Naturalism is based on the belief that everything real comes from nature, and that humans behave as if they were animals responding to their environment without control or understanding of their situation. If this is the definition of naturalism, then Tess of D"Urberville is a naturalistic novel. Naturalism focuses on the progression from organism to environment, struggle, adaptation, fertility, survival, resistance, and extinction.
From the beginning of the novel, one can perceive that Tess is a mere organism, living day-to-day life with few complications. As everyone knows, life is not perfect. This becomes very evident to Tess after she kills the family horse, Prince. Their lively hood is in dancer and Tess feels that she must do something about it because if she does not, her family will struggle to survive. .
Tess must now learn to adapt to her new setting. She is convinced by her mother to go to the D"Urberville mansion and plea her case in hope that her "family" can provide them with a new horse. Tess adapts in two ways here. One way is her living style. She has to learn to take care of hens. Another way she adapts is when she goes from child to adult. Alec prematurely sets her into womanhood.
It is now at this time that Tess must learn to survive. She must take care of herself and her bastard child. The child dies and Tess goes off to work at a dairy farm. Things seem to be getting better for Tess, but then she runs into trouble again. She comes across Alec and it is here that she must show resistance to him. However, she cannot, and she goes back to him. Extinction, the final progression, comes upon Tess after she kills Alec in an act of rage. Now, she and Angel run from authorities until at Stonehenge, in almost a sacrificial way, she is given to the police and executed.