So, today is Saturday, June 10, 2017, and we traditionally offer you answers to the quiz in the “Question and Answer” format. We encounter questions ranging from the simplest to the most complex. The quiz is very interesting and quite popular, we are simply helping you test your knowledge and make sure that you have chosen the correct answer out of the four proposed. And we have another question in the quiz - What happens to an American frog tadpole as it grows into an adult?
Frogs reproduce and breed in water. Their mating season begins during the rainy season. Females lay eggs among the thickets. Tadpoles reach 25 cm in length. During metamorphosis, the tadpole loses its gills, its lungs develop, its limbs grow, and its body shape changes. The tail shortens and the tadpole decreases in size daily; as a result, the adult is only 1/4 the length of the tadpole.
In order to describe all the frogs and toads that live on the American continents (South and North America), a multi-volume publication will be required. Representatives of tailless amphibians are striking in their number and diversity. Some of them live all over the world, others have exclusively “American” registration. Let's get acquainted with the main frog families and their most amazing representatives.
Representatives of this genus got their name from the sharp growths above the eyes. Such horns give the animals the most strange appearance. The color can be varied, often a color scheme, for example, black-brown or red-brown, becomes an ideal camouflage. A frozen individual cannot be immediately identified as a living creature. In America there are:
Amazonian slingshot, found in the Amazon Basin.
Decorated, as the name implies, the amphibian’s skin is decorated with a “cheerful” ornament.
Chakskaya, very voracious, is ready to eat her brother, and with great hunger, even her own skin.
The Brazilian slingshot is a rather large specimen and a “serious predator”: its powerful jaws allow it to deal with rodents and birds. They are not averse to dining with their fellow creatures: they are capable of swallowing other amphibians and reptiles if they are at least a little smaller than the hunter. It is surprising that these slingshots cannot jump, but prefer to walk.
In almost all US states and Canada you can find the beautiful leopard frog.
Its closest sisters - spotted, lowland, forest and noisy - are quite common. They rarely grow more than 5–8 cm and are fertile. For example, a female noisy can lay up to 7 thousand eggs at a time.
These closest relatives of frogs are diverse and quite common on both continents.
Harlequins, there are more than 50 varieties of them, they have well mastered the territory from Bolivia to Costra Rica. The name speaks for itself: harlequins are very brightly colored. All produce poisons of varying degrees of toxicity; they have long been used by indigenous people to lubricate arrowheads. The bright color warns: I am very dangerous. Look at the different representatives of the harlequin family, you will appreciate their colorful “robe”.
An amphibian that “does not like” water uses it, if possible, only for laying eggs and during the growth of tadpoles. But the multi-colored one willingly runs and climbs and swims, but cannot jump. It itself is poisonous and eats the same ones: spiders, wasps.
This “beauty”, almost merging with the surrounding leaves, is unsafe; if the poison gets into the human digestive tract, then an acute attack of heart failure is guaranteed. The Colorado potato is less dangerous to humans; its poison is fatal only to small animals. There have been recorded cases of death of hunting dogs who had the temerity to grab “easy prey.”
- one of the largest in the world, reaching 24 centimeters in length.
Following her is the Toad-aga, she is smaller, but at the same time quite poisonous. Only the bullfrog, up to 25 centimeters long, which also lives in America, can compare with them in size. Only the African goliath frog is larger than them, up to 32 centimeters long with a long jump of 3 meters.
In North America there lives a rare representative of fossil toads that have survived to this day - the long-nosed toad, and in the southeast you can meet another “charming” one - the cone-headed toad.
This order of tailless amphibians includes:
Earless tree frogs, which prefer the northeast of the South American continent. Their body and head are slightly flattened. And they like to spend their free time in the trees. And in Yuzhnaya there lives an amazing frog from the tree frog family. It’s a paradox, but an adult reaches a size of only 5 centimeters, and the tadpoles grow up to 25. There is also a poisonous tree frog – the Brazilian tree frog, with blood-red spots on its back.
Phyllomedusa. Several species are found in South America. Upper Amazonian, looks like a very cute and slightly unhappy creature. It lays its eggs under the leaves; as soon as the tadpoles hatch, they immediately fall into the water. Her neighbors and closest relatives: Wollunkuk, bicolor.
Geographic tree frog She got her name for her color. However, the pearl one was named according to the same principle: for the white spots on the back. And the oarsman tree frog was so nicknamed for the sounds it makes, they resemble the noise of an oar descending into the water. Accordingly, the blacksmith tree frog screams so loudly that it seems like they are hitting the metal with a huge hammer. As you can see, the discoverers of these amphibians did not bother themselves too much in finding names. A relative from the North American states imitates the barking of dogs, her name is the barking tree frog, and in Canada and Hudson Bay there lives a whistling tree frog.
Representatives of this family are united by the ability to make whistling sounds when moving. The ocellated whistler has spots with a border on its skin, very similar to eyes. And the five-fingered one is famous for the fact that it calmly eats its deadly relatives - poison dart frogs. And he himself is quite poisonous, sometimes just standing next to him is enough to start sneezing.
The evil shieldback is an active predator that is not averse to “inviting” its relative to dinner. And then eat it, cannibalism is common in this species.
The cocoon scutum is not afraid of drought; it simply remains in a dry body of water. Every day she sheds, but does not shed her skin, as a result a protective cocoon is formed.
A rare species lives on the South American continent - the armored narrowmouth. And his place of residence is unusual - this little frog prefers to live... underground. Like its distant relatives - Holbrook's spadefoot, plains and lamb's toads, North American and Dakota toads from North America. But the dark-sided narrowmouth is quite content with the deciduous carpets of tropical forests.
This family is unusual in that the father takes care of the offspring. After the female has laid eggs, he fertilizes them and... sends them into his mouth. There, future children are safe, the throat pouch is not only protection, but also additional nutrition from the father’s circulatory system. This does not interfere with eating, the eggs “grow together” with the walls of the sac, and you cannot accidentally swallow them. As soon as the babies are formed, they leave the incubator mouth.
The Surinamese pipa has an equally interesting way of caring for its offspring. Here the mother becomes the main one. After the male fertilizes the eggs in the water, she dives under them and catches them on her back. The father actively helps, pressing them on the mother's back with his paws. After this, the female grows a special skin film that covers the incubator. Once the baby frogs are fully formed, they break through the skin and climb out. After this, the mother’s back resembles... an empty egg cage, covered in cells.
Frogs and their varieties live not only in North and South America. They are distributed all over the world. The diversity of these amphibians makes it possible to organize real competitions in different categories. Let's find out who is the best among them.
This category presents those beauties whose poison can lead to instant or long and painful death. By the way, in some cases there is simply no antidote. So, who should not be touched, but can only be admired:
These frog leaders are so formidable.
Unfortunately, man, through his activities and activity in the development of wild nature, has caused a lot of harm. Some amphibians are almost never seen. The rarest are:
In each family you can find its own unique one. The “unusual” category includes frogs:
Here they are, amazing and unusual representatives of amphibians, living in different parts of the world. Charming, aren't they?
We continue to publish for you a review of episodes of the TV game “Who Wants to Be a Millionaire”. Today in the studio, father and daughter: Yuri Fedorovich Malikov and the talented, stunning, beautiful singer Inna Malikova. The Malikov family chose 200,000 as a fireproof amount. So here we go.
1. What do children leave when they play outside in winter? Option A: Snowball.
2. On what does the peasant renew his path in Pushkin’s poems? Option B: on firewood.
3. What did Cheburashka sing about himself: “I was once a strange toy...”? Option D: unnamed.
4. What is the common name for a driver's license? Option B: certificate.
5. What dance is the plot of the film “Winter Evening in Gagra” built around? Option C: Step.
6. On the territory of which countries is the Belovezhskaya Pushcha Nature Reserve located? Option C: Belarus and Poland.
7. What color are the most difficult ski slopes marked in Russia and Europe? Option D: black
8. What was the sail made of in the song “The Glorious Sea - Sacred Baikal”? Option: from a caftan. The Malikov family did not know the answer to this question. Therefore, they could not do without a hint; they took the “Right to Error”. They took “Overcoat” as their first option, but it turned out to be wrong. Then they took the second option “Kaftan”.
9. In what year was construction completed on the Sagrada Familia in Barcelona? Option D: It's not over yet. It was difficult for the Malikovs to answer this question and they decided to call family friend Anatoly. Anatoly said that he was recently in Barcelona and saw this cathedral; construction has not yet been completed.
10. What number of points in tennis is called the word “Love”? Option A: A. They wanted to call one more person, but the tip had already been used. They can no longer call anyone. Then it was decided to take the clue “help from the audience.” Viewers voted for option D - 40%. Inna decided to agree with the audience and choose option D, but the presenter stopped her and advised her to use another hint. Option D gone.
11. Which member of the Beatles received the middle name Winston at birth? Option A: John Lennon. Although Inna asked a question about music, she did not know the answer to this question. The players decided to go with John Lennon.
12. What happens to the tadpole of the American wonder frog as it grows into an adult animal? Option: shrinks in size. The Malikov family decided to take the money. Option: Inna decided to choose option D: changes gender. They found the question very interesting.
The guests' winnings amounted to 200,000 rubles. And now in the players’ chairs are the famous writer Semyon Altov and the super famous singer and guitarist Valery Syutkin.
1. What was the name of one of Dunno’s friends? Option D: Avoska.
2. Which horse is considered a symbol of poetic inspiration? Option A: Pegasus.
3. What do sailors do with mooring lines when leaving the pier? Option C: They give it away.
4. What is the name for the compiler of a perfume in France? Option C: “Nose.”
5. Where, according to Vladimir Mayakovsky, does the earth begin? Option D: From the Kremlin
6. Which Latin letter gave the English name to the clothing we call a T-shirt? Option D: T
7. How many times is a billion more than a thousand? Option D: a million times. To answer correctly, players had to remember math.
Wood frog tadpoles are not born knowing which predators they should be afraid of and must learn this throughout their lives. Tadpoles that have been taught to fear one of the predators (the fire-bellied newt) also begin to fear other amphibians, which can be interpreted as a kind of “ability to generalize.” Moreover, the stronger the fear of newts, the wider the range of potential predators that causes a characteristic fear reaction in tadpoles.
Some animals have an innate knowledge of which predators they need to watch out for. Others are born without this knowledge and must acquire it throughout their lives. It would seem that the first option is much more reliable and safer. However, this is only true for those species of prey that live in more or less constant conditions and are threatened by the same predators from generation to generation. If the environment of a given prey species changes frequently in unpredictable ways, developing an innate fear of certain types of predators may be less beneficial than a general ability to learn—even though such learning carries enormous risks.
Many species of frogs lay their eggs in a variety of bodies of water, from small, ephemeral puddles to large lakes. In different bodies of water, tadpoles are threatened by different predators. Tadpoles react to danger by reducing their motor activity: they freeze or simply begin to swim more slowly in order to attract less attention to themselves. If a tadpole is afraid of all predators indiscriminately - including those that do not feed on tadpoles in a given reservoir - it will freeze all the time and will have less time to search for food. In such a situation, an innate fear of all types of potential enemies would be more harmful than beneficial for the tadpoles. The behavior of tadpoles (and other prey animals) must maintain a delicate balance between the magnitude of the danger and the intensity of the reaction to it. If the degree of danger posed by the same predator species varies greatly depending on conditions, lifetime learning becomes a more optimal strategy than the development of innate fear.
Little is known yet about the specific mechanisms underlying prey learning to fear predators. Of the established facts, two are the most interesting. Firstly, it has been shown that such learning occurs very quickly - usually a predator only needs to scare the prey once for it to develop a stable fear of this type of predator. In some cases, one can assume the existence of certain innate psychological “blanks” or matrices, that is, an innate predisposition to quickly develop fear of certain types of stimuli. Secondly, the phenomenon of generalization (generalization) in recognizing predators was discovered. This means that animals that have learned to fear a particular predator (in an experiment, a doll can act as a predator) often begin to experience fear also of other objects that are similar to the predator they know in appearance or smell.
In an article by Canadian biologists published on the journal’s website Behavioral Ecology and Sociobiology, interesting experiments are described in which for the first time the ability to “generalize the image of a predator” was demonstrated in the larvae of tailless amphibians.
The authors mention only three earlier studies that examined this phenomenon. If they haven't missed anything, their work is the fourth in the field. The first study was carried out on wallabies Macropus eugenii. It turned out that wallabies are not naturally afraid of foxes, cats, or goats. If you teach a wallaby to be afraid of foxes, then they automatically begin to be afraid of cats (but not goats). Another study found that wild black-tailed deer Odocoileus hemionus columbianus They are afraid not only of pumas, which pose a real threat to them in nature, but also of jaguars, which they never meet. These experiments did not use live predators, but their models, that is, they were talking about recognizing a predator only by its appearance, and not by smell or behavior.
The third study was conducted by the authors of the article discussed in 2007-2008. on a fish Pimephales promelas(black fathead, see fathead minnow). The fish were trained to fear the smell of a species of trout. It turned out that generalization of the image of a predator occurs only if a very high degree of risk is associated with this predator. If the fish perceives this type of trout as moderately dangerous, then the smell of other types of trout does not frighten it. If the fish were made to understand that this trout was extremely dangerous, then they also began to be afraid of the smell of other trout (but not pikes or chukuchans).
In a new experiment, tadpoles of the American wood frog were chosen as the object. Rana sylvatica(see wood frog). In their previous works, the authors showed that these tadpoles do not have an innate fear of tailed amphibians (newts, salamanders), which are their natural enemies.
The wood frog eggs were placed in a large aquarium with clean water, where there were all the necessary conditions for the development of tadpoles, but there were no predators (the authors took all possible measures to ensure that there was no smell of predators there). When the tadpoles hatched and reached two weeks of age, the researchers divided them into three groups and began training. The training was carried out as follows.
Each tadpole was placed in a separate half-liter jar and allowed to get used to the new environment. Then 10 ml of water with the smell of fire-bellied newt was added to the jar Cynops pyrrhogaster. It was water from a two-liter container in which six newts lived for 24 hours. At the same time, another 5 ml of water with the “smell of danger” was added to the jar. The recipe for preparing this potion is reminiscent of the methods of medieval witches or alchemists: one tadpole was ground in a small mortar, the resulting pulp was diluted with water in an amount of 5 or 20 ml, the water was then carefully filtered to remove tissue fragments. The smell of a crushed tadpole is an unconditional frightening stimulus, that is, tadpoles from birth know that this smell signals danger.
Tadpoles from the first group received the “smell of danger” in a high concentration (1 crushed tadpole per 5 ml of water), the second group received a four times smaller dose. Finally, the tadpoles of the third (control) group received 5 ml of clean water.
The idea was that the tadpoles from the first group would associate the smell of a newt with the idea of very great danger. The second group also had to learn to be afraid of newts, but not so much. Finally, the third group had no fear of newts at all.
The reaction of tadpoles to frightening stimuli, as already mentioned, is to slow down their movements. The authors measured the strength of this reaction as follows. A straight line was drawn on the bottom of each jar, dividing the jar in half. For four minutes before adding the scented water, the researchers counted how many times the tadpole crossed the line. If he did this less than six times in four minutes, he was excluded from the experiment. Then odors were added to the water and the number of crossings was counted again for four minutes. The ratio of the number of crossings before and after the addition of odors was used as a measure of fear.
As one would expect, during the training process, tadpoles from the first group were very afraid, those from the second group were weakly afraid, and the control group, which received only the smell of a newt, was not afraid at all.
Three days later, all tadpoles changed the water and began the main stage of the experiment. Each of the three groups of tadpoles was divided into three more parts. The first part was given the smell of a newt, the second - the smell of a tiger salamander, which is a fairly close relative of the newt, the third - the smell of an African clawed frog, which belongs to another order of amphibians.
Of these three species of potential predators, wood frogs can only encounter the tiger salamander in nature.
Tadpoles from the control group, which had not developed a fear of newts, were not afraid of any of the three odors. Tadpoles that had developed a strong fear of newts were frightened by all three smells. What frightened them most was the smell of newt, which was used during “training”. The smell of the salamander, a close relative of the newt, frightened them a little less, and the smell of the clawed frog - even less. Finally, the tadpoles, which had developed only a moderate fear of the newt, were frightened by the smells of the newt and the salamander, but remained indifferent to the smell of the clawed frog.
Thus, in tadpoles, as in fish, the degree of “generalization of the predator image” depends on the magnitude of the danger that is associated with a known predator. The greater the danger posed by a known predator, the broader the “generalizations” the prey makes. As they say, when you get burned by milk, you blow on water. A similar phenomenon was previously discovered in birds, although in that case it was not a question of recognition by prey of predators, but of differentiation between poisonous and non-poisonous prey by predators (see: Unusual camouflage in frogs is associated with the ability of predators to generalize, “Elements”, 03.13.2006 ).
The “ability to generalize” discovered in tadpoles does not mean that tadpoles have any particularly outstanding intelligence. Conditioned reflexes, that is, reactions to certain stimuli developed throughout life, are always “generalized” to one degree or another. In other words, if a reflex has been developed to a specific stimulus, then another, but very similar stimulus will most likely cause the same reaction. Moreover, the more different the stimulus is from the “learned” one, the weaker the reaction will be. This property of conditioned reflexes, which is determined by the basic principles of sensory perception and the functioning of the nervous system, is, in principle, quite sufficient to explain both the phenomenon of “generalization of the image of a predator” and its dependence on the magnitude of the danger.
