AT 3. The order Hymenoptera insects include (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 order Insectivores include (In your answer, write down a series of numbers without punctuation):
1. mouse
2. hedgehog
3. vole
4. mole
5. shrew
6. muskrat
12 The body cavity of the roundworm a) filled with connective tissue b) filled with liquid c) filled with air d) absent
13 In each segment of the earthworm’s body, a) nerve ganglia are repeated b) excretory tubes c) annular blood vessels d) all answers are correct
14 An earthworm has a) sense of smell b) taste c) hearing d) no special sense organs
15 An earthworm breathes a) in an oxygen-free environment b) with atmospheric air c) both options are possible d) there is no respiration
16 The shell of the common pond snail is covered with a layer of a) lime b) 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 an open circulatory system c) an open circulatory system, the function of the heart is performed by two vessels in the front part of the body d) a single-chamber heart and an 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 The cancer heart has a) two sections: an atrium and a ventricle b) three sections: two atria and one ventricle c) one section d) there is no heart
21 The nervous system in cancer consists of a) suprapharyngeal ganglion b) subpharyngeal 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 the cross spider:
a) intracavitary b) partially extracavitary c) completely extracavitary d) liquid components are digested outside the digestive system, and solid ones in the spider’s stomach
24 The body of arthropods consists of:
a) head, chest and abdomen b) head and torso c) cephalothorax and torso 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 reaches insect tissues through diffusion through
a) walls of capillaries b) walls of tracheas c) walls of pulmonary sacs d) enters first the tracheas, then into the capillaries
27 Pisces belong to the type:
a) achordates b) hemichordates c) chordates
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's eyes are always open because they:
a) the eyelids have grown together and turned into a transparent membrane 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 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 environment b) variable, but does not depend on the temperature of the environment c) not constant and depends on the temperature of the environment
33 skin in reptiles
a) has sebaceous glands b) dry (without glands) c) has a small number of glands that secrete mucus
34 The heart of reptiles
a) three-chamber b) three-chamber, except for crocodiles c) four-chamber
35 Fertilization in reptiles
a) external b) internal c) both external and internal
36 Snakes
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) mesh b) ganglion c) diaphragm d) cuticle
38 The following element does not belong to the skeleton of the lower limb
a) tarsus b) femur c) tibia d) radius
39 Animals are characterized by radial symmetry of the body
a) mollusks b) flatworms c) coelenterates d) fish
40 Eliminate unnecessary things
a) scapula b) clavicle c) crow bones d) humerus
41 Bird Science is
a) poultry b) ornithology c) cynology d) zoology
42 Keel on the sternum of birds
a) promotes cutting through 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 their lack of 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) unchangeable and created by higher powers b) were first created and then evolved naturally c) arose and
2) big pond snail
3) red cockroach
4) human roundworm
2. An increase in the level of metabolism in vertebrates is facilitated by the supply of blood to body cells
1) mixed
2) venous
3) oxygenated
4) saturated with carbon dioxide
3. Establish a correspondence between the type of animal and the structural feature of its heart.
ANIMAL STYLE STRUCTURE FEATURES OF THE HEART
A) sand lizard 1) three-chambered without a septum in the ventricle
B) lake frog
D) blue whale 2) three-chamber with an incomplete septum
D) gray rat
E) peregrine falcon 3) four-chambered
4. What type of animals have the highest level of organization?
1) Protozoa
2) Flatworms
3) Coelenterates
4) Annelids
Choose (circle) three correct answers out of six:
5. What signs characterize reptiles as terrestrial animals?
1) the circulatory system has two circulation circles
2) incomplete septum in the ventricle of the heart
3) internal fertilization
4) there is a hearing organ
5) the limbs are dismembered and 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 OF THE STRUCTURE CLASS OF ARTHROPODA
A) body parts: head, chest, 1) Arachnids
B) 3 pairs of walking legs 2) Insects
B) the presence of arachnoid glands
D) 4 pairs of walking legs
D) body parts: cephalothorax,
E) the presence of antennae
Question 1 - 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, uniting 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 - single-celled animals develop very quickly, so the number of amoebas and flagellates can reach 10,000,000 individuals in 1 gram of moist soil, 10,000 ciliates, and 100,000 crustacean amoebas in 1 gram of forest soil. no matter how small the size of these animals is, their total biomass can be significant and reach 1 g per 1 meter squared. Calculate the total biomass of soil unicellular animals per 1 hectare of soil. Write down the answer. Thanks in advance for the solution, I’ll be grateful even if it’s not complete
" and the subsection "" we published the article "Why are there right-handed people? "Today we will continue the topic and consider an even more global issue - why bilateral symmetry in higher animals and humans? Why aren't we like hydras or starfish? Is it even possible for such a development of evolution when bodies will not have 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 hemisphere for the right?”
Why bilateral symmetry? You probably know hundreds of examples of such bodies - horses, dogs, frogs, cats - almost any vertebrate 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 severed rays a new individual can grow... Maybe we too would have such an ability?..
Why does bilateral symmetry occur at all?
Answer: This is due to active movement in space. Let us 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. Example - radiolaria:
Primitive multicellular organisms attached to the bottom live differently. “Up” and “down” already exist, but the probability of prey or predator appearing is the same on all sides. This is how radial symmetry arises. An anemone, hydra or jellyfish spreads its tentacles in all directions; the concepts of “right” and “left” are nothing for them.
With more active movement, the concepts of “front” and “behind” arise. All the main sense organs go forward, because the likelihood of an attack or prey is greater in front than behind, and everything that has already been indifferently crawled, swam, ran and flew past is not so significant.
An even more active movement implies equal 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 relationship between movement rate and symmetry is sea urchins. Slowly crawling species have, like all echinoderms, radial symmetry.
However, some species have mastered life in sea sand, in which they dig and move quite quickly. Exactly corresponding to the rule described above, their spherical shell is flattened, slightly elongated 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.
It's 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 halves depends on the load. Imagine: by chance the right side of the animal’s body moves more, the muscles grow, the blood supply to the right hemisphere is better (after all, there is no crossover of nerves).
The more blood, the more nutrition, and the more development of the right half of the brain. Hence, if there were no crossing of nerves, there would be a huge right half of the body and a huge right hemisphere. While the frail left half of the body with grief was controlled in half by the tiny left hemisphere. Well, or vice versa... Agree, the 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! Thus, the growth of one of the two symmetrical parts of the body, as it were, “pulls up” the other, thereby ensuring their uniform, coordinated development.
General conclusion:
Active movement gives rise to bilateral symmetry.
Consequently, if we lived in other bodies (hydra, jellyfish, starfish, etc.), and led the same active lifestyle, then we would again have bilateral symmetry.
Just like that, no matter how sad it is :)
What kind of animals are not found on our planet! Some amaze with their size, some surprise with their habits and lifestyle, others are distinguished by their incredible colors.
But the most striking in body structure are still the sea and ocean inhabitants. Their body shape can be very unusual, as it has a special symmetry that is not typical for terrestrial animals. This is radial symmetry.
Types of body symmetry in animals
All animals can be divided into four groups according to the types of body symmetry:
- Animals with bilateral symmetry (bilaterally symmetrical). This group includes most species of terrestrial animals and a significant part of marine ones. The main feature is the arrangement of the body organs symmetrically relative to one plane drawn through it. For example, the left and right parts of the body, the back and the front.
- Radial symmetry of the body (radial symmetry). Characteristic of the ocean depths. The main feature is the structure of the body in such a way that several imaginary lines can be drawn through its central axis, relative to which they will be located symmetrically. For example, the rays of starfish.
- Animals with an asymmetrical body shape. When there is no symmetry at all, the shape is constantly changing depending on environmental conditions or the movement of the animal. A typical example is
- Complete lack of symmetry. Such organisms include sponges. They lead an attached lifestyle, can grow over the substrate to different volumes and have absolutely no definite symmetry in their body structure.
Each listed group of organisms derives a certain benefit from its structure. For example, bilateral animals can freely move straight while turning to the sides. Animals with radial symmetry are able to catch prey from different directions. It is convenient for asymmetrical organisms to move around and adapt to environmental conditions.
Radiation symmetry: what is it
The main distinguishing feature of animals with radial symmetry is their unusual body shape. They are usually dome-shaped, cylindrical, or shaped like a star or ball.
Many axes can be drawn through the body of such organisms; relative to each of them there are two completely symmetrical halves. This device allows them to have a number of advantages:
- They move freely in any direction, controlling all directions around them.
- The hunt takes on a larger scale as the prey is felt around the entire body.
- The unusual shape of the body allows it to adapt to the surrounding landscape, blend into it and become invisible.
Radial symmetry of the body is one of the main adaptations for certain classes of animals in the oceanic biocenosis.
Characteristics of radial symmetry of the body
The history of the emergence of such a device as radial symmetry of the body goes back to the ancestors of animals. They were the ones who led a completely sedentary, motionless lifestyle and were attached to the substrate. They benefited from such symmetry, and they gave it a start.
The fact that now many actively swimming animals still have radial symmetry indicates that it has not been reduced in the course of evolution. However, this feature no longer fulfills its intended purpose.
The meaning of radial symmetry
Its main purpose in ancestral forms, as well as in modern ones leading an attached lifestyle, is to provide protection from attacks by predators and to obtain food.
After all, animals with radial symmetry were not able to protect themselves, having run away from a predator, they could not hide. Therefore, the only option for protection was to sense the approach of danger from any side of the body and respond in time with protective mechanisms.
In addition, getting food for yourself when you lead a sedentary lifestyle is quite difficult. And radial symmetry allows it to detect the slightest food sources around the entire body and quickly respond to them.
Thus, the radial symmetry of the body provides extremely important mechanisms of self-defense and food for animals that possess it.
Animal examples
There are many examples of animals that have radial symmetry. Their huge species and numerical diversity adorns the sea and ocean bottoms and water columns, allowing people to admire the intricacy of nature and the beauty of the underwater world.
What animals have radial symmetry? For example, such as:
- sea urchins;
- jellyfish;
- holothurians;
- brittle stars;
- dartertails;
- hydra;
- sea stars;
- ctenophores;
- fixed polyps;
- some types of sponges.
These are the most common examples of body radial symmetry in animals. There are other animals, little studied, and perhaps not yet discovered at all, that are characterized by this feature of their physique.
Coelenterates
This type of animal includes three main classes, the common feature of which is that they are all animals with radial symmetry. The life cycles are dominated by either the stage of a free-swimming jellyfish or the stage of a polyp attached to the substrate. There is one hole, it performs the functions of the oral, anal and genital. Poisonous substances are used for protection
- Hydroid. Main representatives: hydras, hydrants. They lead an attached lifestyle and, like all coelenterates, have two layers in their body structure: ectoderm and endoderm. The middle layer is a gelatinous substance of a watery composition - mesoglea. The body shape is most often goblet-shaped. The main part of life is spent in the polyp stage.
- Jellyfish (scyphoid). The main representatives are all. The body shape is unusual, in the form of a bell or dome. They are also two-layered animals with radial symmetry. The main part of life is spent in the stage of a freely moving jellyfish.
- Corals (polyps). Main representatives: sea anemones, corals. The main feature is the colonial lifestyle. Many corals form entire reefs from their colonies. Single forms are also found; these are different types of sea anemones. The jellyfish stage is not characteristic of these animals at all, only the polyp stage.
In total there are approximately 9,000 species of representatives of this type of animal.
Echinoderms
What other animals have radial symmetry? Of course, everyone knows and very beautiful, unusual and bright echinoderms. This type has about 7 thousand species of these amazing representatives of marine fauna. There are five main classes:
- Holothurians resemble worms, but still have radial symmetry. Brightly colored, they move reluctantly along the seabed.
- Brittle stars - resemble starfish, but are distinguished by higher mobility and poor color - white, milky and beige.
- Sea urchins - may have regular, needle-shaped or may not have spines. The body shape is almost always close to spherical.
- Starfish are five-, eight-, or twelve-rayed animals with pronounced radial symmetry. They are very beautifully colored, lead a sedentary lifestyle, crawl along the bottom.
- Sea lilies are sessile beautiful animals and have the shape of a radial flower. They can separate from the substrate and move to places richer in food.
The lifestyle can be either mobile or attached (sea lilies). The body is two-layered, the mouth opening serves as the anal and genital openings. The exoskeleton is quite strong, calcareous, and beautifully decorated with colored patterns.
The larvae of these animals have bilateral symmetry of the body, and only adult individuals grow the rays to radiality.
Ctenophores
Most often they are small animals (up to 20 cm), which have an absolutely white, translucent body, decorated with rows of combs. This type of animal is considered one of the most ancient. Ctenophores are predators, eating crustaceans, small fish and even each other. They reproduce very intensively.
In the structure of the body, a third mouth opening appears on the upper part of the body; they lead a free-swimming lifestyle. The most common types are:
- beroe;
- Platyktenidae;
- gastrodes;
- venus belt;
- Bolinopsis;
- tjalfiella.
Their radial symmetry, as well as the radial symmetry of some species of coelenterates, is weakly expressed. The body shape resembles a bag or an oval.
Generalization
Thus, radial symmetry of the body is the prerogative of aquatic animals that lead a sedentary or attached lifestyle and gives its owners a number of advantages in hunting prey and evading predators.
Bilateral symmetry is the identical arrangement of body parts of an organism in the left and right halves on either side 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 plane symmetry, since one plane divides the organism into mirror-image halves. We'll learn all about bilateral symmetry and look at some examples. We will also discuss the main advantages.
Definition of symmetry
Symmetry refers 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 an axis. In other words, the body is oriented so that it is reflected from behind an imaginary line through the center of the body. These organisms have a top and a bottom, but they do not have a left and right side, a front and a back. A couple examples of radial symmetry are starfish, jellyfish, and sea anemones.
- There are some organisms that exhibit no symmetry at all. They are classified as asymmetrical. The only animals that truly 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 a little more closely.
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 split 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 cat? They also have bilateral symmetry. Other examples you might 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 that we can see and hear more than most animals with radial symmetry. Bilateral symmetry also determined the formation of the head and tail region. This means that everything can go in one end and come out the other, unlike those organisms that must use the same hole. Without going into too much detail, let's just say that we're all very excited about it.
Another benefit is that bilateral symmetry allows for the development of a more thorough nervous system that can control the body. Many animals have bilateral body symmetry, meaning that they can be divided into matching halves by drawing a line down the center. In this respect, arthropods are built like humans: the right half of an arthropod 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 like the shape of a pie, where each piece is almost identical, although they do not have a left or right side. Instead, they have a top and bottom surface. Organisms that exhibit radial symmetry are, for example, corals, jellyfish and sea anemones, sea urchins and starfish.
Traits of bilaterally symmetrical organisms
Organisms that have bilateral symmetry exhibit front and back, top and bottom, and left and right sides. They generally move faster than animals that do not exhibit bilateral body symmetry. It also has improved vision and hearing capabilities compared to those with radial symmetry.
Basically all marine organisms, including all vertebrates and some invertebrates, have bilateral symmetry. 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 the first life forms, but they develop differently as they grow.
There is one marine animal that exhibits no symmetry at all: sponges. These organisms are multicellular, but remain the only asymmetrical animals. This means there is no place in their bodies where you can split them in half and see mirror images.