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Anatomy of Fish

What makes a fish a fish?

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Things you will learn

1. Fish breathe through gills.

2. Fish have fins to help them swim.

3. Some fish can live in salt water.

4. Some fish can live in fresh water.1. Only a few can live both.

5. Different adaptations of fish.

Vocabulary• External Anatomy - The outside body parts.

• Caudal/Tail Fin - Fin on end of fish; used to propel the fish.

• Dorsal Fin – Backside (top) fin on a fish; used for balance and protection.

• Pectoral Fin – Side (“chest”) fins on a fish; used for balance and steering.

• Anal Fin - Last bottom fin on a fish located near the anal opening; used for

balancing and steering.

• Pelvic Fin – Paired bottom or belly fins on a fish; used in balance and steering.

• Gills - Organ a fish uses to obtain oxygen from the water.

• Operculum - Flexible bony plate that covers the gills.

• Lateral Line - Organ a fish uses to “feel” low vibrations; tiny microscopic pores.

Vocabulary continued…• Nares - Organ a fish uses to smell; similar to nostrils but not used for

breathing.

• Scales - Protective cover on a fish; similar to skin.

• Vertebrate - Organism with a backbone.

• Superior Mouth - A mouth that opens upward (usually surface feeders).

• Inferior Mouth - A mouth that opens downward (usually bottom feeders).

• Terminal Mouth - A mouth located at anterior end of fish’s body (mid water

feeder).

• Camouflage – The ability to blend in with the background or habitat.

• Adaptation - The adjustment or change in behavior or body to become

better suited for survival in a particular environment. 4

Introduction

Over time fish have adapted or changed to survive in their environment.

Different fish species have different appearances, the function of their outside body parts is similar.

However, the outside body parts (external anatomy features) of fish can tell us a lot about a species such as where it lives in the water, how it finds food, and how it protects itself from predators.

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How are fish classified?

Why do you think it’s important to be able to identify fish?

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Anatomy of a fish

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How do fish swim?

Fish swim by moving their caudal fin (back fin) left and right.

Fins All fish have external appendages called fins, fins provide fish with

balance, steering, and protection.

Fins are either single along the centerline of the fish: the dorsal fin,

anal fin, and tail fin; or paired fins: the pectoral fins and ventral fins.

Pectoral fins help fish balance. The top fin or dorsal fin is also used in

balance but its main function is usually protection.

The ventral fin and anal fin are located on the bottom or belly of fish

and help with steering as well as balance.

The caudal fin helps propel fish forward.

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GO FISH

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How do Fish breathe in the water?* Water goes through the mouth and

goes out through the gills,which take oxygen from the water.

Gills Located on either side of fish, gills provide oxygen

to fish from the water.

The gills are covered by a flexible bony plate called the operculum. Some fish have spines located on the operculum as a defense mechanism to protect them from predators.

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Detection of food, sound, direction

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Lateral Line

Running down the length of a fish’s body is the lateral line. This organ is used to feel low vibrations in the water.

The lateral line is made up of a series of microscopic holes located just under the scales of a fish.

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Sense of smell

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Nares Located on a fish’s snout are paired holes, or nares used for

detecting odors in the water.  The nares are made up of many capsules, each containing

receptors. Water flows through the nares as the fish swims.Behind the

nares, in a chamber, are sensors (chemical receptors) that detect chemicals that are dissolved in the water. Once an odor is detected, the nerves send signals to the fish's brain that interpret the smells. These smells might attract the fish or keep it at bay depending on whether the fish interprets the smell to represent

food or danger. Catfish and eels, have a heightened sense of smell.

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Protection of the body

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Scales

Most fish have scales covering the length of their body. Scales protect fish from injury

On top of these scales is a mucus covering known as the slime layer. Slime protects fish from bacteria and parasites in the

water. Anglers should be careful not to remove the slime layer when handling a fish

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Body Type

A fish’s body shape as well as the shape and size of certain external features can tell you a lot about that fish. For example, the body shape of a fish can

indicate where that fish lives in the water and what type of swimmer it is.

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Name that fish1. Mouth is door like, it has a combination of shapes.

2. List at least 2 characteristics of puffer fish.

3. Fast swimming, ultra stream lined, open water fishes.

4. Lack pelvic fins and are scale-less.

5. Arrow like body type, and are surface dwellers

Refer to the handouts.

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Mouth The mouth parts of a fish will vary in size and may or may not

contain teeth, depending on what the fish eats.

The location of the mouth on a fish’s body can also give us a clue as to what the fish’s diet consists of.

A superior mouth (a mouth pointing upward) means the fish will usually eat food located above it, whereas a fish with an inferior mouth (a mouth pointing downward) will usually eat food located

below it.

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Form, Function & AdaptationsFluke Fluke or summer flounder is a flat-lying saltwater fish that lives on the sea floor.

When born, fluke look like any other fish, swimming upright. About a week to a month into its life, one eye rotates to the other side of the head to join the other eye. This adaptation allows fluke to lie flat on the ocean floor and wait for its food; thus it is called a lie-and-wait predator.

Fluke also have many sharp teeth which allow it to eat smaller fish that swim above it.

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Adaptations to Avoid Predation

Clingfishes- have modified pectoral fins to form a powerful sucker used to secure itself to rocks. Flyingfishes- avoid predation by enlarged pectoral finsto glide through the air. Pufferfishes- can swallow large amounts of air or waterto inflate their bodies to deter potential predators.

Puffer Fish are Dangerous!

http://www.youtube.com/watch?v=jyIIbFZt0Aw

http://www.sciencekids.co.nz/videos/animals/pufferfish.html http://www.youtube.com/watch?v=

OkXhC7yzISI#t=29

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Largemouth Bass Largemouth bass live near the bottom of freshwater lakes, ponds,

and streams.

Their greenish brown coloring blends well with the surrounding

aquatic vegetation which protects them from predators

The teeth of a largemouth bass are brush-like with a texture of

sandpaper. Their teeth are suited for gripping, not tearing, and to

swallow prey whole. Adult largemouth bass can easily consume

smaller fish, frogs, and even baby ducks.

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Sea Robin They are a bottom dwelling fish with very large pectoral fins which make the

sea robin look much larger to passing predators.

As an additional defense against predators, sea robins have a very sharp dorsal fin and spines on its gill covers.

Sea robins can also make a barking or croaking sound that scare off predators.

Although the sea robin physically looks different than most other species, its fins still help to balance its body, steer through the water, and protect it against predators.

Because of its odd external characteristics, many humans consider the sea robin to be a trash fish, not suitable to eat, yet in fact it is fine for human consumption.

http://www.youtube.com/watch?v=kfM7O3Xcmyc30

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Betta Fish The betta got its name from an ancient clan of warriors, called the "Bettah." 

The fish were given a combatant name after the fighting fish became popular in the mid-1800s.  In fact, the sport became so renowned in Thailand that the former King of Siam had it regulated and taxed!  Spectators of the sport based their bets on the bravery of the fish, rather than the damage inflicted by the

victor. 

FACT: Betta’s can breath air! They have a unique organ called a labyrinth that allows to breath air like you and me. This was critical to their survival as they generally lived in low-oxygen water like rice paddies and slow moving streams – conditions most other fish could not survive in

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..MORE BETA FISH

http://www.youtube.com/watch?v=saiCxypusbA

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http://www.youtube.com/watch?v=Rds3dxalsi4

Gold Fish

It was one of the earliest fish to be domesticated, and is one of the most commonly kept aquarium fish.

Most common bought and kept fish in households. WHY?

Can live to up to 40 YEARS!!

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http://www.bizarbin.com/biggest-goldfish-ever-caught/

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More characteristics:Not all fish have bones

Many fish have bones, but the shark, for example, has cartilage.

Let’s take a closer look at these two types of fish.

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Shark VS. Bony Fish

ATTRIBUTESHARKS

                          

BONY FISH

            

Skeleton Cartilage only Bones and cartilage

Swimming Can only swim forward. Can swim forwards and backwards

Buoyancy (floating) Large oily liver Gas-filled swim bladder

Gills Gill slits but no gill cover Covered gill slits

Reproduction Eggs fertilized in female's body. Eggs usually fertilized in the water.

Skin Rough, sandpaper-like scales Slippery, overlapping scales

How do you think fishermen determine what type of fish they

want out to catch?

Activity:

GO FISH 39

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THE END.

What have you learned?1. What is the function of the dorsal fin?

2. What is the difference between an inferior and superior mouth of a fish?

3. Where on a fish is the Caudal fin located?

4. What does the body type of a fish indicate?

5. What is an adaptation of the flounder fish?

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Fish Anatomy

QUIZ!42