
Heterocercal
What is the function of a spiracle?
intake of water that exits through the gill slits (water can also enter mouth)
How do sharks achieve neutral buoyancy without a swim bladder?
Cartilagenous skeleton (less dense and therefore lighter)
Shape of pectoral fins and heterocercal tail and surface of head provide lift
Large quantities of oil and lipids in liver (less dense tha seawater)
but still must swim continuously to overcome negative buoyancy
What do the largest sharks eat?
Filter feed plankton (no teeth?)
example - basking shark
beneficial to feed lower on food chain because there is more biomass to feed on
What are shark teeth?
Modified placoid scales or denticles
What are 2 sensory features on sharks and give a brief description of what they do?
Lateral Line Canal- has openings to surface and is connected to the acousitic system and is sensitive to water pressure and vibrations
Ampullary Organs of Lorenzini - pores with jelly filled canal that are sensitive to weak electric fields (possiblely salinity, pressure, and temp) and look like freckles on the head with indentations
What feature do the short digestive tracts of sharks have to increase surface area?
Spiral valves - similar to folded intestines of other creatures (evolution finds different ways to solve the same problem in different organisms)
What is the blood of sharks in refrence to seawater and where is excess NaCl excreted?
Isosmotic
excreted in rectal gland
Is fertilization in sharks external or internal?
internal
What are claspers and what are they for?
modified inner edges of pelvic fins in males used in mating and is inserted into the female cloaca
What reproductive modes are present in sharks? Which is most common?
Oviparous - egg laying
ovoviparous - eggs retained and hatched in uterus, nourished by yolk
viviparous (most common) - nourished through mothers blood through a placenta
What is a mermaid’s purse? What is it made of?
shark/skate egg case made of keratin
never from rays
What kind of development do baby sharks have? Is there metamorphosis?
Direct development, no metamorphosis
In class chondrichthyes what are the skates and rays collectively known as?
batoids
What is the spine of a sting ray?
a modified placoid scale with a venom gland at the base
What is the difference between poison and venom?
poison is ingested ( no poisonus snakes)
venom is injected ( no venomous berries)
What do the largest rays such as the manta ray eat?
plankton
what kind of reproductive mode do rays have?
ovoviviparous
How do rays keep bouyancy?
similar to sharks
no swim bladder or operculum so must keep swimming
Describe Rays
rays: fewer species long thin tail without fins sting ray tail armed w/ spines ovoviviparous 1-lobed pelvic fin bird like swimming motion more streamlined
Describe Skates
Skates: more species thicker tail with fins thorns on tail oviparous 2-lobed pelvic fin undulating swimming motion better camouflage and more bottom dwelling
What are the main differences between skates and rays
Skate tails are fleshy w/ thorns and fins
Ray tails are needle-like w/o fins and thorns
Skates: 2-lobed pelvic fin
Rays: 1-lobed pelvic fin
Summarize class chondrichthyes, subclass elasmobranchii
cartilaginous endoskeleton, placoid scales, 5-7 pairs of gills/slits, no swim bladder, spiral intestinal valve, urea in muscle tissue, blood isosmotic to seawater, direct development, internal fertilization, all 3 forms of reproduction present, well developed senses (vibration - lateral line, electro-ampullary organs of lorenzini)
What is class chondrichthyes, subclass holocephali?
ratfish
Describe subclass holocephali
cartilagenous skeleton, lack scales, males possess pelvic and cephalic claspers, upper jaw fused to skull, ventral mouth, egg capsule similar to mermaids purse, teeth are large plates, dorsal spine, long thin tail, large pectoral fins
What are the 2 subclasses in Superclass gnathostomata, class actinopterygii?
Subclass chrondrostei - sturgeons and paddlefish Subclass Neopterygii - modern bony fishes
What is class Actinopterygii?
ray-finned fishes
What is class Sarcopterygii?
lobe-finned fishes - coelocanths (none local, thought to be extinct until recently)
What are Class Actinopterygii and Class Sarcopterygii often called collectively?
Osteichthyes - bony fishes
What are 2 species of sturgeon in BC?
Green (marine) and White (fresh) sturgeon
What is the largest fish found in fresh water?
sturgeon
Summarize Class Chrondrostei
cartilagenous skeleton, heterocercal tail, head covered in bony plates, 5 rows of bony scutes (remnant ganoid scales), no teeth, 4 barbels, prey on benthic fish and invertebrates
Name 2 Infraclasses in Subclass Neopterygii (modern bony fishes)
Infraclass Holostei - gars and bowfins (no local) Infraclass Teleostei - majority of modern bony fish (salmon, herring, rockfish etc...)
What is the bowfin Genus?
Amia
What is the Gar Pike Genus?
Lepisosteus
