Bilaterally symmetrical animal examples. What animal has bilateral body symmetry? Active movement creates bilateral symmetry
1) Intestinal - three-layer, invertebrate animals.
2) Among them there are both free-floating forms and those attached to the substrate.
3) They reproduce only asexually.
4) Includes classes: hydroid, scyphoid, flagellates.
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1. Annelids are the most highly organized animals among other types of worms.
2. Annelids have an open circulatory system.
3. The body of annelids consists of identical segments.
4. There is no body cavity in annelids.
5. The nervous system of annelids is represented by the peripharyngeal nerve ring and the dorsal nerve chain.
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2. Bull tapeworm is classified as tapeworm.
3. The body of the bull tapeworm has an articulated structure.
4. The bovine tapeworm has a well-developed digestive system and feeds actively.
5. The main owner of the bovine tapeworm is cattle.
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1. Flatworms are three-layered animals.
2. Type flatworms include white planaria, human roundworm and liver fluke.
4. They have a poorly developed nervous system.
5. Flatworms are dioecious animals that lay eggs.
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1. The main classes of the type of arthropods are crustaceans, arachnids, and insects.
2. Insects have four pairs of legs, and arachnids have three pairs.
3. The crayfish has simple eyes, and the cross-spider has complex eyes.
4. In arachnids, spider glands are located on the abdomen.
5. Spider-cross and Maybug breathe with the help of lung sacs and trachea.
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1. The arachnid class is the most numerous class of the arthropod type.
2. The body of arachnids has a cephalothorax and abdomen.
3. Ticks have a fused body.
4. There are three pairs of walking legs.
5. All spiders are terrestrial.
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1. The features that distinguish birds from reptiles include the progressive development of the organs of vision, hearing, and coordination of movements.
2. In birds, thermoregulation is somewhat worse than in reptiles.
3. The four-chamber heart of birds has an incomplete septum in the ventricle.
4. The adaptations of birds for flight include: a streamlined body shape, wings filled with a dense bone substance, the presence of gas exchange in both the lungs and air sacs.
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The housefly is a two-winged insect whose hindwings have evolved into halteres. The mouth apparatus of the licking type, the fly feeds on semi-liquid food. The fly lays its eggs on rotting organic matter. Its larva is white, has no legs, feeds on food waste, grows rapidly and turns into a red-brown chrysalis. An adult fly emerges from the pupa.
What type criteria are described in the text? Explain the answer.
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3. Flatworms have an elongated flattened body.
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1. Flatworms are three-layered animals.
2. Type Flatworms include white planaria, human roundworm and liver fluke.
3. Flatworms have an elongated flattened body.
4. Tapeworms have a well-developed digestive system.
5. Flatworms are dioecious animals that lay eggs.
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1. Fish are aquatic chordate animals.
2. The support of the body of all fish is the internal cartilaginous skeleton
3. Breathing in fish is gill.
4. There are two circles of blood circulation in the circulatory system, and only venous blood in the heart.
5. The central nervous system of fish has the form of a tube, the front part of which is turned into a forebrain, consisting of 5 sections.
6. Most fish are hermaphrodites.
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1. The nervous system of mammals is characterized by a high degree of complexity. 2. In the brain, the cerebellar hemispheres are especially developed, which ensures the complexity of the behavior of mammals. 3. Mammals first developed an inner ear, which led to a dramatic improvement in animal hearing. 4. All mammals, except for the first animals, are viviparous animals. 5. Cubs develop in the placenta, which is located in the abdominal cavity. 6. Mammals that develop a placenta are called placental.
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Read the text and find sentences in it that contain biological errors. First write down the numbers of these sentences, and then formulate them correctly.
1. Fish are cold-blooded animals with a streamlined body shape and breathing with gills. 2. Most of the fish species that exist on Earth have a cartilaginous skeleton. 3. The circulatory system of fish is closed, and the heart consists of a ventricle and an atrium. 4. All fish have two circulations. 5. Venous blood flows in the heart of the fish, which is saturated with oxygen in the gills. 6. The direction of the flow of water, the vibration of the water, the fish perceive by the organs of balance.
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1) The appearance of the first representatives of the type Flatworms was preceded by the appearance of a number of large aromorphoses. 2) In flatworms, a two-layer body structure has formed - the basis for the formation of many organs and organ systems. 3) They have a radial symmetry of the body, which ensures free swimming in the water. 4) Orientation in space was facilitated by the emergence of sensory organs and a diffuse nervous system. 5) Digestive and excretory systems appeared. 6) Permanent sex glands were formed, which determined the most effective forms of sexual reproduction.
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1. Kangaroo is a representative of marsupial mammals. 2. They live in Australia and South America. 3. Kangaroos feed mainly on insect larvae. 4. After giving birth, a baby kangaroo crawls into a bag where it eats.
milk. 5. This method of bearing is due to the fact that the kangaroo has a poorly developed placenta. 6. When moving, the kangaroo rests on four paws, which allows you to make long jumps.
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1. The mole lives in underground passages, which he digs. 2. Due to his lifestyle, he has a number of adaptations. 3. The paws of the mole are adapted for rapid movement. 4. At the same time, the mole's sense of smell and vision are very weak. 5. This is because the mole does not use them for orientation in space. 6. The mustache of a mole is necessary for him to touch.
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1. The type Flatworms include white planaria, tapeworm, echinococcus and earthworm. 2. Free-living worms differ from parasitic forms in structure, way of life and other features. 3. White planaria is an active predator. 4. She has a through intestine with a mouth and anus. 5. With an active lifestyle, the white planaria needs a lot of energy, so it has a well-developed respiratory system.
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1. The appearance of the first representatives of the Flatworm type was accompanied by a number of large aromorphoses. 2. The most important of these was the emergence of a circulatory system in flatworms. 3. The primary body cavity appeared. 4. The free movement of these animals in the water was ensured by ray symmetry. 5. The progress of flatworms has ensured the emergence of the stem nervous, digestive and excretory systems of organs. 6. The development of the reproductive system has led to a fairly high fertility of animals.
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1. Sharks are a superorder of cartilaginous fish with the following distinctive features: an elongated body of a more or less torpedo shape, a large caudal fin and well-developed gill covers.
2. To date, more than 450 species of sharks are known. 3. The whale shark is the largest known fish (its length reaches 20 meters) and the largest marine predator. 4. Representatives of the superorder are widely distributed in the seas and oceans, from the surface to a depth of more than 2000 meters. 5. Sharks mostly live in fresh water. 6. Most sharks belong to the so-called real predators, but 3 species are filter feeders.
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1. Turtles are one of two orders of Pre-sme-ka-yu-shchi-sya, whose fossils can be traced back over 220 million years. 2. These animals are distributed in tropical and temperate climatic zones almost throughout the Earth. 3. A distinctive feature of turtles is the shell, which serves as their main defense against enemies. 4. From an ecological point of view, turtle species are divided into marine and terrestrial, but terrestrial turtles always live in fresh water. 5. All kinds of turtles are poisonous. 6. Many species of turtles are under the threat of extinction of varying degrees and are protected.
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1. Coelenterates are two-layer multicellular animals. 2. They are bilaterally symmetrical. 3. The intestinal cavities include freshwater hydra, jellyfish cornerot, white planaria, sea anemone. 4. Coelenterates have a mesh (diffuse) nervous system. 5. Among the intestinal cavities, both free-floating organisms and attached forms are found. 6. Stinging cells are needed to capture food and move.
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1. Perch is a primary aquatic animal, whale is a secondary aquatic animal. 2. Primary aquatic animals have lateral line organs that perceive pressure, direction of movement, and speed of water flow. 3. The forelimbs of the whale have turned into pectoral fins. 4. The hind limbs of the whale have been modified into a tail fin. 5. Perch and whale have gill breathing. 6. In whales, pelvic bones are attached to the sacral spine.
IN 1. What animals are characterized by radial symmetry of the body, one cavity and stinging cells?IN 3. The order Hymenoptera includes (In response, write down a series of numbers without signs
punctuation):
1. Bee
2. Wasp
3. Forest bug
4. Bed bug
5. Ant
AT 5. The Insectivora order includes (In response, write down a series of numbers without punctuation marks):
1. mouse
2. hedgehog
3. vole
4. mole
5. shrew
6. desman
12 Ascaris body cavity a) filled with connective tissue b) filled with liquid c) filled with air d) absent
13 In each segment of the body of an earthworm, a) nerve nodes b) excretory tubes c) annular blood vessels d) all answers are correct
14 An earthworm from the sense organs has a) smell b) taste c) hearing d) no special sense organs
15 An earthworm breathes a) in an oxygen-free environment b) atmospheric air c) both options are possible d) there is no breathing
16 The shell of an ordinary pond snail is covered with a layer of a) lime b) a horn-like substance c) chitin d) silicon
17 In the circulatory system of the pond snail there are
a) two-chamber heart and one circle of blood circulation b) two-chamber heart and open circulatory system c) open circulatory system, the function of the heart is performed by two vessels in the front of the body d) one-chamber heart and open circulatory system
18 Gastropods include a) naked slug b) livebearer c) bitinia d) all answers are correct
19 The chitinous cover of arthropods performs the functions of a) protection b) thermoregulation c) gas exchange d) all answers are correct
20 Cancer heart has a) two sections: atrium and ventricle b) three sections: two atria and one ventricle c) one section d) the heart is missing
21 The nervous system in cancer consists of a) supraoesophageal ganglion b) suboesophageal ganglion c) ventral nerve cord d) all answers are correct
22 The abdomen of the cross-spider has a) three segments b) five segments c) non-segmented structure d) none of the answers is correct
23 The process of digestion in a cross-spider:
a) intracavitary b) partially extracavitary c) completely extracavitary d) liquid components are digested outside the digestive system, and solid ones in the stomach of a spider
24 The body of arthropods consists of:
a) head, chest and abdomen b) head and trunk c) cephalothorax and trunk d) head, chest and abdomen; cephalothorax and abdomen.
25 In insects, the number of pairs of motor limbs can be equal to
a) 3 b) 4 c) 5 d) all answers are correct
26 Oxygen to the tissues of insects is supplied by diffusion through
a) the walls of the capillaries b) the walls of the trachea c) the walls of the lung sacs d) enters first into the trachea, then into the capillaries
27 Fish are of the type:
a) chordateless b) semichordate c) chordate
28 The body is covered with bony scales: a) only in cartilaginous fish b) only in bony fish c) in all fish, with rare exceptions
29 Fish eyes are always open because they have:
a) the eyelids have grown together and turned into a transparent shell b) the eyelids are absent c) the eyelids are motionless
30 The spinal cord in fish is located
a) under the spine b) in the spinal canal, which forms the upper arches of the vertebrae c) above the spine
31 The circulatory system in fish
a) closed b) open c) open in cartilage and closed in bone
32 Fish body temperature
a) constant, and does not depend on the temperature of the medium b) variable, but does not depend on the temperature of the medium c) non-constant and depends on the temperature of the medium
33 skin of reptiles
a) has sebaceous glands b) dry (without glands) c) has a small amount of glands that secrete mucus
34 The heart of reptiles
a) three-chamber b) three-chamber, except crocodiles c) four-chamber
35 Fertilization in reptiles
a) external b) internal c) both external and internal
36 Snake is
a) legless lizards b) snakes c) a special group of reptiles
37 In all mammals, the thoracic cavity is separated from the abdominal septum
a) mesentery b) ganglion c) diaphragm d) cuticle
38 The following element does not belong to the skeleton of the lower limb
a) tarsus b) thigh c) lower leg d) radius
39 Animals are characterized by ray symmetry of the body
a) mollusks b) flatworms c) coelenterates d) fish
40 Eliminate the excess
a) scapula b) clavicle c) crow bones d) humerus
41 Bird Science is
a) poultry farming b) ornithology c) cynology d) zoology
42 Keel on the sternum of birds
a) contributes to the dissection of air during flight b) increases the area of attachment of the pectoral muscles c) does not matter as an adaptation to flight
43 What digestive organs arose in birds due to the absence of their jaws and teeth
a) goiter b) glandular part of the stomach c) muscular part of the stomach d) small intestine
44 Mammals spread across the Earth due to the fact that
a) were small in size b) fed their young with milk c) were warm-blooded d) all answers are correct
45 Fabrics first appeared in
a) protozoa b) coelenterates c) flatworms d) annelids
46 Darwin's theory states that all organisms
a) immutable and created by higher powers b) were first created and then evolved naturally c) arose and
2) big pond
3) red cockroach
4) human roundworm
2. An increase in the level of metabolism in vertebrates is facilitated by the supply of body cells with blood
1) mixed
2) venous
3) saturated with oxygen
4) saturated with carbon dioxide
3. Establish a correspondence between the type of animal and the structural features of its heart.
TYPE OF ANIMAL FEATURE OF THE STRUCTURE OF THE HEART
A) quick lizard 1) three-chamber without a septum in the ventricle
B) lake frog
D) blue whale 2) three-chamber with an incomplete partition
D) gray rat
E) peregrine falcon 3) four-chamber
4. What type of animals have the highest level of organization?
1) The simplest
2) Flatworms
3) Intestinal
4) Annelids
Choose (circle) three correct answers from six:
5. What signs characterize reptiles as land animals?
1) the circulatory system has two circles of blood circulation
2) incomplete septum in the ventricle of the heart
3) fertilization is internal
4) there is an organ of hearing
5) the limbs are dissected, consist of three sections
6) there is a tail
Match the contents of the first and second columns. Enter the numbers of the selected answers in the table.
6. Establish a correspondence between the structural feature of arthropods and the class for which it is characteristic.
FEATURE CLASS OF STRUCTURE OF ARthropods
A) body parts: head, chest, 1) Arachnids
B) 3 pairs of walking legs 2) Insects
B) the presence of spider glands
D) 4 pairs of walking legs
D) parts of the body: cephalothorax,
E) the presence of antennae
1 question - prove that the cell is a living particle of the body. Question 2 - explain why in most multicellular animals cells are grouped intotissues from which organs are formed that unite into organ systems.
Question 3 - name the differences in the structure and lifestyle of bilaterally symmetrical animals and animals with radial symmetry of the body.
Question 4 - unicellular animals develop very quickly, so the number of amoebas and flagellates can reach 10,000,000 individuals in 1 gram of moist soil, ciliates 10,000 and crustacean amoebas 100,000 in 1 gram of forest soil. no matter how small the size of these animals, their total biomass can be significant and reach 1 - g per 1 meter squared. calculate the total biomass of soil unicellular animals per 1 ha of soil. write down the answer. thanks in advance for the solution, I will be grateful even if it is not complete
"and subsection" "we published the article" Why do righties exist?» Today we will continue the topic and consider an even more global issue - why bilateral symmetry in higher animals and man? Why aren't we like hydras or starfish? Is such a development of evolution possible at all, when the bodies will have non-bilateral symmetry? These are the questions we will answer. At the same time, to the question asked in the previous article “Why is the right hemisphere responsible for the left side of the body, and the left for the right?”
Why bilateral symmetry? You probably know hundreds of examples of such bodies - these are horses, dogs, frogs, cats - almost any vertebrates that you take will be bilaterally symmetrical. But why? It would be nice to have five-ray symmetry, like a starfish ... They say that from one of its torn off rays a new individual can grow ... Maybe we would have such an ability? ..
Why does bilateral symmetry occur at all?
Answer: This is due to active movement in space. Let's explain in detail:
Some unicellular and multicellular creatures live in the water column. Strictly speaking, for them there are no concepts of "right-left" and "up-down", because the force of gravity is negligible, and the environment is the same. Therefore, they look like a sphere - needles and outgrowths stick out in all directions to increase buoyancy. An example is radiolaria:
Primitive multicellular organisms attached to the bottom live differently. The "up" and "down" are already there, but the probability of the appearance of prey or predator is the same from all sides. This creates radial symmetry. An anemone, a hydra or a jellyfish spreads its tentacles in all directions, the concepts of "right" and "left" are nothing to them.
With more active movement, the concepts of "front" and "behind" arise. All the main sense organs go forward, because the probability of an attack or prey is greater in front than behind, and everything that has already been indifferently crawled past, swam, ran and flew by, is not so significant.
An even more active movement implies a uniform interest in both what is on the left and what is on the right. There is a need for bilateral symmetry. An example that explains the dependence of the pace of movement and symmetry is sea urchins. Slowly crawling species have, like all echinoderms, ray symmetry.
However, some species have mastered life in the sea sand, in which they dig and move quite quickly. Exactly according to the rule described above, their spherical shell is flattened, stretched a little and becomes bilaterally symmetrical!
And now the MAIN THING:
In a bilaterally symmetrical animal, both halves should develop equally.
After all any bias in one direction or another is harmful.
Everything is simple.
If there were no crossing of nerves, and the right hemisphere was responsible for the right side of the body:
The degree of development of each of the halves depends on the load. Imagine: by chance, the right side of the animal's body moves more, muscles grow, blood supply to the right hemisphere is better (after all, there is no decussation of nerves).
The more blood, the more nutrition, and the more development of the right half of the brain. Hence, if there was no crossing of nerves, there would be a huge right half of the body and a huge right hemisphere. Whereas the frail left half of the body with grief in half was controlled by the tiny left hemisphere. Well, or vice versa ... Agree, a hybrid would be noble - and non-survival.
Therefore, it is more survivable when the right hemisphere controls the left half of the body. Then stimulation of the right hemisphere will improve the left side of the body! So the growth of one of the two symmetrical parts of the body, as it were, "pulls" the other behind it, thereby ensuring their uniform coordinated development.
General conclusion:
Active movement creates bilateral symmetry.
Therefore, if we lived in other bodies (hydras, jellyfish, starfish, etc.), and led the same active lifestyle, then we would again have bilateral symmetry.
So here it is, no matter how sad 🙂
Bilateral symmetry is the same arrangement of body parts of an organism in the left and right halves on both sides of the central axis or plane. Figuratively speaking, if you draw a line from the head to the tail of an organism - both sides are mirror images of each other. In this case, the organism exhibits bilateral symmetry, which is also known as planar symmetry, since one plane divides the organism into mirror halves. We will learn all about bilateral symmetry and look at some examples. We will also discuss the main benefits.
Definition of symmetry
Symmetry is related to the orientation of an organism based on a plane or around an axis. Given the different shapes and orientations of different organisms, scientists have come up with three main types of symmetry:
- The first type is radial symmetry. With this type, the body plan is based on the axis. In other words, the body is oriented so that it reflects from behind an imaginary line through the center of the organism. These organisms have a top and a bottom, but they do not have left and right sides, front and back. A couple of examples of radial symmetry are starfish, jellyfish, and sea anemones.
- There are some organisms that show no symmetry at all. They are classified as asymmetrical. The only animals that really belong to this classification are sponges.
- The last type of symmetry is bilateral symmetry. This is when the body plan can be divided along a plane that divides the animal's body into right and left sides, which are mirror images of each other. Let's look at this type of symmetry in a little more detail.
Examples of bilateral symmetry
So now you can think of different animals that exhibit bilateral symmetry. Man is the first example we will discuss. Yes, we humans are an example of bilateral symmetry. This can be seen quite simply. Go and look in the mirror and see for yourself. We could draw a line right down the middle of your body, right through your nose, and divide you into right and left mirror images. Even your brain can be divided into equal right and left sides.
Let's look at another example. Do you have a dog or a cat? They also have bilateral symmetry. Other examples you may not have thought of are sharks, butterflies and ants.
Benefits of Bilateral Symmetry
So there are actually some real benefits to bilateral symmetry. The fact that we have two eyes and ears means we can see and hear more than most radially symmetrical animals. Bilateral symmetry also led to the formation of the head and tail region. This means that everything can go in one end and out the other, unlike those organisms that have to use the same opening. Without going into too much detail, let's just say we're all very excited about this.
Another benefit is that bilateral symmetry allows the development of a more thorough nervous system that can control the body. Many animals have bilateral body symmetry, which means they can be split into matching halves by drawing a line down the center. In this respect, arthropods are built like humans: the right half of arthropods is a mirror image of the left half. This is bilateral symmetry.
Bilateral and radial symmetry
Most animals on the planet exhibit bilateral symmetry. This is what people have. It is different from radial. Radially symmetrical organisms are similar to the shape of a pie, where each part is almost identical, although they do not have a left or right side. Instead, they have top and bottom surfaces. Organisms that exhibit radial symmetry are, for example, corals, jellyfish and sea anemones, sea urchins and starfish.
Traits of Bilaterally Symmetric Organisms
Organisms that are bilaterally symmetrical exhibit front and back, top and bottom, and left and right sides. They tend to move faster than animals that do not exhibit bilateral body symmetry. It is also improved vision and hearing capabilities compared to those with radial symmetry.
Basically all marine organisms, including all vertebrates and some invertebrates, are bilaterally symmetrical. This includes marine mammals such as dolphins and whales, fish, lobsters and sea turtles. Interestingly, some animals have one type of body symmetry when they are first life forms, but they develop differently as they grow.
There is one marine animal that does not show symmetry at all: sponges. These organisms are multicellular, but remain the only asymmetric animals. This means there is no place in their bodies where you can split them in half and see mirror images.