Even in biology lessons, teachers talk about various representatives of the fauna. Among them are the first chordates and vertebrates to inhabit our planet. These include fish and amphibians. Read the article about the similarities and differences between fish and frogs.
Fish
Since ancient times, these people inhabited all kinds of bodies of water. Evolution forced them to change, as a result of which the first amphibians came to land. Fish live almost everywhere. They are the largest superclass of primordial chordates. In total, science knows more than twenty thousand species of these animals.
Fish are cold-blooded representatives of the fauna. They are highly dependent on temperature environment, the speed of their life processes changes depending on temperature conditions. IN winter time years, when the water cools to zero degrees and below, the fish simply descend to the bottom of the reservoir, because the temperature there is always above zero.
Fish and frogs are essential components of many food chains. They not only eat other plant and animal organisms, but also become food for predators themselves. Many fish are prey for humans. Due to the fact that a huge number of these animals die as a result of fishing, some species of fish were listed in the Red Book or disappeared from the face of the Earth.
frogs
Amphibians are the first animals to set foot on land. They can live both on land and in water. While fish live in both salt and fresh water bodies, amphibians can only be found near rivers.
Fish and frogs have a number of similarities and differences. Amphibians have pronounced limbs that allow amphibians to jump high. Their skin is bare and covered with mucus. They have well-developed vision - this helps them notice prey from afar and subsequently catch it with their long sticky tongue. Frogs are cold-blooded animals, so their peak activity occurs during warm time of the year. Most often they can be found in wetlands, wet forests and various bodies of water.
Similarities
Describing the similarity between fish and frogs, one cannot help but say that they are similar not only externally, but also internally. This is evident in the fact that newly hatched tadpoles resemble small fish in shape. In adulthood, their similarity is due to the fact that the heads of these representatives of the fauna smoothly merge into the body. The frog has one and only cervical vertebra, and in fish the neck is replaced by posterior gill covers.
In addition, both the fish and the frog have a mouth opening and large eyes. This is one of the most obvious similarities in their external structure. As for the nasal sinuses and nostrils, amphibians and fish have two pairs of them. True, two of the frog's four nostrils are in its mouth, while all of the fish's nostrils are located on its head.
Fish and frogs have well-developed muscles. If y is associated with motor activity, then in fish it is associated with swimming. The fact is that it is important for them to stay in the water and resist its flow. They have separate muscles that control the movements of their eyes, fins, and other parts of their body.
Both representatives of the fauna lay eggs. Moreover, tadpoles are also chordates. Both representatives of the fauna are cold-blooded, which makes them dependent on the temperature around them.
Differences
As stated earlier, fish and frogs have both similarities and differences. They are both external and internal.
First of all, they lie in the structure of the skeleton. The frog has a cervical vertebra, while the fish does not, and the amphibian skull contains fewer bones. The frog's head is movably connected to the body. Her spinal cord protected by several arcs. While fish have gills, amphibians have neither gill bones nor gill covers.
The muscular skeleton also differs among these representatives of the fauna. Due to the fact that the frog not only swims in water, but also moves on land, the muscles of its limbs are well developed. In addition, she can lower and raise her head. Amphibians can move in different directions, while the movements of fish are monotonous and somewhat similar to snakes. The difference between a frog and a fish lies in the structure of their eyes. The fact is that in a fish they are flat, but in an amphibian they are convex.
The body shape of these representatives of the fauna is very different. Firstly, the body shape of the fish is streamlined, which contributes to its high speed of movement in the water. The skin of aquatic inhabitants is usually covered with scales, while the skin of amphibians is bare. This is one of the many differences between amphibians and fish.
Routing
ItemClass
Program
UMK "Harmony"
Teacher
Mokina Svetlana Nailovna
Lesson topic
« Development of fish and amphibians".
Lesson type
lesson in discovering new knowledge
The purpose of the lesson
Lesson Objectives
Educational - form ideas about life cycles fish and amphibians;
Developmental
-
develop the ability to trace the sequence of development of fish and amphibians;
Educating
- cultivate environmentally conscious behavior in nature;
Planned learning outcomes, formation of UUD:
Subject:
- get acquainted with the stages of development of fish and amphibians;participate in a collective discussion of issues, observing the rules of speech behavior; speak on the topic under discussion, listen to your interlocutors.
Metasubject
Be able todetermine and formulate the goal in the lesson with the help of the teacher;plan your action in accordance with the task; make necessary adjustments to the activity after its completion based on its assessment and taking into account the nature of the errors made( Regulatory UUD).
Be able to listen and understand the speech of others; express your thoughts orally (Communicative UUD).
Be able tonavigate your knowledge system;analyze objects;find answers to questions in the text and illustrations;transform information from one form to another: compose answers to questions(Cognitive UUD).
Personal UUD : apply the rules of business cooperation: compare different points of view; take into account the opinion of another person; show patience and goodwill in a dispute (discussion), trust in the interlocutor (participant) of the activity.
Regulatory UUD : to develop the ability to formulate and retain a learning task, the mindset to search for ways to resolve a problematic issue, the ability to monitor and evaluate one’s own activities and the activities of a partner.
Cognitive UUD: develop the ability to identify and formulate problems, put forward hypotheses, and build an algorithm to solve the identified problem.
Communication UUD: develop the ability to work in pairs, carefullylisten and hear each other, negotiate with each other, the ability to express one’s thoughts.
Forms of work
Work in pairs individual work
Basic Concepts
Egg, larva, fry, tadpole.
Interdisciplinary connections
Russian language
Resources
basic
Poglazova O.T., Vorozheikina N.D., Shilin V.D. The world around us, grade 3, part 2.
Poglazova O.T., Shilin V.D. The world. Workbook 3rd grade part 2
additional
Computer, TV, educational presentation,
Cards for working in pairs;
- signs with the basic concepts of the topic;
Palms for reflection.
Lesson stageTeacher activities
Activity
students
Time
(per minute)
Org. moment (stage of self-determination).
Purpose: greeting, creating a positive mood at work.
The cheerful bell rang,
Is everyone ready? All is ready!
We are not resting now,
We are starting to work.
Try to be active
Answer, don't be shy!
Psychological mood of children.
1 min.
Updating knowledge, motivating students.
Target: Repetition of existing knowledge, activation of activities, motivation for subsequent work.
What topic did we work on in the last lesson?
Open your textbooks and repeat the topic of the lesson. Animal development
- Let's test your knowledge. Let's do the "Animal Development" test.
Test
1. Time of appearance of offspring in most animals
A) spring B) autumn C) winter D) summer
2. Mammals have babies
A) appear from eggs B) develop from eggsB) are born
D) several stages of transformation occur
3. Birds and reptiles have young
A) appear from eggsB) develop from eggs B) are born
D) several stages of transformation occur in development
4.What is in the yolk of an egg
A) shell
B) nutrients necessary for its growth and development
C) protein D) nothing5. What role does egg white play?
A) it contains the nutrients necessary for its growth and development B) the protein contains the embryo.
B) noneD) protects the embryo from hitting the walls of the egg .
Open your observation diary and note today's weather.
Animal development.
Children take a test
5 minutes.
Formulation of the problem
Target: Leading children to formulate the topic and set the goal of the lesson.
In order to find out the topic of today's lesson, guess the riddles.
Alive in the water
On land - dead. (fish)
Not a beast, not a bird,
Afraid of everything.
Catches flies -
And into the water - splash! (Frog)
- What is another name for frogs?
- Let's remember everything we know about fish and amphibians.
But for this we will create a cluster
Amphibians
Where do fish live?
part of life in water part on land
What is their skin covered with?
scales
skin bare and moist
What do they breathe?
lungs and skin
What equipment do they have for swimming?
fins
paws
What do they eat?
varied diet
How do they behave in winter?
Inactive. Burbot spawns.
They go into hibernation
Development
eggs - larvae - fry - fish
What do we still not know about these representatives? I'll give you a hint.
- people have a child;
the fox has (little fox);
in a cat - (kitten);
at the duck - (duckling)?;
Guys, who was the frog in childhood? And the fish?
You see how many secrets nature presents to us!
What problem do you think we will solve together today?
Fish
frog
Amphibians
Children fill out the cluster
Determining the topic and purpose of the lesson.
Formulate the topic of the lesson
The topic of our lesson: “Development of fish and amphibians”
What goal will we set?
What tasks will we set for the lesson?
“Development and reproduction of fish and amphibians”
Target : Get acquainted with the development of fish and amphibians. Find out the differences in their development.
Tasks:
1. Observe, examine, analyze, search for information, prove, work with a book.
Learning new material .
When the reservoirs are free of ice in the spring, fish spawning begins. Females of river, lake and sea fish They find shallow places with clean running water and spawn there.The time of egg laying in fish is determined by temperature. Each type of fish has adapted to spawning only when the water is warmed up at a certain level.
Now you and I will find out how fish develops
Open the textbook on page 76, read about fish
Where does fish development begin?
What happens to the eggs?
And what happens to the larva?
Let's return to the cluster and draw up a chain of fish development: eggs - larvae - fry - fish
Amphibians breed in shallow, well-warmed areas of water bodies (ponds, quiet backwaters of rivers, lakes and swamps). Female frogs and toads lay clumps of eggs that are very similar to fish eggs. On warm spring evenings, in late April and May, loud croaking sounds are heard from the ponds. These “concerts” are staged by male frogs to attract females.(Would you like to listen to such a concert?)
Read the text on page 77 in the textbook
Where does frog development begin?
What happens to her next?
How does a tadpole turn into a frog?
Let's go back to the cluster and create a chain of amphibian development:egg - larva (tadpole) - frog
frogsFish
(slide 2)
First, the female lays eggs on stalks of algae
The eggs hatch into tiny tadpoles (similar to fish larvae)
(slide 3)
The eggs hatch into larvae, small funny creatures with eyes and tails.
Soon the tadpole grows back legs.
(Slide 4)
The fry grows, consuming the contents of the yolk sac (reserve nutrients)
Then the front ones grow, and the tadpole becomes like a frog with a tail.
Soon the gills disappear and lungs develop.
(slide 5)
When the supply of nutrients in the bag is completely used up, the fry begins to feed.
The fry feeds and grows.
After 2-3 months, the tail disappears, and our frog becomes fully grown.
(slide 6)
Gradually the fry grows and turns into an adult fish.
Fizminutka
Two girlfriends in the swamp
Two green frogs
Wash early in the morning
We rubbed ourselves with a towel.
They stomped their feet,
Hands patted
Leaned to the right, to the left
And they returned back.
That's the secret of health
Hello to all friends, physical education!
Work in TVET p.22
Opened the TPO and completed task No. 10
Swap notebooks. Please add a plus if everything is correct. Raise your hands if you have it right.
Work in pairs
There are yellow cards on your desks.
Place them in front of you and read them carefully.
Now let’s share our new knowledge with each other. What have you learned from your writing?
Text No. 1 .
The African fish takes very original care of its offspring.tilapia : She carries eggs and fry in her mouth! The fry calmly swim around their mother, swallow something, wait... But as soon as the slightest danger arises, the mother gives a signal, sharply moving her tail and quivering her fins in a special way, and... the fry immediately rushes to the shelter of the mother's mouth.
Text No. 2
Male stickleback builds a nest for the female. When the nest is ready, the male drives the female there, who lays eggs there. The females swim away, and the male guards the nest.
Text No. 3
Most frogs and toads lay their eggs in or near water and leave them unattended. Some lay few eggs and their parents take care of them. Surinamese pipa carries eggs in skin cells. After about 80 days, the little frogs jump out of these cells and begin to lead independent lives.
Text No. 4
Tree frog builds a nest of leaves for the eggs.The tadpoles crawl onto their father's back and he carries them into the constructed pond.
Text No. 5
Caring for the offspring of amphibians, as a rule, is not particularly warm and attentive. Most often, after laying eggs, parents leave water bodies and leave their future offspring.The midwife toad is so named because of the male's unique way of caring for its offspring. It wears calf "cords" wrapped around its hind legs. As the larvae develop, the male carries them into the water or places them near the water.
- Well done. Thank you.
Develop from eggs
Turns into a larva
She turns into a baby
Children listen
Frog development begins with the egg
After one to two weeks, a frog larva appears from the egg - a tadpole.
The tadpole eventually develops limbs, soon loses its gills, and develops lungs.
Summing up the lesson
Let's go back to the beginning of the lesson. - What goal did we set for ourselves?
What conclusion did you come to?
Learn about the development of fish and amphibians. Find out the differences in their development.
Reflection
familiarizing students with the development of fish and amphibians.
Make a senquain?
Option 1 – slave, option 2 – frog
Complete the sentences:
I found out…
I repeated...
It was interesting to me…
Green -everything was clear to me
Yellow – it was interesting, but not everything is clear
Red - nothing was clear and it was not interesting
Slave.
Slippery, smooth.
Swims, dives, plays.
Breathes in water with gills.
Animal.
Frog.
Naked, wet.
Jumps, croaks, swims.
Frogs are the first land animals.
Amphibians.
3 min
8
Page 76-77 retelling.
On the head there is a pair of nostrils for breathing. There are eyes, they can be protected by eyelids. There is a mouth. The skin is bare, moistened with mucus. Amphibians can breathe through their lungs and also through their skin. Some species have gills.
The body temperature of these animals depends on the ambient temperature, so they are active only in warm weather. When the temperature drops, they immediately fall into torpor. Poisonous individuals are also found in nature.
Amphibians reproduce, like fish, by laying eggs. The eggs are not protected by shell or skin, so amphibians usually breed in water. The eggs of amphibians produce a larva that looks very similar to a fish. Further development occurs in water with transformation - metamorphosis. Metamorphosis- this is a deep transformation of the structure of the body, transformation. Then future amphibians lose their gills, and some individuals even lose their tail. Then they grow limbs and come out onto land in the form of an adult animal.
Amphibians feed exclusively on mobile living food. They destroy large numbers of insects and their larvae. They are found everywhere, excluding only too cold or hot zones of the Earth.
The most ancient and surviving to our times due to their underground lifestyle are legless amphibians. There are about 150 species of them in nature. These include all tropical and many aquatic caecilians. These amphibians are distinguished by their unusual body structure. These amphibians have a worm-like cylindrical body. The skin is bare, equipped with mucous poisonous glands. There are transverse rings, like earthworms. Animals have no limbs or tail. Their head is strong, small, and imperceptibly merges into the body. With it, worms make their own dungeons in the damp soil. Due to their burrowing lifestyle, their eyes ended up under their skin. Amphibians find food using their sense of smell and touch. They eat snails, worms, larvae, and insects. They lead a very hidden lifestyle and do not like sunlight. The most famous is the ringed caecilian (Fig. 2).
Rice. 2. Ringed worm ()
Unlike other amphibians, they lay their eggs on land. The female curls up around the clutch of eggs and moistens it with her mucus and incubates it.
The fish snake has small, invisible bony scales in its skin (Fig. 3).
Rice. 3. Fish snake ()
The Central American caecilian does not lay eggs; it immediately gives birth to live young.
Science knows about 350 species tailed amphibians. These animals are similar in appearance to lizards, only the skin is soft and completely devoid of scales. Tailed amphibians include newts and salamanders. These animals have an elongated spindle-shaped body, which imperceptibly turns into a long tail. Curving the tail left and right helps it move through the water. On land, amphibians move with the help of two pairs of underdeveloped limbs. The toes may be webbed and lack claws.
Sirens have only forelimbs (Fig. 4).
Amphibians that live constantly in water breathe through gills. There is a tongue in the mouth, its shape is varied. There are small teeth. Many tailed animals have the ability to grow a new one if they lose a tail or leg. Amphibians do not know how to chew; they swallow food whole. Amphibians grab everything that moves and do not take stationary food that is completely edible. Tailless amphibians feed on insects, grabbing them in motion using a long sticky tongue. Tailed animals feed on worms and arthropods.
Legless amphibians find food by touch or use their sense of smell. They feed on insect larvae and worms.
The Siberian salamander is one of the few amphibians that is not afraid to live in conditions permafrost(Fig. 5).
Rice. 5. Siberian salamander ()
The most well-known tailed amphibian is the newt (Fig. 6). They look like little dragons. Newts love to hunt at night.
The fire salamander is famous for its bright color (Fig. 7). It is interesting that the shape, size, and pattern on the body of salamanders are unique to each individual.
Rice. 7. Salamander ()
The axolotl looks like an adult larva (Fig. 8).
Rice. 8. Axolotl ()
In nature, there is the most numerous order of amphibians - these are tailless amphibians. There are about 3 thousand species. This is the most known to man squad. These include toads, frogs, tree frogs, toads, and spadefoots. Their body is short and squat. The head is wide, without a neck, and goes into the body. There is no tail. The skin is bare, moisturized with secretions. There is a pair of moving eyes on the head. Amphibians use their vision to find prey. There is a pair of nostrils. The forelimbs are shorter than the hind limbs. They have membranes that help them swim. Amphibians jump on land and lead an active lifestyle. They are helped to catch prey by small teeth and a sticky tongue that folds in the mouth.
The bullfrog is a predator (Fig. 9). She even attacks chickens and eats young ducklings. Her cry resembles the roar of a bull.
Rice. 9. Bullfrog ()
The Surinamese pipa is famous for carrying tadpoles in cells on its back (Fig. 10). Adult frogs emerge from them.
Rice. 10. Surinamese pipa ()
The hairy frog defends itself with sharp claws, like those of a cat (Fig. 11).
Rice. 11. Hairy frog ()
The tiny Colombian frog (Fig. 12) fits in a teaspoon, and its poison is the most powerful of all animal poisons.
Rice. 12. Colombian frog ()
Flying frogs deftly jump from trees, straightening their membranes (Fig. 13). This helps keep them in the air.
Rice. 13. Flying frogs ()
Amphibians play big role in a person's life. They destroy a huge number of insects, thereby bringing benefits agriculture. They also eat insects that carry diseases. Amphibians are also used in medical laboratory research. Man even breeds amphibians as pets. In some countries they are even eaten.
Bibliography
- Samkova V.A., Romanova N.I. The world around us 1. - M.: Russian Word.
- Pleshakov A.A., Novitskaya M.Yu. The world around us 1. - M.: Enlightenment.
- Gin A.A., Faer S.A., Andrzheevskaya I.Yu. The world around us 1. - M.: VITA-PRESS.
- Worldofnature.ru ().
- Floranimal.ru ().
- Zoodrug.ru ().
Homework
- What are amphibians?
- How do amphibians reproduce?
- What are the three orders of amphibians? Describe each order of amphibians.
- * Prepare a story about the most unusual and interesting, in your opinion, representative of the Amphibian class.
Reproduction of amphibians. Amphibians are dioecious animals. Males have paired testes. Spermatozoa enter the cloaca through the genitourinary canals. Females have developed large ovaries. The eggs that mature in them enter the body cavity and are released from it through paired oviducts into the cloaca. Reproduction of amphibians (with rare exceptions) occurs in the spring. Having awakened from winter torpor, they accumulate in fresh water bodies. By this time, the females develop eggs in the ovaries, and the males develop seminal fluid in the testes (Fig. 233).
Brown frogs, for example, lay eggs in shallow, well-warmed areas of the reservoir. Green frogs (lake and pond frogs) lay their eggs at greater depths, most often among aquatic plants. Males release seminal fluid onto the eggs. Female newts place single fertilized eggs on the leaves or stems of aquatic plants.
The eggs (eggs) of amphibians have dense transparent shells that protect their internal contents from mechanical damage. In water, the shells swell and become thick. The eggs themselves have a black pigment that absorbs the heat of the sun's rays, necessary for the development of the embryo.
Development of amphibians. The larvae hatch from the eggs approximately a week (in frogs) or two to three weeks (in newts) after the start of embryo development. In frogs and other tailless amphibians, the larvae are called tadpoles. By appearance and their lifestyle is more similar to fish than to their parents (Fig. 234, 235). They have external gills, which are then replaced by internal ones, lateral line organs. The skeleton of the larvae is completely cartilaginous, there is a notochord. They have a two-chambered heart, and blood flows in the body through one circulation.
Amphibian larvae are mainly herbivorous. They feed on algae, scraping them off rocks and higher aquatic plants. As the larvae grow and develop, limbs appear and lungs develop. At this time, they often rise to the surface of the water and swallow atmospheric air. With the appearance of the lungs, a septum is formed in the atrium, and a pulmonary circulation occurs. The tadpoles' tail dissolves, the shape of the head changes, and they become similar to adult tailless individuals.
From the beginning of laying eggs to the transformation of larvae into adult animals, it takes about 2–3 months.
The females of most amphibians lay a lot of eggs. However, some of it is not fertilized, some is eaten by various aquatic animals or dries out when the reservoir becomes shallow. The larvae also die from various unfavorable conditions and serve as food for predators. Only a small proportion of the offspring survive to adulthood.
40: Amphibian Ecology
Conditions of existence and distribution. Amphibians belong to the group of poikilothermic (cold-blooded) animals, i.e. their body temperature is not constant and depends on the ambient temperature. The life of amphibians is highly dependent on environmental humidity.
This is determined big role in their life, skin respiration complements and sometimes even replaces imperfect pulmonary respiration. The bare skin of amphibians is always moist, since oxygen diffusion can only occur through a water film. Moisture from the surface of the skin constantly evaporates, and evaporation occurs the faster, the lower the environmental humidity. Evaporation from the surface of the skin constantly lowers body temperature, and the drier the air, the more the temperature will drop. The dependence of body temperature on air humidity in combination with poikilothermy (“cold-bloodedness”) leads to the fact that the body temperature of amphibians not only follows the temperature of the environment, as in fish or reptiles, but, due to evaporation, is usually 2-3° lower than it ( this difference can reach 8-9° when the air is drier).
The great dependence of amphibians on humidity and temperature determines their almost complete absence in deserts and subpolar countries and, conversely, a rapid increase in the number of species towards the equator and their exceptional richness in humid and warm tropical forests. So, if there are 12 species of amphibians in the Caucasus, then over vast areas Central Asia, 6 times larger than the Caucasus, only two species live - the green toad and the lake frog. Only a few species penetrate north to the Arctic Circle. Such are the grass and sharp-faced frogs and the Siberian four-toed newt.
Skin breathing various types amphibians play a different role. Where the respiratory function of the skin is low, the skin becomes keratinized and evaporation from the surface decreases, and consequently, the body’s dependence on environmental humidity decreases. As a rule, the distribution of species by habitat is determined by the degree of skin participation in respiration.
Among our amphibians, the Ussuri clawed newt and the Semirechensk newt are among the species that constantly live in water, in which gas exchange occurs almost exclusively through skin respiration alone. Our green frogs do not move any significant distance from bodies of water, receiving more than 50% of the oxygen they need for breathing through their skin.
Land amphibians include almost all toads, which evaporate twice as much from the body surface less water than green frogs. Some land amphibians spend a significant part of their time buried in the ground, like our spadefoot spadefoot. A number of species live in trees; An example of a typical tree form is the tree frog, found in our region. southern regions the European part of Russia, the Caucasus and the Far East.
The peculiarity of the structure of the skin of amphibians has another ecological consequence - representatives of this class are not able to live in salt water with a concentration exceeding 1.0-1.5%, since their osmotic balance is disturbed.