What is the essence of the evolutionary concept of Lamarck?

French scientist Jean Lamarck proposed his evolutionary concept. It is based on two principles that Lamarck called “teachings.” The first doctrine is the doctrine of gradation, and the second is the doctrine of variability.
According to the first teaching, living organisms were formed from inanimate nature, so to speak, self-educated. This process is permanent. Then organisms become more complex in the course of evolution. Lamarck himself identified 6 steps of gradation from the simplest ciliate at the first step to mammals at the sixth grade.
The second doctrine spoke of the constant transformation of living organisms under the influence of the environment. In fact, Lamarck meant mutations, but he gave this process a purposeful character, that is, living organisms, as a result of their actions, could acquire any traits that were passed on to the next generation.