These amazing whales and dolphins. Order: Cetacea = Cetaceans Whales are excellent swimmers

Latest genetic research dolphins allow us to assert that the ancestors of animals are ungulates. These are their closest relatives. The answer to the question about how many chromosomes do dolphins have, suggests a hypothesis about the primary habitat of these mammals on land.

How many chromosomes do dolphins have

Chromosomes are special structure that makes up DNA. It is located in the nucleus of the cell of the body. The task of the chromosome is to store information about the structure of the body, its individual characteristics and gender. The dolphin has 44 chromosomes. Since they are located in cells in double quantity, there are 22 pairs in total. A certain set of chromosomes establishes the karyotype of any representative of the animal or plant world.

The number of chromosomes in other inhabitants of the sea:

1. Penguin - 46.
2. Blue whale - 44.
3. Sea urchin - 42.
4. Shark - 36.
5. Seal - 34.

Dolphins belong to the species of cetaceans, subspecies - toothed whales (dolphins, sperm whales, killer whales). In total, there are about 50 species of dolphins. They mostly live in sea water, but there are a few varieties that live in large rivers. Dolphins, like terrestrial animals, warm-blooded, viviparous, feed their young with their milk. They breathe with lungs, for this they emerge from the water several times during the day. A dolphin is completely different from a shark. The sea predator belongs to the class of fish, as it has gills, and its offspring do not feed on milk. Sharks don't have milk.

genetic research

Dolphins communicate with us

The existing theory about the origin of humans from monkeys has become less convincing after recent studies of dolphin chromosomes. As it turned out, humans and dolphins have a striking similarity in chromosome structures. Among other organisms living on earth, the dolphin was closest to the artiodactyls and the hippopotamus. Many similarities have been found with elephants. Human, dolphin and elephant are distinguished by the proportional volume of the brain relative to the body. Special structure nervous system determines a significant number of synapses (nerve connections) and cerebral convolutions. These properties allow dolphins to learn quickly.

Dolphins have more high intelligence than a monkey. Marine life they recognize themselves in the mirror, understand the intonation of human speech, know how to imitate and strictly follow the rules that have developed in the pack. Cetaceans communicate using low-frequency sounds. Sea water contains magnesium sulfate, which absorbs high frequency noise. Therefore, the inhabitants of the sea have learned to use sounds that can propagate in the water over long distances.

The human genes responsible for sleep are simply mutated in dolphins. Therefore, these mammals sleep in a special way. In the process of research, scientists have discovered DNA that is responsible for the wakefulness of one half of the brain while the other is sleeping. This happened in the process of mutation. Scientists have concluded that after humans, dolphins have the highest intelligence on the planet.

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Order: Cetacea Brisson, 1762 = Cetaceans

The organs of hearing are greatly modified. The auricle is reduced. The external auditory meatus opens behind the eye with a small opening. An interesting opinion is that the rudimentary auditory meatus can serve as an independent sensory organ that perceives changes in pressure. The eardrum curves outward (baleen whales) or inward (toothed whales). From the outside, the eardrum of baleen whales is covered with a kind of ear plug, consisting of keratinized epithelium and earwax. Cetaceans are capable of capturing a wide range sound waves from 150 to 120-140 thousand Hz (Slijper, 1962), i.e. even ultrasonic vibrations. High degree the development of the auditory parts of the brain of toothed whales indicates a special acuteness of their hearing, almost unique among mammals; baleen whales have poorer hearing compared to land mammals. Cetaceans are capable of echolocation, as are the bats. Due to the fact that vocal cords cetaceans are absent, they cannot make sounds in the usual way for mammals. It is possible that the sounds are produced by the vibration of the lower part of the septum between the nasal sacs, or by the vibration of the fold of the external valve as a result of the passage of air from the dorsal nasal sacs. Dolphins are capable of emitting series of short sound pulses, the duration of which is 1 ms, and the repetition rate varies from 1-2 to several hundred hertz.

The body temperature of cetaceans is similar to that land mammals and ranges from 35 to 40°C (the upper limit was noted in injured whales or dolphins caught after chasing). Preservation high temperature bodies in water, which conducts heat many times better than air, is carried out by a thick layer of subcutaneous fatty tissue in the skin.

In female baleen whales, the genital and anal openings are separated from each other by a considerable space, while in toothed whales they are located in a single depression and are surrounded by a common sphincter. Males are constantly or very long during the year capable of fertilization. It has been suggested that ovulation in cetaceans is provoked by sexual intercourse. In females, at the beginning of pregnancy, two or three embryos may be in the uterus, of which only one soon remains. Diffuse placenta.

Childbirth takes place under water. The cub is born fully developed, capable of independent movement. The proportions of its body are very similar to the proportions of the body of adult whales, and the dimensions reach 1/2-1/4 of the body length of the mother. Females of some cetaceans can be fertilized shortly after giving birth during the lactation period. Feeding of the cubs is done under water, the duration of each meal is a few seconds. Milk is splashed into oral cavity cub by contraction of special muscles of the female. The mammary glands of the female are located on the sides of the genital opening. Two nipples (one on each side) lie in slit-like folds and protrude only during lactation. The female whales produce different quantity milk per day: from 200-1200 g in dolphins to 90-150 liters in fin whales and 200 liters in blue whale(Sleptsov, 1955). The milk is thick and usually cream-colored. It is characteristic that its surface tension is 30 times greater than that of water, which is especially important, since the stream of milk does not blur in water. Nutrition whale milk quite high.

The growth of cubs during feeding them with milk occurs quickly. For example, a blue whale calf grows from 7 to 16 m in 7 months of life, i.e., the average daily increase in length is 4.5 cm.

Sexual dimorphism is manifested mainly in the different body lengths of males and females. Female baleen whales are larger than males, while most toothed whales, on the contrary, are smaller. The diploid number of chromosomes in tweeds of toothed whales and 4 species of baleen (sei whale, minke whale, fin whale and gray whale) is 44, and in sperm whales - 42.

Widespread in all oceans and most seas globe. Factors that determine the distribution of cetaceans are food availability and water temperature. Some species are widespread and are found in both warm and cold seas (some species from the dolphin family), others have a smaller range (gray whales live in subtropical, temperate and cold waters of the northern half of Pacific Ocean and in the Chukchi Sea), the range of the third is even more limited (narwhal does not leave the waters of the Arctic), and finally, the range of river, lake and estuarine forms is quite insignificant.

Most species are herd animals; They live in groups from a few heads to hundreds and thousands of individuals. They are found both near the coasts and in the open sea. Representatives of some species are able to climb up major rivers flowing into the sea, and certain types constantly live in rivers. Most whales have a specialized diet, and among them there are planktophages, teutophages, ichthyophages and sacrophages. They feed on mass or piece prey. Among cetaceans, there are fast swimmers (killer whales, many dolphins) and relatively slow moving ones (gray whales). Most whales are constantly kept in surface waters. Some, such as sperm whales, can dive to considerable depths. population various kinds cetaceans is not the same. Many of them are very numerous and can be found in herds of thousands (dolphin-dolphin), others, on the contrary, are very rare and meetings with them have been noted only a few times (some representatives of the genus of belt-toothed, pygmy sperm whale).

Excessive fishing has a detrimental effect on the number of whales, significantly reducing it, and in some cases may threaten the complete destruction of these animals. Thus, the currently negligible number of bowhead whales is a consequence of the predatory killing of these once numerous animals.

Most species are characterized by periodic migrations. In some species, the length of migration routes is relatively small (Azov Black Sea porpoise - from Sea of ​​Azov to Black and back); others are huge (some large whales - from tropical waters to high latitudes).

Cetaceans are predominantly monogamous. Mating periods and puppies are usually extended in time. They give birth to one, rarely two cubs. Strongly developed maternal instinct.

Enemies, except for a man and a killer whale, practically do not have. The remains of dolphins have been found in the stomachs of tiger and Greenland sharks.

Practical value in the recent past was quite large. Some of the cetaceans are still harvested annually in large quantities(sperm whales), others hunt only by chance. Almost all whale organs are used to produce valuable food and technical products. Fishing for cetaceans can only be carried out with strict observance of the measures necessary to maintain their numbers. At present, in order to preserve cetaceans, it is advisable to stop their fishing for a number of years.

From school textbooks on biology, everyone had a chance to get acquainted with the term chromosome. The concept was proposed by Waldeyer in 1888. It literally translates as a painted body. The first object of research was the fruit fly.

General about animal chromosomes

The chromosome is the structure of the cell nucleus that stores hereditary information. They are formed from a DNA molecule, which contains many genes. In other words, a chromosome is a DNA molecule. Its quantity in different animals is not the same. So, for example, a cat has 38, and a cow has -120. Interestingly, the smallest number earthworms and ants. Their number is two chromosomes, and the male of the latter has one.

In higher animals, as well as in humans, the last pair is represented by XY sex chromosomes in males and XX in females. It should be noted that the number of these molecules for all animals is constant, but for each species their number is different. For example, consider the content of chromosomes in some organisms: chimpanzees - 48, crayfish -196, wolves - 78, hare - 48. This is due to different levels organization of an animal.

On a note! Chromosomes are always arranged in pairs. Geneticists claim that these molecules are the elusive and invisible carriers of heredity. Each chromosome contains many genes. Some believe that the more of these molecules, the more developed the animal, and its body is more complex. In this case, a person should not have 46 chromosomes, but more than any other animal.

How many chromosomes do different animals have

Need to pay attention! In monkeys, the number of chromosomes is close to that of humans. But each type has different results. So, different monkeys have the following number of chromosomes:

• Lemurs have 44-46 DNA molecules in their arsenal;
• Chimpanzees - 48;
• Baboons - 42,
• Monkeys - 54;
• Gibbons - 44;
• Gorillas - 48;
• Orangutan - 48;
• Macaques - 42.

In the canine family ( predatory mammals) have more chromosomes than monkeys.

• So, the wolf has 78,
• coyote - 78,
• in a small fox - 76,
• but the ordinary one has 34.
• The predatory animals of the lion and tiger each have 38 chromosomes.
• The cat's pet has 38, and its dog opponent has nearly twice as many, 78.

In mammals that have economic importance, the number of these molecules is as follows:

• rabbit - 44,
• cow - 60,
• horse - 64,
• pig - 38.

Informative! The biggest chromosome sets among animals possess hamsters. They have 92 in their arsenal. Also in this row are hedgehogs. They have 88-90 chromosomes. And the smallest number of these molecules are endowed with kangaroos. Their number is 12. A very interesting fact is that the mammoth has 58 chromosomes. Samples are taken from frozen tissue.

For greater clarity and convenience, the data of other animals will be presented in the summary.

The name of the animal and the number of chromosomes:

The number of chromosomes in different types animals

As you can see, each animal has different amount chromosomes. Even among members of the same family, the indicators differ. Consider the example of primates:

• gorilla has 48,
• the macaque has 42, and the monkey has 54 chromosomes.

Why this is so remains a mystery.

How many chromosomes do plants have?

Plant name and number of chromosomes:

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How many chromosomes does a dolphin have you will learn from this article.

How many chromosomes does a dolphin have?

At common dolphin kind " Delphinus delphis", as well as in freshwater Amazonian dolphin species "Inia geoffrensis" in the cell of the body is 44 chromosomes, that is 22 pairs.

Dolphins are mammals, despite their relative small view, and to the order of cetaceans. They are related to killer whales and whales. There are about 50 species in total. Common features all dolphins - a flexible, streamlined body, modified limbs-fins, a small pointed head, dorsal. Interestingly, these mammals do not see well, they lack charm and vibrissae. Instead of a nose, dolphins have nostrils that have merged into a breathing hole on the parietal part of the head. Also, animals do not have ears. But they have excellent echolocation.

Chromosomes are the genetic material found in a cell of an organism. Each of them contains a DNA molecule in a twisted helix. The complete set of chromosomes is called a karyotype. Each chromosome is a complex of proteins and DNA. And all types of living organisms have their own, permanent and different from the rest of the chromosome species set.