The first edition of Biology, written by Dr. Rob Brooker, Dr. Eric Widmaier, Dr. Linda Graham, and Dr. Peter Stiling, has reached thousands of students and provided them with an outstanding view of the biological world. Now, the second edition has gotten even better! The author team is dedicated to producing the most engaging and current text that is available for undergraduate students who are majoring in biology. We want our students to be inspired by the field of biology and become critical thinkers. To this end, we have made the following changes throughout the entire book.