Life in fresh waters 4. Fresh waters

Let's approach the shore of a small pond on a fine, sunny day. From a distance he appears lifeless. Its surface is calm, no waves or the slightest movement is noticeable on it. But if we look closely, we will see after a minute that this dead, quiet pond is full of life. Two or three green frogs got scared by our careless steps and splashed into the water. Raking with their hind legs, they went to the bottom of the pond and hid there among the mud. A dragonfly quickly flew past us, and here was another, and a third. Water striders glide along the surface of the pond on widely spaced legs. They are commonly called "water spiders", but this is incorrect. They are actually water bugs. The water strider, like a regular bedbug, has a long and sharp proboscis with which it sucks juice from its prey. Bouncing above the water, it catches small mosquitoes and midges or strikes with its proboscis tiny crustaceans swimming near the very surface of the water. The adhesion of water particles near the surface is greater than in the thickness of the reservoir. Therefore, water forms a denser film on its surface. Water striders run along this surface film, like speed skaters on ice.

The shiny beetle of the spinner, even faster than the water strider, describes spirals and circles across the surface of the pond. It not only glides through the water, but also dives into the depths. This bug has interesting feature: each eye of the spinner is double - one half of it looks up into the air, the other half looks under the water. Therefore, it is very difficult to catch a spinner with a net.

And here is another good swimmer. It is easy to distinguish it from water bugs: its body is as if covered with a silvery film of air. This is a smooth water bug. It swims on its back with its belly up and attacks its prey - insect larvae, tadpoles - like a shark, from below.

There are inhabitants in the pond who periodically swim from the depths to the surface to breathe or even gain air supply. This is, for example, big beetle swimmer It rises from the depths, raking with its wide rear legs-oars, puts the tip of its abdomen out, draws air into the cavity under the elytra, and after a few minutes dives into the depths again.

The pond snail also rises to the surface for air. It cannot swim in the water column and slowly crawls up the plant stem. At the top, the pond snail separates from the stem and floats for a long time, suspended from below to the surface film by the wide area of its “leg”. Having opened the breathing tube, the pond snail takes air into its body. If you touch a snail floating near the surface with a twig, its fleshy “leg” will shrink, the adhesion to the surface film will be broken and the pond snail will sink to the bottom. Helping the pond snail swim near the surface is the abundant secretion of mucus, which trails behind it like a silvery path.

But many aquatic animals do not need to reach the surface of the water to breathe. They breathe air dissolved in water. This is how, for example, the long blackish leech, the aquatic larvae of dragonflies, caddisflies and other insects, and the toothless shell, sitting deep in the bottom sand, breathe.

Fresh water life

PLACE OF WORK: MKOU PYANKOVSKAYA OOSH

SVERDLOVSK REGION

The world around us 4th grade. School of Russia. Pleshakov A.A.

Topic: Life of fresh water

Target: to form students’ ideas about fresh water as a natural community.

Tasks

educational:

introduce the diversity of living organisms in fresh water bodies and the role of humans;

developing:

develop children’s cognitive activity, interest, ability to observe, compare, generalize and draw conclusions;

educational:

teach children to understand the beauty of fresh water;

cultivate love careful attitude to the nature of his native land.

Formed UUD:

Cognitive – identify the known and the unknown, realize the cognitive task, read, extract necessary information;

Communication – participate in general conversation, following the rules speech behavior;

Regulatory – act according to plan, monitor the process and results of activities, make the necessary adjustments, adequately evaluate your achievements;

Personal – acquire new knowledge and skills

Lesson progress

I. Org. moment(1 min.)

We will start the lesson with a warm-up

We straighten our backs.

They stretched on their toes,

Turned right left

And they smiled at each other.

One, two, three, four, five

It's time for us to start our lesson.

II. Update background knowledge

1. Test(on cards)(5 min.)

Slide No. 1-6

1. The following grow in the meadow:

A) only herbaceous plants

B) mosses and lichens

B) shrubs and herbaceous plants

2. They live in the meadow:

A) swans, hazel grouse, silkworms

B) bumblebees, owls, wood grouse

C) wagtails, dung beetles, fillies

3. Meadow plants are:

A) timothy, clover, cornflower

B) lily of the valley, sedge, moss

C) blueberry, peony, fescue

4. Meadows and forests are called nurses:

A) dung beetles and gravedigger beetles, woodpeckers

B) bees, wild boars, jays

C) ground beetles, grasshoppers, bark beetles

5. What power circuits are typical for meadow community?

A) acorns→mice→owls

B) bluegrass→mice→owls

C) plant remains→earthworm→wagtail

Key: 1 – a, 2 – c, 3 – a, 4 – a, 5 – b, c

2. Messages, crosswords, food chains(5 min.)

III. Self-determination for activity(5 min.)

Look at the screen. (labeled on the screen – river, lake, pond, forest)

Slide No. 8

Eliminate unnecessary illustrations.

Justify your answer. (The forest is land, the rest is water) I believe that...... (remove the forest)

How to call the remaining objects of nature in one word. (Water)

- What will we talk about in class? (About life in bodies of water.)

Slide No. 9

What lesson goal can be set in connection with the topic? ( Learn about animals and plants in bodies of water and their relationships.)

What will we do to achieve this goal? ( We will work from a textbook, in a notebook, with a key atlas, in groups, in pairs, we will reason, draw conclusions, prove our point of view.)

What would you like to know about this topic? Formulate your questions.

I write it down on the board.

IV. Discovery of new knowledge

1. Conversation.(2 min.)

Let us remember that reservoirs are divided into two groups based on their origin. Which? (Natural and artificial)

What about the composition of the water? (fresh and salted.)

What types of fresh water bodies can you name? (river, lake, stream, canal, pond, reservoir)

2. Work in groups(10 min.)

Today we will have three editorial departments of the Life of Fresh Water magazine.

Game conditions:

We will divide the class into three sections.

Each department receives a task card.

All employees must actively participate in the discussion of all issues and prepare a report on the work of the department in the form of a poster.

Cards are distributed, children are divided into 3 sections:

1 department works on the topic “Plants of the reservoir”

Department 2 works on the topic “Animals of the reservoir”

Department 3 works on the topic “Man and the body of water”

Card No. 2

Find out:

Name the animals of the reservoir.

Animals of the pond

Card No. 3

Find out:

Human

Fizminutka

Report of departments on the work done(6 min.)

– Is fresh water- community? Prove it. (Plants release oxygen into the water, which animals breathe. Crucian carp feed on plants and insect larvae, and pike feed on crucian carp).

You've done a good job, now let's apply what you've learned.

V. Incorporation of new knowledge into the knowledge system

1. Modeling.In pairs(3 min.)

Using the illustrations on p. 180-181, write down 2-3 power chains characteristic of a fresh water body (notebook p. 84 No. 6).

EXAMINATION

2. Assignments in a notebook.On one's own(3 min.)

EXAMINATION

VI. Summing up the lesson(2 min.)

WHAT WAS THE PURPOSE OF THE LESSON?

WHAT KNOWLEDGE HAVE WE DISCOVERED TODAY?

WHERE CAN I APPLY NEW KNOWLEDGE?

HAVE WE ANSWERED ALL THE QUESTIONS posed at the beginning of the lesson?

VII. Reflection(2 min.)

COMPLETE THE SENTENCE: “Now I know that...”

What did you do well in the lesson?

Grading.

VIII. Homework(differentiated) (1 min.)

To choose from:

A message about the plants and animals of the reservoir from the Red Book of our region.

Illustrate the food chains characteristic of a freshwater body.

Create a crossword puzzle “The life of a pond”

Application

Card No. 2

Work plan for department 2 “Water animals”

Find out:

Name the animals of the reservoir.

Is the body of water rich in animal diversity? (Make a diagram of “Animals of the reservoir”)

Animals of the pond

Peculiarities of life of some animals of the reservoir.

Card No. 3

Work plan of the 3rd department “Man and the Reservoir”

Find out:

The importance of fresh water bodies for humans. (In diagram form)

Human

What human actions can lead to disruption of the ecological balance of a reservoir?

Make rules for behavior near water. (The rules may be in the drawings.)

Test

FI _________________________

Grade

Test