Ichthyology Exam 1 Sample ESF

What are three of the key evolutionary steps in fishes for Semicircular Canals and what is an examaple of the fish group that first evolved this innovation?

In the conceptual model for a buccal pump system, there are two chambers. What structures form the boundary between these two chambers?

Gill arches

Why do mid-water meso-pelagic fishes in the ocean have swim bladders full of fat?

A bubble of air would expand and contract with the fishes movement in the water column, wheras the fat does not.

Of the fishes in the world. only about 1% move back and forth from marine to freshwater. What might explain that pattern? (Why so few?)

This requires a lot of energy input investment. In order to do this, fishes have to be able to alter their morphology, like add or remove chlroride cells. This process has energy trade offs that not all fish can afford.

What are some special features of the jaws and teeth of sharks that might explain why they have continued to be reasonably successful while others like placoderms have gone extinct?

Jaws: They have protrusible jaws which increases the mouth opening

Teeth: They have replacement dentition. When a teeth falls out it is replaced.

Briefly discuss the functional and ecological significance of each of the following anatomical features that have evolved in higher teleosts.

Protrusible premaxilary bone: This is the upper jaw reaching out ward when fish pop open their mouth. Allows foreful suction and allows for more effiecient breathing and obtaining of food.

Homocercal Tail: This tail allows for better thrust resulting in powerful swimming. It is lobed and symmetrical which reduces Yaw and pitch and roll that exist with the heterocercal tails of more primitive fishes.

Pelvic Fins moved forward with the first ray spiny: This resulted in increased balance and stability along with predator deturrence

Spiny Dorsal Fin: Increased meneurverability and less roll of fish, along with protection from predators

What is the number of semicircular canals in hagfish, lamprey, and sharks?

Hagfishs have one, lamprey have 2, sharks have 3

How does the primary sensory system that fishes use for finding food change as one moves from offshore surface waters to the deepest parts of the ocean?

In shallow water the primary sensory used is vision. As it gets deeper, the lateral line system is used. The deeper water requires fish to use olfactory and chemoreceptor systems in addition to the lateral line.

Why do mesopelagic fishes often have bioluminescent bacteria in spots along the belly?

The bioluminescence of the bacteria on the belly provides camoflauge because from the bottom these fishes look like the moon or other sources of light.

How do marine teleosts solve the problem of osmoregulation

They are hyposmotic so they use chloride cells to expel ions and salts. They also drink ionic salt water and have very concentrated urine.

Briefly discuss how the morphology, ecology and/or evolution of fishes have been influenced by water as a UNIVERSAL SOLVENT

Water contains nutrients, salts, organic matters that the fish need and can extract via the gills. Water also contains less oxygen than air so the fish evolved thecounter current exchange system to take it up.

If you found a fish with only rods in the retina of they eye, what might you infer about its ecology?

It lives in very deep water where little light penetrates the cornea.

Why are freshwater fishes unlikely to freeze in the winter?

Water freezes at 0 degrees Celsius and Fish freeze at -0.7 degrees Celsius

Includes the group that ultimately gave rise to humans

Sarcopterygii

New York freshwater fish without jaws

Brook lamprey

Extinct fossil fish with strong jaws and bony exoskeleton

Placoderm

Have ganoid scales

Gars

Placoid scales and spiral valve intestine

Sharks

Fish with a Webarian apparatus

Common shiner

Modern fishes with a spiny dorsal fin

Yelow Perch

What are the anatomical specializations of the gills in a typical fish (teleost) that allow it to breathe the oxygen in water?

- Buccal pump which allows for water to pass through the gills.

- The gills are also articulated with many small blood vessels to increase surface area and facilitate an efficient counter current exchange in which water in blood flow in opposite directions.

Most coral reefs occur between:

Tropic of Cancer and Tropic of Capricorn

Why are kelp forests sometimes called Rainforests of the Sea?

Kelp forests, like rainforests, grow vertically from the bottom up and have canopy layers and an understroy. They are highly productive and support a diverse ecosystem.

How is the breating system in adult parasitic lampreys different from that of a teleost fish?

Minnows are naturally absent from:

South America

What are the two types of electro-reception organs found in the skin of fishes, and what is the main difference in the elctro-sensory systems between fish groups that have these two different types of receptor organs?

1. Ampullae of Lorenzini

- Sharks

- Can recieve electric signals from environment but cnt generate a field

2. Tubelous System

- Includes modified muscles at end of body that can generate electric field

What are the two main fuctional roles of the otolith bones in more advanced fishes?

1. Helps fish be sure it is swimming upright

2. Helps in hearing. Sound waves will move it and this will be sensed by the cupula.

What is the functional/ecological significance of the evolution of a full complement of paired and medial fins?

- Provides fish with stability and reduce effects of yaw, pitch and roll

- Better predation and escape

What is the primary basis for determining phylogenetic relatedness of two fish groups?

Shared, derived characters

In the typical teleost fish, nitrogenous wastes from the breakdown of proteins are excreted where and in what chemical form?

Ammonia excreted from the gills

What important morphological innovation may have facilitated the spectacular evolutionary success (in terms of number of species) of the freshwater Ostariophysi (minnow, catfish, etc.)?

Webbarian Apparatus

Wallaces line separates which two main zoogeographic regions?

Oriental and Australia

What are the main differences between osmoregulation mechanisms in hagfishes and sharks?

1. Hagfishes are osmoconformers and isosmotic so they waste no energy in osmoregulation.

2. Sharks are hyposmotic so they retain salts from urea and excrete

Describe the most efficient body shape for moving through water

A tear drop with the maximum diameter about 1/3 the way down the body and coming to a point at the end

What are three of the key evolutionary steps in fishes for the evolution of SEMICIRCULAR CANALS and what fish group first evolved this innovation?

a. 1 S.C. (Myxiniformes)

b. 2 S.C. (Petromyzantiformes)

c. 3 S.C. (Sharks and all higher fishes)

What are three of the key evolutionary steps in fishes for the evolution of FISH JAWS and what fish group first evolved this innovation?

a. Jawless (lampreys)

b. Detachable maxilla (bowfins)

c. completely protrucible mouth (perciformes)

What are three of the key evolutionary steps in fishes for the evolution of the CAUDAL FIN and what fish group first evolved this innovation?

a. Heterocercal (sharks)

b. Abbreviate heterocercal (bowfins)

c. Homocercal (teleosts)

In the conceptual model for a buccal pump system, there are two chambers. What structures form the boundary between those two chambers?

Gill arches

Why do mid-water meso-pelagic fishes in the ocean have swimbladders full of fat?

A bubble of air would expand and contract with the movement in the water column. Fat does not.

What are three derived features of the "percomorph body plan"?

1. Protrusible mouth

2. Spines and rays

3. Pelvicdorsal and pelvic fins thoracic???

What are three different morphological systems that fishes have evolved for breathing atmoshpheric oxygen? (not oxygen in water)

1. Phystostomous swim bladder

2. Elaborations of gill arches

3. Upturn of mouth to use the surface film

Briefly discuss how the morphology, ecology, and evolution of fishes have been influenced by water being a universal solvent.

Since water is a universal solvent, it allows osmoregulation as well as exchange to occur. The fish can exchange salts and gases with ease. terrestrial animals cannot do this because they are not submerged in a universal solvent.

In general terms, there are three different ways that fish breath by moving water past their gills. How do lampreys differ from higher bony fishes in terms of how each of their systems work?

1. ?? Total flow?

What is the primary basis for determining phylogenetic relatedness of two fish groups?

Shared derived characteristics

Which continent lacks minnows?

South America

A fish with a neotropical distribution occurs on which continent?

North America

Which two biogeographic areas are separated by Wallace's Line?

Asia from Australia

What is the functional/ecological significance of the evolution of a full compliment of paired and medial fins?

To be able to control pitch and roll, and yaw. The fins acts as rudders to stabilize the forces

Teleost fishes with abdominal pelvic fins can be expected to have what type of swim bladder?

?

What are the anotomical structures and physiological processes of a higher teleost fish (e.g. perch) that allow it to control the amount of gas in the swim bladder?

?

Why so many freshwater fish?

1. freshwater ecosystems are isolated like islands

2. Freshwater ecosystems have a lot of productivity and nutrients

3. Freshwater ecosystems are often very shallow allowing for more light.

List three mechanisms used by freshwater teleosts to maintain osmotic balance

1. Larger kidney to produce dilute urine/ kidney can reabsorb ions

2. Don't drink water

3. chlronize cells that transport ions in

Teleosts fishes with thoracic pelvic fins can be expectted to have what type of swim bladder?

physoclistous