A&P Exam #4, Fish

Are fish monoecious or dioecious

Dioecious

Are sharks monoecious or dioecious

Dioecious

Ampullae of Lorenzini

Electroreceptors all around a shark's head that can detect electrical stimuli; this allows sharks to sense muscle contractions of prey or other predators in the water

Describe Fish sense of sight

Fish have vision as good as human vision, and have color vision.

Nutritional deficiencies

Fish need to get aromatic amino acids form their diet, this inability to synthesize their own aromatic amino acids is passed down to all their vertebrate descendants

Why do fish produce so many eggs

Fish produce 4 to 6 million eggs because only 1 million survive to reproductive maturity.

From what distinctive feature does this class derive its name

Get name form cartilaginous skeleton

Operculum

Hard plate that covers the gills in bony fish, the flexing of this plate pumps water over the gills and can act as an efficient bellows system when stationary.

When did bony fish evolve

Originated at the same time as sharks; 400 MYA

What types of fins do most sharks possess

Paired pectoral and pelvic fins; 1 or 2 median dorsal fins; one median caudal fin; medial unpaired anal fin.

Subclass Actinopterygii

Ray-finned fish; have parallel bony rays that support and stiffen each fin to compensate for the lack of muscles within fins.

Name some other types of Chondrichthyes

Rays, Skate, Sawfish, Stingrays, Manta rays

Shark Excretory system

Regulate salt concentration in the blood by using a specialized kidney and rectal glands

What are rays/spines used for

bony rays (spines) cover the skin and aid in protection.

From what distinctive feature does this class derive its name

cartilaginous skeleton

Spiral Valve

corkscrew shaped lower portion of the small intestine in sharks and rays; slows food in gut and increases surface area for nutrient absorption; evolved to compensate for shark's short intestine.

Rectal glands

excretory organ in sharks that secretes a very high concentration of salt

OSTEICHTHYES (bony fish)

formerly considered a class is now divided into two.

What are the two classes of bony fish

1) Subclass Sacopterygii (Lobe-finned fish) and 2) Subclass Actinopterygii (ray-finned fishes)

What are the five key characteristics of fish

1) Vertebral column, 2) Jaws and paired appendages, 3) internal gills, 4) single-loop blood circulation, 5) nutritional deficiencys

Shark sense organs

1) lateral line system, 2) highly sensitive eyes, 3) large olfactory organs that can smell up to a kilometer away, 4) Ampullae of Lorenzini

What are two significant adaptations of bony fish

1) swim bladder, 2) gill cover

Heterocercal Tail (Shark)

Asymmetrically shaped; functions like a propeller, the shark extends its vertebral column upward and swings its tail back and forth to create thrust and lift.

Where do fish lay their eggs

Bury eggs in sediment and guard nests, scatter them among aquatic vegetation, incubate in mouths ("mouthbrooders")

How many species of sarcopterygians are alive today

Only 8 species alive today, 6 are lungfishes and 2 are coelcanths

What kind of caudal fin do ray-finned fish they have

Homocercal

Do sharks have internal or external fertilization

Internal.

Sarcopterygians are commonly known as

Lobe-finned fish.

Subclass Sacropterygii

Lobe-finned fish; have paired fins that consist of a long fleshy muscular lobe that is supported by central core of bones with fully articulated joints

What type of structures do most sarcopterygians use for respiration

Most Sacropterygians use lungs for respiration at some point in their lives, also may use gills

Describe the pathway of food in a shark digestive system

Mouth --> large pharynx (throat) --> Short esophagus --> stomach --> intestine with spiral valve --> rectum with rectal glands --> cloaca

Lateral Line system

Series of sensory organs under the skin in fish that detects changes in pressure waves, equivalent to a sense of hearing

What are shark fins exploited for

Shark fins are used to make purses, shoes, belts, wallets etc.

Describe the evolution of shark teeth

Shark teeth developed from rough scales that were present on the mouths of early sharks; these teeth retained scale-like qualities such as continually being replacement, arranged in rows of 20, not set in the jaw.

Do sharks take care of their young

Sharks do not exhibit ANY parental care.

Shark Respiratory

Sharks have mouth that opens into a large pharynx containing gill slits; most sharks breathe by swimming with their mouths open to allow water to pass over their gills.

Fish digestive system

Stomach; stores food --> intestines; capable of digestion and absorption --> pyloric ceca; fingerlike appendages that open off of intestines that function to secrete enzymes for digestion

Otoliths

Structure in inner ear composed of calcium carbonate crystals obtained from the water

Homocercal Tail (perch)

Symmetrically shaped

What is the advantage of possessing this type of fin

These lobe fins are fleshy and might be used like legs to support the body and walk

From what source do most fish obtain the oxygen they need to survive

Through gills

Do fish communicate

Through sounds; grunts, click, howl, honk during feeding and courtship - this communication coevolved with hearing.

Describe the flow of water to and from the respiratory area of the fish

Water flow is opposite the flow of blood; this is the BEST arrangement for extracting oxygen.

How do fish hear

Weberian ossicles; a set of time bones that allow them to pick up sound through their body

Vertebral Column

a key characteristic of fish; an internal skeleton with a bony or cartilaginous spine that surrounds the dorsal nerve cord and a bony or cartilaginous skull that encases the brain.

Single-loop blood circulation

a key characteristic of fish; blood is pumped from the 2-chambered heart --> gills --> body --> back to the heart

Internal gills

a key characteristic of fishes; organs rich with blood vessels for gas exchange.

Clasper

a shark organ that has been modified in males to be used in copulation to transfer sperm to female sharks

Swim bladder

gas-filled sac that allows bony fishes to regulate their buoyant density; filled and drained with gases internally - gasses are taken from the blood, and the gas gland secretes the gases into the swim bladder. Gas is released from the bladder by a muscular valve.

Jaws and Paired appendages

most fish have two pairs of fins; pectoral and pelvic. But hagfish and lampreys DO NOT.

What is the advantage of ray-finned fish possessing this type of tail

symmetrical homocercal tail is desighned for great speed.

Actinopterygians are commonly known as

ray-finned fish.