Fishes Table of Contents Section 1 Introduction to Vertebrates Section 2 Jawless and Cartilaginous Fishes Section 3 Bony Fishes
Section 1 Introduction to Vertebrates Objectives Identify the distinguishing characteristics of vertebrates. List an example for each of the nine classes of vertebrates. Describe the characteristics of the early vertebrates. Explain the importance of jaws and paired fins for fishes.
Section 1 Introduction to Vertebrates Characteristics Vertebrates are members of the subphylum Vertebrata, within the phylum Chordata. All Chordates share the following characteristics. Notochord Dorsal hollow nerve cord Pharyngeal gill slits Post-anal tail
Section 1 Introduction to Vertebrates Characteristics, continued Vertebrates are distinguished from chordates by: Vertebrae - bones or cartilage that surround the dorsal nerve cord and form the spine. A cranium - a skull that protects the brain An endoskeleton - an internal skeleton made of bone or cartilage
Section 1 Introduction to Vertebrates Characteristics, continued Vertebrates are divided into nine classes: Myxini - hagfishes Cephalaspidomorphi - lampreys Chondrichthyes - sharks, rays, skates, and ratfishes Actinopterygii - ray-finned fishes Sarcopterygii - lobe-finned fishes Amphibia - frogs, toads, salamanders, and caecilians Reptilia - lizards, snakes, and turtles Aves - birds Mammalia - mammals
Section 1 Introduction to Vertebrates Evolutionary Relationships Among Chordates
Section 1 Introduction to Vertebrates Vertebrate Evolution Most biologists think that vertebrates originated about 560 million years ago. The first fish were jawless. About 450 million years ago, the first fishes with jaws and paired fins appeared. Jaws are thought to have evolved from the first pair of gill arches, the skeletal elements that support the pharynx.
Section 1 Introduction to Vertebrates Evolution of Jaws
Section 1 Introduction to Vertebrates Vertebrate Evolution, continued The advantages to jaws and paired fins: Paired fins increased fishes stability and maneuverability in water Jaws allowed fishes to seize and manipulate prey
Section 1 Introduction to Vertebrates Origin of Jaws
Section 1 Introduction to Vertebrates Advantage of Paired Fins
Section 2 Jawless and Cartilaginous Fishes Objectives Identify three characteristics that make fishes well suited to aquatic life. Describe three sensory systems in fish. Evaluate the similarities between jawless fishes and early vertebrates. Identify two characteristics of cartilaginous fishes. Contrast reproduction in lampreys with reproduction in cartilaginous fishes.
Section 2 Jawless and Cartilaginous Fishes Fish Adaptations Fish have several adaptations that make them well suited to life in water: Streamlined body plan - allows fish to move rapidly in water Adaptations for buoyancy - stored gases or lipids help maintain vertical position in water Efficient respiration - internal gills exchange gases efficiently
Section 2 Jawless and Cartilaginous Fishes Fish Adaptations, continued Adaptations for salt and water homeostasis - The concentration of solutes in a fish s body usually differs from the concentration of solutes in the water. Fish have adaptations to maintain ion and water homeostasis.
Section 2 Jawless and Cartilaginous Fishes Fish Adaptations, continued Sensory adaptations - Fish have a variety of organs that allow them to sense their environment. Sight: fish eyes are similar to eyes of land vertebrates Sound: fish have internal ears sensitive to sound Chemoreception: the ability to detect chemicals in the environment includes the senses of smell and taste. Fish have nostrils and tastebuds. Tastebuds may be located in their mouths, on their lips, fins, and skin, and on whisker-like organs called barbels.
Section 2 Jawless and Cartilaginous Fishes Fish Adaptations, continued Unique senses: Lateral line: the lateral line is a system of canals in the skin that allow fish to sense vibration in the water Ampulae of Lorenzini: cartilaginous fishes have sense organs called ampulae of Lorenzini that can detect weak electrical fields Electroreception and Magnetoreception: some fish have the ability to detect electrical and magnetic fields
Section 2 Jawless and Cartilaginous Fishes Lateral Line in Fishes
Section 2 Jawless and Cartilaginous Fishes Lateral Line System
Section 2 Jawless and Cartilaginous Fishes Characteristics of Fish
Section 2 Jawless and Cartilaginous Fishes Jawless Fishes Only two classes of jawless fishes are alive today: Hagfishes (class Myxini) Hagfishes are bottomdwellers that feed on dead and dying fish. Lampreys (class Cephalaspidomorphi) Lampreys can be free-living or parasitic. Parasitic lampreys attach themselves to their host with disc-shaped mouths and feed on the blood and body fluids of other fishes. All lampreys breed in fresh water. Fertilization occurs outside the body - external fertilization.
Section 2 Jawless and Cartilaginous Fishes Cartilaginous Fishes All cartilaginous fishes: belong to the class Chondrichthyes. have skeletons made of cartilage - a flexible lightweight material made of cells surrounded by tough fibers of protein. have skin covered with placoid scales - small, toothlike spines that feel like sandpaper. Placoid scales probably reduce turbulence and increase swimming efficiency.
Section 2 Jawless and Cartilaginous Fishes Cartilaginous Fishes, continued Sharks: Sharks have torpedo shaped bodies that reduce turbulence when swimming, called a fusiform body shape. Some sharks are filter feeders, and have slender projections on the inner surface of their gills, called gill rakers, that filter the water. The mouth of a typical shark has 6 to 20 rows of teeth. When a tooth breaks or wears down, a replacement moves forward. One shark may use more than 20,000 teeth over its lifetime.
Section 2 Jawless and Cartilaginous Fishes Cartilaginous Fishes, continued
Section 2 Jawless and Cartilaginous Fishes Cartilaginous Fishes, continued Rays and Skates: Rays and skates have flattened bodies with paired wing-like pectoral fins and, in some species, whip-like tails. Rays have diamond- or disk-shaped bodies. Most skates have triangular bodies. Rays and skates are primarily bottom dwellers, and most feed on mollusks and crustaceans.
Section 2 Jawless and Cartilaginous Fishes Cartilaginous Fishes, continued Ratfishes: Ratfishes are a small group of strange looking fish that have a flap of skin covering their gill slits. Ratfishes have long, rat-like tails and feed on crustaceans and mollusks.
Section 2 Jawless and Cartilaginous Fishes Cartilaginous Fishes, continued Adaptations in Cartilaginous Fishes: Some sharks push water through their mouth and over their gills by swimming. Most cartilaginous fish pump water over their gills by expanding and contracting their mouth cavity and pharynx. When lying on the bottom, rays and skates draw water in to their gills through spiracles, two large openings on the top of the head, behind the eyes.
Section 2 Jawless and Cartilaginous Fishes Cartilaginous Fishes, continued Adaptations in Cartilaginous Fishes: Sharks convert ammonia to urea in their bodies. Sharks retain large amounts of urea in their bodies to raise the concentration of solutes in their bodies to the same level as that found in sea water. Sharks still tend to take up sodium and chloride ions. The rectal gland removes excess sodium and chloride ions from the body.
Section 2 Jawless and Cartilaginous Fishes Cartilaginous Fishes, continued Adaptations in Cartilaginous Fishes: Cartilaginous fishes maintain their position in the water in two ways. 1. The caudal and pectoral fins generate lift, or upward force, as the fish swims. 2. Many cartilaginous fish store large amounts of lipids, usually in the liver. Lipids are less dense than water.
Section 2 Jawless and Cartilaginous Fishes Cartilaginous Fishes, continued Reproduction in Cartilaginous Fishes: Fertilization occurs inside the body of the female, called internal fertilization. Some cartilaginous fish lay eggs. The eggs of many species develop within the female s body. In some species, the mother nourishes the developing young while they are in her body.
Section 3 Bony Fishes Objectives List three characteristics of bony fishes. Distinguish between lobe- finned fishes and ray-finned fishes. Describe three key features of bony fishes external anatomy. Summarize the major body systems in bony fishes. Describe the function of the swim bladder. Discuss reproduction in bony fishes.
Section 3 Bony Fishes Characteristics of Bony Fishes Bony fishes have three key features: Bone - the skeletons of most bony fishes contain bone. Lungs or swim bladder - early bony fishes had lungs, organs which exchange gas between the air and blood. Most bony fishes today have a swim bladder, a gas-filed sac that is used to control buoyancy. Scales - scales protect the body of a bony fish and reduce friction when swimming.
Section 3 Bony Fishes Swim Bladder in Bony Fish
Section 3 Bony Fishes Swim Bladder
Section 3 Bony Fishes Characteristics, continued There are two main groups of bony fishes: Lobe-finned fishes - have fleshy fins supported by a series of bone. Ray-finned fishes - have fins that are supported by long, segmented, flexible bony elements called rays.
Section 3 Bony Fishes Characteristics of Bony Fishes
Section 3 Bony Fishes Ray-Finned Fishes
Section 3 Bony Fishes External Anatomy Operculum Most bony fish have an operculum, a hard plate that opens at the rear and covers and protects the gills. Fins The fins of most fish are supported by rays or spines. Rays are flexible, spines are rigid. Skin The skin of most bony fish are covered with scales. Scales are thin, round disks of a bonelike material that grow from pockets in the skin and overlap like shingles.
Section 3 Bony Fishes External Structures of Fish Yellow Perch
Section 3 Bony Fishes Anatomy of a Bony Fish
Section 3 Bony Fishes Internal Anatomy Skeleton The major parts of a fish s skeleton are the skull, spinal column, pectoral girdle, pelvic girdle, and ribs.
Section 3 Bony Fishes Internal Anatomy, continued Digestive system Food passes from the mouth into the pharynx, through the esophagus, to the stomach. From the stomach food passes into the intestine, where nutrients are absorbed. Undigested material is eliminated through the anus.
Section 3 Bony Fishes Internal Structure of Fishes Yellow Perch
Section 3 Bony Fishes Internal Anatomy, continued Circulatory system The circulatory system of a fish delivers oxygen and nutrients to the cells of the body. The circulatory system consists of a heart, blood vessels, and blood. The heart pumps blood through arteries to small, thinwalled vessels called capillaries, in the gills. From the gills, the blood travels to the body tissues, where nutrients and wastes are exchanged. The blood returns to the heart through veins.
Section 3 Bony Fishes Internal Anatomy, continued Circulatory system The heart of a bony fish has two chambers in a row, as shown below. Blood from the body enters the sinus venosus, moves into the atrium, then into the ventricle. From the ventricle it enters the conus arteriosus, and then goes to the gills.
Section 3 Bony Fishes Fish Heart Structure
Section 3 Bony Fishes Fish Heart and Single-Loop Circulation
Section 3 Bony Fishes Internal Anatomy, continued Respiratory system Fish use gills for gas exchange. Water flows across the gill filaments in a direction opposite to blood flow, called countercurrent flow. Countercurrent flow allows more oxygen to diffuse into the blood than would be possible if blood and water flowed in the same direction.
Section 3 Bony Fishes Respiration in Fishes
Section 3 Bony Fishes Parts of Fish Gills and Countercurrent Flow
Section 3 Bony Fishes Internal Anatomy, continued Excretory system The kidneys filter chemical wastes from the blood to form urine, a solution containing ammonia, ions such as salts, and water. The kidneys help regulate the ion and water balance in fish. The gills also allow wastes to diffuse from the blood into the water and help regulate ion and water balance in fish.
Section 3 Bony Fishes Fish Kidneys
Section 3 Bony Fishes Parts of a Nephron
Section 3 Bony Fishes Internal Anatomy, continued Swim bladder The swim bladder is a thin-walled sac in the abdominal cavity that contains a mixture of oxygen, carbon dioxide, and nitrogen obtained from the bloodstream. Swim bladders evolved from balloonlike lungs, which ancestral bony fishes may have used to supplement the oxygen absorbed by the gills. In some fish the swim bladder is known to amplify sound by vibrating and transmitting sound to the inner ear.
Section 3 Bony Fishes Internal Anatomy, continued Nervous system The nervous system of a bony fish includes the brain, spinal cord, nerves, and various sensory organs. The fish brain consists of several parts: Olfactory bulb - processes information about smell Cerebrum - integrates information from other parts of the brain Optic tectum - processes information about sight and from the lateral line system Cerebellum - coordinates muscle movement and balance Medulla oblongata - controls the function of some organs and relays information from the spinal cord
Section 3 Bony Fishes Internal Anatomy, continued Nervous system The fish brain has a well-developed medulla to coordinate muscle control.
Section 3 Bony Fishes Reproduction Spawning Reproductive behavior in bony fishes is called spawning. Fertilization in most fish takes place outside the body. Many species of fishes lay large numbers of eggs. Some species of fish carry the eggs within their bodies until the eggs hatch.
Standardized Test Prep Multiple Choice 1. Which of the following is true of sharks and rays? A. They have lungs. B. They have placoid scales. C. Most species live in fresh water. D. They do not have a lateral line system.
Standardized Test Prep Multiple Choice 1. Which of the following is true of sharks and rays? A. They have lungs. B. They have placoid scales. C. Most species live in fresh water. D. They do not have a lateral line system.
Standardized Test Prep Multiple Choice, continued 2. Which of the following is not involved in controlling buoyancy? F. a fat-filled liver G. the rectal gland H. the swim bladder J. continuous swimming
Standardized Test Prep Multiple Choice, continued 2. Which of the following is not involved in controlling buoyancy? F. a fat-filled liver G. the rectal gland H. the swim bladder J. continuous swimming
Standardized Test Prep Multiple Choice, continued 3. What is the function of the lateral line system? A. initiates migration B. detects vibrations C. acts as camouflage D. keeps fish moving in a straight line
Standardized Test Prep Multiple Choice, continued 3. What is the function of the lateral line system? A. initiates migration B. detects vibrations C. acts as camouflage D. keeps fish moving in a straight line
Standardized Test Prep Multiple Choice, continued 4. What do sharks use claspers for? F. startle other fish G. increase maneuverability H. transfer sperm while mating J. hold on to prey while feeding
Standardized Test Prep Multiple Choice, continued 4. What do sharks use claspers for? F. startle other fish G. increase maneuverability H. transfer sperm while mating J. hold on to prey while feeding
Standardized Test Prep Multiple Choice, continued Interpreting graphics The table below shows the salinity of fresh water, salt water, and the body fluids of fish. Use the table to answer questions 5 and 6.
Standardized Test Prep Multiple Choice, continued 5. What tendency do freshwater fish have in a freshwater environment? A. lose water and salts B. take on water and salts C. take on water and lose salts D. lose water and take on salts
Standardized Test Prep Multiple Choice, continued 5. What tendency do freshwater fish have in a freshwater environment? A. lose water and salts B. take on water and salts C. take on water and lose salts D. lose water and take on salts
Standardized Test Prep Multiple Choice, continued 6. What tendency do saltwater fish have in a saltwater environment? F. lose water and salts G. take on water and salts H. lose water and take on salts J. take on water and lose salts
Standardized Test Prep Multiple Choice, continued 6. What tendency do saltwater fish have in a saltwater environment? F. lose water and salts G. take on water and salts H. lose water and take on salts J. take on water and lose salts
Standardized Test Prep Multiple Choice, continued 7. Bony fishes : Osteichthyes :: Shark : A. Aves B. Agnatha C. Mammalia D. Chondrichthyes
Standardized Test Prep Multiple Choice, continued 7. Bony fishes : Osteichthyes :: Shark : A. Aves B. Agnatha C. Mammalia D. Chondrichthyes
Standardized Test Prep Multiple Choice, continued The figure below shows the external anatomy of a bony fish. Use the figure to answer the following question.
Standardized Test Prep Multiple Choice, continued 8. Which of the fins shown on the fish are dorsal fins? F. 1 & 2 G. 2 & 4 H. 5 & 6 J. 5 & 4
Standardized Test Prep Multiple Choice, continued 8. Which of the fins shown on the fish are dorsal fins? F. 1 & 2 G. 2 & 4 H. 5 & 6 J. 5 & 4
Standardized Test Prep Short Response Countercurrent flow enhances the diffusion of oxygen from water into the bloodstream of fishes. Explain the meaning of countercurrent flow in gills.
Standardized Test Prep Short Response, continued Countercurrent flow enhances the diffusion of oxygen from water into the bloodstream of fishes. Explain the meaning of countercurrent flow in gills. Answer: In countercurrent flow, water flows over fishes gills in a direction opposite to blood flow. This allows for efficient gas exchange.
Standardized Test Prep Extended Response Base your answers to parts A & B on the information below. Humans have a four chambered heart with two ventricles. One ventricle pumps blood to the lungs and the other pumps blood that returns from the lungs to the body. Part A Compare the structure and blood flow of the fish heart to the human heart. Part B Which heart is able to pump blood more forcefully around the body? Why?
Standardized Test Prep Extended Response, continued Answer: Part A The fish heart has a collecting area, a simple atrium-ventricle arrangement, and an elastic exit chamber. Blood with or without O 2 is not separated in the fish heart. The human heart s two circuits separate oxygenated and deoxygenated blood. Part B: The human heart can pump blood more forcefully since it has essentially two pumps. Since one pump pumps blood to the lungs, the other can be dedicated to pumping blood to the rest of the body.