Which naturalist's work included ideas about how species adapted to their environments over time?

The work of Jean-Baptiste Lamarck is well-known for its focus on the idea of how species adapt to their environments over time. He proposed the concept of inheritance of acquired characteristics, suggesting that organisms could pass on traits that were modified during their lifetime to their offspring. For example, he posited that a giraffe's long neck evolved because ancestors of the giraffe stretched their necks to reach higher leaves and this trait was then inherited by future generations. This idea was an early attempt to explain how evolutionary changes occur in response to environmental pressures, highlighting the concept of adaptation.

Lamarck’s theories laid the groundwork for later evolutionary thought, even though they differ from the modern understanding of heredity and natural selection as proposed by Charles Darwin. Nevertheless, Lamarck's emphasis on the relationship between organisms and their environments for the purposes of adaptation is a critical aspect of evolutionary biology, which is why his work is highly relevant in discussions about species adaptation over time.