Ecology: Biology of Interactions. 6.20. (Supplement) Biological Features of Humans
Thus, humans are “built” with many shortcomings. Their elimination has slowed down: carriers of biological defects can survive and leave offspring thanks to cultural adaptations. A serious problem has become the growth, due to medical progress, in numbers of carriers of more or less severe anomalies...
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6.19. (addendum) The Mechanism of Human Behavior as a Result of the Evolution of the Behavior Mechanism of Other Animals
D. Shabanov, M. Kravchenko. Ecology: Biology of Interaction Section 6. Human Ecology and Conservation
6.21. (Addendum) Main Stages of Anthropogenesis
6.20. (supplement) Biological features of humans Which medical school specialties are the hardest to get into? Gynecology, dentistry, and surgery. Specialists in these fields are the most in-demand because they ensure the functioning of systems that were restructured in the last stages of human biological evolution. To intensify cultural inheritance, a flexible, reprogrammable brain was needed, and to accommodate it, a voluminous skull. Developmental restructuring occurs in evolution due to regulators that inhibit some parts of the developing system and accelerate others. In the course of human evolution, the development of the facial part slowed down, and the cerebral part accelerated. Disproportions arose in the facial skull, resulting in the chin (anatomists and physiologists have long tried to establish the function of this part of the body). The growth of the base of the lower jaw turned out to be regulated better and slowed down less than the part bearing the teeth! Unfortunately, as a result of these restructurings, tooth development turned out to be significantly deregulated, leading to a sharp increase in the frequency of their diseases. With the increase in the size of the brain and skull, childbirth became significantly more complicated. The transition to upright walking led to the pelvis, which covered the abdominal organs from the sides, becoming cup-shaped, supporting them from below. As a result, the pelvic outlet became narrower, and childbirth became even more difficult. The vertical position of the spine led to changes in the loads acting on it. Partially, they are compensated by the spinal curves that arise as the support system develops; but the spine is still a source of many health problems. Apparently, the pinching of certain nerves is often the real cause of many diseases. Thus, humans are "made" with many flaws. Their elimination has slowed down: carriers of biological defects can survive and leave offspring thanks to cultural adaptations. A serious problem has become the increase, due to medical advances, in the number of carriers of more or less serious anomalies. The need to prolong the period of susceptibility to cultural inheritance has led to a delay in human maturation and a lengthening of childhood. Humans cannot be born with a ready-made neural network structure of the brain: they must form it through interaction with the environment and other people. Naturally, the role of the hereditary component is also very important in this process. Apparently, certain hereditary predispositions can significantly alter the brain's ability to learn. An example could be Turner syndrome – a genetic anomaly in which patients have only one sex chromosome (female) and develop as short, infertile women. The mental development of such patients is normal, but with a characteristic impairment of spatial thinking. Brain dysfunction manifests itself quite specifically! By the way, humans have another amazing biological feature. Humans are the only constantly sexual animals. The reproduction of other animals is timed to a certain period in one way or another. For example, mammals are characterized by the estrous reproductive cycle of females. During it, at the time of ovulation (release of an egg), i.e., when the female is capable of becoming pregnant, estrus (heat) occurs, accompanied by the shedding of the uterine epithelium and characteristic discharge. These external manifestations serve as a signal for males, stimulating competition for a sexual partner and mating. Humans have a menstrual cycle, during which ovulation occurs covertly, between menstruations. Armed with modern knowledge, people calculate the moment of ovulation (e.g., for contraception) and make mistakes! Contrary to the value system of modern society, the biological task of an organism is to leave offspring. The menstrual cycle forces the male (i.e., the man) to regularly engage in sexual relations with the female (woman), "catching" the moment when she is capable of becoming pregnant. Therefore, he must live with her constantly! It is difficult to say definitively at what stage of human evolution this trait appeared, but its close connection with the creation of a relatively stable family – a social structure that creates favorable conditions for cultural inheritance – is understandable. Since the male cares for the offspring of the woman he lives with, he must ensure that they are his offspring (men who raise other people's children leave fewer of their own offspring and disappear from the population). Therefore, he must prevent her from having contact with other men! For women, marital infidelity is biologically permissible, as she will raise her child anyway. If the external father of the child is more viable than the permanent partner, it will only increase the child's chances of survival. And for men, a relationship on the side is quite acceptable. His biological costs for a child are small (unlike a woman's!). If, in addition to the children raised with a permanent partner, he has offspring "on the side," his contribution to future generations will only increase. That is why in male-dominated societies, a double moral standard is stable: a woman's infidelity is a disgrace, while a man's is a prank or a feat. Additional materials: Column: Double standard Column: Why should women be beautiful? Column: The reward for beauty Column: Strategies we are unaware of Column: The brain as an inadaptation
6.19. (addendum) The Mechanism of Human Behavior as a Result of the Evolution of the Behavior Mechanism of Other Animals
D. Shabanov, M. Kravchenko. Ecology: Biology of Interaction Section 6. Human Ecology and Conservation
6.21. (Addendum) Main Stages of Anthropogenesis