Quiz #7: Cartilaginous and Bony Fishes

List 5 characteristics of Subclass Holocephali (ratfishes/chimeras).

1. Benthic 2. Mouth ventral 3. No teeth long flat plates for crushing food 4. Upper jaw is fused to cranium 5. No Gill slits have operculum.

Describe 3 ways that sharks enhance buoyancy.

1. Cartilaginous skeletons are lighter and less dense than bone and there is not as much skeleton. 2. Huge fatty liver of sharks provides buoyancy. 3. The heterocercal shape of the caudal fin of sharks provides lift.

What are the key threats to elasmobranch populations?

1. For food. 2. For fins. 3. As bycatch (accidentally catched) Humans are the biggest threat.

List the 3 features about shark reproduction make them particularly vulnerable to overfishing and explain why they do.

1. It takes a long time for them to become sexually mature, up to 20 years. 2. There gestation periods are long. 3. They on,y produce a couple of pups per pregnancy.

Name & describe the 3 different methods of reproduction found within Class Chondrichthyes. Which reproductive mode of Chondrichthyes is most common?

1. Ovipary: shark lays eggs, embryo feeds on yoke and when it finishes the yoke, it hatches. 2. Ovovivipary (most common): eggs are fertilized and stored in female's body. The eggs have yoke and the female does not give any more nutrients to embryos. When they finish yoke, they hatch. So there is a live birth. 3. Vivipary: the mothers are attached to babies through umbilical chord and placenta through whole life as an embryo and live birth occurs.

List 5 characteristics of Subclass Holocephali (ratfishes/chimeras).

1. Pointed head and long tail 2. No teeth, only large flattened plates so they crush their food. 3. Mouth on ventral side. 4. No scales 5. Upper jaw is totally fused to their cranium (not seen in any other fish)

List 4 characteristics of Class Chondrichthyes.

1. Skeletons made from cartilage 2. Range in size (small shark to whale shark) 3. Skates and rays are benthic 4. Ventral mouth

Describe 3 ways in which the mouth of a bony fish differs from that of cartilaginous fishes.

1. Teeth attached to jawbone vs in cartilaginous fish it's embedded in tissue. 2. Protrusible jaws: they can push jaw away from head and reach mouth forward. Great suction and feeding and also great biting because toothy jaw is close to prey. 3. There mouths are terminal and more ventral, so it's at the end of the anterior end of the body.

List 7 characteristics of jawless fishes (Infra-phylum Agnatha).

1. fully cartilaginous 2 no fins on side of body 3. no scales and tough skin 4. oral hole 5. respiratory pits 6. they slime 7. have vision

What is a fish?

A vertebrate animal and includes all vertebrates that are not tetrapods

List the 5 defining characteristics of Phylum Chordata

Animals in the phylum Chordata share five key chacteristics that appear at some stage during their development: a notochord, a dorsal hollow (tubular) nerve cord, pharyngeal gill arches or slits, a post-anal tail, and an endostyle/thyroid gland

List the 4 defining characteristics of Phylum Chordata, Subphylum Vertebrata.

As chordates, all vertebrates have a similar anatomy and morphology with the same qualifying characteristics: a notochord, a dorsal hollow nerve cord, pharyngeal slits, and a post-anal tail.

Define & describe myomeres.

Bands of muscles. Help fish swim.

Know that bony fish hearts are more powerful than those of other fishes.

Bony fishes have stronger hearts than other fishes.

List the characteristics that distinguish teleosts (ray-finned bony fishes) from cartilaginous fishes.

Bony skeleton Awesome diversity Live in every possible aquatic habitat

What is shark-finning and why does it occur?

Cutting the fin off of a shark and it's for shark fin soup and the fin adds no taste it's just for aesthetics.

Describe cycloid and ctenoid scales.

Cycloid are smooth and ctenoid scales have doing border.

List the uses of the following fins in bony fish locomotion: dorsal, pectoral, pelvic

Dorsal: steering and mobility Pelvic: balance, turn, brake Pectoral: maneuver and stability. in tripod fish it allows them to stand

List the 3 major groups (Phyla) of fishes.

Fishes are typically divided into three groups: superclass Agnatha (jawless fishes), class Chondrichthyes (cartilaginous fishes), and superclass Osteichthyes (bony fishes).

Describe the anatomy of a fish gill, defining the following terms: operculum, gill arches, gill rakers, gill filaments, lamellae.

Gill arches support gills Gill filaments are the thick sections of gills see blood through them Operculum stops water or legs water in like Gill slits but better Gill rackers are what hold the Gill filaments Lamella is where water flows between

What is the key difference between subphylum Urochordata & subphylum Vertebrata?

In Urochordata, the notochord, nerve cord, and postanal tail is only found in the larval stage. They never have a bony backbone. The main difference between chordates and vertebrates is that chordates do not have a vertebral column whereas all vertebrates have a vertebral column.

How are we evolutionarily related to fish?

In the embryotic stage, human embryos and fish embryos both have gill slits, tails, dorsal hollow nerve cord, and notochords.

Describe the structure and function of the lateral line of fishes.

Lateral line can detect vibrations in water. Can let the fish know if prey or predators are close, if there are objects in the water, etc. they can feel water pressure. The purpose of the lateral line is to help the shark detect motion or vibrations in the water. Thus, the shark can use its lateral line to detect its surroundings and its prey

Why are coelocanths called 'living fossils'?

Marine Biologists thought they were extinct 70 million years ago.

What is a swim bladder? Which organisms have it? What is its purpose?

Most bony fish have it. The swim ladder is a gas filled sack and it compensates for the fact that the skeleton is made up of heavy bone and there is heavy muscle. Only fish that need to be moving through the water column need a swim bladder cuz it takes up a lot of energy to swim. Helps with buoyancy in fish.

How does the operculum of bony fishes increase respiratory efficiency compared to spiracles or gill slits?

Operculum protects gills and increases efficiency of respiration because it can create negative pressure in the mouth when operculum closes. So not only when they open their mouths do they get water, but water gets pulled in by negative pressure and then they can only their gills and let the water out. So they use their operculum to oxygenate their gills. They open mouth Close operculum Close mouth Open operculum Water is sucked in through mouth, but water is being sucked in because of the operculum. Creates more water flow over gills.

Describe placoid scales, what tissues they are derived from and list a benefit of having them.

Placoid scales (or denticles) are spiny, toothlike projections seen only in cartilaginous fishes. Placoid scales are composed of a vascular (supplied with blood) inner core of pulp, a middle layer of dentine and a hard enamel-like outer layer of vitrodentine. Placoid scales are rough to the touch and the structure they form is nearly impossible to penetrate. These scales function to protect a fish from predators and can even be used to injure or kill prey.

Define homocercal tail and explain what advantage bony fish have in this fin structure?

Same lengths of each lobe. This shape tail focuses the muscular contractions because the way the tail is put together allows the muscular contractions to focus right in the caudal peduncle allowing more flapping to happen by tail which causes more speed.

Define & describe pharyngeal jaws.

Set of jaws back in the throat. Can be very powerful. Fish will sit upright and chew food with their pharyngeal jaw.

Describe the basic body plan (external anatomy) of subclass Elasmobranchi (sharks, rays, skates)

Sharks, skates, and rays have ventral mouth. Sharks have dorsal fins, pectoral fins, posterior fins, heterocercal tail, teeth embedded in jaws. In many sharks that are predators, their teeth allow them to tear and rip apart their prey. In smaller sharks that are not ferocious predators, like the bamboo shark, their teeth are smaller and suited to eating animals like snails and crustaceans. In rays, they eat prey that is hidden down into the sand or mud since they are benthic fish. Therefore, instead of having teeth all around their mouth, they have bony flattened plates that are attached together so that the ray can grab its food into its jaw and clamp down on its prey. The ray can break down the shell of its food and eat the meat of the animal.

Describe characteristics of each of the 5 senses in bony fishes (smell, taste, vision, lateral line, hearing).

Smell: they have nars (nasal openings) not that strong in bony fishes Taste: they have taste buds in mouth, lips, some on skin, fins and extended on barbels. Vision: they have spherical lenses so they have to move their whole lens towards or away (rather than just changing the shape like humans do) vision is important in bony fishes m Lateral Line: detects vibrations in water helps to detect prey/predators/objects in water/change in water currents, etc. Hearing: got otoliths to tell them what direction sound is coming from

Define heterocercal tail.

The caudal fin is the tail of the shark. Heterocercal means that the upper lobe of the caudal fin is larger than the lower lobe of the caudal fin. The heterocercal shape of the caudal fin provides lift for the shark.

Describe hagfish and lamprey, distinguishing them from each other in terms of mouth structure, feeding, lifestyle (lab)

The hagfish's body shape is long and cylindrical. It has velvet smooth skin, and it does not have scales. It has a skull but no spine. The hagfish has no fins, but it does have a paddle-like tail. There are small holes that run along its body, and some are used for breathing while others are used for sliming. The hagfish does not have a jaw, and its mouth has multiple rows of sharp teeth. Its head and mouth are at the end of its cylindrical body. The lamprey does have a suction cup mouth, and it is ringed with sharp teeth. The lamprey will latch on to a fish and use its rough tongue to break down an organism's scales and skin in order to feed on the host's blood and bodily fluids

Sharks & rays have a sensory system that other organisms do not - what is it?

The lateral line.

Why are the banded myomeres so much more efficient than bundled muscles (like us).

The muscles are attached to backbone. Muscles make swimming super efficient since it doesn't make the fish burn that many calories to swim because of the good and strong muscles.

Define fish operculum.

The operculum is a gill cover that is bony. The fish can control the opening that is hiding their gills, whereas sharks are not able to do this since they do not have an operculum. Fish can ingest a lot of water and create a flow of water over their gills, meaning that, unlike a shark who must be facing a current or swimming in order to have water pass over their gills, a fish can be still and have water move over their gills.

What are otoliths and what do they allow fish to do well?

The otoliths are ear stones and they are dense bones under the head of the fish by the ear. When a sound wave passes through, it moves through the body and makes you vibrate. The more dense, the vibration will occur at a lower speed. The otoliths vibrate at a different frequency and they are going to lag a bit, and the fish will know what direction the sound is coming from.

How does the electrosensory system of sharks work?

The purpose of the Ampullae of Lorenzini is to allow the sharks to detect electrical currents in the water. Thus, the Ampullae of Lorenzini help the shark detect the heartbeats and nervous systems of organisms in the water.

Some sharks have a nictating membrane on their eyes - what is this and what function does it serve?

The purpose of the nictitating membrane on the eye of the shark is to protect the eye. Due to the fact that the shark does not have any eyelids, this membrane comes up over the eye and protects it, especially when the shark is about to attack their prey, because in that moment, they do not rely on vision and are totally blinded by their attack.

What are spiracles, which kinds of elasmobranchs do they occur in, how do they help them breathe?

The spiracle is a small hole behind each eye that opens to the mouth in some fish. Helps to pump water over the gills when the animal is on the floor and can't get water into gills. Spirales aid in respiration in jawless fish. Occurs in elasmobranchs and jawless fish.

What is the largest shark and how does it feed?

The whale shark and they filter feeder.

What allows bony fish to detect direction of sounds moving through water?

Their otoliths

Describe a physical characteristic of coelacanths (Class Coeloncanthi) that indicates an evolutionary link with tetrapods (4-legged animals).

There are paired fins on side of body that have bone, suggesting they came from tetrapods.

Define Ampullae of Lorenzinii

These are pores and inside the pores there is a gel. These pores can pick up on electricity so they can pick up electrical currents, so it knows if there is a living organism close by or if it's under stress cuz if can hear the heartbeat.

Many sharks have advanced abilities in osmoregulation. What mechanism do they use that is unique?

They can hold on to their urea, which is salt, put it back into their blood stream so they can be as salty as sea water. They pull water through gills, excrete extra salt through peeing.

Describe a physical characteristic of coelacanths (Class Coeloncanthi) that indicates an evolutionary link with tetrapods (4-legged animals).

They have paired fins that have bones like tetrapods.

What % of a fish is muscle?

Up to 75%

Describe respiration in fishes, including how they maintain a maximum of oxygen absorption from the water.

Water flows in one direction and blood that's coming from the body that's missing oxygen flowing in opposite direction so you're maximizing the diffusion gradient so you're getting the most possible oxygen extracted from the water into the bloodstream that fish can use.

What is a tadpole larva (resemble frog tadpoles, but are not them) and how do they reveal the relationship between tunicates and vertebrates?

a larva that crashes onto the substrate, attaches to substrate by attachment points, nerve chord/notochords disintegrate and they become sessile and filter feed. One clue that tunicates are related to vertebrates is found in the tunicate larva, or tadpole. It even looks like a tiny tadpole, and has a nerve cord down its back, similar to the nerve cord found inside the vertebrae of all vertebrates.

Define diphycercal tail.

having a tail or caudal fin with the spinal column extending horizontally to the end of the tail

What kinds of animals are in subphylum Urochordata?

sea squirts, tunicates

Which sense is most of the brain of a shark dedicated to?

smell