Topic: Fish – aquatic animals

Author: Elżbieta Szedzianis

Target group

6th‑grade student of the elementary school.

Core curriculum

9) Fish. Student:

a) observation of fish representatives (photos, films, schemes, aquarium cultures, etc.) and presents their common features and describes the adaptation of fish to life in water,

b) defines fish as cold‑blooded animals,

c) presents the method of reproduction and development of fish,

d) explains the importance of fish in nature and for humans

Lesson objectives

Students describe the external body structure of fish and their adaptations for their habitat.

The criteria for success

• you will describe fish’s adaptations for life in water;

• you will explain the meaning of the term “streamlined body shape”;

• you will define the term “vertebrates”;

• you will discuss the concept of cold‑blooded organisms.

Key competences

• communication in the mother tongue;

• communication in foreign languages;

• mathematical competence and basic competences in science and technology; 

• digital competence;

• learning to learn;

• social and civic competences.

Methods/forms of work

Alternative and direct observation, working with a model of a fish, working with film, working with text.

Individual activity and activity in groups.

Teaching aids

• abstract;

• interactive whiteboard or traditional blackboard;

• tablets/computers;

• fan;

• Styrofoam eggs;

• Styrofoam cones;

• knives;

• glue;

• scissors;

• stiff paper;

• table tents;

• model of fish locomotor system;

• Fresh roaches or other small fish;

• magnifying glass;

• glass electric kettle filled with water.

Lesson plan overview

Introduction

1. The teacher asks students where they have observed live fish. The teacher asks the students to explain how they moved and which organ caused their movements.

2. The teacher informs the students that they will learn the fish’s adaptations for life in water during the classes. The teacher suggests students to make a map of concepts on the interactive whiteboard, the central element of which will be the term fish.

Realization

1.) The teacher displays on the screen an interactive illustration showing the structure of the perch's body. The teacher asks students to define the boundaries of its head, trunk and tail.

2.) The teacher displays photographs of selected fish species with different body shapes. The teacher asks students to indicate the fastest swimming fish and justify their choice. The teacher writes in the map of concepts the term: „Streamlined body shape”. Students explain its meaning and give examples of organisms, objects or machines of this shape. Then they explain what it determines.

3.) The teacher presents a hand‑held fan, fans himself/herself and the students. The teacher asks which part of the fish's body is fan similar to (fins) and asks students to determine the features of this similarity, and then writes them on a map of concepts.

4.) The teacher asks students why the diver needs fins. The following questions are asked in such a way that the students notice that the water offers higher resistance than the air. The teacher explains that water is thicker than air.

5.) The teacher divides the students into groups. Each group receives Styrofoam eggs, cones, knives, glue, scissors and stiff paper. The students' task is to make a model of a fish and label the fins.

6.) Students present their models and explain what is the relationship between the external body structure of a fish and the aquatic environment.

7.) The teacher asks students to search the Internet for information about the fastest and slowest fish. Students list names of particular species and discuss their body structure. The teacher makes sure that students use the term „streamlined body shape”.

8.) The teacher says that many people think that fish owe their swimming speed to their fins. The teacher asks students to express their opinion on the subject using table tents (a green card means „I agree”, a red card - „I disagree”, a yellow card - „I have doubts”). The teacher asks if the fan or the diver’s fins can move independently and what sets them in motion. The teacher shows students a model of fish’s skeleton with muscles. The teacher demonstrates how the trunk muscles contract, causing the tail to move. The teacher asks students what two elements are needed for the movement.

9.) The teacher discusses the body structure of fish's skeleton and explains where the following terms came from: „Vertebrates” and „internal skeleton”. Both terms are written by students in the map of concepts. The teacher asks students what organisms belong to vertebrates, apart from fish.

10.) Students, working in groups, observe roaches or other small fish bought in a shop and indicate individual parts of their body. If students have difficulty completing the task, they can use an interactive illustration showing the structure of the perch’s body. Then they stroke the skin of the fish and explain the importance of scales and mucus. Finally, using a magnifying glass, they look for a lateral line.

11.) Students read the definition of the lateral line organ in the „Glossary”, and then they explain its meaning in their own words.

12.) Students fill the map of concepts with new terms.

13.) Students lift the gill covers and observe the gills through the magnifying glass. They describe them, trying to use as many adjectives as possible. One of the students adds new terms to the map.

14.) The teacher explains that oxygen (and other gases) is dissolved in water. The teacher proves this by showing boiling of water in a glass electric kettle. The teacher then explains how the gills work and displays a video entitled „Wymiana gazowa w skrzelach” (Gas exchange in gills).

15.) The teacher asks students to read the definition of cold‑blooded organisms in the “Glossary” and determine whether they are cold‑blooded organisms themselves.

16.) The teacher encourages students to change the lyrics to the song „Było morze...” (There was a sea ...), so that it corresponds to the topic of the lesson. Then the whole class sings the song.

Summary

1.) The students observe the map of concepts and fill it if needed. The teacher saves the map and sends it to the students.

2.) The teacher displays the criteria for success and asks the students to assess their skills acquired during the classes. If needed, the teacher explains the terms that students do not understand, clarifies any doubts.

Homework for the interested students

Students do an interactive exercise.

The following terms and recordings will be used during this lesson

Terms

Texts and recordings

Fish – aquatic animals

The fish's body consists of the head, trunk and tail, its skin is covered with scales that overlap in a regular arrangement like roof tiles, forming a flexible covering. It allows the body to bend and protects it against mechanical injuries. The surface of the body is covered with mucus. Scales and mucus make the skin slippery and reduce water friction during movement. Fins, special folds of skin stretched on a rigid ray frame, are a characteristic element of fish's body structure. The fins occur in pairs (paired fins)– pectoral and pelvic fins as well as individually – dorsal, caudal and anal fins. Fins have a large surface, therefore they facilitate movement in water.

In addition to the well‑developed organs of the sense of sight, hearing, taste and touch, fish also have a lateral line organ. With its use, fish perceive water movement as well as changes in its temperature, pressure and chemical composition. The lateral line provides excellent orientation in the water, also in the dark, helps to avoid obstacles and move in the shoal.

Fish have different shapes. They depend on the environment in which they live, their mode of life and the food intake method.

The fish live in fresh and salty waters around the globe: in rivers, streams, ponds, lakes, seas and oceans. Fish are cold‑blooded vertebrates (poikilotherms), which means that their body temperature depends on the temperature of the environment.

The shape of the fish's body depends on its mode of life. Fast swimming fish (herring, tuna and pike) have a spindle‑like, streamlined body shape. Species that live among aquatic plants or rocks, such as bream and carp, have a laterally flattened body, making it easier for them to swim between obstacles. Flounders live at the bottom of the sea and are flattened dorsoventrally. Thanks to it, they can bury themselves in sand. The body of seahorses can develop special protrusions that mask them among seaweed. Porcupine fish has got scales transformed into spikes that protect it against attacks by predators. Threatened, it fills its body with water and takes on the appearance of a spiky sphere.

Most fish have got masking colouring. The pectoral part of the body of many fish is bright, which makes it more difficult for predators looking for victims from the bottom to spot them against a clear sky. In turn, the dark dorsal part makes it more difficult to spot them from the air. Some fish take a warning colouring.

The fish take oxygen dissolved in water by means of gas exchange organs called gills. They are located on both sides of the pharynx. They consist of numerous, small and thin gill laminae, which take on a red colour because they contain many blood vessels. They can be hidden under operculums, as pike's, or they may lack covering, as shark’s are (than on the sides of the body we observe individual gill slits). Oxygen‑containing water enters the fish's mouth and then squeezes outside between the gill laminae. Oxygen from the water penetrates into the blood through diffusion, and carbon dioxide from blood vessels penetrates into the water and with it leaves the body. The number of respiratory movements depends on the activity of the fish and the oxygen content in the water.

• Fish are cold‑blooded animals living in fresh and salt water.

• The body of most fish is of a streamlined shape and is divided into the head, trunk and tail.

• Fish skin coverage reduces friction between them and water during movement.

• Fish are characterized by the presence of paired and individual fins.

• A distinctive sense of fish is their lateral line informing them about water movements.

• Fish's gas exchange occurs through the gills.

• Most fish are oviparous, reproduce through external fertilization.