Comparative embryology and anatomy data clearly show similarities in the structure and development of the human body with animals.
A person is characterized by the main features inherent in the Chordate type and the Vertebrate subtype. In humans (as in all chordates), in the early stages of embryonic development, the inner skeleton is represented by the chorda, the neural tube is laid on the dorsal side, the body has bilateral symmetry. As the embryo develops, the chord is replaced by a spinal column, a skull, five parts of the brain are formed. The heart is located on the ventral side, the skeleton of paired free limbs appears.
For humans, the main features of the class Mammals are characteristic. The human spine is divided into five sections, the skin is covered with hair and contains sweat and sebaceous glands. As for other mammals, a human being is characterized by live birth, the presence of a diaphragm, mammary glands and the feeding of cubs with milk, a four-chamber heart, and warm-bloodedness.
For a person, the main features of the placental subclass are characteristic. The mother carries the fetus inside her body, and the fetus is nourished through the placenta.
For humans, the main features of the Primate squad are characteristic. These include limbs of a grasping type, the presence of nails, the location of the eyes in one plane (which provides volumetric vision), the replacement of milk teeth with permanent teeth, etc.
There are many common signs in humans with anthropoid apes: a similar structure of the brain and facial parts of the skull, well-developed frontal lobes of the brain, a large number of convolutions of the cerebral cortex, the disappearance of the caudal spine, the development of facial muscles, etc. In addition to morphological signs of the similarity of humans and anthropoid apes is evidenced by a number of other data: similar Rhesus factors, antigens of blood groups (ABO); the presence of a menstrual period and pregnancy lasting 9 months, as in chimpanzees and gorillas; similar sensitivity to the causative agents of the same diseases, etc.
Recently, methods are widely used to determine the evolutionary affinity of organisms by comparing their chromosomes and proteins. The relationship between species is greater, the greater the similarity between proteins. Studies have shown that human and chimpanzee proteins are 99% similar.
The presence of atavisms in a person (outer tail, multisuckling, abundant hair on the face, etc.) and rudiments (appendix, auricles, third eyelid, etc.) also testify to the relationship between humans and animals.