Rudiments- organs that were well developed in ancient evolutionary ancestors, and now they are underdeveloped, but have not completely disappeared yet, because evolution is very slow. For example, a whale has pelvic bones. In a person:
- body hair,
- third eyelid,
- coccyx,
- muscle that moves auricle,
- appendix and caecum,
- wisdom teeth.
atavisms- organs that should be in a rudimentary state, but due to developmental disorders have reached a large size. A person has a hairy face, a soft tail, the ability to move the auricle, and multiple nipples. Differences between atavisms and rudiments: atavisms are deformities, and everyone has rudiments.
Homologous Organs- outwardly differ, because they are adapted to different conditions, but have a similar internal structure, since they arose from one source organ in the process divergences. (Divergence is the process of divergence of signs.) Example: bat wings, human hand, whale flipper.
Similar bodies- outwardly similar, because they are adapted to the same conditions, but have a different structure, because they arose from different organs in the process convergence. Example: the eye of a human and an octopus, the wing of a butterfly and a bird.
Convergence is the process of convergence of characteristics in organisms that have fallen into the same conditions. Examples:
- aquatic animals of different classes (sharks, ichthyosaurs, dolphins) have a similar body shape;
- fast running vertebrates have few fingers (horse, ostrich).
Choose one, the most correct option. The development of a small number of fingers in the limbs of the horse and ostrich is an example
1) convergence
2) morphophysiological progress
3) geographic isolation
4) environmental isolation
Answer
Choose one, the most correct option. An example of a vestigial organ in humans is
1) caecum
2) multiple nipples
3) gill slits in the embryo
4) scalp
Answer
Choose one, the most correct option. As a result of what evolutionary process did aquatic animals of different classes (sharks, ichthyosaurs, dolphins) acquire a similar body shape
1) divergences
2) convergence
3) aromorphosis
4) degeneration
Answer
Choose one, the most correct option. Which pair of aquatic vertebrates supports the possibility of evolution based on convergent similarity?
1) blue whale and sperm whale
2) blue shark and bottlenose dolphin
3) fur seal and sea lion
4) European sturgeon and beluga
Answer
Choose one, the most correct option. The development of limbs of different structures in mammals belonging to different orders is an example
1) aromorphosis
2) idioadaptation
3) regeneration
4) convergence
Answer
Choose one, the most correct option. What sign of a person is considered atavism?
1) grasping reflex
2) the presence of an appendix in the intestine
3) abundant hairline
4) six-fingered limb
Answer
RUDIMENTS
Choose three correct answers from six and write down the numbers under which they are indicated. The rudiments are
1) human ear muscles
2) whale's hind limb belt
3) underdeveloped hairline on the human body
4) gills in terrestrial vertebrate embryos
5) multiple nipples in humans
6) elongated fangs in predators
Answer
RUDIMENTS - ATAVISMS
1. Establish a correspondence between an example and a sign: 1) rudiment, 2) atavism. Write down the numbers 1 and 2 in the order corresponding to the letters.
A) wisdom teeth
B) multi-nipple
B) muscles that move the ear
D) tail
D) strongly developed fangs
Answer
2. Establish a correspondence between the evolutionary characteristics of a person and their examples: 1) rudiment, 2) atavism. Write down the numbers 1 and 2 in the order corresponding to the letters.
A) muscles of the ear
B) tail vertebrae
B) facial hair
D) outer tail
D) appendix of the caecum
Answer
3. Establish a correspondence between the structural features of the human body and comparative anatomical evidence of its evolution: 1) atavisms, 2) rudiments. Write down the numbers 1 and 2 in the order corresponding to the letters.
A) folds of the nictitating membrane
B) additional pairs of mammary glands
B) full body hair
D) underdeveloped ear muscles
D) appendix
E) caudal appendage
Answer
4. Establish a correspondence between the structures of the human body and evidence of evolution: 1) rudiment, 2 atavism. Write down the numbers 1 and 2 in the order corresponding to the letters.
A) ear muscles
B) appendix
B) coccygeal vertebrae
D) thick hairline all over the body
D) multi-nipple
E) the remainder of the third century
Answer
COLLECT 5:
A) coccyx
SIMILAR
Choose three correct answers from six and write down the numbers under which they are indicated. An example of similar bodies is
1) human hand and butterfly wing
2) hawthorn spines and barberry spines
3) trapping sundew leaves and barberry spines
4) butterfly wing and bird wing
5) kidney scales and tendrils of peas
6) tendrils of peas and tendrils of grapes
Answer
HOMOLOGICAL - SIMILAR FEATURES
Establish a correspondence between the characteristics of organs and comparative anatomical evidence of evolution: 1) homologous organs, 2) similar organs. Write down the numbers 1 and 2 in the order corresponding to the letters.
A) lack of genetic relationship
B) performing various functions
C) a single plan for the structure of five-fingered limbs
D) development from identical embryonic rudiments
D) formation in similar conditions
Answer
HOMOLOGUE - SIMILAR EXAMPLES
1. Establish a correspondence between the example and the type of organs: 1) Homologous organs 2) Similar organs. Write the numbers 1 and 2 in the correct order.
A) The forearm of a frog and a chicken
B) Mouse legs and bat wings
C) Sparrow wings and locust wings
D) whale fins and crayfish fins
D) Burrowing limbs of a mole and a bear
E) Human hair and dog hair
Answer
2. Establish a correspondence between the forms of adaptation of organisms to the environment and the organs that they have formed: 1) homologous, 2) similar. Write down the numbers 1 and 2 in the order corresponding to the letters.
A) the streamlined shape of the head of a shark and a dolphin
B) owl wing and bat wing
C) the limb of a horse and the limb of a mole
D) human eye and octopus eye
E) carp fins and fur seal flippers
Answer
3. Establish a correspondence between the example and the type of comparative anatomical evidence of evolution: 1) homologous organs, 2) similar organs. Write down the numbers 1 and 2 in the order corresponding to the letters.
A) walking limbs of crayfish and pseudopods of caterpillars
B) lizard scales and bird feather
C) the eyes of an octopus and a dog
D) bird and dragonfly wings
D) butterfly and beetle legs
E) cat claws and monkey nails
Answer
DIVERGENCE - CONVERGENCE
1. Establish a correspondence between an example of an evolutionary process and the ways in which it is achieved: 1) convergence, 2) divergence. Write the numbers 1 and 2 in the correct order.
A) the forelimbs of a cat and upper limbs chimpanzee
B) the wing of a bird and the flippers of a seal
C) octopus tentacle and human hand
D) penguin wing and shark fins
D) different types mouthparts in insects
E) butterfly wing and bat wing
Answer
2. Establish a correspondence between the example and the process of macroevolution that it illustrates: 1) divergence, 2) convergence. Write down the numbers 1 and 2 in the order corresponding to the letters.
A) the presence of wings in birds and butterflies
B) coat color in gray and black rats
B) gill breathing in fish and crayfish
G) different shape beaks of great and crested tits
D) the presence of burrowing limbs in a mole and a bear
E) streamlined body shape in fish and dolphins
Answer
3. Establish a correspondence between animal organs and evolutionary processes, as a result of which these organs were formed: 1) divergence, 2) convergence. Write down the numbers 1 and 2 in the order corresponding to the letters.
A) the limbs of a bee and a grasshopper
B) dolphin flippers and penguin flippers
C) bird and butterfly wings
D) the forelimbs of the mole and the insect of the bear
D) the limbs of a hare and a cat
E) squid and dog eyes
Answer
4. Establish a correspondence between the organs of animals and the evolutionary processes as a result of which these organs were formed: 1) convergence, 2) divergence. Write down the numbers 1 and 2 in the order corresponding to the letters.
A) limbs of a mole and a hare
B) butterfly and bird wings
c) eagle and penguin wings
D) human nails and tiger claws
D) crab and fish gills
Answer
5. Establish a correspondence between the signs of organisms and the form of evolution, as a result of which this sign was formed: 1) divergent, 2) convergent. Write down the numbers 1 and 2 in the order corresponding to the letters.
A) the structure of the teeth of a tiger and a beaver
B) butterfly and swallow wings
C) the limbs of a dolphin and a horse
D) streamlined body shape in sharks and ichthyosaurs
D) tendrils of grapes and tendrils of peas
E) dragonfly and bee wings
Answer
Look at the drawing of wings in different animals and determine: (A) what evolutionists call these organs, (B) to what group of evolutionary evidence these organs belong, and (C) by what mechanism of evolution they were formed.
1) homologous
2) embryological
3) convergence
4) divergence
5) comparative anatomical
6) similar
7) driving
8) paleontological
Answer
Consider the drawing depicting the inhabitants of the waters of different classes of vertebrates and determine (A) what kind of evolutionary process the drawing illustrates, (B) under what conditions this process takes place, and (C) what results it leads to. For each lettered cell, select the appropriate term from the list provided. Write down the chosen numbers, in the order corresponding to the letters.
1) homologous organs
2) convergence
3) occurs in related groups of organisms that live and develop in heterogeneous environmental conditions
4) vestigial organs
5) occurs in the same conditions of existence of animals belonging to different systematic groups that acquire similar structural features
6) similar bodies
7) divergence
Answer
Choose two correct answers from five and write down the numbers under which they are indicated. Evolutionary terms include
1) divergence
2) monitoring
3) natural selection
4) plasmid
5) panspermia
Answer
Read the text. Choose three sentences that indicate comparative anatomical methods for studying evolution. Write down the numbers under which they are indicated in the table. (1) Similar organs testify to the similarity of adaptations to the same environmental conditions in different organisms that arise in the course of evolution. (2) An example of homologous organs are the forelimbs of a whale, a mole, a horse. (3) Rudiments are laid in embryogenesis, but do not fully develop. (4) Embryos of different vertebrates within a phylum have a similar structure. (5) Phylogenetic series for elephants and rhinos have been compiled.
Answer
© D.V. Pozdnyakov, 2009-2019
Atavisms and rudiments in humans are considered as one of the arguments of evolutionary theory. Body parts that formed from ancestors modern people under pressure environment but are now obsolete. Organs that have lost their original significance in the process of human evolution are called rudimentary. , which were characteristic of distant ancestors, but were absent from relatives, is called atavism.
List of main rudiments:
- ear muscles;
- wisdom teeth;
- coccyx;
- appendix;
- pyramidal muscle;
- epicanthus.
Rudiments of modern man
The appendix is the remnant of an organ that, in the ancestors of humans, had digestive functions. Now the appendix can protect against the loss of symbiotic bacteria that help the body's digestion. However, he probably possessed this function in the ancestors of man.
The auricular muscles are the temporoparietal, anterior and posterior muscles. They allow you to move the auricle in different directions. Modern man does without moving his ears, but in some representatives of the homosapiens species this ability is clearly expressed.
In modern monkeys, especially macaques, the ear muscles are much better developed. This is because primates use them to be alerted to danger. But the ear muscles of chimpanzees and orangutans, like those of humans, became minimally developed and non-functional, but did not completely disappear.
Wisdom teeth are designed to chew tough and hard foods. plant origin. It is believed that the ancestors of people had more powerful jaws, which gave them the ability to chew on foliage. Thorough chewing compensated for the inability to digest the cellulose that was part of the plant food. Changes in the structure of nutrition led to the fact that naturally less strong jaws were formed. But the wisdom teeth survived. In a new generation of people, wisdom teeth began to erupt less often, which confirms the evolutionary theory of rudiments. Due to the uselessness and even harmfulness of these parts of the body, there is the possibility of surgical removal of wisdom teeth.
It is interesting that different peoples the development of wisdom teeth is not the same. The Tasmanians retained powerful jaws and well-developed wisdom teeth. In Mexico, on the contrary, they almost do not grow.
The coccyx is the remnant of a vestigial tail, which in different periods development had all mammals. During prenatal development, a human fetus has a tail for about four weeks. It is most noticeable in embryos that are between 31 and 35 days old. The tail bone, located at the end of the spine, has lost its importance in promoting balance and mobility. Now the coccyx retains its value as an attachment point for muscles, tendons and ligaments. Sometimes a birth defect causes a person to have a short tail at birth.
Since 1884, 23 babies have been born with a tail. In all other respects, these children were normal. All of them had their tails surgically removed, and these children continued their normal human lives.
In the inner corner of the eye there is a small fold, lunate. It is a remnant of the nictitating membrane, a translucent or transparent third eyelid that allows some animal species to moisten the eye without losing visibility. In cats, seals, polar bears and camels, the nictitating membrane is completely preserved. Other mammals have only its rudiments.
Atavisms of modern people
A person in the months of his prenatal development partially goes through the evolutionary path of his ancestors. It is known that human embryos in different weeks of existence resemble the evolutionary ancestors of humans. In some cases, atavistic signs may persist in a born child.
Some genes that have disappeared phenotypically may not disappear from human DNA. They remain dormant for generations. The lack of genetic control can lead to the revival of dormant genes in an individual. It can also be caused by external stimulation.
One of the most striking examples of atavism is hairline. The common ancestors of humans and monkeys had bodies covered with thick hair. And today it happens that the hairline of a person covers his entire body, leaving only the palms and soles of his feet smooth. It happens that both men and women have an extra pair of nipples - this is also a legacy of distant ancestors.
Sometimes microcephaly (a small head with normal proportions of the rest of the body) is also considered an atavism. Usually this pathology is accompanied by a lack of mental abilities of a person. Atavisms also include the cleft lip, an anomaly of human development, which they are trying to eliminate surgically.
Some human reflexes are also referred to as atavisms. Hiccups are a legacy of amphibian ancestors. She helped pass water through the gill slits. Newborns have a grasping reflex. It is considered an atavism that humans received from primate ancestors. So baby monkeys grabbed the wool of their mothers.
Atavisms and rudiments have partially changed, partially acquired a new meaning. It can be observed that some rudiments die off among peoples in whose environment they become unnecessary, but are preserved in others where these parts of the body have not become rudimentary.
Many people are not even aware that they have a third eyelid. It is located in the inner corner of the eye and looks like a thickening of the mucous membrane. This part of the eye is a remnant of the nictitating membrane, which has changed in the course of evolution. Such a membrane is still present in some animals, birds and fish. This includes cats, chickens, lizards and sharks. Many experts consider the third eyelid in humans to be a useless organ, since it does not perform any important functions.
What it is
The third eyelid is located in the inner corner of the eyes. In humans, this is a poorly developed rudimentary organ, but in some animals such a fold is well developed. In cats and chickens, you can see a translucent nictitating membrane that performs a protective function. It protects the eyes of birds from small debris in flight. A crocodile needs such a film to see well in the water.
This film protects the eyes well and helps to moisturize the mucosa. At the same time, the quality of vision is preserved.
It is noteworthy that the human embryo has rudiments of the nictitating membrane, but as the fetus develops, this part of the eye atrophies.
Why does a person need
In humans, the vestigial nictitating membrane is called the crescentic fold. Such a rudiment looks like a vertical fold, consisting of mucous tissue. It is located in the inner corner of the eye and has a very small size.
Such a fold is quite well developed among representatives of the Negroid race and Malays. In them, such a fold can even include special cartilage, like the upper and lower eyelids.
Such a fold produces a mucous secretion that moisturizes the eye and protects the mucous membrane from debris. After that, the mucus, along with the smallest debris, moves into the lacrimal canal and is excreted along with the lacrimal fluid through the nasopharynx.
Not far from the semilunar fold is the so-called lacrimal meat. Thanks to this part of the rudiment, a person can cry. If this part of the visual organs becomes inflamed, then there are problems with the removal of tear fluid.
Functions in animals
The third eyelid in animals plays a protective role. It promotes high-quality hydration of the mucous membrane and helps to remove small debris that gets into the eyes during the day.
For waterfowl and birds, such a membrane helps to see well under water, acting like goggles for swimming. In birds, the nictitating membrane protects the eyes from debris during flight. You can also see the third eyelid in cats, in these animals it is especially well developed. To see how the membrane functions, it is enough to slightly open the cat's eyes during sleep. The eyeball will be, as it were, covered with a dense film.
It is not known for what reason human body lost this function in the course of evolution. Scientists suggest that a few centuries ago, such a membrane was developed in people very well. 
Any inflammatory diseases in the inner corner of the eyes lead to disruption of the process of tear fluid removal.
Diseases
Diseases of the third century are extremely rare. They are mainly associated with developmental anomalies and various tumors. In diseases, a change in the shape of the membrane and its color is observed. Occasionally, atrophy of the semilunar fold occurs. This leads to constant tearing, which is associated with a violation of the output of tear fluid:
- Purulent inflammation of the lacrimal caruncle. The disease develops rapidly, begins with acute pain and significant redness in the inner corner of the eye. The patient has a fever, severe headache and general malaise. Due to this, the lacrimal meat increases in size, when you touch it, severe pain occurs. After a while, pustules appear in the tissues, which merge together and form an abscess. The patient's condition improves after opening the abscess. Recovery is observed after 5 days. Antibacterial ointments and drops are used for treatment.
- Argyrosis of the lunate fold. The membrane becomes dirty gray, as is the mucous membrane of the eyelids with the conjunctiva. This pathology develops due to too long use of drugs based on silver salts. Argyrosis does not impair the removal of lacrimal fluid. The treatment does not give an effect, the tissues are stained irreversibly.
- Tumors of a different nature in the lacrimal caruncle. Mostly benign neoplasms are observed - polyps, cysts, papillomas and fibromas. Melanoblastomas and sarcomas are rare.
Some people have nevi on this rudiment. These are birthmarks that are related to malformations. Sometimes their growth and malignant degeneration of cells is observed.
Should it be removed
Good reasons are needed to remove the third eyelid. These can be various tumors of the visual organs or a violation of the quality of vision. The decision to remove the rudiment is made by the doctor. It should be borne in mind that with an unsuccessful operation, the outflow of lacrimal fluid can be severely impaired.
The third eyelid is necessary for animals and birds to protect the visual organs. In humans, such a membrane is a rudiment, therefore it does not perform protective functions. With inflammation of the nictitating membrane, the process of diverting tear fluid is disrupted.
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Rudiments are "extra", non-functioning organs or structures that are scattered throughout the human body. They prove the difference between modern man and his ancestors.
website collected 6 evidence of evolution that is preserved on your body.
long palmar muscle
Place your hand on a flat surface, palm up. Close your little finger together and thumb, and then lift them up slightly. Did you see the ligament on your wrist? This muscle is a "legacy" of our ancestors and is responsible for the release of claws and enhances the grip when jumping from tree to tree. Don't worry if you don't find it - modern life she is useless.
Goose pimples
The main causes of goosebumps are cold and danger. In this case, the spinal cord produces excitation of peripheral nerve endings that lift the hairline. In the cold, this allows you to keep more heat inside the cover, and in case of danger, it gives the animal a more massive appearance. Goosebumps are also associated with strong emotional experiences and may appear from admiration.
epicanthus
Epicanthus - a skin fold on the upper eyelid, characteristic only of the Mongoloid race. Most researchers believe that it arose as a result of the natural conditions of human habitation: severe cold, deserts and hot sun.
Semilunar fold
This tiny fold of skin at the corner of the eye is a remnant of the nictitating membrane. In birds, reptiles and fish, it is fully functional and serves to keep the surface of the eye moist and unharmed. At some point, it became unnecessary for people, but they still have a small piece of this fold, connected to the muscles.
The lunate fold (rudiment of the third eyelid) is a vertical fold of the mucous membrane (conjunctiva). It is located at the inner corner of the eyelids and has a small size. This fold is highly developed among the Negroes and Malays, and may contain cartilage, like the eyelids. It produces mucus that collects foreign bodies (dust, dirt, causing damage to the cornea). Then they move to and . Next to the semilunar fold is the lacrimal caruncle. It has no specific functions. Pathologies in this area of the eyes can cause lacrimation disorders.
Diseases of the semilunar fold and lacrimal caruncle
Diseases of the lacrimal caruncle and semilunar fold are quite rare. They are manifested by developmental anomalies, dystrophic changes, inflammation, tumors. Anomalies in the development of the semilunar fold and lacrimal caruncle are manifested by changes in their shape. In some cases, atrophy of the semilunar fold is observed, it can cause lacrimation due to loss of contact of the lacrimal openings with the liquid.
Anatomically, the lacrimal meat is a formation, its structure includes sweat and sebaceous glands, fatty tissue, hair follicles. A purulent inflammation of the lacrimal caruncle may develop. The disease, as a rule, develops and begins with sharp pains and redness in the inner corner of the eye, while there is an increase in temperature, some malaise and headache. The lacrimal meat sharply increases in size, painful when touched. Further, purulent plugs appear in its tissues, which merge, forming an abscess. When the abscess breaks through, the inflammation subsides, and recovery occurs in the next four to five days.
With argyrosis (pigmentation) of the crescentic fold, a dirty gray color appears, extending to the eyeball and conjunctiva of the eyelids. Pathology develops as a result of too long instillation of eye drops, which include silver salts (collargol, silver nitrate, protargol). Argyrosis of the semilunar fold, lacrimal caruncle does not affect the lacrimal function. Treatment with cosmetic purpose ineffective, since this process is irreversible, silver particles cannot be removed from tissues.
Benign and malignant tumors can form in the lacrimal meat. More often, benign neoplasms (papillomas, adenomas, fibromas) predominate; polyps and cysts occur. Of malignant tumors, melanoblastomas and sarcomas predominate. Birthmarks (nevi) are sometimes formed on the crescentic fold, which are malformations. In some cases, there is a tendency to their growth and malignant degeneration.