Lamarck was a zoologist, naturalist and biologist who believed that animals behaviors directly influenced their traits.
Lamarck declared that when environments changed, organisms could change their traits to survive.
Lamarck thought that any trait could appear overtime during a lifetime if needed for the animal to survive. For example, he thought that if a giraffe continued to stretch its neck to reach leaves, over time it would develop a longer neck eventually have offspring with long necks.
Charles Darwin was a naturalist, geologist, biologist who traveled around the world collecting evidence about the plants animals he observed their evolution. He concluded that organisms change over time, all organisms descended from a common ancestor, evolution is gradual, what drives evolution is natural selection.
Natural selection consists of 4 steps. Overproduction, inherited variation, the struggle to survive, successful reproduction.
Natural Selection is a process where organisms that have the traits better suited to the environment survive reproduce successfully then other organisms.
Traits can develop change throughout a life time.
On what basis?
Animals do not determine their evolution, natural selection does. For example, when I was traveling I went to Galapagos Islands. there were multiple finches with different kinds of beaks. Their beaks differed based on the type of food they eat. Although they all came from a common ancestor, each is a different species because over time their location changed, meaning the traits that are the best fit to the said environment are the most successful. Therefore, my theory is correct.
Lamarck, your theories of evolution are misguided incorrect.