The similarity between humans and animals is confirmed by the structure of the human embryo at the early stages of intrauterine development (the presence of a tail, gill slits, etc.).
The human body has signs of similarity with the organisms of vertebrates.
In the internal structure, this is expressed in the presence of:
- spine and skull,
- nervous system (spinal cord and brain),
- closed circulatory system, etc.
The similarity with mammals is even more pronounced:
- mammary glands,
- four-chambered heart,
- differentiated teeth, etc.
In the external structure, this is expressed by the fact that the human body, like that of terrestrial mammals, consists of a head, a body, and two pairs of limbs.
Man has the greatest similarity with primates in the following parameters:
- lack of a tail,
- the shape of the eyes and ears,
- the thumb of the upper extremities is opposed to the rest,
- the presence of nails.
In addition, humans and primates have similar biochemical parameters:
- blood groups,
- biochemical composition of blood,
- the same diseases.
At the same time, only a person is characterized by true upright walking, a developed brain, and articulate speech.