Download Chapter 36 Vocabulary

Chapter 39 Vocabulary- Fishes
Section 1 Introduction to Vertebrates
1. vertebrate- animal with a backbone
2. cranium- skull that protects brain
3. gill arches- skeleton elements that support the pharynx
Section 2 Jawless and Cartilaginous Fishes
1. chemoreception- ability to detect chemicals in the environment
2. lateral line- ability to sense vibration in the water
3. external fertilization- fertilization occurs outside the body of either parent
4. cartilage- flexible, lightweight material made of cells surrounded by tough fibers of protein
5. placoid scale- small, tooth-like spines that feel like sandpaper
6. internal fertilization- fertilization occurs inside the body of the female
Section 3 Bony Fishes
1. swim bladder- a gas-filled sac that is used to control buoyancy
2. lobe-finned fish- fleshy fins that are supported by a series of bones (lungfish & coelacanth)
3. ray-finned fish- have fins that are supported by long, segmented, flexible bony elements called rays
4. operculum- a hard plate on each side of the head that opens at the rear and covers and protects the gills
5. countercurrent flow- water flows across gill filaments in a direction opposite to blood flow
6. optic tectum- receives and processes information from the fish’s visual, auditory, and lateral-line
systems
7. spawning- reproductive behavior of bony fishes
Phylum Chordata
 Subphylum Vertebrata
o Class Myxini- hagfishes
o Class Cephalaspidomorphi- lampreys
o Class Chondrichtheyes- sharks, rays, skates, & ratfishes
o Class Actinopterygii- ray-finned fishes (most familiar fish)
o Class Sarcopterygii- lobe-finned fishes (lungfish & coelacanth)
Chapter 39 Review- Fishes
Section 1 Introduction to Vertebrates
 Vertebrates are chordates and have a hollow dorsal nerve cord, notochord, pharyngeal pouches, and a
post-anal tail.
 The characteristics that distinguish vertebrates from other chordates are vertebrate, a cranium, and an
endoskeleton.
 Vertebrates are classified into nine classes: class Myxini (hagfish), class Cephalaspidomorphi
(lampreys), class Chondrichthyes (sharks & rays), class Sarcopterygii (lobe-finned fishes), class
Actinopterygii (ray-finned fishes), class Amphibia (amphibians), class Reptilia (reptiles), class Aves
(birds), & class Mammalia (mammals).
 Early vertebrates were jawless fishes, which had bony scales, cartilaginous skeletons, and no paired fins.
 Paired fins increased stability and maneuverability in fishes; jaws allowed fish to seize and manipulate
prey.
Section 2 Jawless and Cartilaginous Fishes
 Fishes have streamlined bodies, paired fins, and secrete mucus that reduces friction when swimming.
The fish body plan makes them well suited to aquatic life.
 Fishes have a variety of organs that allow them to sense their environment. Fish can see, smell, and taste
the world around them. They can also sense vibration, and some can sense electrical fields.
 Like early vertebrates, living agnathans lack jaws and paired fins and retain a notochord throughout life.
 Lampreys and hagfish are two types of jawless fishes that are alive today. Hagfishes burrow into and
dead fish. Parasitic lampreys attach themselves to their host with their disk-shaped mouths and feed on
the host’s blood.
 Cartilaginous fishes have internal skeletons made of cartilage, and their skin is covered with placoid
scales.
 Jawless fishes reproduce by external fertilization (fertilization occurs outside of the body of either
parent). Most cartilaginous fishes reproduce by internal fertilization (the male inserts sperm into the
female’s body, and the young develop in an egg inside the female).
Section 3 Bony Fishes
 Bony fishes are characterized by three key features: scales on the body, lungs or a swim bladder, and
bone in the skeleton.
 Lobe-finned fishes have fleshy fins with a central bony axis, while ray finned fishes have non-fleshy fins
supported by long flexible bones called rays.
 The external anatomy of a bony fish has several distinct characteristics- an operculum, fins, and scales.
 A fish’s heart has two chambers that work together to move blood through the body.
 Water flows over fishes gills in a direction opposite to blood flow. Oxygen diffuses from the water into
the blood very efficiently as a result of this process, which is called countercurrent flow.
 Fish adjust their overall density by regulating the amount of gas in the swim bladder, enabling them to
move up or down in the water
 Unlike cartilaginous fishes, most bony fishes reproduce by external fertilization in a process called
spawning.