By 256 Lab Exam 1 Studyguide

BY 256 LabExam 1 Study Guide

Agnathans

• Jawless Fishes (no jaws or paired appendages)• Suctorial Mouth with teeth• Gill apertures• Single nostril• Lateral line system (detects pressure)• 2 chambered heart

White Pin- median nostrialGreen Pin- Lateral EyeRed Pin- in mouth (buccal funnel)

Lamprey

• Cephalospidomorphi • Cartilaginous• 7 gill slits• Retains notochord• Anadromous life cycle• Spend 5yrs as larva (ammocoete)• Parasites (anticoagulant producers)• Die after mating and reproducing

Hagfish

• Myxini• Most primitive living vertebrate• No larval form• > 7 gill slits• Knotting behavior that helps during feeding and escaping predators• Slime producers

Gnathostomata

• Jawed Fish• Chondrichthyes

• Elasmobranchii (sharks, skates, and rays)

• Holocephali (chimera)

• “Osteichthyes”• Sarcopterygii (fleshy finned fish)• Actinopterygii (ray-finned fish)

• Chondrostei (sturgeons and paddlefish)• Neopterygii

• Holostei (bowfin and gar)• Teleostei (perch and darter)

Chondrichthyes

• Cartilaginous skeleton• No swim bladder

• Elasmobranchii (sharks, skates, and rays)• Holocephali (chimera)

Sharks

• Elasmobranchii• Jaws with many rows and teeth (homodont dentiton)• Spiracle (modified 1st gill slit, detects pressure)• Ampullae of Lorenzini (detects electrical fields of other animals)• Spiral valve (Shelves inside intestines that increase surface area)• Rectal Gland (salt regulation & osmoregulation)• Liver (fatty, large, used for buoyancy)• Placoid Scales

Skates and Rays

• Flattened Body • Reduced Tails• Spiracles• Skates have a more elaborate tail and larger fins. They are oviparous,

lay eggs. Mermaid's Purse, egg case that protects developing embryo until it hatches.• Rays ovoviviparous, their embryos develop inside mother’s body.

Chimera (Rat Fish)

• Holocephali• No Scales• Gill Covers (operculum)

Osteichthyes

• Bony skeleton and jaws• Dermal scales • Operculum• 2-chambered heart• Arose in Devonian Period• Is the largest group of living vertebrates• Over 23,000 living species

Sacropteygii

• Fleshy or lobe Finned• Primitive• Lungfish• Coelacanth

Lungfish

• Gulp air at surface of water• African lungfish can survive desiccation through aestivation• Build mucous cocoon in dry season• Found only in Africa, S. America, and Australia• Dipnoi sp. (Lungfish

Coelacanth

• Thought to be extinct• Presence of a “Rostral organ”

• Part of the electrosensory system

• Intracranial joint in the skull• Allows the anterior portion of the cranium to swing upwards

• Hollow, oil-filled notochord extending the length of the body• Other specific characters

• Vertebrae are incompletely formed or totally lacking bony centra (vertebral bodies) • Oil-filled gas bladder

• An out-pocketing of the gut• Fleshy “lobed” or limb-like fins

• Are internally supported by bone• Paired fins move in a synchronized tetrapod-like pattern

Actinopterygii

• Ray Finned Fish• Gas (swim) bladder

• Important structure for maintaining position in the water column (energy-saving)• Types of swim bladders

• Physostomous• Retains connection with the gut via duct (primitive)• Gulp air

• Physoclistous• No connection with gut• Found in higher teleosts• Gases exchanged via blood in gas gland and removed via “ovale organ” area of bladder

• Two Branching clads: Chondrostei and Neopterygii

Chondrostei

• Primitive • Largely cartilaginous• Ganiod Scales• Sturgeon and Paddlefish• Have a heterocercal tail ( similar to shark tail)• Possess rudimentary spiral valve in the intestine• Sturgeons- Restricted to N. Hemisphere• Paddlefish- 1 species found in N. America, 1 species in China

Neopterygi

• More “modern” of Actinopterygii• Ray-finned fish• Most have gas bladder (swim bladder)• 2 main groups• Holostei (intermediate) Gar and Bowfin• Teleostei (advanced) most fish species

Holostei

• Intermediate ray-finned fish• Gar:

• Ganoid scales• Abbreviate heterocercal tail• Inhabits backwaters (freshwater and marine)

• O2 levels in the water gar inhabit can be < 3.5ppm• Gar gulp air using gas bladder as a lung• Physostomous swim bladder

• Bowfin:• Cycloid scales• Abbreviate heterocercal tail• Inhabits backwaters (freshwater) where O2 levels can be low

• Gulp air in similar fashion to gars (physostomous swim bladder)

Telostei

• Advanced ray-finned fishes• Scale types of teleosts

• Scale types of teleosts• Cycloid and ctenoid scales

• Represent ~96% of all living fishes• ~21,000 species of teleosts

• All have a physoclistous swim bladder• Teleosts are the most diverse group of fishes

Darters

• Almost all darters are extremely intolerant to pollution• Good ecological indicators.

• Swim bladders:• Most darters have poorly developed swim bladders• Some lack a swim bladder entirely• Darters have to “dart” around on the bottom

• All are insectivores/carnivores• Most prefer fast-moving water over riffles