Although chimpanzees are our closest relatives, they were still unknown in most of the world until Charles Darwin wrote about them in 1859 and they became popular. Only recently, a lot of hitherto unknown information has been discovered that allows us to take a different look at the misconceptions and exaggerations that are used in abundance in the works fiction. However, our similarities and differences are not what many imagine them to be. By studying our closest relatives, we can better understand ourselves.
1. Number of species
Left - pan troglodytes, right - pan paniscus Chimpanzees are often incorrectly referred to as monkeys, but they actually only refer to big family monkeys, just like us. Other prominent representatives of primates are orangutans and gorillas. There is only one species of human at present, and that is Homo sapiens. In the past, many scientists have tried to prove that there are several kinds of humans, and are often quick to add that they belonged to the "higher" species. However, all humans can produce offspring of their own kind, and therefore we are all one species. As far as chimpanzees are concerned, there are actually two species: pan troglodytes, which is the common chimpanzee, and pan paniscus, which is the slender chimpanzee or bonobo. These two chimpanzee species are completely separate species. Humans and chimpanzees as species evolved from a common ancestor, possibly sahelanthropus tchadensis, about five or seven million years ago. Only fossils remain of this ancestor.
2. DNA
Human chromosomes on the left, chimps on the right It is often said that human and chimpanzee DNA match 99%. Genetic comparison is not an easy task due to the nature of the gene mutation, so a more accurate estimate is somewhere between 85% and 95%. While this number may sound impressive, DNA has already been proven to be used by all living things for basic cellular functions. For example, we have about half the same DNA as a banana, and yet no one emphasizes this fact to show how similar a person can be to a banana! Thus, 95% do not say as much as it seems at first glance. Chimpanzees have 48 chromosomes, two more than humans. It is believed that this is a legacy from a human ancestor, two pairs of chromosomes merge into one pair. Interestingly, humans have the least genetic variation among all animals, so inbreeding can cause genetic problems. Even two completely unrelated people tend to be genetically more similar than two chimpanzee brothers.
3. Brain size
Chimpanzee brain from above, from below - human brain The brain of a chimpanzee has an average volume of 370 cc. On the other hand, humans have an average brain size of around 1350cc. see However, the brain and its size in itself is not an absolute indicator of intelligence. Some Nobel Prize winners have had brain volumes below 900 cc. see, and some - more than 2000 cubic meters. see The structure and organization of the different parts of the brain is the best way definitions of intelligence. The human brain has a large surface area, so it has many more convolutions than the chimpanzee brain, which means that the human brain has more connections between parts of the brain. And also a relatively large frontal lobe allows us to have much more developed abstract and logical thinking.
4. Social communication skills
Chimpanzees spend a lot of time socializing. Much of their communication is in caring for each other. Juvenile and young chimpanzees often play, run after each other, and tickle each other. Adult chimpanzees often play with their offspring as well. Attention displays include hugging and kissing, and this occurs between chimpanzees of any age and gender. Bonobos are particularly outspoken, and almost every courtesy has a sexual connotation, regardless of gender. Chimpanzees strengthen friendships and spend a lot of time together grooming each other. Humans also spend about the same amount of time communicating, but we do it more verbally than physically. Nevertheless, most of a lot of meaningless chatter, it's just a more complex version of chimpanzee behavior - and it serves slightly different purposes than strengthening our bonds. People also show a closer relationship through physical contact - friendly pats on the back or hugs. Dimensions social group primates accurately reflect the size of their brains. Chimpanzees have about 50 close friends and acquaintances, while humans have between 150 and 200.
5. Language and facial expressions
Chimpanzees have complex systems of greetings and messages that depend on the social status of the communicating chimpanzees. They communicate verbally using a variety of calls, grunts, and other vocalizations. Most of their communication, however, is done through gestures and facial expressions. Many expressions from their facial expressions - surprise, smiles, imploring facial expressions and facial expressions of consolation - are the same as in humans. However, people smile showing their teeth, which for chimpanzees and many other animals is a sign of aggression or danger. Most human communication is done through vocalizations. Humans clearly have more complex vocal cords, which allows them to produce a wide range of sounds, but also prevents them from drinking and breathing at the same time, as chimpanzees do. In addition, humans have very muscular tongues and lips, allowing them to perform precise manipulations of their voices. This is why humans have pointed chins while chimpanzees have sloping chins - humans have most of the labial muscles in the mandible at the chin, but chimpanzees don't have many of these muscles and therefore don't need a prominent chin.
6. Nutrition
Chimpanzees and humans are omnivores (eat plants and meat). Humans are more carnivorous than chimpanzees and have smaller intestines for digesting meat. Chimpanzees sometimes hunt and kill other mammals, often other monkeys, but otherwise chimpanzees make do with fruit and sometimes insects. People are much more dependent on meat - people can only get vitamin B12 naturally from animal products. Based on our digestive system and the way of life of the surviving tribes, it is believed that humans evolved by eating meat, at least, every few days. People also tend to eat on a schedule rather than continuously eating throughout the day, which is feature other carnivores. This may be because meat could only be available after a successful hunt, and was therefore eaten in large quantities but infrequently. Chimpanzees will eat fruit throughout the day, while most humans will eat no more than three meals a day.
7. Sex
Bonobos are known for their sexual appetite. The common chimpanzee may become angry or aggressive, but bonobos relieve tension through sexual pleasure. They also greet each other and show their affection for each other through sexual arousal. The common chimpanzee does not use sex for recreation, and mating takes only ten or fifteen seconds, often during meals or during other activities. Friendship and emotional attachments have nothing to do with who the common chimpanzee associates with, and females in estrus usually mate with several males, who sometimes wait patiently for their turn one after another. Humans experience sexual pleasure like bonobos, but sex takes much longer and more effort to reproduce, resulting in long-term partnerships. Unlike humans, chimpanzees have no concept of sexual jealousy or rivalry, as they do not have long-term partners.
8. Walking upright
Both humans and chimps are bipedal and can walk on two legs. Chimpanzees often do this to see further, but prefer to move around on all fours. Humans have been walking upright since childhood and have developed a cup-shaped pelvis to support their internal organs. Chimpanzees walk by leaning forward during movement so that the pelvis does not support their organs, and they have wider hips. This makes childbirth much easier for a chimpanzee than for a human, whose cup-shaped pelvis is in the path of the large birth canal. Humans have straight legs with their toes forward for easy walking, while chimpanzees have a protruding big toe and their feet are more like hands. They use their legs for climbing and crawling sideways, diagonally, or for rotational movements.
9. Eyes
In humans, the iris of the eye is white, while the iris of a chimpanzee's eye is typically dark brown. This makes it easier to see where a person is looking, and there are several theories as to why this is. It can be an adaptation to a more complex social situation, when it is advantageous to see who others are looking at and what they think while doing so. This can help when hunting in complete silence, where eye direction is very important for communication. Or it could just be a genetic mutation with no purpose - some chimpanzees also have white irises. Both humans and chimpanzees can see in color, which helps them choose ripe fruits and plants for food, have binocular vision, their eyes look in the same direction. This helps to see in depth and is more important during hunting than the eyes on the sides of the head, like rabbits, which helps them avoid getting caught.
10. Tools
For many years it was believed that among animals, only humans use tools. Observations of chimpanzees conducted in 1960 showed the use of pointed branches to catch termites, but much has changed since then. Both humans and chimpanzees can change environment creating tools to solve everyday problems. Chimpanzees make spears, use rocks as hammers and anvils, and crush leaves to use as a makeshift sponge. It is believed that as a result of upright walking, our forelimbs are much more free to use tools, and we have elevated the use of tools to an art. We live in a constant environment of the products of our abilities, and much of what people think makes us "successful" is rooted in our tool making.
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Exactly 200 years ago, on February 12, 1809, Charles Darwin was born. In many ways, it was through his efforts that people finally understood who they were. A species of higher apes. And the clearer this, for some, unpleasant answer became, the more acute the question arose - how does a person differ from other higher primates.
And it's surprisingly difficult to answer. Although differences from the closest surviving relative, the chimpanzee, are visible naked eye, it is not possible to present a criterion - a necessary and sufficient condition - for the belonging of any monkey to humans.
According to individual signs - even anatomical, even craniometric, even phrenological - there are more than enough differences. Which allowed for long and long years to rank peoples and races according to the “degree of perfection”, or evolutionary distance from monkeys. The ranking itself was carried out by the Europeans, because the main measure of perfection was, as a rule, the whiteness of the skin. Signs on which blacks or Asians moved farther from monkeys (for example, the length of the penis or the amount of hair on the body, respectively) were not considered.
But there is no general definition that distinguishes a person from a monkey.
Don't believe? Try it yourself at your leisure to come up with such a criterion, and so that without any reservations. The time to complete this task will be limited only by your stubbornness.
But even if it was not possible to fully understand the differences, this is not a reason to abandon the search for their reasons - albeit formal ones. By the end of the 20th - beginning of the 21st centuries, anthropologists became interested in genetics. And since "the genotype determines the phenotype," let's compare the DNA of humans and chimpanzees, and maybe we'll find some kind of "gene of humanity." Then we will figure out what external and internal differences this gene is translated into.
Chimpanzee and several other monkey genomes read in last years, - gorillas, orangutans and macaques - somewhat disappointed those who hoped to find a person in their comparison with the genome of Craig Venter and. We consist of almost identical proteins, and even the frequency of the main type of mutations - single nucleotide substitutions ("snip") in the genes of these proteins (and this is the basis of variability and interspecies differences in many lines of living beings) in primates - on the way from a monkey to a man is steadily fell. The activity of mobile genetic elements - transposons and the like, with which significant rearrangements of the genome are sometimes associated even in the absence of changes in the proteins themselves, also fell.
At the same time, purely subjectively, the differences between humans and even the most perfect of other primates seem to be more significant than the differences between, say, a chimpanzee from a gorilla. If only because chimpanzees and gorillas still get along with each other nearby, on the same continent, and man has captured the entire planet. And not out of evil, but simply because its activity is able to change landscapes over vast territories, it threatens the existence of the same gorillas.
A group of American, Spanish and Italian scientists led by Ivan Eichler from the University american state Washington decided to deal with the second type of mutation - gene copy number variations (CNV, copy number variations). With such mutations, unlike "snip", nothing changes in the genetic code of a protein. Instead, as the name implies, there is a change in the number of copies - a gene encoding a certain protein can be copied twice when rewriting the genome, which means that the protein itself will be synthesized twice as much. The reverse situation is also possible, when the gene is completely deleted.
Eichler and colleagues compared the CNV profiles of macaque, orangutan, chimpanzee and humans. According to modern ideas, it was in this order that the branches of the evolutionary tree grew, at the ends of which the listed species of monkeys now sit. results comparisons are published in the latest issue of Nature, dedicated to the 200th anniversary of the birth.
As it turned out when comparing monkey DNA, the rate of duplication of genes on the branch leading to chimpanzees and humans has doubled.
Between about 8 and 6 million years ago, when the last common ancestor of humans and chimpanzees, who is not also the ancestor of the gorilla, lived, on average, 60 genes doubled per million years. In the common ancestor of all hominids, this rate, according to the analysis, is 3-4 times less. True, the time span of this older branch before branching into pongins (orangutans) and hominins (chimpanzees, gorillas and humans) is longer, so the total number of doublings is practically the same.
According to Ivan Eichler, it is striking that this acceleration of doublings occurred at exactly the same time when the rate of accumulation of single mutations, "snip", on the contrary, fell sharply for all hominids. At the same time, scientists also found examples of the independent occurrence of the same doublings in different monkeys - for example, doublings that an orangutan and a person have, but not a chimpanzee.
Over the approximately 2-3 million years of the existence of a common ancestor of chimpanzees and humans, we have collectively accumulated 20-25 million base pairs that are copies of other segments of the genome. Over the next 5-6 million years - only 16-17 million pairs. At the same time, doublings do not occur evenly throughout the genome, but in separate, for some reason, unstable regions.
Even more surprisingly, the main duplication spurt refers specifically to the common branch of chimpanzees and humans.
However, Eichler and his colleagues, it seems, do not intend to draw not the most pleasant conclusions.
“There is still no definitive answer as to why humans and chimpanzees are so different,” He speaks Thomas Marc-Bone of Eichler's research group. “Maybe the difference of a person is not there at all.”
Some scientists believe that genes are really not so important for a person. As Nature columnist Erica Hayden says in a popular article, published in the same anniversary issue of Nature, all more scientists tend to think about the disproportionate role of the "cultural" component - as opposed to the "material", genetic, based on DNA - in the human heritage. Human abilities for technological innovation and education to some extent softened the pressure of natural selection in its "Darwinian" form, allowing us to retain many "harmful" mutations in the genome and not fix many "useful" ones in it.
A modern example of this is the Oxford geneticist Gilin McQueen. Thanks to glasses and people with not much good eyesight can live to adulthood and pass on their genes - including poor eyesight - to the next generations. Our distant ancestors there were no such chances.
At the same time, no one is going to throw "material" genetics off its pedestal or expose its leading role in the transfer of information from generation to generation. Important role in this case, differences in the number of copies of the gene are also taken into account. It's just that "now it's time to figure out what all these differences mean and how they are reflected in the genes," concludes Marc-Bone.
Ecology
Chimpanzees are known to be our closest living relatives, but few knew this until Charles Darwin popularized the idea in 1859 with his famous On the Origin of Species. Many of us still do not know what we really have in common and how we differ. Perhaps by learning more about our closest relatives, we can learn more about ourselves?
1) Number of species
Chimpanzees belong to the family hominid to which we belong. In addition, this family also includes orangutans and gorillas. Currently, there is only one kind of person: homo sapiens(reasonable person). Many scientists argue over which of our distant ancestors also belonged to people, but many of them convince everyone that they themselves belong to some kind of "higher" species. Humans are capable of producing fertile offspring, which means we belong to the same species. Chimpanzees actually have two species - the common chimpanzee ( Pan troglodytes) and the pygmy chimpanzee ( pan paniscus) or bonobos. The two species are distinct and do not interbreed. Man and both of these species of chimpanzee descended from the same common ancestor, possibly Sahelanthropus, between 5 and 7 million years ago.
2) DNA
You may have heard that chimpanzee and human DNA are 99 percent the same. Genetic comparison is very difficult to make because of the repetitive and mutable nature of genes, so it would be better to say that we have 85 to 95 percent of our genes in common. Even these numbers seem impressive, although much of the DNA is used as the basis for cellular functions in virtually every living organism on the planet. For example, human DNA is half the same as that of a banana, but we can hardly say that we are similar to a banana. 95 percent coincidence is also not so much. Chimpanzees have 48 chromosomes, 2 more than we do. It is believed that this happened due to the fact that in the human ancestor, two pairs of chromosomes joined into one pair. Interestingly, humans have the smallest genetic variation of all animals, which is why inbreeding can cause so many problems. Two completely unrelated humans will not have as much gene variation as two chimpanzees born of the same parents.
3) Brain size
The brain volume of a chimpanzee is on average 370 ml, while that of a human being is 1350 ml. However, brain size alone does not indicate intelligence. Some Nobel Prize winners have had brain volumes between 900 ml and 2000 ml. The structure and organization of different parts of the brain better determines the level of intelligence. The human brain has a higher surface area and is more tortuous than the chimpanzee brain. Comparatively larger frontal lobes allow us to reason logically and think more abstractly.
4) Sociality
5) Language and facial expressions
Chimpanzees a complex system greetings and communication, which depends on social status individuals. They can communicate verbally, that is, use different sounds - screams, grunts, snorts, yells, pants, and so on. Many of these sounds are accompanied by gestures and facial expressions. Facial expressions - surprise, smirk, prayer, consolation - are the same as those of us humans. However, people smile showing their teeth, when, as for chimpanzees and other animals, showing teeth is a sign of aggression or danger. For communication, a person most of all uses vocalization, that is, speech. Humans have unique vocal cords that allow us to produce big variety different sounds, but we can't drink and breathe at the same time, like chimpanzees.
A person has a rather muscular tongue and lips, which allows us to perform virtuoso manipulations with sounds. That is why we have a pointed chin, when, like a chimpanzee, it is slightly cut off. Chimpanzees do not have as many facial muscles as humans do.
6) Nutrition
Man and chimpanzee are omnivorous creatures, so we eat both plants and meat. However, humans are more carnivorous than chimpanzees, and our digestive system is designed to digest enough meat. Chimpanzees sometimes kill and eat other animals, often monkeys of other species, but much more often prefer fruits and sometimes eat insects. People are much more dependent on meat, as the vitamin B12 we need can only be obtained from meat products.
Based on studies of the digestive systems and lifestyles of some ancient tribes, scientists believe that people have adapted to eat meat at least once every few days. People prefer to eat at certain times and do not spend the whole day eating - this is another feature of carnivorous creatures. This is due to the nutritional properties of the product, as well as the fact that in order to obtain it, you need to go hunting.
7) Sex
Bonobos are famous for their sexual appetites. Common chimpanzees can become enraged and use force in some situations, when, like bonobos, they prefer to resolve everything peacefully through sexual pleasure. They also greet each other and express affection through sexual stimulation. Common chimpanzees do not have sex for fun, and their mating lasts no more than 10-15 seconds, while they can eat or do something else.
Friendship or emotional attachment does not matter in the choice of mating partners, and a female in estrus usually mates with several partners who patiently wait for their turn.
Humans are known to experience sexual pleasure, as are bonobos, and procreative sex can last quite a long time with a lot of effort. Moreover, people often start long-term relationships with partners. Unlike humans, chimpanzees have no concept of sexual jealousy or rivalry, as they are not prone to long-term relationships with the same sexual partner.
8) Body structure
Both humans and chimpanzees can walk on two legs. Chimpanzees stand up only when they need to look into the distance, but usually move on four legs. People start walking early age and have a bowl-shaped pelvis that supports all the internal organs. Chimpanzees do not need to support internal organs, as they do not normally walk on their hind legs. Childbirth in chimpanzees is much easier than in humans, since our pelvis is perpendicular to the birth canal. The toes on the human foot are all located on one side, which allows you to push off while walking, when, like a chimpanzee, the big toe stands separately, like on the hand, which makes the legs look like hands. The chimpanzee uses all of its limbs to climb trees or move on the ground.
9) Eyes
Humans have white eyeballs that are visible around the pupils, while chimps are dark brown. Looking at a person, you can understand where he is looking, and there are several theories about why this is necessary. This may be an adaptation to more complex social situations where it is important for us to understand the direction of the other person's gaze. It can also help a person hunting in groups when eye direction is a vital ability for communication. Or it's just a mutation with no particular purpose - some chimpanzees can also see white eyeballs.
Both humans and chimpanzees are able to distinguish colors, which allows us to choose ripe fruits and plants for food, and we also have binocular vision - that is, the eyes look in the same direction. This allows you to see the depth of objects, which is very important for hunting. It would be very inconvenient if our eyes were located on both sides of the head, as in many animals that do not need to hunt, such as rabbits.
10) Use of tools
Long years It was believed that only a person knows how to use tools. However, observations of chimpanzees in the 1960s showed that this was not the case - monkeys could use pointed branches to catch termites. Both man and chimpanzee are able to change the environment in order to obtain objects - tools - that help solve pressing problems.
Chimpanzees can make darts, use rocks as a hammer and anvil, and roll leaves to make homemade washcloths. It is believed that when a person began to walk straight, he needed to use tools more, and it was we who began to turn these tools into objects of art. Today we are surrounded by objects that were created by us out of necessity.
Another genetic experiment by Chinese researchers has caused controversy in the scientific community. Specialists from several research centers in China, in collaboration with colleagues from the United States, introduced the human version of the gene responsible for brain growth into the genome of monkeys.
It is noted that after the modification, macaque embryos developed naturally. As a result, 11 GM monkeys were born in the lab, but only five survived. Each of these individuals had between two and nine copies of the human MCPH1 gene.
According to the researchers, none of these animals had a brain size exceeding normal, although the development of this organ took longer than usual.
MRI scan of the brain and analysis of tissue sections showed a change in the nature of neuronal differentiation and a delay in maturation nervous system, which is typical for people, writes the China Daily news agency.
It should be clarified that one of the key differences between humans and non-human primates is that we take much longer to form neural networks during development, which greatly lengthens childhood. Apparently, the same trait appeared in this case in macaques.
"The two main features of a person are big sizes brain and slow development of the nervous system inside the womb. Now we have managed to reveal the molecular mechanisms of development of both features Homo sapiens, which, as it turned out, are included at the earliest stages of brain development,” said David Haussler from the University of California at Santa Cruz (USA).
The human and chimpanzee genomes share 99 percent, but our nervous systems develop very differently and suffer from different problems in old age. These differences prevent scientists from using primates to study human disease and how humans acquired the ability to speak and think articulately.
In recent years, researchers have discovered several hundred genes responsible for brain development that differ in structure between human and chimpanzee genomes. However, they were never able to find those sections of DNA that are responsible for the unusually large size of our brain compared to the rest of the body. Many neuroscientists and geneticists suspect that the reason for the striking difference between the two species lies not so much in the structure of genes, but in differences in their activity in different parts of the brain.
Haussler and his colleagues were able to find this, as they say, "Holy Grail of human brain evolution" by studying the structure of various genes on the first human chromosome, the deletion of which very often leads to the development of microcephaly, and duplication or damage - to macrocephaly or severe forms of autism.
In this area genetic code, as the scientists explain, there is a set of genes from the NOTCH2 family responsible for the development of "blanks" of neurons and the formation of future brain tissues in the embryo of mammals. Their structure is almost the same in the DNA of all primates, and, as scientists from Russia have recently shown, they work in the same way during the development of the embryo.
By observing the activity of these DNA regions in stem cell cultures, Haussler and his colleagues noticed one simple thing that for some reason all other scientific teams missed. It turned out that an "extra" gene works in human cells, which is absent or does not work in the blanks of neurons in chimpanzees, gorillas and other primates.
After studying its structure, experts came to the conclusion that the NOTCH2NL gene appeared in the DNA of our ancestors about three to four million years ago as a result of a series of "successful" mistakes when copying the first chromosome. The first error resulted in one of the NOTCH2 family genes being partially copied and inserted into the DNA of the first Homo. This turned it into a "junk" pseudogene that played no role in the body's work.
Starch was the main "accomplice" of the evolution of the human brainSwitching to a diet high in starches and other high-calorie carbohydrates 3 million years ago allowed our ancestors' brains to rapidly grow to reach today's size.The second mistake “repaired” its damaged parts, as a result of which a new DNA segment appeared in the protohuman genome, which radically changed the program for the development of the nervous system, which was then copied several more times during subsequent evolution. As the experiments of scientists on stem cells have shown, the removal of NOTCH2NL leads to the fact that the blanks of nerve cells begin to "grow up" faster and divide less often.
"One stem cell involved in brain growth can give birth to two neurons or another blank and one nerve cell. NOTCH2NL makes them choose the second option, which allowed our brain to grow in volume. As often happens in the history of evolution, a small change in work stem cells led to very big consequences," the experts conclude.
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