Final answer:
Evolution does not usually progress toward greater complexity. Species adapt to their environment, but there is no goal to become more complex. Bacteria are an example of simple organisms that have evolved without becoming more complex.
Step-by-step explanation:
Evolution does not usually progress toward greater complexity. In a larger sense, evolution is not goal directed. Species do not become "better" over time; they simply track their changing environment with adaptations that maximize their reproduction in a particular environment at a particular time. Evolution has no goal of making faster, bigger, more complex, or even smarter species, despite the commonness of this kind of language in popular discourse.
For example, bacteria are simple single-celled organisms that have evolved over time to survive in different environments. They have not necessarily become more complex in the process. Therefore, the answer to the question is No, evolution does not usually progress toward greater complexity.