Final answer:
Lamarck's theory of inheritance of acquired characteristics suggested that traits developed during an organism's life were inherited by offspring, influencing species evolution.
Step-by-step explanation:
Jean-Baptiste Lamarck proposed the theory of the inheritance of acquired characteristics, a concept asserting that traits developed by an organism during its life could be passed on to its offspring. Lamarck believed that an individual's environment could bring about changes, such as the lengthening of a giraffe's neck due to the need to reach higher foliage. These changes, according to Lamarck, were then inherited by the next generation, which would further enhance and pass them on, driving evolutionary change in a species. This aspect of Lamarck's evolutionary theory is known as Lamarckian inheritance. Although Lamarckian inheritance has been generally discredited, because traits acquired during an organism's life are not typically passed on to the next generation, Lamarck's work was influential in the development of evolutionary thought. Consequently, Lamarck is acknowledged as a significant figure in the history of evolutionary biology.