Student grades and motivational outcomes in introductory physics courses can influence their retention in science, technology, engineering, and math (STEM) disciplines and future career aspirations. In recent years, many research studies have focused on inequities in calculus-based introductory physics courses, e.g., by investigating gender differences in students' motivational beliefs such as self-efficacy, interest, and identity and how they change from the beginning to the end of a physics course or course sequence. However, these issues have not been investigated in introductory physics courses for bioscience majors, in which women outnumber men. Although women outnumber men in these courses, societal stereotypes and biases about who can do and excel in physics may impact women in these courses unless there is an intentional effort to create equitable and inclusive learning environments. In this dissertation I address the question of equity in introductory physics courses for students on the bioscience track by investigating the relationship between gender, motivational beliefs, and physics performance. Through my quantitative studies, I first analyzed gender differences in students' self-efficacy, sense of belonging, and recognition by others and how they predict course grade. Then, I investigated whether the relation between gender and physics identity was mediated by students' self-efficacy, interest, and recognition by others. Lastly, I investigated how students' perception of the inclusiveness of the learning environment including students' sense of belonging, interactions with their peers, and recognition by instructors and TAs predicts their physics identity and grades in the introductory physics courses. These findings can be invaluable for instructors striving to make these courses more equitable and inclusive. Throughout the thesis, there is discussion of how these findings can provide guidelines to improve women's experiences and achievement.